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INSTYTUT TECHNOLOGII DREWNA
WOOD TECHNOLOGY INSTITUTE
DREWNO
PRACE NAUKOWE ● DONIESIENIA
KOMUNIKATY
WOOD
RESEARCH PAPERS ● REPORTS ● ANNOUNCEMENTS
Vol. 53
POZNAŃ 2010
Nr 184
Wydanie publikacji dofinansowane przez Ministerstwo Nauki i Szkolnictwa Wyższego
The journal is financially supported by Polish Ministry of Science and Higher Educations
Recenzenci (Reviewers): dr inż. Mariusz Jóźwiak, dr inż. Robert Kłos, prof. dr hab.
Krzysztof J. Krajewski, dr Zofia Krzoska-Adamczak, dr hab. inż. Jadwiga ZabielskaMatejuk, prof. ITD
Publikacje indeksowane są w bazach danych (Publications are indexed in the databases): Science Citation Index Expanded – http://thomsonreuters.com, SCOPUS –
http://www.scopus.com, BazTech – http://baztech.icm.edu.pl, DREWINF – http://www.
itd.poznan.pl, The Central European Journal of Social Sciences and Humanities –
http://cejsh.icm.edu.pl
Artykuły polskojęzyczne zawierają streszczenia w języku angielskim, a obcojęzyczne –
w języku polskim. Spisy treści, streszczenia i pełne teksty artykułów są dostępne na
stronie www.itd.poznan.pl/pl/drewno
Prace naukowe i doniesienia uzyskują 6 punktów według klasyfikacji MNiSW
Polish language articles have summaries in English language, and foreign language
articles have summaries in Polish language. Tables of contents, summaries, and full
versions of the articles are available at www.itd.poznan.pl/en/wood
Wydawca (Editorial Office): Instytut Technologii Drewna
ul. Winiarska 1, 60-654 Poznań, Polska (Poland)
Adres Redakcji (Publishers' address): Instytut Technologii Drewna
ul. Winiarska 1, 60-654 Poznań
tel. +48/61 849 24 01, +48/61 849 24 61, fax +48/61 822 43 72,
e-mail: [email protected]
© Copyright by Instytut Technologii Drewna w Poznaniu
Poznań 2010
ISSN 1644-3985
Projekt okładki (Cover design): Piotr Gołębniak
Redaktor (Editor): Edward Grześkowiak
Skład komputerowy (Computer typesetting): BookArt Poznań
Druk (Print): Studio Poligrafia, ul. Bułgarska 10, 60-321 Poznań, tel. 061 867 53 72
Nakład (Edition): 520 egz.
SPIS TREŚCI – CONTENTS
Jadwiga ZABIELSKA-MATEJUK: VII Sympozjum ,,Czwartorzędowe sole amoniowe i obszary ich zastosowania w gospodarce” (VII Sympozjum on
„Quaternary ammonium salts and their application in the economy”) .....
5
Prace naukowe – Research papers
Jadwiga ZABIELSKA-MATEJUK, Juliusz PERNAK, Aleksandra KROPACZ, Mariusz
KOT, Anna STANGIERSKA: Activity of new ammonium ionic liquids against
fungi causing wood moulding (Aktywność nowych amoniowych cieczy
jonowych wobec grzybów wywołujących pleśnienie drewna) ....................
11
Andrzej FOJUTOWSKI, Andrzej NOSKOWIAK, Mariusz KOT, Aleksandra
KROPACZ, Anna STANGIERSKA: The assessment of mechanical properties
of wood treated with ionic liquids (Ocena właściwości mechanicznych
drewna zabezpieczonego cieczami jonowymi) ............................................
21
Mariusz KOT, Grzegorz KOWALUK: Wood hydrophobization by ammonium
ionic liquids (Hydrofobizacja drewna za pomocą amoniowych cieczy
jonowych) ...................................................................................................
39
Dorota FUCZEK, Jadwiga ZABIELSKA-MATEJUK, Juliusz PERNAK, Weronika
PRZYBYLSKA: Wettability of wood surfaces treated with ionic liquids
(Badania zwilżalności drewna zabezpieczonego powierzchniowo cieczami
jonowymi) ....................................................................................................
45
Iwona FRĄCKOWIAK, Jadwiga ZABIELSKA-MATEJUK, Dorota FUCZEK,
Mariusz KOT: Application of ammonium ionic liquids in particleboard
technology (Zastosowanie cieczy jonowych w technologii płyt wiórowych)
55
Mariusz OLEKSY, Maciej HENECZKOWSKI, Henryk GALINA, Katarzyna
LECKA-SZLACHTA: The influence of bentonites modified with quaternary
ammonium salts on biocidal properties of compositions of water-dilutable
paints and lacquers, and mineral plasters (Wpływ bentonitów modyfikowanych czwartorzędowymi solami amoniowymi na właściwości biobójcze
kompozycji farb i lakierów wodorozcieńczalnych oraz tynków mineralnych) ............................................................................................................
65
Doniesienia – Reports
Grzegorz KOWALUK, Dorota FUCZEK: Screw holding performance of panels
made of fibrous chips (Zdolność utrzymywania wkręta płyt wytworzonych
z wiórów włóknistych) ................................................................................
77
Komunikaty – Announcements
Grzegorz PAJCHROWSKI: 11. Światowa Konferencja Inżynierii Drewna
(11th World Conference on Timber Engineering) .......................................
83
Drewno. Pr. Nauk. Donies. Komunik. 2010, vol. 53, nr 184
Jadwiga ZABIELSKA-MATEJUK 1
VII SYMPOZJUM „CZWARTORZĘDOWE SOLE
AMONIOWE I OBSZARY ICH ZASTOSOWANIA
W GOSPODARCE”
Przedstawiono program Sympozjum oraz omówiono wystąpienia specjalistów
zajmujących się badaniami czwartorzędowych soli amoniowych z uwzględnieniem
cieczy jonowych.
Słowa kluczowe: sympozjum, czwartorzędowe sole amoniowe, ciecze jonowe
W dniach 1–2 lipca 2010 w Centrum Kongresowym Instytutu Ochrony Roślin
w Poznaniu odbyło się kolejne już, VII Sympozjum „Czwartorzędowe sole amoniowe i obszary ich zastosowania w gospodarce”. Organizatorami Sympozjum
był Instytut Technologii Drewna w Poznaniu, Wydział Technologii Chemicznej
Politechniki Poznańskiej, Instytut Ochrony Roślin oraz Instytut Chemii Przemysłowej. VII Sympozjum zostało objęte honorowym patronatem Wicepremiera,
Ministra Gospodarki Waldemara Pawlaka i Minister Nauki i Szkolnictwa Wyższego prof. Barbary Kudryckiej. Uczestnikami sympozjum byli specjaliści
z wyższych uczelni, instytutów naukowo-badawczych oraz przedstawiciele przemysłu, zajmujący się chemią czwartorzędowych soli amoniowych, technologią
ich uzyskiwania, aplikacją w przemyśle chemicznym i w drzewnictwie, mikrobiologią, biotechnologią , ochroną środowiska, toksykologią i konserwacją.
W trakcie konferencji wygłoszono 16 referatów plenarnych oraz zaprezentowano 74 postery. Otwarcia Sympozjum dokonali prof. Juliusz Pernak i doc. dr
Władysław Strykowski, dyrektor Instytutu Technologii Drewna, który odczytał
adresy kierowane do uczestników od Wicepremiera W. Pawlaka, Minister
B. Kudryckiej i Prezydenta Poznania R. Grobelnego. Słowa powitania i życzenia
owocnych obrad skierował również dyrektor Instytutu Ochrony Roślin, prof.
Marek Mrówczyński.
Jadwiga ZABIELSKA-MATEJUK, Wood Technology Institute, Poznan, Poland
6
Jadwiga ZABIELSKA-MATEJUK
Pierwszy prelegent, prof. Juliusz Pernak, zaprezentował ciecze jonowe jako
związki wielofunkcyjne o bardzo wysokim potencjale aplikacyjnym. Zainteresowanie cieczami jonowymi narodziło się na przełomie wieku i trwa do dnia
dzisiejszego. Związki te są intensywnie badane przez wiele ośrodków akademickich i przemysłowych na całym świecie. W ostatnim czasie ogłoszono już
trzecią generację cieczy jonowych, w których kation lub anion, bądź jednocześnie kation i anion są aktywne biologicznie. Prelegent omówił nową grupę
cieczy jonowych, opisaną jako herbicydowe ciecze jonowe, przedstawił sposoby
wyznaczania właściwości fizykochemicznych, akceptowane przez międzynarodowe środowiska badawcze.
Kolejny prelegent, prof. Tadeusz Praczyk (IOR), przedstawił aktywność biologiczną cieczy jonowych zawierających anion (4-chloro-2- metylofenoksy)octanowy i anion (2,4-dichlorofenoksy)octanowy. Stwierdził, że ciecze te
cechowały się lepszym działaniem na chwasty niż znane obecnie preparaty
w formie soli. Biologiczna aktywność herbicydowych cieczy jonowych była
porównywalna do form estrowych MCPA i 2,4-D. Ważną zaletą cieczy jonowej
jako herbicydu jest bardzo niska prężność par, niskie dawki i działanie wielofunkcyjne.
Prof. Mirosław Szafran (UAM) zaprezentował syntezę i właściwości
spektroskopowe betain – bipolarnych związków chemicznych, posiadających
właściwości powierzchniowo czynne, które znalazły zastosowanie jako
dodatki do szamponów, detergentów i dezodorantów. Betainy są szeroko stosowane w przędzeniu włókien, w przemyśle papierniczym ułatwiają proces drukowania oraz nadają połysk, również papierom fotograficznym, są dodawane do
mikrobiocydów, środków antyseptycznych.
Dr hab. Jadwiga Zabielska-Matejuk (ITD) omówiła ciecze jonowe jako
skuteczne fungicydy do ochrony przed atakiem grzybów niszczących drewno,
dobrze penetrujących i utrwalających się w materiale lignocelulozowym. Zwróciła uwagę na dobrą aktywność grzybobójczą herbicydowych cieczy jonowych,
podkreślając wielofunkcyjność tych związków. Przedstawiła wpływ cieczy
jonowych na zmniejszenie nasiąkliwości drewna, jak również kinetykę i izotermy adsorpcji tych związków na drewnie sosny. Badany mechanizm potwierdził
chemiczny charakter adsorpcji.
Tematem referatu dr Katarzyny Marteny (PP) była aktywność powierzchniowa cieczy jonowych. Amfifilowość cieczy jonowych jest bardzo istotnym
zagadnieniem, gdyż właściwości powierzchniowe i międzyfazowe mają decydujący wpływ na obszar aplikacji. W roztworach wodnych ciecze jonowe tworzą
agregaty w zależności od rodzaju stosowanego kationu czy anionu oraz stężenia.
Wartości krytycznego stężenia micelowania (CMC) są zbliżone lub zdecydowanie niższe niż otrzymywane dla typowych kationowych surfaktantów, co wskazuje na większą tendencje do agregacji cząsteczek cieczy jonowych.
VII Sympozjum ,,Czwartorzędowe sole amoniowe i obszary ich zastosowania w gospodarce”
7
Prof. Zofia Dega-Szafran (UAM) omówiła syntezę i właściwości fizykochemiczne czwartorzędowych soli 1,4- diazabicyklo-(2,2,2) oktanu. Podkreśliła
kulistą budowę cząsteczek i ich przenikalność dielektryczną, wykorzystywaną
w budowie kondensatorów.
Kolejna prelegentka, dr Barbara Dmowska, przedstawiła sole N-Dglikozylo- i alditoliloamoniowe, ich syntezy i właściwości przeciwgrzybowe
oraz wyniki badań cytotoksyczności i mutagenności.
Badania wpływu czwartorzędowych soli amoniowych na działanie osadu
czynnego z oczyszczalni ścieków omówiła prof. Elżbieta Grabińska-Sota (PŚ).
Wytypowane w doświadczeniu ciecze jonowe są rozkładane przez mikroorganizmy osadu czynnego w powyżej 80 procentach dla roztworu o zawartości
10 mg/L cieczy.
Wystąpienie dr Ewy Janos poruszało problematykę przydatności cieczy jonowych jako rozpuszczalników w reakcji Diesla-Aldera, dzięki którym można
uzyskać czysty produkt reakcji. Prelegentka nakreśliła plany badawcze chiralnych cieczy jonowych.
W drugim dniu obrad przedstawiono sześć referatów plenarnych. Bardzo
interesująco była omówiona przez prof. Ryszarda Kaliszana (UG) możliwość
aplikacji cieczy jonowych w chromatografii cienkowarstwowej, pozwalających
na rozwinięcie chromatogramów i lepszy rozdział substancji analizowanych.
Prof. Grzegorz Węgrzyn (UG) przedstawił wyniki badań wykrywania mutagenności związków chemicznych, w tym cieczy jonowych, mechanizm mutacji
w budowie DNA oraz nowe testy biologiczne na bakteriach przydatne w badaniach mutagenności substancji chemicznych.
Równowagi fazowe oraz właściwości ekstrakcyjne cieczy jonowych były
przedmiotem wystąpienia prof. Urszuli Domańskiej-Żelaznej (PW). Ciecze
jonowe mogą być stosowane do rozdziału podobnych rozpuszczalników aromatycznych i alifatycznych. Wyznaczono współczynniki aktywności w rozcieńczeniu nieskończenie wielkim.
Zastosowanie cieczy jonowych – soli tetraalkiloamonowych w syntezie
organicznej katalizowanej związkami palladu przedstawiła prof. Anna Trzeciak
(UW). Podkreśliła, że ciecze jonowe mogą służyć również jako katalizatory,
podnosząc wydajność reakcji nawet do kilkudziesięciu procent.
Prof. Stefan Baj (PŚ) zreferował aplikacje cieczy jonowych w syntezie substancji nadtlenowych.
Złoty jubileusz katalizy międzyfazowej był tematem wystąpienia prof. Michała Fedoryńskiego (PW).
Ostatni prelegent, prof. Piotr Stepnowski (UG), omówił zastosowanie
technik separacyjnych do rozdzieleń i analizy składników cieczy jonowych,
oznaczania zanieczyszczenia i pozostałości.
Tematem zaprezentowanych posterów był między innymi problem odkwaszania papieru. Ze względu na wielkie zniszczenia zbiorów bibliotecznych
8
Jadwiga ZABIELSKA-MATEJUK
i archiwalnych rozpoczęto na całym świecie badania nad neutralizacją kwaśnego papieru. Przedstawione przez dr hab. Ewę Drzewińską i dr Agnieszkę
Wysocką-Robak metody odkwaszania niestety nie spełniają do końca wszystkich parametrów, które decydują o skuteczności metody oraz bezpieczeństwie
środowiska. Zastosowanie cieczy jonowych stwarza nową perspektywę w tej
dziedzinie.
Interesującym kierunkiem badań, zasygnalizowanym na konferencji, było
wykorzystanie cieczy jonowych do ekstrakcji związków o charakterze grzybobójczym z kory Cinnamonium zeylanicum, porównanie z ekstrakcją za pomocą
tradycyjnych rozpuszczalników organicznych oraz ocena działania otrzymanych
ekstraktów w stosunku do różnorodnych patogenów grzybowych, powodujących
choroby skóry człowieka, choroby roślin i pszczół, a także biodeteriorację materiałów technicznych.
W celu ograniczenia rozwoju mikroorganizmów zarówno w procesie produkcji papieru, jak i w wyrobach gotowych, a także podczas przechowywania
w bibliotekach, archiwach czy muzeach stosuje się różnego rodzaju biocydy.
Wśród nich na uwagę zasługują coraz częściej wykorzystywane ciecze jonowe.
W wyniku badań możliwości zastosowania azotanu benzalkoniowego i azotanu
didecylodimetyloamoniowego w postaci kompleksów z solą sodową kwasu poliakrylowego oraz solą sodową karboksymetylocelulozy jako środków biocydowych w powłokach otrzymanych z lateksu kopolimeru etylenu z octanem winylu
stwierdzono, że czwartorzędowe sole amoniowe złączone z anionowymi polimerami są stabilnymi funkcyjnymi dodatkami o charakterze biocydowym, selektywnie się uwalniającymi. W ten sposób funkcjonalizowane biocydy można
wprowadzać do innych farb poprawiając ich stabilność, właściwości reologiczne
i biocydowe.
W ramach prezentacji posterowych przedstawiono badania dystrybucji
cieczy jonowych w środowisku oraz ich sorpcji na powierzchni gleb i minerałów, oceny oddziaływania na organizmy glebowe oraz poruszono wiele innych
interesujących kwestii związanych z aplikacją cieczy jonowych w różnych
obszarach gospodarki. W podsumowaniu Sympozjum prof. J. Pernak podziękował wszystkim wykładowcom i uczestnikom za przedstawienie najnowszych
osiągnięć w pracach nad czwartorzędowymi solami amoniowymi, podkreślił
rangę tej tematyki badawczej zarówno w kraju, jak i w świecie, zapraszając
wszystkich na kolejną konferencję.
VII Sympozjum było współfinansowane z projektu rozwojowego realizowanego przez ITD nr POIG.01.03.01-30-74/08 pt. „Ciecze jonowe w innowacyjnych technologiach związanych z przetwarzaniem surowców lignocelulozowych”. W niniejszym numerze czasopisma „Drewno” opublikowano wyniki
badań cieczy jonowych przedstawione w formie sześciu posterów podczas konferencji.
VII Sympozjum ,,Czwartorzędowe sole amoniowe i obszary ich zastosowania w gospodarce”
9
VII SYMPOZJUM ON „QUATERNARY AMMONIUM SALTS
AND THEIR APPLICATION IN THE ECONOMY”
Summary
The Symposium programme and the latest achievements of specialist in various scientific disciplines who deal with synthesis, physical chemistry, surface and biological
activity, toxicology and analytical of quaternary ammonium salts were presented. The
application of quaternary ammonium salts, as well as the ionic liquids for protection of
wood, wood products and paper, for catalysis, separation processes, and biomass degradation were showed.
Keywords: symposium, quaternary ammonium salts, ionic liquids
PRACE NAUKOWE – RESEARCH PAPERS
Jadwiga ZABIELSKA-MATEJUK, Juliusz PERNAK, Aleksandra KROPACZ,
Mariusz KOT, Anna STANGIERSKA 1
ACTIVITY OF NEW AMMONIUM IONIC LIQUIDS
AGAINST FUNGI CAUSING WOOD MOULDING
The results of the tests of the effectiveness of the action of new, not yet described
in the literature group of biocidal ionic liquids were synthesised and presented.
Those ionic liquids are derivatives of the leading structure, i.e. didecyldimethylammonium nitrate, and demonstrate strong action against mould fungi. Natural
quaternary ammonium salts, mainly extracts from coconut and soybean, and from
vegetable fats, were the basis for syntheses. Mycological tests were carried out on
the wood of pine Pinus sylvestris L. (sapwood) in accordance with the method assumed binding for the assessment of biocide efficacy.
Keywords: ionic liquids, biocidal activity, wood, moulds
Introduction and aim of the research
Wood is very susceptible to depreciation and processes of biological degradation
caused by microorganisms. Microorganisms present in air are undesirable
Juliusz PERNAK, Poznan University of Technology, Poznan, Poland
Aleksandra KROPACZ, Wood Technology Institute, Poznan, Poland
Mariusz KOT, Poznan University of Technology ,Wood Technology Institute, Poznan,
Poland
Anna STANGIERSKA, Wood Technology Institute, Poznan, Poland
12
Jadwiga ZABIELSKA-MATEJUK, Juliusz PERNAK, Aleksandra KROPACZ, Mariusz KOT, Anna STANGIERSKA
biological factor which, if allowable concentrations assumed for a certain environment are exceeded, poses a threat to people. Mould fungi account for around
70% of the whole air micro flora. In residential buildings a few dozen species of
bacteria, over 400 species of moulds and a dozen or so species of fungi causing
decay of wood and wood-based materials [Barabasz, Pikulicka-Dziurman 2009]
may be found. Microorganisms settling so-called “sick buildings” are isolated
from air, walls, and from furniture as well. Wood, which still is one of the most
common furniture maker’s and structural materials in construction industry,
unfortunately is an excellent substratum for the growth of fungi, which is the
reason why it becomes the main source of mould in indoor air.
The main factor stimulating the growth of mould fungi in apartments is an
elevated humidity of environment, i.e. above 60% of air relative humidity,
although we know some species for which humidity of 30–40% is sufficient
[Gutarowska, Jakubowska 2001].
Tests of microbiological contamination of usable rooms proved a high and
diverse level of microbiological contamination in the tested air. The following
moulds were identified: Rhizopus, Penicillium, Aspergillus, Cladosporium and
Alternaria [Stach et al. 2004].
Moulding of wood is a process brought about by many species of fungi,
most often growing on the surface. Usually moulding does not cause any
stronger deterioration of physical and chemical properties; however it is responsible for depreciation of wood through change of its colour and making its
surface pattern blurry, thus for depreciation of wood commercial value and its
competitiveness in relation to other technical materials. Infected wood cannot be
used in line with its intended use not only due to worsening of its aesthetics, but
also because of allergenic properties of many of moulds found on it, which
surely have a negative influence on health of people staying in rooms. Mould
fungi and their secondary metabolites prove to be toxic to the organisms of
people and animals. Numerous tests proved that they are directly responsible for
many conditions of respiratory system and skin, part of cancerous diseases
or numerous allergies. People who are exposed to mould infected materials for
a longer period may have such symptoms of infections and allergies as: rhinitis,
sinusitis, laryngitis, bronchitis, alveolitis, conjunctivitis, dermatological lesions,
reduction of immune system resistance, chronic fatigue syndrome, and in unusually extreme cases damage to immune system may lead to death [Grajewski,
Twarużek 2004]. Bearing in mind that wood being one of more popular
materials found in human nearest environment, is at the same time a good substratum for mould growth, it requires protection that would be simultaneously
solid and harmless to human. With a view to achieve that, fungicides limiting
possibilities of fungi attack on wood are introduced into wood [Pernak et al.
2004, 2006; Cybulski et al. 2008; Zabielska-Matejuk 2004; Zabielska-Matejuk
et al. 2009].
Activity of new ammonium ionic liquids against fungi causing wood moulding
13
Diversity of species and the resistance of mould fungi to chemical preparations
poses a problem when structures of effective active substances combating this
group of imperfect fungi are being designed. This paper presents attempts to
develop new, not yet described in the literature biocidal ionic liquids that are derivatives of the lead structure, i.e. didecyldimethylammonium nitrate, and demonstrate strong action against mould fungi. Natural quaternary ammonium salts,
mainly extracts from coconut and soybean, and from vegetable fats, were the basis
for the syntheses.
The aim of the research was to develop a manner of synthesising new ionic
liquids and determine their efficacy against species of mould fungi that overgrow
wood and wood-based materials.
Test materials and methods
Syntheses
New, not yet described in the literature biocidal ionic liquids with ammonium
cation and organic herbicide anions were synthesised: [Ciech][1], [Ciech][3],
[Rok][1], [Rok][2], [BA][Glif], as well as ionic liquids with natural cation and
nitrate anion: [Eth C/12][NO3], [Arq1230][NO3] and [Arq C35][NO3] (table 1.)
The synthesis of the above-mentioned ionic liquids consisted in replacement
of halide anion with herbicide anion or nitrate(V) anion. The reactions were
carried out in water environment with a little surplus of inorganic salt.
By selecting adequate surpluses of inorganic salts participating in the synthesis and regulating the temperature and time of the ion exchange process, very
pure ionic liquids, whose effectiveness not infrequently reached 98–99%, were
obtained.
In order to confirm the structure of the new ionic liquids, analyses using thin
layer chromatography (TLC) and proton and carbon spectra of nuclear magnetic
resonance (1H NMR and 13C NMR) were carried out, as well as elementary
analyses. The content of ionic liquid in the product was determined using two
phase titration method in chloroform-water system. The structures of ionic
liquids are presented in Diagram 1 and the description is given in table 1.
CH3
R2
N+
R1
X-
CH3
R1, R2 – alkyl C8-C18,
X – NO3, herbicide,
14
Table 1. Tested ionic liquids
Tabela 1 . Badane ciecze jonowe
Ionic liquid
Ciecz jonowa
[Ciech][1]
Content
of cation
active
substance
[%]
Zawartość
substancji
aktywnej
[%]
88.0
[Ciech][3]
98.0
[Rok][1]
95.0
[Rok][2]
99.0
[BA][Glif]
[Arq1230][NO3]
[Arq C35] NO3]
[EthC/12][NO3]
95.0
75.0
98.0
99.0
Solvent
Description
Rozpuszczalnik
Opis
isopropanol
modified structure of CIECH group
products
izopropanol
isopropanol
izopropanol
isopropanol/water 1:1
izopropanol/woda 1:1
isopropanol/water 1:1
izopropanol/woda 1:1
water
woda
water
woda
water
woda
water
woda
zmodyfikowana struktura produktów
grupy CIECH
modified structure of CIECH group
products
zmodyfikowana struktura produktów
grupy CIECH
synthesis from a market product of
PCC Rokita S.A. Company
synteza z produktu rynkowego firmy
PCC Rokita S.A.
synthesis from a market product of
PCC Rokita S.A. Company
synteza z produktu rynkowego firmy
PCC Rokita S.A.
ionic liquid with anion containing
herbicide
ciecz jonowa z anionem zawierającym
herbicyd
nitrate(V) with dodecyltrimethylammonium cation
azotan(V) z kationem dodecylotrimetyloamoniowym
nitrate(V) with cation obtained from
coconut oil
azotan(V) z kationem uzyskanym z oleju
kokosowego
nitrate(V) with cation obtained from
natural vegetable products (coconut
oil ethoxylates)
azotan(V) z kationem uzyskanym
z naturalnych produktów roślinnych
(etoksylatów oleju kokosowego)
15
Method for testing wood resistance to mould fungi
Mycological tests were carried out in accordance with the method assumed binding for the assessment of biocide efficacy against mould fungi and described in
ITB Instruction 355/98 [Ochrona drewna ... 1998]. Water solutions, alcohol solutions (isopropanol) or water-alcohol solutions (isopropanol-water 1:1) of the
tested ionic liquids were applied on the samples of pine wood (Pinus sylvestris L.
(sapwood)) of the dimensions of 40 × 40 × 4 mm. The applied amount was 15, 25,
50, 100 and 150 g of pure active substance per 1 m2 of the wood surface. After
conditioning the protected samples as well as the control samples were exposed to
the action of two sets of fungi. The samples were placed on agar culture medium
in Petri dishes and then infected by spraying them with spore water made from the
following species of mould fungi:
Set I – Aspergillus niger V. Tieghem, Penicillium funiculosum Thom, Paecilomyces varioti Rainier, Trichoderma viride Persoon ex Fries, Alternaria tenuis Link
ex Fries,
Set II – Chaetomium globosum Kunze.
The test material was put for 4 weeks into an incubator where the temperature
was 27±2°C and relative humidity 90%. Simultaneously the vitality of spores on
the control dishes with agar culture medium was checked. Unprotected pine wood
was used as reference material. The assessment of mycelium growth was carried
out according to a 4-degree assessment scale:
0 – no visible under the microscope growth of fungi on a sample,
1 – trace growth of fungi on a sample, poorly visible to the naked eye, but well
visible under the microscope, or visible to the naked eye growth limited only to
the brims of a sample,
2 – visible to the naked eye growth of fungi on a sample, but less than 15% of the
surface covered by fungus,
3 – over 15% of the surface covered by fungus visible to the naked eye.
The final result of a sample coverage by mould was the arithmetic mean from
the assessments of six test samples from each set.
The control samples should demonstrate fungi growth on over 75% of the surface of each sample.
Test results and discussion
The results of determinations of the degree of wood coverage by the mould fungi
are presented in tables 2 and 3 and in fig. 1.
The degree of mould coverage of the wood protected with [Ciech][1],
[BA][Glif] ionic liquids after 4-week action of the mould fungi mixture (set I)
16
and where the application was 25 g/m2 was 0, which proves very high activity of
the compounds with herbicide anion against the mixture of test fungi.
Table 2. The resistance of pine wood (sapwood) protected with the ionic liquids to
the action of the mould fungi mixture – Set I
Tabela 2. Odporność drewna sosny (biel) zabezpieczonego cieczami jonowymi na działanie
mieszaniny grzybów pleśniowych – Zestaw I
Ionic liquid application on the wood surface
Ionic liquid
Ciecz jonowa
Naniesienie cieczy jonowej na powierzchnię drewna
15 [g/m2]
25 [g/m2]
50 [g/m2]
100 [g/m2]
150 [g/m2]
Surface coverage degree
Stopień porośnięcia powierzchni
[Ciech][1]
0.3
0.0
0.0
0.0
0.0
[Ciech][3]
1.0
1.0
0.8
0.2
0.0
[Rok][1]
0.8
0.3
0.3
0.2
0.0
[Rok][2]
2.0
0.7
0.0
–
–
[BA][Glif]
1.8
0.0
0.0
–
–
[Arq1230][NO3]
1.8
0.7
0.3
–
–
[Arq C35][NO3]
2.3
0.7
0.0
–
–
[Eth C/12][NO3]
3.0
2.5
0.5
0.5
0.3
Table 3. The resistance of pine wood (sapwood) protected with the ionic liquids to
the action of Chaetomium globosum fungus – Set II
Tabela 3. Odporność drewna sosny (biel) zabezpieczonego cieczami jonowymi na działanie
grzyba Chaetomium globosum – Zestaw II
Ionic liquid application on the wood surface
Ionic liquid
Ciecz jonowa
Naniesienie cieczy jonowej na powierzchnię drewna
15 [g/m2]
25 [g/m2]
50 [g/m2]
100 [g/m2]
150 [g/m2]
Surface coverage degree
Stopień porośnięcia powierzchni
[Ciech][1]
0
0
0
0
0
[Ciech][3]
0.8
0.5
0
0
0
[Rok][1]
0.3
0.2
0
0
0
[Rok][2]
0
0
0
–
–
[BA][Glif]
0
0
0
–
–
[Arq1230][NO3]
0
0
0
–
–
[Arq C35][NO3]
0
0
0
–
–
[Eth C/12][NO3]
1.8
0.7
0
0
0
17
In the case of the rest of the ionic liquids with ammonium cation and organic
herbicide anions ([Ciech][3], [Rok][1], [Rok][2]) and the samples protected with
the ionic liquids with natural cation and nitrate anion ([Arq1230][NO3]
[ArqC35][NO3]) already the application of 25 g/m2 resulted in the situation
where the maximum coverage degree did not exceed 1. Such result allow classification of the protected wood as a material that is practically resistant to mould
fungi (class 2).
The fact that wood was well protected with [Ciech][1], [Ciech][3] and
[Rok][1] liquids already at the application level of 15 g/m2 should be well noticed. The mean mould coverage degree ranged from 0.3 to 1.0.
0 [g/m2]
15 [g/m2]
Średni stopień zapleśnienia
Mean degree of mould coverage
3
2,5
25 [g/m2]
50 [g/m2]
100 [g/m2]
2
150 [g/m2]
1,5
1
0,5
0
[Ciech][1]
[Ciech][3]
[Rok][1]
[Rok][2]
[BA] [herb1] [Arq1230][NO3] [Arq C35][NO3] [Eth C/12][NO3]
Control
Ionic liquids
Ciecze jonowe
Fig. 1. The results of determination of the resistance of pine wood protected with
the ionic liquids to the action of the mould fungi – Set I – Mixture
Rys. 1. Wyniki oznaczania odporności drewna sosny zabezpieczonego cieczami jonowymi
na działanie grzybów pleśniowych – Zestaw I – Mieszanina
In the case of Chaetomium globosum fungus the degree of coverage was 0 for
application level of 50 g/m2, which indicates exceptional efficacy of the tested
ionic liquids against that species.
The pine control wood demonstrated the 3. degree of coverage by mould as
a result of the action of both sets of the test fungi.
Conclusions
1. The seven tested ionic liquids demonstrated strong anti-mould action. In the
case of Chaetomium globosum fungus (set II) already the lowest application
(15 g/m2) was sufficient to protect the wood effectively.
18
2. The ionic liquids with ammonium cation and organic herbicide anions
([Ciech][1], [BA][Glif]) demonstrated the strongest action against the mould
fungi. Those ionic liquids completely inhibited the growth of the mould
mixture (set I) on the surface of protected material already when the application was 25 g per m2 of wood.
Acknowledgements
This study was carried out with the financial support of the European Regional
Development Found within the framework of the Innovative Economy Operational Programme in Poland, project number P016.01.03.01-30-074/08.
References
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mieszkaniowym, Mater. V Konf. Nauk. Rozkład i korozja mikrobiologiczna materiałów
technicznych. Łódź 2009:114
Cybulski J., Wiśniewska A., Kulig-Adamiak a., Liwicka L., Cieniecka-Rosłonkiewicz A.,
Kita K., Fojutowski A., Nawrot J., Materna K., Pernak J. [2008]: Long-alkyl-chain
quaternary ammonium lactate based ionic liquids. Chemistry – A Eur. J.14:9305
Chowdhury S., Mohad R.S., Dcott J.L.[2007]: Reactivity of ionic liquids. Tetrahedron
63:2363-2389
Grajewski J., Twarużek M. [2004]: Zdrowotne aspekty oddziaływania grzybów pleśniowych i mikotoksyn. Alergy [21] 3:45–49
Gutarowska B., Jakubowska A.[2001] : Ocena zanieczyszczenia pleśniami powietrza
pomieszczeń na uczelni. Mater. VI Ogólnokr. Konf. Problemy jakości powietrza
wewnętrznego w Polsce – Jakość powietrza w budynkach edukacyjnych. Warszawa
:103–113
Ochrona drewna budowlanego przed korozją biologiczną środkami chemicznymi.
Wymagania i badania. [1998]. Instrukcja ITB Nr 355/98
Pernak J., Śmiglak M., Griffin S.T., Hough W.L., Wilson T.H., Pernak A., ZabielskaMatejuk J., Fojutowski A., Kita K., Rogers R.D. [2006]: Long chain quaternary
ammonium-based ionic liquids and potential applications. Green Chem. 8:1–10
Pernak J., Zabielska-Matejuk J., Kropacz A., Foksowicz-Flaczyk J. [2004]: Ionic liquids
in wood preservation. Holzforschung [58] 3:286–291
Stach A., Piotraszewska-Pająk A., Stryjakowska-Sekulska M., Filipiak M., Silny W.
[2004]: Mikroflora powietrza wokół i wewnątrz budynków dydaktycznych wyższej
uczelni w Poznaniu. Postępy Dermatologii i Alergologii, [21] 3:121–127
Zabielska-Matejuk J., Stangierska A., Skrzypczak A. [2009]: Ciecze jonowe w ochronie
drewna budowlanego przed korozja biologiczną. Ochrona przed korozją – w druku
Zabielska-Matejuk J. [2004]: Badania aktywności biologicznej nowych czwartorzędowych
soli amoniowych metodą pożywkową i przyspieszoną metodą klockową. Drewno, [47]
172:21–36
19
AKTYWOŚĆ NOWYCH AMONIOWYCH CIECZY JONOWYCH
WOBEC GRZYBÓW WYWOŁUJĄCYCH PLEŚNIENIE
DREWNA
Streszczenie
Drewno użytkowane w warunkach wysokiej wilgotności ulega deprecjacji i procesom
destrukcji biologicznej wywołanej działaniem mikroorganizmów. Szczególnie jest podatne na atak grzybów pleśniowych, wywołujących powierzchniowe przebarwienia, co
pogarsza estetykę drewna oraz obniża jego konkurencyjność w stosunku do innych materiałów technicznych. Różnorodność gatunkowa oraz oporność grzybów pleśniowych na
preparaty chemiczne jest problemem przy opracowaniu struktur skutecznych substancji
czynnych, zwalczających tę grupę grzybów niedoskonałych.
Zsyntezowano nową, nieopisaną w literaturze, grupę biobójczych cieczy jonowych,
pochodnych struktury wiodącej – azotanu didecylodimetyloamoniowego, wykazujących
silne działanie w stosunku do grzybów-pleśni. Bazą dla syntez były czwartorzędowe sole
amoniowe pochodzenia naturalnego, głównie ekstrakty z kokosa, soi oraz tłuszczów
roślinnych. Badania mikologiczne wykonano na drewnie sosny Pinus sylvestris L.(biel),
zgodnie z metodą przyjętą jako obowiązującą w ocenie skuteczności działania biocydów.
Opracowane ciecze jonowe wykazały aktywność wobec gatunku Chaetomium globosum,
oraz mieszaniny: Aspergillus niger, Penicillium funiculosum, Alternaria alternata, Paecylomyces varioti, Trichoderma viride. Jako najsilniej działające ciecze jonowe wymienić
należy związki o kationach: didecylodimetyloamoniowym, benzalkoniowym, dodecylotrimetyloamoniowym i cocotrimetyloamoniowym oraz szeregu anionów organicznych
i nieorganicznych (również o właściwościach herbicydowych).
Słowa kluczowe: ciecze jonowe, aktywność grzybobójcza, drewno, pleśnienie
Andrzej FOJUTOWSKI, Andrzej NOSKOWIAK, Mariusz KOT,
Aleksandra KROPACZ, Anna STANGIERSKA 1
THE ASSESSMENT OF MECHANICAL PROPERTIES
OF WOOD TREATED WITH IONIC LIQUIDS
The impregnation of wood with wood preservatives may have an influence on its
physical and mechanical properties. The knowledge about the character of that
influence is of great importance for characterisation of functional properties of
wood and, as a consequence, determination of its use classes. The ionic liquids
(ILs) of imidazolium tetrafluoroborates series, which for instance very well penetrate into Scots pine wood, are active against wood-destroying fungi and
generally have a positive, although insignificant, influence on physical and
mechanical properties of wood, especially on its resistance to colour change
during exposure to light. However, various ILs may differ widely in that respect.
Under POIG.01.03.01-30-074/08 project investigations were undertaken to
clarify the influence of didecyldimethylammonium nitrite ([DDA][NO2]) and IL
with didecyldimethylammonium cation and anion of herbicide character
([DDA][herbicide]) on selected physical and mechanical properties of Scots pine
wood (Pinus sylvestris L.). The miniature sapwood samples were subjected to
sorption with the ILs by vacuum method. The properties of the treated wood were
compared with those of control wood, i.e. untreated wood, using twin specimens.
The average retention of ILs in wood was on the level of 3.6kg/m3, 7.4kg/m3, and
18.2kg/m3. The tested ILs had only a very small influence, from -0.5% to +1.6%,
on the compression strength of wood along the grain when oven-dry wood was
tested. However, at equilibrium moisture content the compression strength along
the grain, bending strength, and modulus of elasticity at bending of wood treated
Andrzej FOJUTOWSKI, Wood Technology Institute, Poznan, Poland
Andrzej NOSKOWIAK, Wood Technology Institute, Poznan, Poland
Mariusz KOT, Poznan University of Technology, Wood Technology Institute, Poznan,
Poland
Aleksandra KROPACZ, Wood Technology Institute, Poznan, Poland
Anna STANGIERSKA, Wood Technology Institute, Poznan, Poland
22
Andrzej FOJUTOWSKI, Andrzej NOSKOWIAK, Mariusz KOT, Aleksandra KROPACZ, Anna STANGIERSKA
with ILs were distinctly lower, i.e. by 10%, 20% and 15% respectively. The equilibrium moisture content of wood treated with ILs was greater by 2-3% than that
of control wood, which may be the reason for deterioration of wood mechanical
properties. However, this speculation requires further investigations.
Keywords: ionic liquids, wood, Scots pine, compression strength, bending
strength, equilibrium moisture
Introduction
Ionic liquids which belong to a special class of molten salts whose melting
points are at the temperatures below 100oC, are considered as potential “green”
and neoteric solvents [Li et al. 2004; Pernak et al. 2001; Pernak et al. 2004;
Rogers, Seddon 2002; Wasserscheid, Welton 2002; Welton 1999]. The insignificant vapour pressure is a special advantage of ILs, because solvent emission to
the atmosphere is very low. The synthesis, properties and application of ILs, for
instance as potential wood preservatives, have been extensively studied recently
[Cybulski et al. 2008; Kartal et al. 2005, 2006; Sheldon 2001; Rogers, Seddon
2002; Kubisa 2004; Pernak et al. 2004, 2005, 2006]. Some of ionic liquids, such
as for example imidazolium tetrafluoroborate, lactate, pyridinium chlorides and
acesulfamates, and many others, are active against wood-destroying fungi and
penetrate deep into the pine wood structure [Pernak et al. 2004; ZabielskaMatejuk, Pernak 2009; Zabielska-Matejuk et al. 2010]. Ionic liquids (ILs)
of imidazolium tetrafluoroborates series generally have positive, although
insignificant, influence on physical and mechanical properties of wood, especially on its resistance to colour change during exposure to light [Fojutowski et
al. 2007]. However, various different ILs may differ widely in that respect. For
example 1-butyl-3-methylimdazolium chloride dissolves cellulose from pulp
[Swatloski et al. 2002] and some imidazolium-based derivates are capable of
wood liquefaction [Honglu, Tiejun 2006]. The impregnation of wood with wood
preservatives may have an influence on physical and mechanical properties of
wood. The knowledge about the character of that influence is of great
importance for characterisation of functional properties of wood and, as a consequence, determination of its use classes presented in EN 335. Under
POIG.01.03.01-30-074/08 project investigations were undertaken to clarify the
influence of didecyldimethylammonium nitrite ([DDA][NO2]) and IL with
didecyldimethylammonium cation and anion of herbicide character
([DDA][herbicide]) on selected physical and mechanical properties of Scots pine
wood (Pinus sylvestris L.). The above-mentioned ILs were used in the investigation as very interesting compounds for wood protection, because of their strong
effectiveness against wood-attacking fungi [Zabielska-Matejuk et al. 2010].
The assessment of mechanical properties of wood treated with ionic liquids
23
Materials and experiment methods
Wood used in the tests
The Scots pine wood (Pinus sylvestris L.) came from fresh coniferous class III
forest stands of the Wielkopolsko-Pomorski (III) natural forest region. Only
sapwood of the wood was used. The defect-free wood, e.g. without sapstain, rot,
worm holes, was gently artificially dried below 60°C before further treatment.
The quality of the sapwood samples was in line with PN-EN 113 requirements.
Identical (twin) samples of sapwood were cut from selected boards and used for
the tests.
Ionic liquids (ILs)
The ILs used in the tests were prepared in the Poznan University of Technology
laboratory, according to the described method [Zabielska-Matejuk et al. 2010].
The main substances used in the tests were didecyldimethylammonium nitrite
([DDA][NO2]) and IL with didecyldimethylammonium cation and anion of
herbicide character ([DDA][herbicide]). The concentration of each of the tested
ILs was 91–97% and they were easy dissolved in propanol-2 and water-propan2-ol mixture.
Investigated wood properties and method of their determination
The following wood properties were investigated:
− compression strength along the grain was measured in two variants according
to PN-D-04102 and in accordance with ISO 3787 using a computerised
“Instron” apparatus with the force load range up to 50 kN and 5 mm/min rate
of head movement:
a) using 6 twin pairs (a pair: control specimens – specimens treated with ILs
solution of individual concentration) of specimens 20 × 20 × 30 mm artificially dried before the test at 103±2°C and tested oven-dry according to
PN-72/C-04907, or
b) using for each test series (control or treated with ILs solution of individual
concentration) 30 specimens 20 × 20 × 30 mm conditioned in 65±5% relative humidity and 20±2°C to equilibrium moisture,
− bending strength was measured according to PN-D-04103 and modulus of
elasticity (MOE) according to PN-D-04117 in accordance with ISO 3133
using 36 specimens of 20 × 20 × 300 mm for each test series; Before the
test specimens were conditioned in 65±5% relative humidity and 20±2°C to
equilibrium moisture. An computerised “Instron” apparatus with a force load
24
range up to 50 kN and 5mm/min rate of head movement was used for the
tests. MOE was determined from the linear part of the force displacement
curve using a standard procedure [Dias de Moraes et al. 2004],
− moisture content of wood according to PN-EN 13183-1.
Preparation of wood specimens
To minimise the effect of wood heterogeneity on the test results a special procedure for specimen collection was used. Seven specimens were cut along the
grain one by one from one strip. 36 strips were used for tests of wood bending
strength and modulus of elasticity at bending and 30 for tests of compression
strength along the grain at equilibrium moisture content. To achieve good comparability of the test results the specimens were specially arranged: the first
specimen from each strip was intended for the test with 0.5% [DDA][NO2]
concentration, the second – with 1.0% [DDA][NO2], the third – with 2.5%
[DDA][NO2], the forth (central) was the control (not impregnated), the fifth –
with 2.5% [DDA][herbicide], the sixth – with 1.0% [DDA][herbicide], and the
seventh – with 0.5% [DDA][herbicide]. The specimens for compression strength
determination on oven-dry wood were cut in pairs along the grain. In each pair
one sapwood sample was then treated with IL solution, while the other was used
as the control (not impregnated). 12 specimens were cut from one strip for each
kind of ILs and each solution concentration.
Treatment of wood with IL and preparation to the tests
At the room temperature [DDA][NO2] and [DDA][herbicide] are highly viscous,
semi-solid substances, hence their solutions were prepared to treat the wood. ILs
solutions of the following concentrations were used for wood impregnation:
0.5%; 1.0% and 2.5% in water-propan-2-ol mixture (10:1). The wood specimens
were impregnated with ILs solutions by vacuum-pressure method according to
the procedure described in PN-EN 113. The ILs retention in wood was determined by weighing the wood samples before and after the treatment and was
expressed in kg/m3. Before the treatment the wood specimens were dried to
oven-dry mass at 103±2°C. After the treatment wood specimens were conditioned to constant mass in a conditioning chamber at 20oC and 65% relative
humidity, except the specimens intended for determination of compression
strength along the grain in oven-dry wood which were dried to oven-dry mass at
103±2°C. Control wood was conditioned or dried in the same way as the wood
specimens treated with ILs.
25
Expression of results
The absolute values of the properties were determined for individual samples.
Those numbers were then used to calculate relative values (∆r) according to
eq. 1:
(1)
∆r=[(Wf – Wc)/Wc] ⋅ 100 [%]
where: Wf represented the value for treated wood,
Wc represented the value for control sample.
The values recorded are average, minimum and maximum values with standard deviation and coefficient of variability. The assessment of significance of
changes in wood properties is based on statistical test data according to ISO
2854, PN-N-01052/03 item 3.4: Comparison of means in two populations
assuming the confidence level of 95% (significance level of α = 0.05).
Results and discussion
Ionic liquids retention in wood specimens
The results of wood impregnation with the solutions of ionic liquids
[DDA][NO2] and [DDA][herbicide] presented in table 1 show very even retention of the ILs in wood. The retention of ILs in wood for both ILs used and both
dimensions of the wood specimens is at three levels: about 3.6 kg/m3, 7.5 kg/m3
Table 1. Retention of ionic liquids in Scots pine sapwood (Pinus sylvestris L.)
Tabela 1. Retencja cieczy jonowych w bielu drewna sosny zwyczajnej (Pinus sylvestris L.)
[DDA][NO2]
[DDA][herbicide]
Concentration of solution [%]
Ionic liquids
Ciecze jonowe
Stężenie roztworu [%]
2.5
Specimens for
Próbki do
1.0
0.5
2.5
1.0
0.5
Retention of ionic liquids in wood specimens [kg/m3]
Retencja cieczy jonowych w próbkach drewna [kg/m3]
2
Bending Strength + MOE1
Zginanie statyczne+MOE
1
Compression strength
Wytrzymałość na ściskanie
1
18.7
17.33
15.74
20.2
18.9
18.2
7.7
7.1
6.4
8.3
7.6
7.3
3.8
3.6
3.3
4.2
3.8
3.7
Modulus of elasticity at bending / Moduł sprężystości przy zginaniu
Maximum / Maksimum
3
Average / Średnia
4
Minimum / Minimum
2
19.6
17.5
15.9
20.4
18.9
18.4
7.7
7.1
6.4
8.3
7.8
6.9
3.7
3.5
3.0
4.2
3.8
3.6
26
and 18 kg/m3 according to the ILs solutions used: 0.5%; 1.0% and 2.5%, respectively. The wood was easily saturated with the ILs solutions by vacuum-pressure
method without using high-pressure, but only by changing the pressure from
vacuum to atmospheric.
Compression strength along the grain of oven-dry wood
The values of compression strength along the grain (table 2) for the control samples ranged from 90.4 to 103.1 N · mm-2 and for the samples impregnated with
the ILs the strength ranged from 88.7 to 105.8 N · mm-2. The variability coeffiTable 2. Compression strength along the grain of oven-dry Scots pine sapwood
(Pinus sylvestris L.) control specimens and specimens impregnated with ionic liquids
Tabela 2. Wytrzymałość na ściskanie wzdłuż włókien w stanie zupełnie suchym próbek
bielu drewna sosny zwyczajnej (Pinus sylvestris L.) nasyconych cieczami jonowymi i kontrolnych
Specimens
description
Opis
próbek
Values
Twin
pairs
Twin
pairs
Twin
pairs
Twin
pairs
Twin
pairs
Twin
pairs
Pary
bliźniacze
Pary
bliźniacze
Pary
bliźniacze
Pary
bliźniacze
Pary
bliźniacze
Pary
bliźniacze
C1 N22.5%
C
Wartości
H1.0% C H0.5%
Average
[N ⋅ mm-2]
95.3
94.8
99.8 101.4 98.1
97.8
97.5
98.6
98.4
97.5 96.1 97.1
Minimum
[N ⋅ mm-2]
90.4
93.1
99.1
93.1
95.1
94.1
91.5
88.7 93.3 95.4
Maximum
[N ⋅ mm-2]
101.1
97.2 101.7 104.9 103.1 102.2 100.6 102.9 102.8 105.8 98.5 99.0
Standard
deviation
[N ⋅ mm-2]
3.5
1.4
1.1
2.2
3.6
3.7
1.9
3.6
4.2
6.3
2.0
1.6
3.7
1.5
1.1
2.2
3.7
3.8
2.0
3.7
4.2
6.5
2.0
1.6
Średnia
[N ⋅ mm-2]
Minimum
[N ⋅ mm-2]
Maksimum
[N ⋅ mm-2]
Odchylenie
standardowe
[N ⋅ mm-2]
Variation
coefficient [%]
Współczynnik
zmienności [%]
1
N1.0% C N0.5% C H32.5% C
Compression strength along the grain
Wytrzymałość na ściskanie wzdłuż włókien
99.0
93.4
Control, Not impregnated / Kontrola, Nienasycone
Impregnated with [DDA][NO2] solutions / Nasycone roztworami [DDA][NO2]
3
Impregnated with [DDA][herbicide] solutions / Nasycone roztworami [DDA][herbicyd]
2
27
cients of the control and impregnated test pieces (for all tested IL retention
levels) were between 1.1 and 4.2% and about 1.5–6.5%, respectively, pointing to
a little scatter of results. The values of compression strength along the grain
were very close for the treated and control samples. Therefore, for the pairs of
twin samples at the confidence level of 95% the mean relative differences in
compression strength along the grain of about minus 0.31% to +1.60% between
the samples impregnated with the ILs (on every retention level) and the control
samples (table 3) proved not to have been statistically significant. It demonstrates that compression strength along the grain of oven-dry wood containing to
about 19 kg/m3 of [DDA][NO2] or [DDA][herbicide] may be at the same level as
that of control, not impregnated wood.
Table 3. Relative changes of compression strength along grain of Scots pine sapwood (Pinus sylvestris L.) control specimens and specimens treated with ionic liquids, dried to 0% moisture content
Tabela 3. Względne zmiany wytrzymałości na ściskanie wzdłuż włókien próbek bielu drewna sosny zwyczajnej (Pinus sylvestris L.) kontrolnych i nasyconych cieczami jonowymi,
wysuszonych do wilgotności 0%
Ionic liquids
Ciecze jonowe
[DDA][NO2]
[DDA][herbicide]
Ionic liquid concentration [%]
Stężenie cieczy jonowej [%]
2.5
1.0
0.5
2.5
1.0
Relative changes of compression strength along grain [%]
0.5
Względne zmiany wytrzymałości na ściskanie [%]
-0.52
1.60
-0.31
1.12
-0.91
1.04
Compression strength along the grain of wood in equilibrium moisture
condition
The values of compression strength along the grain (table 4 and fig. 1) for the
control samples ranged from 44.7 to 66.7 N · mm-2 and for the samples impregnated with the ILs from 30.3 to 61.7 N · mm-2. The variability coefficients of the
control and impregnated test pieces (for all tested IL retention levels) were about
9.3% and between 9.2 and 14.2%, respectively, pointing to a relatively little
scatter of results. The values of compression strength along the grain were lower
by about 10% (in the range from 7.7% to 13.6%) for the wood samples impregnated with [DDA][NO2] or [DDA][herbicide] than for the control samples. The
level of the mean relative difference in compression strength along the grain
between the impregnated and control samples at the confidence level of 95%
proved to have been statistically significant. The compression strength along the
28
grain of the impregnated and control wood in equilibrium moisture condition
was distinctly smaller than that of the oven-dry wood, which had been expected.
However, the equilibrium moisture of the wood impregnated with the ILs was by
2–3% greater than the equilibrium moisture content of the control wood, which
might have been the reason for less compression strength along the grain of the
impregnated wood than of the control wood.
Table 4. Compression strength along the grain of Scots pine sapwood (Pinus sylvestris L.) control specimens and specimens impregnated with ionic liquids, tested at
equilibrium moisture
Tabela 4. Wytrzymałość na ściskanie wzdłuż włókien w stanie wilgotności równowagowej
próbek bielu drewna sosny zwyczajnej (Pinus sylvestris L.) nasyconych cieczami jonowymi
i kontrolnych
Specimens
description
Impregnated with
Not
2
1 [DDA][NO2] solutions [%]
Opis próbek impregnated1
Nasycone roztworami
Nienasycone
Control
Values
Kontrola
2.5
1.0
0.5
Wytrzymałość na ściskanie wzdłuż włókien
53.7
52.5
50.6
53.9
50.3
51.7
Minimum [N ⋅ mm-2]
44.7
39.3
38.8
30,3
40.3
39.5
39.5
66.7
61.7
60.9
60.3
61.0
56.8
59.6
5.4
5.3
5.4
7.2
5.0
4.9
4.7
9.3
9.9
10.4
14.2
9.3
9.8
9.2
Variation
coefficient [%]
Współczynnik zmienności [%]
2
0.5
58.2
Odchylenie standardowe [N ⋅ mm-2]
2
1.0
Average [N ⋅ mm-2]
Średnia [N ⋅ mm-2]
Maximum [N ⋅ mm-2]
Maksimum [N ⋅ mm-2]
Standard deviation
[N ⋅ mm-2]
1
2.5
Nasycone roztworami
[DDA][herbicyd]2 [%]
Compression strength along the grain
Wartości
1
[DDA][NO2]2 [%]
Impregnated with
[DDA][herbicide]
solutions2 [%]
Equilibrium moisture: 10.1%
Wilgotność równowagowa: 10.1%
Equilibrium moisture in normal conditions (65% R.H., 20°C) of wood impregnated with the
solution of:
– [DDA][NO2]: 2.5%–12.6%; 1.0%–13.2%; 0.5%–13.0%, or
– [DDA][herbicide]: 2.5%–12.6%; 1.0%–12.9%; 0.5%–13.0%
Wilgotność równowagowa dla klimatu normalnego (65% wilgotności względnej, 20°C) drewna nasyconego roztworem:
– [DDA][NO2]: 2.5%–12.6%; 1.0%–13.2%; 0.5%–13.0%, lub
– [DDA][herbicyd]: 2.5%–12.6%; 1.0%–12.9%; 0.5%–13.0%
29
[DDA][herbicide] / [DDA][herbicyd]
Fig. 1. Compression strength along the grain of Scots pine sapwood (Pinus sylvestris
L.) specimens impregnated with ionic liquids and control specimens tested at equilibrium moisture1 as a function of type and concentration of ionic liquids
Rys. 1. Wytrzymałość na ściskanie wzdłuż włókien w stanie wilgotności równowagowej1
próbek bielu drewna sosny zwyczajnej (Pinus sylvestris L.) nasyconych cieczami jonowymi
i kontrolnych w zależności od rodzaju i stężenia cieczy jonowych
1
1
Equilibrium moisture see legend to table 4
Wilgotność równowagowa w legendzie do tabeli 4
Bending strength and modulus of elasticity of wood in equilibrium moisture
condition
The mean bending strength of treated wood containing to about 17.5 kg/m3 of
the IL was smaller than that of the control sample. The respective mean value
was 107.5 N · mm-2 for the control wood and for the test pieces impregnated with
the ILs the respective values were in the range from 81.1 to 87.8 N · mm-2
(table 5 and fig. 2). The mean relative difference for each of the tested ILs was
30
of about minus 20% (between 18.3 and 24.6%). Similar results were obtained for
modulus of elasticity for the control and impregnated samples. The mean value
was 11604 and ranged from 9618 to 10239 N · mm-2, respectively, (table 6 and
fig. 3). The mean values of relative differences between modulus of elasticity for
the impregnated and control samples were minus 14.3% for wood with
Table 5. Bending strength of Scots pine sapwood (Pinus sylvestris L.) specimens at
equilibrium moisture
Tabela 5. Wytrzymałość próbek bielu drewna sosny zwyczajnej (Pinus sylvestris L.) na
zginanie statyczne przy wilgotności równowagowej
Specimens
description
Impregnated with
Not
2
impregnated
Opis próbek
Nasycone roztworami
1
Nienasycone
Control
Values
Kontrola
2.5
1.0
0.5
Wytrzymałość na zginanie statyczne
86.2
81.1
87.8
86.6
82.6
83.8
64.7
68.1
55.2
64.8
60.5
57.2
Maximum [N ⋅ mm-2]
134.4
102.5
105.6
103.4
114.7
105.8
102.3
11.5
9.6
9.4
12.6
11.6
11.2
13.2
10.7
11.1
10.9
15.5
13.2
12.9
16.0
Variation coefficient
[%]
2
0.5
86.4
1
1.0
107.5
Standard deviation
[N ⋅ mm-2]
1
2.5
Nasycone roztworami
[DDA][herbicyd]2 [%]
Bending strength
Wartości
[DDA][NO2]2 [%]
Impregnated with
[DDA][herbicide]
solutions2 [%]
Equilibrium moisture: 10.6%
Wilgotność równowagowa: 10.6%
Equilibrium moisture in normal conditions (65% R.H., 20°C) of wood impregnated with the
solution of:
– [DDA][NO2]: 2.5%–12.7%; 1.0%–12.5%; 0.5%–12.5%, or
– [DDA][herbicide]: 2.5%–12.5%; 1.0%–12.7%; 0.5%–12.6%
2
Wilgotność równowagowa dla klimatu normalnego (65% wilgotności względnej, 20°C) drewna nasyconego roztworem:
– [DDA][NO2]: 2.5%–12.7%; 1.0%–12.5%; 0.5%–12.5%, lub
– [DDA][herbicyd]: 2.5%–12.5%; 1.0%–12.7%; 0.5%–12.6%
31
[DDA][NO2] and minus 14.0% for wood with [DDA][herbicide]. The differences were statistically significant at the confidence level of 95%. The equilibrium moisture level of the wood containing the ILs was about 2% greater than
the equilibrium moisture of the control wood, similar to the equilibrium moisture
of the wood tested for compression strength along the grain.
Fig 2. Bending strength of Scots pine sapwood (Pinus sylvestris L.) specimens at
equilibrium moisture1 as a function of type and concentration of ionic liquids
Rys.2. Wytrzymałość próbek bielu drewna sosny zwyczajnej (Pinus sylvestris L.) na zginanie statyczne przy wilgotności równowagowej1 w zależności od rodzaju i stężenia cieczy
jonowych
1
1
32
Table 6. Modulus of elasticity at bending of Scots pine sapwood (Pinus sylvestris L.)
specimens at equilibrium moisture1
Tabela 6. Moduł sprężystości przy zginaniu statycznym próbek bielu drewna sosny zwyczajnej (Pinus sylvestris L.) przy wilgotności równowagowej1
Specimens
description
Impregnated with
Not
Opis próbek impregnated1
Nasycone roztworami
Nienasycone
Control
Values
Kontrola
Maximum [N ⋅ mm2
]
Standard deviation
[N ⋅ mm-2]
Variation coefficient
[%]
1
1
2.5
1.0
0.5
Nasycone roztworami
[DDA][herbicyd] [%]
2.5
1.0
0.5
Modulus of elasticity at bending
Wartości
[DDA][NO2] [%]
Impregnated with
[DDA][herbicide]
solutions [%]
Moduł sprężystości przy zginaniu statycznym
11604
10056
10109
9679
10239
10066
9618
9212
7736
7700
6243
8188
8309
6994
13167
11252
12520
12184
13578
12736
11750
997
1042
1098
1407
1201
1135
1445
10.9
14.5
11.7
11.3
15.0
8.6
10.4
33
Fig. 3. Modulus of elasticity at bending of Scots pine sapwood (Pinus sylvestris L.)
specimens at equilibrium moisture1 as a function of type and concentration of ionic
liquids
Rys. 3. Moduł sprężystości przy zginaniu statycznym próbek bielu drewna sosny zwyczajnej
(Pinus sylvestris L.) przy wilgotności równowagowej1 w zależności od rodzaju i stężenia
cieczy jonowych
1
1
Conclusions
1. As a result of the tests carried out on identical wood specimens it was
observed that impregnation of Scots pine sapwood with ionic liquids
[DDA][NO2] and [DDA][herbicide] in the amount ranging from 3.5 to
19.0 kg/m3:
− had no effect on the compression strength parallel to grain tested according to PN-C-04907:1972 standard on oven-dry wood (change in the
34
compression strength of wood above minus 5%, from -0,5% to +1,6%,
not statistically significant at the confidence level of 95%),
− resulted in a 2–3% increase in the equilibrium moisture content of wood
under standard conditions (RH 65%/20°C),
− decreased bending strength, compression strength parallel to grain, and
modulus of elasticity in the state of equilibrium moisture content under
standard conditions (RH 65%/20°C) by around 20%, 10% and 15%, respectively.
2. The differences between average values of the bending strength, compression strength and modulus of elasticity at bending of the control samples and
the samples impregnated with the ionic liquids were statistically significant
(at the confidence level of 95%).
3. The differences between average values of the bending strength, compression strength and modulus of elasticity at bending of the samples impregnated with the ionic liquids of various concentrations (different retention degrees) were statistically insignificant (at the confidence level of 95%).
4. Further studies should be conducted to check whether the decrease in the
strength and modulus of elasticity observed at the wood moisture content
equivalent to the equilibrium moisture content under standard conditions is a
result of higher equilibrium moisture content of the wood impregnated with
the tested liquids or an effect those liquids have on the wood tissue.
Acknowledgements
This investigation received financial support from project POIG.01.03.01-30-074/08 “Ionic liquids in innovative technologies connected with processing
of lignocellulosic raw materials” co-financed by the European Regional
Development Found within the Innovative Economy Operational Program
2007–2013.
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List of standards
ISO 2854:1976 Statistical interpretation of data – Techniques of estimation and tests relating
to means and variances
ISO 3133:1975 Wood – Determination of ultimate strength in static bending
ISO 3787:1976 Wood – Test methods – Determination of ultimate stress in compression
parallel to grain
PN-79/D-04102 Drewno - Oznaczanie wytrzymałości na ściskanie wzdłuż włókien
PN-77/D-04103 Drewno - Oznaczanie wytrzymałości na zginanie statyczne
PN-63/D-04117 Fizyczne i mechaniczne własności drewna – Oznaczanie współczynnika
sprężystości przy zginaniu statycznym
PN-72/C-04907 Środki ochrony drewna – Oznaczanie wpływu na wytrzymałość drewna
36
PN-EN 113:2000/A1:2004 Środki ochrony drewna – Metoda badania do oznaczania skuteczności zabezpieczania przeciwko podstawczakom rozkładającym drewno – Oznaczanie wartości grzybobójczych
PN-EN 335-1:2007 Trwałość drewna i materiałów drewnopochodnych – Definicja klas
użytkowania – Część 1: Postanowienia ogólne
PN-EN 335-2:2007 Trwałość drewna i materiałów drewnopochodnych – Definicja klas
użytkowania – Część 2: Zastosowanie do drewna litego
PN-EN 13183-1:2004 Wilgotność sztuki tarcicy – Część 1: Oznaczanie wilgotności metodą
suszarkowo-wagową
PN-N-1052–03:1984 p.3.4 Statystyka matematyczna – Badania statystyczne – Porównywanie wartości średnich w dwóch populacjach
OCENA WŁAŚCIWOŚCI MECHANICZNYCH DREWNA
ZABEZPIECZONEGO CIECZAMI JONOWYMI
Streszczenie
Impregnacja drewna środkami ochrony drewna może wpływać na jego fizyczne, mechaniczne i biologiczne właściwości. Wiedza o charakterze tego wpływu ma istotne znaczenie dla ustalenia klas użytkowania drewna. W badaniach drewna sosny (Pinus sylvestris
L.) zabezpieczonego cieczą jonową: tetrafluoroboranem 3-heptyoloksymetylo-1-metyloimidazoliowym, stwierdzono pozytywny jej wpływ na właściwości fizycznomechaniczne drewna, m.in. na zwiększenie trwałości barwy. Różne ciecze jonowe mogą
mieć różny wpływ na właściwości drewna, chociaż nie można wykluczyć podobieństw
wpływu związków o zbliżonej budowie. W ramach projektu badawczego
POIG.01.03.01-30-074/08 podjęto badania oddziaływania dwóch cieczy jonowych:
azotynu didecylodimetyloamoniowego [DDA][NO2] i cieczy z kationem didecylodimetyloamoniowym i anionem o charakterze herbicydu [DDA][herbicyd], wprowadzonych
w roztworach wodno-alkoholowych do drewna metodą próżniowo-ciśnieniową, na jego
wytrzymałość. Retencje cieczy jonowych w drewnie zróżnicowano przez zastosowanie
trzech różnych ich stężeń w roztworach. Badania wykonano na bielu drewna sosny
(Pinus sylvestris L.), jako drewnie modelowym. Podstawowej oceny wpływu cieczy
jonowych na wytrzymałość drewna dokonano przez zbadanie wytrzymałości na ściskanie wzdłuż włókien (zgodnie z PN-C-04907:1972) po wysuszeniu nasycanych cieczami
jonowymi próbek do stanu zupełnie suchego. Następnie dokonano oznaczeń wytrzymałości na ściskanie wzdłuż włókien metodą według PN-D-04102:1979 oraz wytrzymałości i modułu sprężystości przy zginaniu drewna metodami: według PN-D-04103:1977
i PN-D-04117:1963. Oznaczenia te wykonano stosując drewno o równowagowym stanie
wilgotności w klimacie normalnym (wilgotność powietrza 65%/20°C).
37
W rezultacie badań wykonanych na bliźniaczych próbkach drewna stwierdzono, że
nasycanie bielu drewna sosny zwyczajnej cieczami jonowymi [DDA][NO2] i [DDA]
[herbicyd] w ilości 3,5 do 19,0 kg/m3:
– nie wpływa na wytrzymałość na ściskanie wzdłuż włókien badaną zgodnie z normą
PN-C-04907:1972 w stanie zupełnie suchego drewna (zmiany w zakresie od –0,5%
do +1,6% kwalifikowane są według normy jako brak zmian),
– powoduje zwiększenie wilgotności równowagowej drewna w klimacie normalnym
(65%/20°C) o 2–3%,
– zmniejsza wytrzymałość na zginanie statyczne, wytrzymałość na ściskanie wzdłuż
włókien oraz moduł sprężystości drewna w stanie wilgotności równowagowej, dla
klimatu normalnego (65%, 20°C), odpowiednio o około: 20%, 10% i 15%.
Różnice pomiędzy wartościami średnimi wytrzymałości na zginanie, wytrzymałości
na ściskanie i modułu sprężystości przy zginaniu próbek kontrolnych i próbek nasycanych cieczami jonowymi są statystycznie istotne (przy poziomie ufności 95%).
Różnice pomiędzy wartościami średnimi wytrzymałości na zginanie, wytrzymałości
na ściskanie i modułu sprężystości przy zginaniu próbek nasycanych cieczami jonowymi
o różnych stężeniach (różne stopnie retencji) są statystycznie nieistotne (przy poziomie
ufności 95%).
Dalszych badań wymaga sprawdzenie czy obniżenie wytrzymałości i modułu sprężystości przy wilgotności drewna odpowiadającej wilgotności równowagowej dla klimatu normalnego jest wynikiem wyższej wilgotności równowagowej drewna nasycanego
testowanymi cieczami, czy oddziaływania tych cieczy na tkankę drzewną.
Słowa kluczowe: ciecze jonowe, drewno, sosna, wytrzymałość na ściskanie, zginanie, wilgotność
równowagowa
Mariusz KOT, Grzegorz KOWALUK1
WOOD HYDROPHOBIZATION BY AMMONIUM IONIC
LIQUIDS
Strongly hydrophobic ammonium ionic liquids penetrating the wood structure and
protecting solid wood from water absorption were developed. By covering the
surface of wood with ammonium ionic liquid the wood is hydrophobically and
antiseptically protected for a long time. As it was mentioned above, swelling and
water absorption of protected wood is several times less compared to unprotected
wood. The dimensional stability is also improved.
Keywords: wood, ionic liquid, hydrophobization, swelling, water absorption
Introduction
Ionic liquids (IL's) are a class of chemical compounds composed of organic
cations and organic or inorganic anions with melting points below 100°C [Welton 1999; Wasserscheid, Keim 2000; Wasserscheid, Welton 2008; Deetlefs,
Seddon 2010; Dupont et al. 2002; Kichner 2009]. Typically IL's have broad
liquid ranges, low vapour pressures, are thermally stable, and may be noncoordinating as well. They have attracted significant attention due to their potential application in wood preservation [Pernak et al. 2008; Stasiewicz et al. 2008;
Pernak et al. 2004, 2005; Zabielska-Matejuk et al. 2004, 2008].
In this study the properties of one of the ammonium ionic liquids, i.e. didecyldimethylammonium dodecylbenzenesulfonate [DDA][ABS], are presented.
The above-mentioned ionic liquid has been successfully synthesised in high
yields by exchange reaction. The halide anion was replaced by new dodecylbenzenesulfonate anion. The new ionic liquid is solid in the room temperature, but
in 55 degree Celsius it melts and becomes a highly hydrophobic oil. In this form
it can be applied on wood surface.
Mariusz KOT, Poznan University of Technology, Wood Technology Institute, Poznan,
Poland
Grzegorz KOWALUK, Wood Technology Institute, Poznan, Poland
40
Mariusz KOT, Grzegorz KOWALUK
N+
8
8
11
-
O3S
Fig. 1. Didecyldimethylammonium dodecylbenzenesulfonate [DDA][ABS]
Rys. 1. Dodecylobenzenosulfonian didecylodimetyloamoniowy [DDA][ABS]
The aim of the investigation was to verify the possibilities of wood hydrophobization using the ammonium ionic liquid. The investigation included measurement of water absorption by and swelling of solid wood impregnated with the
above-mentioned liquid.
Materials and methods
Didecyldimethylammonium dodecylbenzenesulfonate used in the investigation
is a solid substance when stored in the room temperature and changes to the
liquid state when warmed up to a temperature of 70–90 deg. C in water bath.
Beech wood was used in the tests. 20 samples of the dimensions as in fig. 2
were prepared. The above-mentioned ionic liquid was applied on half of the
samples by immersion. The excess of the liquid was mechanically removed. The
average surface covering was about 80 g/m2. On covering the samples with the
ionic liquid all of them were conditioned at normal conditions (20 deg. C, 65%
R.H.) for 18 hours.
Depth of soaking
Głębokość moczenia
Ionic liquid covering level
Poziom pokrycia cieczą jonową
Fig. 2. The sample used for swelling and water absorption tests
Rys. 2. Próbka do badań spęcznienia i nasiąkliwości
Wood hydrophobization by ammonium ionic liquids
41
Fig. 3. The samples during soaking in water (unprotected samples at the front)
Rys. 3. Próbki podczas moczenia w wodzie (z przodu próbki niezabezpieczone)
The samples were soaked in water at the temperature of 20 deg. C for total
time of 168 hours. During that time successive measurements of the dimensions
and weight were made. The measurement of the dimensions was taken at the 25.
mm of the sample length from the immersed end. The measurements were taken
after 10 min, 30 min, 2 h, 6 h, 24 h, 72 h and 168 h since the immersion was
started. The samples were immersed in water to the depth of 50 mm (fig. 3).
The visual differences between the water absorption of the uncovered (unprotected) samples and the samples covered (protected) with the ammonium ionic
liquid are shown in fig. 4. As it can be seen the most dynamic water uptake can
be observed after the first 10–30 min from the beginning of the test. After 6 h
from the test start the unprotected samples absorbed about 18% mass of water
with the reference to the initial sample weight. At the same time the samples
covered with the ionic liquid took less than 5% mass of water. After about 70–72
42
hours of soaking of the uncovered samples the intensity of the water absorption
process got weaker. In the case of samples covered with the ionic liquid the dynamics of the water uptake was more regular and no changes similar to those
which occurred in the case of unprotected samples were observed. After 7 days
of soaking the total water uptake was over 60% in the case of unprotected samples and about 30% in the case of samples protected with the ionic liquid.
180
25
160
20
water
absorption
Water
absorption [%]
[%]
Nasiąkliwość [%]
[%]
nasiąkliwość
140
120
15
protected
Protected
10
unprotected
Unprotected
100
5
80
0
Zabezpieczone
zabezpieczone
Niezabezpieczone
niezabezpieczone
0
1
2
3
4
5
6
7
60
40
20
0
0
12
24
36
48
60
72
84
96
108
120
132
144
156
168
180
Soaking time
time [h]
soaking
[h]
Czas moczenia [h]
czas
moczenia [h]
Fig. 4. The water absorption of the unprotected samples and the samples protected
with the ionic liquid
Rys. 4. Nasiąkliwość próbek zabezpieczonych i niezabezpieczonych cieczą jonową
The swelling of the uncovered samples and the samples covered with the
ammonium ionic liquid when soaked in water is presented in fig. 5. In comparison with the water absorption dynamics the biggest intensity of the swelling
process could be observed during 2 initial hours of the test. The biggest differences between the intensity of swelling of both types of the samples were observed after 2 h of the test elapsed. Interestingly, in the case of unprotected samples the intensity of swelling decreased asymptotically after about 70–72 hours
of the test, thus at the same time when water absorption decreased as well. After
7 days of soaking the swelling of all the samples (uncovered and covered with
the ionic liquid) was almost the same. It can be pointed out, that the ammonium
ionic liquid reduces water absorption by wood and, what was proved above,
minimises the intensity of swelling of wood.
43
Wood hydrophobization by ammonium ionic liquids
12
Protected
protected
zabezpieczone
Zabezpieczone
unprotected
Unprotected
Swelling
[%][%]
swelling
Spęcznienie
[%][%]
spęcznienie
10
niezabezpieczone
Niezabezpieczone
8
6
5
4
3
2
1
0
6
4
2
0
1
2
84
96
108
3
4
120
132
5
6
7
0
0
12
24
36
48
60
72
144
156
168
180
Soaking time
soaking
time[h][h]
Czas moczenia [h]
czas
moczenia [h]
Fig. 5. The swelling of the unprotected samples and the samples protected with the
ionic liquid
Rys. 5. Spęcznienie próbek zabezpieczonych i niezabezpieczonych cieczą jonową
Conclusions
The research has shown that the investigated ammonium ionic liquid
([DDA][ABS]) significantly minimises water absorption by wood. During the
initial phase of soaking (i.e. after 10 minutes) the absorption by wood impregnated with the above-mentioned ionic liquid was over 6 times less in comparison
with the untreated wood. That difference was getting smaller as the soaking time
lengthened and after 7 days was about 2 times higher to the advantage of wood
protected with the ionic liquid. The biggest difference (over 2.5 times bigger)
between swelling of protected and unprotected wood was observed after about 2
hours of soaking. With time that difference was decreasing asymptotically. After
the whole test (7 days) the swelling of protected and unprotected samples was
almost equal.
Acknowledgements
Development Fund within the framework of the Innovative Economy Operational Programme in Poland in the years 2007–2013, project number
POIG.01.03.01-30-074/08 “Ionic liquids in innovative technologies connected
with processing of lignocellulosic raw materials”.
44
References
Deetlefs M., Seddon K. [2010]: Assessing the greenness of some typical laboratory ionic
liquid preparations. Green Chem. 12: 17–30
Dupont J., de Souza R.F., Suarez P. A. Z. [2002]: Ionic liquid (molten salt) phase organometallic catalysis. Chem. Rev. 102: 3667–3691
Kichner B. (vol. ed) [2009]: Ionic Liquids, Springer-Verlag Berlin, Heidelberg
Pernak J., Jankowska N., Walkiewicz F., Jankowska A. [2008]: The use of ionic liquids
in strategies for saving and preserving cultural artifacts. Polish J. Chem. 82: 2227–2230
in wood preservation. Holzforschung 58: 286–291
Stasiewicz M., Fojutowski A., Kropacz A., Pernak J. [2008]: 1-Alkoxymethyl-X-dimethylaminopyridinium-base ionic liquids in wood preservation. Holzforschung 62: 309–
317
Wasserscheid P., Keim W. [2000]: Selective trimerization of α-olefins with triazacyclohexane complexes of chromium as catalysts. Angew. Chem. Int. Ed. 39: 3772–3789
Wasserscheid P., Welton T. [2008]: Ionic Liquids in Synthesis, Wiley-VCH
Welton T. [1999]: Room-Temperature Ionic Liquids. Chem. Rev. 99: 2071–2084
Zabielska-Matejuk J., Stangierska A., Skrzypczak A. [2008]: Badania aktywności hydrofilowych i hydrofobowych cieczy jonowych w stosunku do grzybów rozkładu szarego
oraz procesów ich sorpcji na glebie. DREWNO-WOOD 2008 [51]179: 5–28
Zabielska-Matejuk J., Urbanik E., Pernak J. [2004]: New bis-quaternary ammonium and
bis-imidazolium chloride wood preservatives. Holzforschung 58: 292–299
HYDROFOBIZACJA DREWNA ZA POMOCĄ AMONIOWYCH
CIECZY JONOWYCH
Streszczenie
Opracowano ciecze jonowe, o charakterze bardzo silnie hydrofobowym, które przenikając do struktury drewna zabezpieczają ją przed wnikaniem wody. Poprzez powierzchniowe naniesienie cieczy jonowej uzyskuje się drewno odporne przez długi czas na
działanie wody oraz posiadające powierzchnię antyseptyczną. Drewno zabezpieczone
w opisany sposób charakteryzuje się kilkakrotnie mniejszą nasiąkliwością i spęcznieniem, jak również mniejszymi odkształceniami, w porównaniu z drewnem niezabezpieczonym.
Słowa kluczowe: drewno, ciecz jonowa, hydrofobizacja, pęcznienie, nasiąkliwość
Dorota FUCZEK, Jadwiga ZABIELSKA-MATEJUK, Juliusz PERNAK,
Weronika PRZYBYLSKA ∗
WETTABILITY OF WOOD SURFACES TREATED
WITH IONIC LIQUIDS
The aim of the research was to measure the wettability of wood surface protected
with three ionic liquids differing in terms of cation and anion structure as well as
fungicidal properties. Herbicidal ionic liquids with functional anion, nitrate(V)
with cation derived from natural coconut oil and ionic liquid with dodecylbenzenesulfonate anion were tested. The investigation was carried out on pine wood
Pinus sylvestris L. The presented results indicate that the ionic liquids containing
12-carbon hydrophobic alkyl chain in their structure, i.e. [DDA][ABS] and
[ArqC35][NO3], worsened wood wettability, thus improved the protection of wood
against water.
Keywords: wettability, contact angle, ionic liquids, wood
Introduction
Microbiological destruction processes of wood caused not only by fungi, but
also by algae, bacteria, insects or marine organisms, can be sufficiently inhibited
or eliminated thanks to preservation of wood with chemicals often aided by
physical treatment, e.g. high temperature processing. Current wood protection,
having no negative consequences for the environment, prefers replacement of
classic preservatives with biodegradable components. Heat treatment of wood,
leading to elimination of nutrients for fungi, increases wood natural resistance to
Dorota FUCZEK, Wood Technology Institute, Poznan, Poland
Jadwiga ZABIELSKA - MATEJUK, Wood Technology Institute, Poznan, Poland
Juliusz PERNAK, Poznan University of Technology, Wood Technology Institute, Poznan,
Poland
Weronika PRZYBYLSKA, Wood Technology Institute, Poznan, Poland
46
Dorota FUCZEK, Jadwiga ZABIELSKA-MATEJUK, Juliusz PERNAK, Weronika PRZYBYLSKA
microbiological decomposition and simultaneously decreases its susceptibility to
damping [Hakkou et al. 2005; Noskowiak 2007]. The hydrophobization effect
together with improved durability can be achieved through modification of wood
with organosilicon compounds [Tinggaut et al. 2005; Gosh et al. 2008; Sèbe,
Brook 2001], synthetic resins [Bach et al. 2005] and other hydrophobic agents.
Fungistatic and fungicidal properties of quaternary ammonium salts and then
ionic liquids have opened those compounds the door to application in wood
preservation [Pernak et al. 2004, 2005; Zabielska-Matejuk 2005]. The consequence of the amphiphilic character of those compounds is their adsorption on
the surface of microorganism cells, which is especially visible in the case of
chemotrophic bacteria that are constituents of water biocenosis and soil. It can
cause their elimination from the environment.
The possibility of ionic liquid structure modification is one of the most precious features of those organic compounds. They facilitate matching of a biologically active structure to a microorganism species and, in the case of an increase in resistance, exchange of the functional group for a more efficient. The
introduction of the hydrophobic alkyl chain (relatively specific anions) into the
ionic liquid structure makes it possible to obtain multifunctional compounds that
are biocidal and able to protect a lignocellulosic conglomerate, such as wood,
against water. This property of ionic liquids makes the process of wood preservation easier, because they lower wettability, hygroscopicity and impregnability
of wood, thus inhibiting colonisation of wood by microorganisms and their
growth in it. The investigation of changes in wettability of wood surface before
and after the treatment with ionic liquids can be a confirmation of the hydrophobic character of protection with those chemicals. The assessment of wood surface wettability can be made on the basis of the measurement of contact angles,
calculation of free surface energy, work of adhesion, and critical surface tension
of wetting [Gray 1962; Gunnells et al. 1994; Liptakowa, Paprzycki 1984; Lis,
Proszyk 2001].
In this study wettability (contact angle) of wood surface protected with three
ionic liquids differing in terms of cation and anion structure as well as fungicidal
properties was investigated. Herbicidal ionic liquids with functional anion, nitrate(V) with cation derived from natural coconut oil and ionic liquid with dodecylbenzenesulfonate anion were tested.
The ionic liquids were developed and synthesised in the Institute of Chemical
Technology and Engineering of the Poznan University of Technology by M. Kot
[Pernak et al. 2009]. Structures of the synthesised compounds were confirmed
by the analysis of 1 H NMR and 13C NMR spectra (Varian 300 VT type spectroscope). The prepared compounds had the form of wax.
Wettability of wood surfaces treated with ionic liquids
47
For the research the following compounds were taken into consideration:
− [Ciech][1] – ionic liquid with didecyldimethylammonium cation and herbicidal anion,
− [DDA][ABS] – didecyldimethylammonium dodecylbenzenesulfonate,
− [ArqC35][NO3] – nitrate(V) with cation derived from natural coconut oil
[Zabielska-Matejuk, Pernak 2009].
The investigation was carried out on Scots pine sapwood Pinus sylvestris L.
of the density of 480–520 kg/m3. The samples’ dimensions were 100 × 50 × 10 mm
(the longer edges were parallel to the fibers). The measurements of contact angle
were performed on samples conditioned at a temperature of 20±1°C and
humidity of 65±2% to a moisture content of 12±1%. The isopropanol solution of
[Ciech][1] and [DDA][ABS] and water solution of [ArqC35][NO3] in the
amount of 50 g pure active substance on m2 of wood were applied using a paint
brush on the sanded surfaces (100 × 50 mm) of tangential and radial section of
the samples. Then the samples were conditioned for 4 weeks in the dishes over a
saturated solution of ammonium nitrate with a moisture content of 12±1%. The
average angle measured between the covered surface and the water drop
remaining on it, called the contact angle, was determined on the basis of
a 10-measurement set (5 measurements on early wood and 5 measurements on
late wood). The average contact angle was determined every second for 60, 180
or 240 seconds (depending on the preservative type and section of wood). For
the purpose of comparison the contact angle for uncovered wood (control
samples) was also measured. For each drop around 5µl of redistilled water of
a temperature of 23±1°C was used.
The measurements were taken using a KSV CAM 101 apparatus.
The highest value of the contact angle was determined for wood with didecyldimethylammonium dodecylbenzenesulfonate. The contact angles of samples protected with [DDA][ABS] remained around the level of 50 deg for over 4 minutes. Wood treated with that ionic liquid demonstrated much better water repellency than in the case of untreated wood and wood treated with other preservatives. Better resistance to water, in comparison with untreated wood, was
obtained also for nitrate(V) with cation derived from natural coconut oil treatment. In the case of [Ciech][1] the water drop applied on the wood surface spilt
and soaked into it immediately. As it is illustrated in fig. the water drop was
absorbed into the protected surface after 2 seconds of measurements.
48
80
[DDA] [ABS]
[ArqC35][NO3]
[Ciech] [1]
Control sample/Próbka kontrolna
70
Kąt zwilżenia
Contact angle
60
50
40
30
20
10
0
0
20
40
60
80
100
120
140
160
180
Time [s]
Czas [s]
Fig. 1. Contact angles determined on the wood radial section
Rys. 1. Kąty zwilżania wyznaczone na przekroju promieniowym
80
Control sample, early wood/Próbka kontrolna, drewno wczesne
Control sample, late wood/Próbka kontrolna, drewno późne
[DDA] [ABS] early wood/[DDA] [ABS] drewno wczesne
[DDA] [ABC] late wood/[DDA] [ABC] drewno późne
[Arq C35][NO3] early wood/[Arq C35][NO3] drewno wczesne
[Arq C35][NO3] late wood/[Arq C35][NO3] drewno późne
70
Kąt zwilżenia
Contact angle
60
50
40
30
20
10
0
0
50
100
150
200
250
300
Time [s]
Czas [s]
Fig. 2. Contact angles determined on the tangent section of the control samples and
the samples treated with [DDA][ABS] and [ArqC35][NO3]
Rys. 2. Kąty zwilżania wyznaczone na przekroju stycznym dla próbki kontrolnej oraz dla
próbek zabezpieczonych [DDA][ABS] i [ArqC35][NO3]
70
Control sample, early wood/Próbka kontrolna, drewno wczesne
Control sample, late wood/Próbka kontrolna, drewno późne
60
[Ciech] [1] early wood/[Ciech] [1 ] drewno wczesne
[Ciech] [1] late wood/ [Ciech] [1] drewno późne
Kąt zwilżenia
50
Contact angle
49
40
30
20
10
0
0
50
Time [s]
100
Czas [s]
Fig. 3. Contact angles determined on the tangent section of the control samples and
the samples treated with [Ciech] [1]
Rys. 3. Kąty zwilżania wyznaczone na przekroju stycznym dla próbki kontrolnej oraz dla
próbki zabezpieczonej [Ciech] [1]
The tested ionic liquids behaved differently depending on whether early or
late wood was concerned. The results presented in fig 4 and fig 5 indicate that
early wood treated with [DDA][ABS] and [ArqC35][NO3] demonstrated better
water repellency than late wood.
However, this difference is much bigger in the case of the tangential section
of wood treated with nitrate(V) with cation derived from natural coconut oil.
Unlike behaviour was observed in the case of unprotected wood, where water
repellency of early wood was smaller than that of late wood on the tangential
section. According to Herczeg [1965] it is hard to draw unequivocal conclusions
whether this phenomenon is a consequence of greater roughness or the
differences in chemical composition of early wood and late wood, such as the
content of extractives. However, it can be assumed that better penetration of the
above-mentioned ionic liquids into early wood can cause its better protection
against water.
Even though both ionic liquids [DDA][ABS] and [ArqC35][NO3] improved
water repellency of wood, the application of the latter can be limited. This limitation is caused by the white marks which occurred after water absorption of the
wood samples. The explanation of this phenomenon can be that nitrate(V) with
cation derived from natural coconut oil is soluble in water.
50
80
70
40
Kąt zwilżenia
Contact angle
50
30
[DDA] [ABS] early wood – tangent section
[DDA] [ABS] drewno wczesne – przekrój styczny
[DDA] [ABS] late wood – tangent section
20
[DDA] [ABS] drewno późne – przekrój styczny
[DDA] [ABS] early wood – radial section
[DDA] [ABS] drewno wczesne – przekrój promieniowy
10
[DDA] [ABS] late wood – radial section
[DDA] [ABS] drewno późne – przekrój promieniowy
0
0
50
100
150
200
250
300
Time [s]
Czas [s]
Fig. 4. The contact angles of early wood and late wood protected with [DDA] [ABS]
depending on the wood section
Rys. 4. Kąty zwilżania drewna wczesnego i późnego zabezpieczonego [DDA][ABS]
w zależności od przekroju
70
[Arq C35][NO3] early wood – tangent section
[Arq C35][NO3] drewno wczesne – przekrój styczny
[Arq C35][NO3] late wood – tangent section
60
[Arq C35][NO3] drewno późne – przekrój styczny
[Arq C35][NO3] early wood – radial section
Kąt zwilżenia
Contact angle
50
[Arq C35][NO3] drewno wczesne – przekrój promieniowy
[Arq C35][NO3] late wood – radial section
[Arq C35][NO3] drewno późne – przekrój promieniowy
40
30
20
10
0
0
50
100
150
200
250
300
Time [s]
Czas [s]
Fig. 4. The contact angles of early wood and late wood protected with [Arq C35]
[NO3] depending on the wood section
Rys. 4. Kąty zwilżania drewna wczesnego i późnego zabezpieczonego [Arq C35 [NO3]
w zależności od przekroju
51
Fig. 5. The average contact angles determined on the radial section
Rys. 5. Średnie kąty zwilżania wyznaczone na przekroju promieniowym
The contact angle, determined by drawing a tangent to the drop at the contact point between the liquid and the solid intersection, is the most direct indicator of wettability. From the practical point of view, this parameter can be very
useful for selection of a proper method for finishing of wood or unfinished
panels. Chemical treatment of wood by different compounds with reactive
groups, especially with polymer, can lead to an increase in the hydrophobic
character of wood, both on its surface and inside it [Bach et al. 2005].
This study demonstrates a possibility of quick assessment of the influence of
ionic liquids on wood wettability using the contact angle measurement. The
presented results indicate the potential of ionic liquids for protection of wood
52
against water, especially of didecyldimethylammonium dodecylbenzenesulfonate which significantly decreases the absorption of water by wood. The contact angle of wood protected with ionic liquids depends on the length of the hydrocarbon chain in their structure. The compounds with a hydrophobic dodecyl
alkyl substituent in the anion of [DDA][ABS] were the most effective in terms
of decreasing the wetting of the treated Scots pine sapwood. The compound
developed from coconut oil [ArqC35][NO3], containing a mixture of hydrocarbon chain ranging from C8 to C14, demonstrated lower wood hydrophobization
ability. The introduction of herbicidal anion into the structure ionic liquids with
didecyldimethylammonium cation caused an increase in the treated wood wettability in comparison with the control wood.
Conclusions
The results presented above lead to the following conclusions:
− the two out of the three tested ionic liquids, i.e. [DDA][ABS] and
[ArqC35][NO3] containing the long hydrocarbon chain, worsened the
wettability of wood, thus improved the protection of wood against water,
− the wood treated with [Ciech][1] had higher wettability than the untreated
wood,
− in the case of wood treated with [DDA][ABS] and [ArqC35][NO3]
significant differences in terms of early wood and late wood wettability on
the tangential section were observed.
Acknowledgements
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53
Hakkou M., Pètrissans M., Bakali E., I., Gèrardin P., Zoulalian A., [2005] : Wettability
changes and mass loss during heat treatment of wood. Holzforschung 59: 35–37
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i obszary ich zastosowania w gospodarce. Wyd. ITD: 325–328
Noskowiak A. [2007]: Modyfikacja drewna. Technologia drewna, wczoraj, dziś, jutro. Studia
i Szkice na Jubileusz Profesora Ryszarda Babickiego. Wyd. ITD: 107–114
Pernak J., Zabielska – Matejuk J., Kropacz A., Foksowicz-Flaczyk J. [2004]: Ionic
liquids in wood preservation. Holzforschung 58: 286–291
Pernak J., Zabielska-Matejuk J., Stangierska A., Kropacz A., Kot M. [2009]: Ammonium ionic liquids in wood preservation. Annals of Warsaw University of Life Science
69: 178–182
Sèbe G., Brook M. A. [2001]: Hydrophobization of wood surfaces: covalent grafting of
silicone polymers. Wood Science and Technology 35: 269–282
Tingaut P., Weigenand O., Militz H., Jèso B., Sèbe G. [2005]: Functionalisation of wood
by reaction with 3-isocyanatopropyltriethoxysilane: Grafting and hydrolysis of the
triethoxysilane and groups. Holzforschung 59: 397–404
Zabielska-Matejuk J. [2005]: Antifungal properties of new quaternary ammonium compounds in relation to their surface activity. Wood Science and Technology [39]3: 235–
243,
Zabielska-Matejuk J., Pernak J. [2009]: Mycological study of ammonium ionic liquids.
Drewno-Wood [52]182:115–121
BADANIA ZWILŻALNOŚCI DREWNA ZABEZPIECZONEGO
POWIERZCHNIOWO CIECZAMI JONOWYMI
Streszczenie
Przedstawiono badania zwilżalności drewna zabezpieczonego powierzchniowo trzema
cieczami jonowymi, o zróżnicowanej strukturze zarówno kationu, jak i anionu oraz
skuteczności działania grzybobójczego. Zbadano „herbicydowe ciecze jonowe” z funkcyjnym anionem, azotan(V) z kationem pochodzenia naturalnego z oleju kokosowego oraz
ciecz jonową z anionem dodecylobenzosulfonowym. Badania wykonano na drewnie sosny
Pinus sylvestris L. Wykazano, iż ciecze jonowe zawierające w strukturze 12-weglowy,
hydrofobowy łańcuch alkilowy [DDA][ABS] oraz [ArqC35][NO3], wprowadzone do drewna
wpływają na pogorszenie jego zwilżalności, a tym samym na zwiększenie jego odporności na
działanie wody.
Słowa kluczowe: zwilżalność, kąt zwilżania, ciecze jonowe, drewno
Iwona FRĄCKOWIAK, Jadwiga ZABIELSKA-MATEJUK, Dorota FUCZEK,
Mariusz KOT∗
APPLICATION OF AMMONIUM IONIC LIQUIDS
IN PARTICLEBOARD TECHNOLOGY
Within the framework of Project no. POIG.01.03.01-30/074/08 “Ionic liquids in
innovative technologies connected with processing of lignocellulosic raw materials” the Wood Based Panels and Glues Department of the Wood Technology Institute in Poznan carried out research aiming at application of ionic liquids in
particleboard technology. The objective of the research was application of
[DDA][NO3] and [BA][NO3] ionic liquids in preservation technology of panels
resistant to biotic factors. The method for application of ionic liquids to particleboards, the type and amount of chosen ionic liquids, as well as their influence on
standard parameters of the panels were investigated. In the tests the amine resin
available on the domestic market and particles obtained from debarked Scots pine
chips were used. The results of the research demonstrated that ionic liquids worsened parameters of the panels, but improved their resistance to decay fungi.
Keywords: particleboard, ionic liquids, decay fungi, mould fungi
Introduction
The term “ionic liquids” refers to salts composed entirely of ions. The most
characteristic features of those salts are: melting point below 100°C, low vapour
pressure, and chemical and thermal stability. Depending on the end use the
Iwona FRĄCKOWIAK, Wood Technology Institute, Poznan, Poland
Mariusz KOT, Poznan University of Technology Wood Technology Institute, Poznan,
Poland,
e-mail :[email protected]
56
Iwona FRĄCKOWIAK, Jadwiga ZABIELSKA-MATEJUK, Dorota FUCZEK, Mariusz KOT
properties of ionic liquids can be adjusted accordingly by altering their anions
and cations.
Recently the interest in application of ionic liquids in wood related industries
has been growing. Ionic liquids are considered to be new generation of solvents
which emit no volatile organic compounds. Extensive research on wood dissolution in ionic liquids and extraction of cellulose from wood waste using ionic
liquids has been carried out [Libert, Heinze 2008]. Kilpelainen et al. [2007] investigated the details of dissolution of wood-based lignocellulosic materials with
ionic liquids. Xie et al. [2007] described effective homogenous chemical modification of wood in ionic liquids. Another interesting application of ionic liquids
can be wood preservation [Pernak et al. 2004, 2005; Zabielska-Matejuk 2005,
2008; Han et al. 2009]. According to Zabielska-Matejuk [2008] some ionic liquids demonstrated good penetration into wood and effective wood protection
against decay, stain or mould fungi. The possibility of modification of the structure of ionic liquids facilitates design of compounds with specific properties
such as for example biocidal activity and the ability to protect wood [ZabielskaMatejuk, Pernak 2009].
Recent developments in the above-mentioned field show great potential of
ionic liquids and might lead to improvement of performance of both wood and
wood composites. Particleboards in common with wood intended mostly for
building industry must be protected from biotic and degradation factors to ensure
their long-term performance. Currently used wood preservatives might be environmentally unfriendly and harmful to human health. Introduction of ionic liquids into wood-based panels technology is aimed at improvement of biological
durability of those materials. The important issue is finding such preservatives
which have not only good fungicidal parameters but also insignificant influence
on glue curing time and board parameters.
The aim of the research was to study the influence of the type, amount and
the method of application of ionic liquids on standard parameters of panels. The
produced panels were also tested for their resistance to Coniophora puteana
fungus after 16 weeks of incubation and to mould fungi. The study involved the
use of [DDA][NO3] and [BA][NO3] ionic liquids.
During the research two types of ionic liquids were selected:
− [DDA][NO3] – didecyldimethylammonium nitrate(V),
− [BA][NO3] – benzalkonium nitrate(V).
The ionic liquids were developed and synthesized in the Institute of Chemical Technology and Engineering of the Poznan University of Technology.
Two methods for application of ionic liquids to particleboards were proposed. The first method consisted in dissolution of ionic liquid in water and
57
Application of ammonium ionic liquids in particleboard technology
pouring of that solution into the particleboard laboratory blender before gluing
of chips. The second method consisted in dissolution of ionic liquid directly in
glue.
One-layer particleboards of the dimensions of 700×500×16 mm were produced from particles made of peeled, pine chips in laboratory conditions. The
nominal density of the panels was 680 kg/m3. As a binding agent ureaformaldehyde resin (molar ratio of formaldehyde to urea 1.10) was used.
All the produced panels were tested for bending strength [PN-EN 310] and
internal bond strength perpendicular to the plane of the board [PN-EN 319].
Table 1. Research variant
Tabela 1. Wariant badań
Sample
Type of ionic liquid
added
Amount of ionic
liquid added
[kg/m3]
Próbka
Rodzaj dodanej cieczy
jonowej
Ilość dodanej
cieczy jonowej
[kg/m3]
0
–
–
A1.1
[DDA][NO3]
4.5
A1.2
[DDA][NO3]
4.5
A2.1
[DDA][NO3]
4.5
A2.2
[DDA][NO3]
9.0
B1.1
[BA][NO3]
4.5
B1.2
[BA][NO3]
4.5
B2.1
[BA][NO3]
9.0
B2.2
[BA][NO3]
9.0
Method of ionic liquid
addition to particleboard
Metoda dodania cieczy
jonowej do płyty wiórowej
–
in water solution
w roztworze wodnym
in glue
w kleju
in water solution
w roztworze wodnym
in glue
w kleju
in water solution
w roztworze wodnym
in glue
w kleju
in water solution
w roztworze wodnym
in glue
w kleju
The resistance to mould fungi was tested using a method based on Building
Research Institute Instruction No. 355/98 [1998]. The tested specimens of particleboards protected with the ionic liquids were of the dimensions of 50 × 50
thickness mm. On reaching the moisture content of 12±1% the samples were
exposed to the action of a mixture of pure cultures of the following fungi: Aspergillus niger v. Tieghem, Penicillum funiculosum Thom, Pecilomyces varioti
Bainer, Trichoderma viride Persoon ex Fries, Alternaria tenuis Link ex Fries
(mixture), or to the action of a pure culture of Chaetomium globosum Kunzefor
58
fungus for 4 weeks. The growth of mycelium on the surface of samples was
measured after 4 weeks of incubation at the temperature of 27±1oC and 90%
relativity humidity using the following scale in accordance with the abovementioned instruction:
0 – no visible under the microscope growth of fungi on the sample,
1 – trace growth of fungi on the sample hardly visible to the naked eye but well
visible under the microscope or visible to the naked eye growth limited to the
edge of the sample,
2 – visible to the naked eye growth of the fungi on the sample, but less than 15%
of the surface is covered with fungus,
3 – over 15% of the surface is covered with fungi visible to the naked eye.
To compare the degree of mould coverage, control boards and the samples of
Scots pine sapwood were tested.
The resistance of tested materials to wood-decaying fungi was defined by
determination of mass loss of the tested samples due to brown rot fungi action,
according to methods based on PN-EN 113 and PN –ENV 12 083 (Basidiomycotina). The particleboard samples of the dimensions of 50 × 30 thickness mm
protected with ionic liquids were sterilised with steam in an autoclave. Then the
samples were exposed to the action of a pure culture of Coniophora puteana
(Schum. ex Fr.) Karst fungus for 16 weeks and mass loss of specimens was determined. It was compared with the mass loss of Scots pine sapwood to calculate
the DSI (Decay Susceptibility Index) expressed as:
DSI = T × 100/S
(1)
where: T – mean loss in board mass [%],
S – mean loss in the mass of the appropriate set of specimens of Scots
pine sapwood [%].
The DSI values of 100 indicate the same decay resistance as that of pine
wood, lower DSI values for particleboards protected with the ionic liquids meant
they proved more resistant to the attack of the fungus.
The results of the internal bond and bending strength measurements done for the
particleboard with the additives of [DDA][NO3] and [BA][NO3] ionic liquids are
presented in fig. 1. Both mentioned ionic liquids worsened the parameters of
particleboards. The bending strength dropped about 44 in relation to the control
board marked “0” when 4.5 kg/m3 of [DDA][NO3] ionic liquid in water solution
was added. Double amount of that ionic liquid also applied in water solution did
not cause further fall in the bending strength. When the same ionic liquid was
added in the amounts of 4.5 and 9 kg/m3 directly to the glue, a smaller but still
59
significant fall in the bending strength was observed. A similar situation was
observed for [BA][NO3], but in that case the ionic liquid decreased the bending
strength by about 30% independently of the application method and the additive
amount. However, the method for [DDA][NO3] application influenced the internal bond of the panels. In that case addition of the ionic liquid directly to glue
was a more preferable method. The way of application of the second ionic
liquid, i.e. [BA][NO3], did not cause as much differences between the values of
the internal bond of the panels. During particleboard production different preservatives can be added to glue, but chips can be treated before gluing as well.
From the practical point of view, according to Drouet [1992], application of
preservatives separately is more beneficial, because it facilitates fast shifting of
production. However, Basturk [2008] draws attention to the fact that the method
of applying chemical solution directly to the dried particles before or after glue
application also has its limitations. The researcher suggests that, due to the moisture content of adhesive, only 5 to 7% of chemical solution should be used for
treatment, otherwise an excessive increase in the moisture content can cause
blisters and delamination during pressing.
The results of mechanical tests presented in fig. 1 and fig. 2 demonstrate
clear influence of ionic liquids selected for this research on the particleboards’
parameters. However, it can be pointed out that, in comparison with didecyldimethylammonium nitrate (V), benzalkonium nitrate (V) affected mechanical
properties of the panels to a smaller extent.
20
Internal bond /Wytrzymałość na rozciąganie
18
Bending strength/Wytrzymałość na zginanie statyczne
16
0,7
14
0,6
12
0,5
10
0,4
8
0,3
6
0,2
4
0,1
2
2
0,8
Bending strength [N/ mm ]
0,9
0
0
0
A1.1
A1.2
A2.1
A2.2
B1.1
B1.2
B2.1
B2.2
Tested panels
Badane płyty
Fig. 1. Bending strength and internal bond of the tested particleboards
Rys. 1. Wytrzymałość na zginanie oraz rozciąganie badanych płyt wiórowych
Wytrzymałość na zginanie statyczne [N/mm2]
2
Internal bond [N/mm ]
Wytrzymałość na rozciąganie [N/mm2]
1
60
2
Modulus of elasticity [N/mm ]
Moduł sprężystości przy zginaniu statycznym [N/mm2]
3000
2700
2400
2100
1800
1500
1200
900
600
300
0
0
A1.1
A1.2
A2.1
A2.2
B1.1
B1.2
B2.1
B2.2
Tested panels
Badane płyty
Fig. 2. Modulus of elasticity of the tested particleboards
Rys. 2. Moduł sprężystości badanych płyt wiórowych
Table 2 presents the resistance of the tested materials to wood-decaying
fungi and the mixture of moulds. Independently of the application method
(in water or in glue), the particleboards protected with [DDA][NO3] ionic
liquids in the amount of 9 kg of dry mass per m3 of the panel demonstrated the
highest resistance to brown rot Coniophora puteana. The decay susceptibility
index (DSI) was 45.6 and 51.8. In the case of application of the same amount of
benzalkonium nitrate(V), i.e. [BA][NO3], the worst protection effect was
obtained. The mass loss caused by the test fungi ranged from 28.3 to 31.5%.
(DSI was from 91.6 to 101.9). After applying a smaller amount of the ionic
liquids to the glue (4.5 kg/m3) the protection against destruction by microorganisms was not achieved. The control samples degradation during the test
was about 40.7%.
The degree of mould coverage of the surface indicates various resistances of
the particleboards with the ionic liquid to the mixture of mould fungi and to
Chaetomium globosum. The method of application and the amount of ionic
liquids introduced into the particleboards did not resulted in complete protection
of their surface against the growth of mould fungi.
Tabela 2. Odporność płyt wiórowych zabezpieczonych cieczami jonowymi na działanie Coniophora puteana po 16 tygodniach inkubacji
oraz na działanie grzybów pleśniowych
Table 2. Resistance of particleboards protected with the ionic liquids to Coniophora puteana after 16 weeks of incubation and
to mould fungi
61
62
Conclusions
On the basis of the obtained results the following conclusions can be drawn:
− Both ionic liquids applied significantly lowered mechanical properties of the
panels. However, in comparison with didecyldimethylammonium nitrate(V),
benzalkonium nitrate(V) affected the panels’ mechanical properties to
a smaller extent.
− The method of application of [DDA][NO3] ionic liquids had essential
influence on the internal bond. In that case, a more preferable method was
addition of the ionic liquid directly to glue. The method of [BA][NO3]
application did not cause as much difference between the values of the
internal bond of the panels as it did in the above-mentioned case.
− There were no significance differences in mechanical properties of the
panels depending on the amount of the ionic liquids applied. A greater
amount of the ionic liquids in particleboards can lead to better protection
against fungi without causing further fall in the internal bond and bending
strength of the panels.
− Independently of the application method (in water or in glue), [DDA][NO3]
ionic liquids in the amount of 9 kg of dry mass per m3 of the panel
demonstrated the highest resistance to brown rot fungi.
Acknowledgements
References
Bastürk A., M. [2008]: Treatment of the wood-based particie type panels to protect against
degradation and fire. KSU Journal of Science and Engineering [11]2: 111–118
Drouet T. [1992]: Technologia płyt wiórowych. Wyd. SGGW, Warszawa
Liebert T., Heinze T. [2008]: Interaction of ionic liquids with polysaccharides. 5 Solvents
and reaction media for the modification of cellulose. Bioresources [3]2: 576–601
Pernak J., Zabielska – Matejuk J., Kropacz A., Foksowicz-Flaczyk J. [2004]: Ionic liquids in wood preservation. Holzforschung 58: 286–291
Han S. H., Li J., Zhu S., Chen R., Wu Y., Zhang X., Yu Z. [2009]: Potential application of
ionic liquids in wood related industries. Bioresources [4]2: 825–834
63
Kilpelainen I., Xie H. B., King A., Granstrom M., Argyropoulos D. S. [2007]: Dissolution
of Wood in Ionic Liquids, J. Agric. Food Chem. [55]22: 9142–9148
Xie H., King A., Kilpelainen I., Granstrom M., Argyropoulos D. S. [2007]:
Thorough Chemical Modification of Wood-Based Lignocellulosic Materials in Ionic Liquids.
Biomacromolecules 8: 3740–3748
Zabielska – Matejuk J., Pernak J. [2009]: Mycological study of ammonium ionic liquids.
Drewno. Pr. Nauk. Donies. Komunik. [52] 182: 115–122
Zabielska-Matejuk J. [2008]: Przedłużanie trwałości drewna i materiałów drewnopochodnych. Gazeta Przemysłu Drzewnego nr 2/12
Zabielska-Matejuk J. [2005]: Antifungal properties of new quaternary ammonium compounds in relation to their surface activity. Wood Science and Technology [39]3: 235–243
List of standards
PN-EN 312 Particleboards– Specifications
PN-EN 310 Wood – based panels – Determination of modulus of elasticity in bending and of
bending strength
PN-EN 319 Particleboards and fiberboards – Determination of tensile strength perpendicular
to the plane of the board
ZASTOSOWANIE CIECZY JONOWYCH W TECHNOLOGII
PŁYT WIÓROWYCH
Streszczenie
W Zakładzie Materiałów Drewnopochodnych i Klejów w ramach Projektu nr
POIG.01.03.01-30/074/08 „Ciecze jonowe w innowacyjnych technologiach związanych
z przetwarzaniem surowców lignocelulozowych” realizowane są badania zmierzające do
zastosowania cieczy jonowych w technologii płyt wiórowych. Celem badań jest wykorzystanie cieczy jonowych w technologiach zabezpieczania płyt na działanie czynników biotycznych. Dotychczasowe badania obejmowały opracowanie sposobu wprowadzania cieczy do
wiórów przeznaczonych do wytwarzania płyt, poznanie wpływu rodzaju i ilości wybranych
cieczy jonowych – [DDA]NO3], [BA][NO3] – na standardowe właściwości. Stosowano klejową żywicę aminową dostępną na rynku krajowym i wióry pozyskane z korowanych zrębków sosnowych. Badania wykazały, że zastosowane ciecze jonowe obniżają właściwości
mechaniczne płyt, poprawiają natomiast ich odporność na grzyby rozkładu brunatnego.
Słowa kluczowe: płyta wiórowa, ciecze jonowe, grzyby rozkładu brunatnego, grzyby pleśniowe
Mariusz OLEKSY, Maciej HENECZKOWSKI, Henryk GALINA,
Katarzyna LECKA-SZLACHTA ∗
THE INFLUENCE OF BENTONITES MODIFIED
WITH QUATERNARY AMMONIUM SALTS
ON BIOCIDAL PROPERTIES OF COMPOSITIONS
OF WATER-DILUTABLE PAINTS AND LACQUERS,
AND MINERAL PLASTERS
The research led to the obtainment of compositions of water-dilutable paints and
lacquers as well as mineral plaster with the additive of nanofiller called Nanobent® (bentonite modified with quaternary ammonium salt) which is a commercial
product of ZGM Zębiec near Starachowice. The resistance of the abovementioned substances to mould fungi Aspergillus niger and Penicillium chrysogenum was tested. The best results were obtained for the composition with 3%
additive of Nanobent ZR2 filler which practically completely inhibited the growth
of mould fungi, even in the presence of whole culture medium containing glucose.
Keywords: acrylic emulsion paint, acrylic lacquer, mineral plaster, bentonite,
quaternary ammonium salt, Nanobent ZR and ZR2, Aspergillus niger,
Penicillium chrysogenum, fungicidal properties
Introduction
Paints, lacquers, mineral plasters and other water-dilutable products are exposed to the attack of bacteria, yeast, and fungi. An environment of high humidity is perfect for growth of those microorganisms. Fungi grow well in conditions
of lower humidity and usually attack the surface of a coating, which phenomenon was described by [Spychaj, Spychaj 1996]. Coating-making materials containing proteins (lecithin, casein or polysaccharides) often used as condensing
Mariusz OLEKSY, Rzeszow University of Technology, Poland
Maciej HENECZKOWSKI, Rzeszow University of Technology, Poland
Henryk GALINA, Rzeszow University of Technology, Poland
Katarzyna LECKA-SZLACHTA, Rzeszow University of Technology, Poland
66
Mariusz OLEKSY, Maciej HENECZKOWSKI, Henryk GALINA, Katarzyna LECKA-SZLACHTA
agents described in the German patent [1990] are especially susceptible to
microorganism attack. Those compositions can be protected by additive of
biocidal agents – bactericides and fungicides. Bactericides are preservatives
which prevent undesired changes in liquid paints, and fungicides deter destruction of dry coating by microorganisms from fungi group. Bacteria may penetrate
into paints during production, filling up and emptying of containers, and during
transport or storage, which was described by [Edge M. et al. 2001; D’Arcy
2001].
Gobbert et al. [2002] observed that in order not only to counteract microorganism action in finished product but also to protect coating made of that product, biological contamination that may occur in technological process should be
eliminated.
The aim of this research was enrich the compositions of emulsion paint,
acrylic lacquer and mineral plaster with bentonite modified with quaternary
ammonium salt of multi-functional action, i.e. simultaneously acting as
a tixotropic agent, condensing agent and fungicidal agent.
Experimental part
Testing of the resistance to microorganisms of the compositions of emulsion
paint, acrylic lacquer and mineral plaster with an additive of modified bentonites
were carried out in accordance with methodology described in line with recommendations of Polish standard PN-EN ISO 846.
The following materials were used in the tests:
1. Salt-agar culture medium without glucose,
2. Salt-agar culture medium with glucose added,
3. Solution of mineral salts,
4. Mould fungus Aspergillus Niger ATCC 16404,
5. Mould fungus Penicillium chrysogenum ATCC 10106,
(materials 1–5 are produced by MERCK Company, Germany)
6. Emulsion paint,
7. Acrylic lacquer,
8. Mineral plaster,
(materials 6–8 are produced by “Śnieżka” Company, seated in Pustynia near
Dębica, they are “raw” products without any tixotropic and biocidal agents
added)
9. Nanofiller Nanobent® ZR1,
10. Nanofiller Nanobent® ZR2,
(materials 9–10 are produced by ZGM “Zębiec” Company in Zębiec near
Starachowice)
11. Finishing plaster by “Nowa Doliny Nidy” Company, Pińczów.
The influence of bentonites modified with quaternary ammonium salts on biocidal properties...
67
The test consisted in exposure of the compositions of emulsion paint, acrylic
lacquer and mineral plasters with the additive of Nanobent (bentonite modified
with quaternary ammonium salt) to mould fungi. The samples were applied on
gypsum discs and exposed to the suspension of mixture of fungal spores in the
presence of whole or deficient culture medium and incubated for a defined time
in specified conditions of temperature and humidity. Each inhibition of growth
on the gypsum disc as well as on the culture medium indicates fungicidal action
of the coating-making substance additive. After the exposure of a sample
finished, the sample was assessed visually in accordance with the scale given in
table 1.
In order to test the resistance of the compositions of paints, water-dilutable
lacquers and mineral plasters to mould fungi, previously prepared gypsum discs
of the diameter of 3 cm and the thickness of 2–3 mm were used. To obtain an
impenetrable surface the discs were twice covered with the adequate tested composition with one-day interval.
Two groups of samples were prepared:
− group 0: control samples inoculated with microorganisms without modified
bentonite added,
− group I: samples inoculated with microorganisms and incubated with the
additive of modified bentonite.
At least five samples from each composition were prepared for visual assessment.
Previously prepared gypsum disc was placed on a sterile Petri dish and the
dish was then filled with culture medium up to the height of about 5 mm. 5 ml of
a solution of mineral salt and wetting agent was added to each sample with culture. The surface of spores’ culture was gently scraped off with a sterile inoculating loop in order to obtain the water suspension of spores. The operation was
repeated three times with the same test tube. Then the suspension of spores of
each culture was mixed with a glass rod and filtered through a thin layer of sterile cotton wool in order to remove fragments of mycelium. Two sterile Petri
dishes were filled with culture medium and inoculated with one drop taken from
each suspension of spores. Incubation was carried out in the temperature of
24ºC ±1ºC in an incubator for 3–4 days.
Using a Pasteur pipette a drop of the spores’ suspension was evenly applied
on the surface of each sample from group I and on agar. The samples were incubated for 4 weeks in an incubator in the temperature of 29ºC±1ºC and humidity
of 95%. If the mycelium growth was visible to the naked eye during the 4-week
incubation period, the test was finished. If the result was not positive, the time of
the test was extended.
68
Table 1. The results of the tests of the resistance of the compositions of emulsion
paint, acrylic lacquer and mineral plaster to the action of mould fungi P. chrysogenum and A. niger after 28 days of incubation (Grades: 0–1 very good result, 2–4
some infected areas occurred, 5–6 negative result)
Tabela 1. Wyniki badań odporności kompozycji farby emulsyjnej, lakieru akrylowego,
tynku mineralnego na działanie grzybów pleśniowych P. chrysogenum i A.niger po 28
dniach inkubacji (Oceny: 0–1 bardzo dobry wynik, 2–4 – istnieją obszary zakażone, 5–6negatywny wynik)
Fungi growth assessment
Ocena wzrostu grzybów
No.
Type of coating used
Lp.
Rodzaj zastosowanej powłoki
On individual samples
min
max
6
6
6
6,6,6,6,6,6
6
6
6
3,3,3,2,2,2
2
3
2.5
6,6,6,6,6,6
6
6
6
3,3,2,2,2,2
2
3
2.3
6,6,6,6,6,6
6
6
6
3,3,2,2,2,2
2
3
2.3
2,2,1,1,1,1
1
2
1.3
1,1,1,0/1,0/1,
0
1
0.75
0/1,1,1,1,1,1
0
1
0.83
0/1,0/1,0/1,0/1,0/1,0/1
0
0
0
6,6,6,6,6,6,6
6
6
6
1,1,1,1,1,1,1
1
1
1
Na poszczególnych próbkach
1
Gypsum
6,6,6,6,6,6
Gips
Average of
6 samples
Średnia
z 6 prób
With the additive of glucose
Z dodatkiem glukozy
2
3
4
5
6
7
Paint without additives
Farba bez dodatków
Paint with 3% Nanobent ZR2
Farba z 3% Nanobent ZR2
Lacquer without additives
Lakier bez dodatków
Lacquer with 3% Nanobent
ZR2Lakier z 3% Nanobent ZR2
Plaster without additives
Tynk bez dodatków
Plaster with 3% Nanobent ZR2
Tynk z 3% Nanobent ZR2
Without the additive of glucose
Bez dodatku glukozy
8
9
10
11
12
13
Paint without additives
Farba bez dodatków
Paint with 3% Nanobent ZR2
Farba z 3% Nanobent ZR2
Lacquer without additives
Lakier bez dodatków
Lacquer with 3% Nanobent ZR2
Lakier z 3% Nanobent ZR2
Plaster without additives
Tynk bez dodatków
Plaster with 3% Nanobent ZR2
Tynk z 3% Nanobent ZR2
In the first place the growth of mould fungi was assessed with the naked eye,
and then, if there was such need, it was verified under the microscope (magnification of 40×). The record of visual assessment results contains photographical
69
documentation. If the results of visual assessment of the samples in one group
differed by more than two scale intervals, the determinations were repeated using new samples.
Analysis and discussion of results
In the first stage of research the resistance of emulsion paint, acrylic lacquer and
mineral plaster without any nanofillers added to mould fungi Aspergillus niger
and Penicillium chrysogenum was tested. Then tests of the compositions with
the additive of Nanobent ZR1 filler were conducted. The resistance of a substratum (gypsum discs) to mould fungi was tested as well. The time of fungi incubation on the tested samples was 28 days on deficient salt-agar culture medium
without glucose and on whole culture medium with glucose added. The obtained
test results are presented in photo 1–7.
As it can be seen in photo 1 (attached) the whole surface of the gypsum disc
was covered by mould fungus Aspergillus niger. In those conditions the gypsum
disc proved to have been a perfect material for fast and effective growth of the
mould fungus. It should be mentioned here, that gypsum absorbs and accumulates humidity well, which results in good comparability of fungi growth in laboratory conditions with the conditions present in practice, which was one of the
reasons why we have decided to use gypsum disc as a substratum. Subsequently
tests of resistance of the composition of emulsion paint without any additive of
filler (so-called control sample – comparative sample) to mould fungus Aspergillus niger were carried out. As it could have been expected, the lack of fungicidal
additives in the emulsion paint contributed to fast growth of the mould fungus.
The whole surface of the gypsum disc with the layer of applied paint was covered by the fungus (photo 1).
The following stage of the tests allowed determination whether introduction
of Nanobent ZR1 into the tested compositions effectively inhibited the growth of
mould fungi. The nanofillers were added to the compositions of emulsion paint,
acrylic lacquer and mineral plaster in the amounts of 1.5% or 3% of the weights.
Photo 2a presents a gypsum disc with emulsion paint containing filler applied on
it. The disc was exposed to mould fungus Aspergillus niger. As it can be seen
that disc was covered by the mould fungus in 90%, which might have been
a result of either penetrable surface of the coating or weak biocidal properties of
the modified bentonite used, and also of conditions created by whole culture
medium which were favourable to the growth of the mould fungus. In photo 2b,
which illustrates the result of incubation for the composition in which the
content of Nanobent ZR1 additive was 3%, it was observed that the addition of
the above-mentioned bentonite had a clear influence on the improvement of
biocidal properties. Around 40% of the disc surface was not infected by the
mould fungus.
70
Photo 1. The appearance of: a – gypsum disc, b – emulsion paint without any
Nanobent added exposed to mould fungus Aspergillus niger on whole culture medium
Fot. 1. Wygląd: a – krążka gipsowego, b – farby emulsyjnej bez dodatku Nanobentu,
w wyniku działania grzyba pleśniowego Aspergillus niger na pożywce pełnowartościowej
Photo 2. The appearance of emulsion paint with 1.5% (a and c) and 3% (b and d)
additive of Nanobent ZR1 on whole culture medium (a and b) and deficient culture
medium (c and d) resulting from exposure to mould fungus Aspergillus niger
Fot. 2. Wygląd farby emulsyjnej z 1,5% (a i c) i 3% (b i d) dodatkiem Nanobentu ZR1 na
pożywce pełnowartościowej (a i b) i niepełnowartościowej (c i d) w wyniku działania grzyba
pleśniowego – Aspergillus niger
71
In the case of emulsion paint composition, in the presence of deficient
culture medium (photo 2 c–d), much better biocidal effect of Nanobent ZR 1
additive against mould fungus Aspergillus niger was observed, even when the
concentration was lower (1.5%). Around 94% of the disc surface was not
infected by mould fungus Aspergillus niger. Only small clusters of the fungus
were visible on the sides and fringes of the disc with the paint coating applied. It
might have been due to penetrable surface resulting from shrinkage cracks
occurred during drying of the composition.
Then the resistance of acrylic lacquer composition to Aspergillus niger
fungus was tested on whole and deficient culture medium. At the start a test of
resistance of the control sample (a disc coated with acrylic lacquer without
additives – photo 3a) was carried out, and then the resistance of the composition
with an additive of Nanobent ZR1 (photo 3b–c) was tested. As it might have
been expected, the lacquer coating without the additive of modified bentonite
was not much resistant to the attack of microorganisms and the whole surface
was covered by the growth of the mould fungus.
Based on the test results presented in photos 3b and 3c it was observed that
the resistance to mould fungus Aspergillus niger in the case of acrylic lacquer
composition with a 1.5% additive of Nanobent ZR1 (photo 3b) on whole culture
medium was unsatisfactory – around 70% of the disc surface was covered by the
mould fungus. A significant improvement of those properties was observed in
the case of composition with a 3% content of Nanobent ZR1 additive (photo 3c),
where areas infected with the mould fungus were present on the surface of the
painted disc only in the amount of ~30%. In the case of testing the acrylic lacquer composition resistance to mould fungus growth in the presence of deficient
culture medium (photo 4.) the growth of that mould fungus was assessed in
accordance with standard to have been 1.3 in the case of a 1.5% additive of
Nanobent ZR1 (photo 4a) and 0.5 in the case of a 3% content of Nanobent ZR1
agent (photo 4b), which was a very good result proving good biocidal properties
of the additive used.
In the following stage of research a control test of resistance of mineral plaster (without any additive of nanofillers) to the mould fungi action was carried
out. As it could have been expected, the test was unsuccessful. The whole
surface of the gypsum disc with the plaster applied was covered by the fungus
(photo 5a). Then the tests of the disc coated with the composition of mineral
plaster with a 2% and a 4% additive of Nanobent ZR1 filler were carried out
(photo 5 b, c and photo 6 a, b).
72
Photo 3. The appearance of: a – acrylic lacquer without the additive of, and
b – with a 1.5% and c – with a 3% additive of Nanobent ZR1 filler as a result of the
action of mould fungus Aspergillus niger on whole culture medium
Fot. 3. Wygląd: a – lakieru akrylowego bez dodatku oraz b – z 1,5% i c – z 3% dodatkiem
napełniacza Nanobent ZR1, jako skutek działania grzyba pleśniowego – Aspergillus niger
na pożywce pełnowartościowej
Photo 4. The appearance of acrylic lacquer with a 1.5% (a) and with a 3% (b) additive of Nanobent ZR1 agent as a result of the action of mould fungus Aspergillus
Niger on deficient culture medium.
Fot. 4. Wygląd lakieru akrylowego z 1,5% (a) i 3% (b) dodatkiem środka Nanobent ZR1 na
pożywce niepełnowartościowej, jako skutek działania grzyba pleśniowego Aspergillus Niger
Based on the obtained test results presented in photos 5 and 6 it was observed that the additive of Nanobent ZR1 agent had clear effect on inhibition of
the growth of the mould fungi. A 1.5% additive of that product (photo 5b) was
the reason why the bigger part of the surface, on which the composition was
applied, was not covered by the fungus. In the case where a 3% additive of the
tested Nanobent filler was added to the mineral plaster composition, a clear increase in inhibition of the fungus growth on the disc surface was visible. In that
73
case only small areas infected with mould fungus Aspergillus niger occurred.
Probably it was a result of local leakiness in the coating applied on the disc.
Photo 5. The appearance of: a – mineral plaster without the additive of, b – with
a 1.5% and c – with a 3% additive of nanofiller Nanobent ZR1 as a result of the
action of mould fungus Aspergillus niger on whole culture medium
Fot. 5. Wygląd: a – tynku mineralnego bez dodatku, b – z 1,5% i c – 3% dodatkiem nanonapełniacza Nanobent ZR1, jako skutek działania grzyba pleśniowego – Aspergillus niger
na pożywce pełnowartościowej
During the tests of the resistance of mineral plaster to the mould fungus on
deficient culture medium (photo 6) a clear inhibition of the mould fungus growth
resulting from addition of Nanobent ZR1 nanofillers to the tested plaster was
observed, and it may be considered a satisfactory result.
Photo 6. The appearance of mineral plaster with a 1.5% (a) and a 3% (b) additive
of Nanobent ZR1 agent as a result of the action of mould fungus Aspergillus niger
on deficient culture medium
Fot. 6. Wygląd tynku mineralnego z 1,5% (a) i 3% (b) dodatkiem środka Nanobent ZR1 na
pożywce niepełnowartościowej w wyniku działania grzyba pleśniowego – Aspergillus niger
74
Photo 7. The appearance of coating made of acrylic lacquer (a), emulsion paint (b)
and mineral plaster (c) with a 3% additive of Nanobent ZR2 nanofiller after incubation of mould fungus Aspergillus niger on whole culture medium
Fot. 7. Wygląd powłoki wykonanej z lakieru akrylowego (a), farby emulsyjnej (b)
i tynku mineralnego (c) z 3% dodatkiem nanonapełniaczy Nanobent ZR2 po inkubacji
grzyba pleśniowego – Aspergillus niger na pożywce pełnowartościowej
The second part of the experiments was devoted to testing of the resistance
of selected compositions to the other mould fungus species, i.e. Penicillum chryzogenum. Based on the obtained test results it was observed that the results of
those tests were identical with the above-described results obtained for the compositions exposed to mould fungus Aspergillus N.
To recapitulate, it may be stated that the results of the tests of the resistance
of the tested compositions containing bentonite Nanobent ZR1 to mould fungi
Aspergillus niger and Penicillum chryzogenum did not allow an unambiguous
confirmation that the additive of that modified aluminosilicate influenced inhibition of the mould fungi growth. Thereby another type of modified bentonite
called Nanobent ZR2, also produced by ZGM Zębiec, seated in Zębiec near
Starachowice, was selected for tests. Due to the fact that the best results were
obtained for a 3% additive of Nanobent ZR1 agent, the same concentration of
the second of the nanofillers was used in further tests. The test results are given
in table 1. Based on the obtained results it was observed that the additive of
Nanobent ZR2 nanofiller to emulsion paint, acrylic lacquer and mineral plaster
has a clear effect on improvement of the tested compositions’ resistance to fungi.
Chosen results are presented in photo 7, in which it can be seen that the whole
surface of the gypsum disc on which coatings of acrylic lacquer, emulsion paint
and mineral plaster containing the additive of Nanobent ZR2 agent were applied,
practically was free from infection with the mould fungus. That resistance was
observed even in conditions as favourable to fungus growth, as they can be on
whole culture medium with the additive of glucose.
It should be mentioned here, that in the case of all samples, where emulsion
paint, acrylic lacquer and mineral plaster containing the additive of Nanobentu
75
ZR2 were used, the results of the tests of the resistance to the action of the
above-mentioned mould fungi were identical.
Conclusions
1. The presence of modified Nanobent nanofillers adds biocidal properties to
the compositions of water-dilutable paints and lacquers, and mineral plasters
in comparison with the above-mentioned compositions without the additive
of modified Nanobent nanofillers.
2. The additive of a product of the trade name Nanobent ZR2 to the compositions of water-dilutable paints and lacquers, and mineral plasters had clearly
better effect on inhibition of the mould fungi growth than the additive of
Nanobent ZR1 product.
References
D’Arcy N. [2001]: Plast. Additives Compoudinng, 12: 95
Edge M., Allen N.S., Turner D., Robinson J., Seal K. [2001]: Prog. Org. Coat. 43: 10
Gobbert Ch., Schichtel M., Nonninger R. [2002]: Farbe u. Lack, 7: 20
Patent niemiecki [1990]: DE 4, 226, 222
Spychaj T., Spychaj S. [1996]: Farby i kleje wodorozcieńczalne. WNT, Warszawa
WPŁYW BENTONITÓW MODYFIKOWANYCH
CZWARTORZĘDOWYMI SOLAMI AMONIOWYMI
NA WŁAŚCIWOŚCI BIOBÓJCZE KOMPOZYCJI FARB
I LAKIERÓW WODOROZCIEŃCZALNYCH
ORAZ TYNKÓW MINERALNYCH
Streszczenie
Celem niniejszej pracy było otrzymanie kompozycji farb i lakierów akrylowych oraz
tynków mineralnych z 1,5 i 3,0 % dodatkiem bentonitów Nanobent ZR1 i ZR2 (bentonitów
modyfikowanych dwiema różnymi IV-rz. solami amoniowymi), które zostały wdrożone do
produkcji w ZGM Zębiec w ramach grantu celowego nr 03933/C ZR7-6/2007. Powłoki
uzyskane z użyciem tych kompozycji zbadano pod kątem odporności na działanie grzybów
pleśniowych Aspergillus niger i Penicillium chrysogenum zgodnie z zaleceniami polskiej
normy PN-EN ISO 846.
76
Zbadano odporność farby emulsyjnej (fot. 1), lakieru akrylowego oraz tynku mineralnego bez dodatku modyfikowanych bentonitów na działanie grzybów pleśniowych: Aspergillus
niger oraz Penicillium chrysogenum. Następnie przeprowadzono badania wpływu dodatku
środka Nanobent ZR1 na zahamowanie wzrostu grzybów pleśniowych w kompozycjach
z farbą i lakierem akrylowym oraz tynkiem mineralnym (fot. 2–6). Zbadano również odporność podłoża (krążków gipsowych) na działanie grzybów pleśniowych (fot. 1).
Ponieważ najlepsze rezultaty uzyskano dla 3% dodatku nanonapełniacza Nanobent ZR1
(fot. 2–6), stąd w dalszych badaniach biobójczej skuteczności środka Nanobent ZR2 stosowano takie samo stężenie. Otrzymane wyniki badań zestawiono w tabeli 2 i na fot. 7. Na ich
podstawie stwierdzono, że najlepsze rezultaty uzyskano dla kompozycji z 3% dodatkiem
produktu Nanobent ZR2, gdzie praktycznie nie zaobserwowano wzrostu grzybów pleśni
pleśniowych, nawet w obecności pożywki pełnowartościowej (z glukozą).
Słowa kluczowe: farba emulsyjna akrylowa, lakier akrylowy, tynk mineralny, czwartorzędowe
sole amoniowe, właściwości biobójcze, Aspergillus niger, Penicillium chrysogenum
DONIESIENIA – REPORTS
Grzegorz KOWALUK,1 Dorota FUCZEK
SCREW HOLDING PERFORMANCE OF PANELS MADE
OF FIBROUS CHIPS
The aim of the research was to investigate the face screw withdrawal resistance of
panels produced from fibrous chips of willow Salix Viminalis L. and black locust
Robinia Pseudoacacia L. A series of laboratory 3-layer panels were produced
from fibrous chips as well as from industrial particles. The results were compared
to commercial industrial panel performance. The investigation shows that the
panels from black locust have lower screw withdrawal resistance in comparison
with the industrial panel. In the case of higher density willow panel the screw
withdrawal resistance was better than that of the industrial panel.
Keywords: particleboard, fibrous chips, screw, withdrawal resistance, SWR,
willow, black locust
Introduction
A lot of research on screw, nail and other joints withdrawal resistance from
wood has been conducted [Eckelman 1975; Aytekin 2008; Taj et al. 2009].
Some of it aim to find the correlation between chosen features of wood and the
screw withdrawal resistance, and other to confirm the validity of those correlations and/or to apply them to other materials. According to Fakopp Enterprise
the bending strength of wooden beams can be determined on the basis of the
screw withdrawal force as well. The correlation coefficient between the screw
withdrawal force and the bending strength (modulus of rupture – MOR) is 0.72,
and between the screw withdrawal force and shear modulus it is 0.86.
Grzegorz KOWALUK, Wood Technology Institute, Poznan, Poland
78
The literature on determination of the screw withdrawal resistance of particleboards is not so numerous. The fundamental work of Eckelman [1975]
proposes the package of formulas on the basis of which the average screw
holding strength of particleboard can be predicted.
Because particleboards made of fibrous chips are rather new and uncommon
type of panels, standard mechanical features of those panels were investigated,
as well as the influence of changes in panel production parameters on the final
product properties [Kowaluk 2009; Kowaluk et al. 2010]. Thus far there have
been no investigations on the screw withdrawal resistance of panels produced
from fibrous chips.
The aim of the research was to investigate the face screw withdrawal resistance of panels produced from fibrous chips of willow Salix Viminalis L. and
black locust Robinia Pseudoacacia L.
The following materials were used in the investigations:
− commercially available 3-layer 16 mm thick particleboards of the density of
645 kg/m3 (hereinafter called: i),
− 3-layer 16 mm thick particleboards of two densities (600 and 660 kg/m3)
produced in laboratory conditions from industrial particles (hereinafter
called: ip600 and ip660),
produced in laboratory conditions from fibrous chips of willow Salix Viminalis L. (hereinafter called: w600 and w660),
produced in laboratory conditions from fibrous chips of black locust Robinia
Pseudoacacia L. (hereinafter called: r600 and r660).
The parameters of the production of fibrous chips and panels as well as the
density profiles and main strength features (bending strength, internal bond and
modulus of elasticity) of the produced panels were set according to Kowaluk et
al. [2010].
The direction of the screw axis/load was perpendicular to the panel’s face
layer. The main dimensions of the screw intended for wood and wood-based
materials used in those investigations were as follows: thread part diameter
4 mm and thread part length 45 mm. The screws were driven through the panel.
The tests were carried out on a testing machine registering the maximum force.
The ANOVA test was performed to investigate statistical significance
of the differences of the results obtained. The assumed significance level was
0.05.
79
Screw holding performance of panels made of fibrous chips
As it is clearly visible in fig. 1, among the investigated panels made of fibrous
chips w660 panel is characterised by the highest SWR. The resistance of w660
panel to screw withdrawal is higher than the SWR of the industrial i panel. The
low value of the screw withdrawal resistance of r660 and r600 panels can be
connected with the low values of the internal bond [Kowaluk et al. 2010]
in those panels. This observation is in accordance with the observation of
Semple and Smith [2006] who found a correlation (r2 > 0.7) between the screw
withdrawal resistance and the internal bond. In the case of panels produced from
fibrous chips (i.e. r660, r600, w660 and w600) the dependence between the
SWR and the panel density can be observed: the SWR increases as the panel
density increases. That observation confirms the conclusion of Eckelman [1975]
that the specific gravity of particleboards is a useful predictor of the joints holding. Another important observation should be pointed out, namely that the type
of particles can influence the SWR. In the case of industrial particles (ip660 and
ip600) the SWR is independent of the panel density, and there are important
differences between the SWRs of panels produced in the same way from fibrous
chips.
1400
1200
Siła [N]
Force [N]
1000
800
600
400
200
0
i
ip660
ip600
r660
r600
Panel type
Rodzaj płyty
Fig. 1. The screw withdrawal resistance of the investigated panels
Rys. 1. Wytrzymałość badanych płyt na wyciąganie wkręta
w660
w600
80
Table 1. Statistical significance of the differences of the SWR mean values
Tabela 1. Statystyczna istotność różnic średnich wartości wytrzymałości na wyciąganie
wkręta
w600
0.00068
0.08282
0.14130
0.50838
0.02307
w660
0.28260
0.16202
0.06993
0.00411
7.25E-06
r600
0.00066
0.02194
0.01942
0.02996
r660
0.00082
0.05726
0.04408
ip600
0.06190
0.82186
ip660
0.10384
i
ip660
ip600
r660
r600
0.00101
w660
In comparison with the results achieved by Joščák et al. [2009] concerning
chipboards and joints for excenters, the investigated panels made of fibrous
chips, even those panels of lower density, are characterised by comparable
SWR.
According to table 1 significant differences of the mean values of the SWR
obtained for the investigated panels can be observed between r600 and the rest
of the panels, i and w600 and r660, ip600 and r660, w660 and r660, w600 and
w660, and the strongest difference can be observed between w660 and r600.
Conclusions
On the basis of the above-mentioned results the following conclusions can be
drawn and remarks made:
1. The screw withdrawal resistance of panels produced from fibrous chips of
black locust Robinia Pseudoacacia L. is lower than in the case of the industrial panel, even when the density of the black locust panel is higher than that
of the industrial panel.
2. There is a significant interrelation between the density of fibrous chip panel
and the screw withdrawal resistance, i.e. the screw withdrawal resistance increases as the panel density increases.
3. There is no significant influence of the panel density on the screw withdrawal resistance in the case of panels produced from industrial particles.
Acknowledgements
This research was carried out with the financial support of the Ministry of
Science and Higher Education in Poland in the years 2007–2010, project number
N 309 1068 33.
Screw holding performance of panels made of fibrous chips
81
References
Aytekin A. [2008]: Determination of screw and nail withdrawal resistance of some important
wood species. Int. J. Mol. Sci. 9: 626–637
Eckelman C. A. [1975]: Screwholding performance in hardwoods and particleboard. For.
Prod. Journal [25] 6: 30–35
Joščák P., Murár R., Katin S. [2009]: Withdrawal strength of fastening means from
wooden materials. Ann. WULS - SGGW, For. and Wood Technol. 68: 339–344
Kowaluk G. [2009]: Influence of the method of milling on the geometry of fibrous chips and
bending strength of produced particleboards. Proc. 3rd Int. Sc. Conf. Woodworking Techniques. Zalesina, Croatia: 323–331
Kowaluk G., Zbieć M., Beer P. [2010]: The quality of milling of the particleboards produced from fibrous chips. Ann. WULS-SGGW, For and Wood Technol. 71
Kowaluk G., Pałubicki B., Pohl P. [2010]: Investigation on drilling of the particleboards
produced from fibrous chips. Proc. of 7th Int. Sc. Conf. Chip and Chipless Woodworking
Processes, Terchová, Slovakia: 111–116
Screw withdrawal resistance meter – users guide. Fakopp Enterprise, www.fakopp.com,
http://www.fakopp.com/site/downloads/Screw_Withdrawal.pdf, opening 05.10.2010
Semple K. E., Smith G. D. [2006]: Prediction of internal bond strength in particleboard from
screw withdrawal resistance models. Wood and Fiber Science [38] 2: 256–267
Taj M. A., Najafi S. K., Ebrahimi G. [2009]: Withdrawal and lateral resistance of wood
screw in beech, hornbeam and poplar. Eur. J. Wood Prod. 67: 135–140
ZDOLNOŚĆ UTRZYMYWANIA WKRĘTA PŁYT
WYTWORZONYCH Z WIÓRÓW WŁÓKNISTYCH
Streszczenie
Przedstawiono wyniki badań zdolności utrzymywania wkręta płyt wytworzonych z nietypowych cząstek drzewnych – wiórów włóknistych. W warunkach laboratoryjnych wykonano
serię trójwarstwowych płyt o różnych gęstościach, z dwóch rodzajów wiórów włóknistych.
Surowcem do produkcji wiórów włóknistych była wierzba Salix Viminalis L. oraz robinia
Robinia Pseudoacacia L. Wykonano również płyty z wiórów przemysłowych. Wyniki zostały porównane z badaniami płyty przemysłowej. Badania wykazały niższą wytrzymałość na
wyciąganie wkręta płyt wytworzonych z wiórów włóknistych z robinii, w porównaniu do
płyty przemysłowej. Płyty o wyższej gęstości z wierzby charakteryzowała istotnie wyższa
wytrzymałość na wyciąganie wkręta niż płyty komercyjne.
Słowa kluczowe: płyta wiórowa, wióry włókniste, wkręt, wytrzymałość na wyrywanie, wierzba,
robinia
KOMUNIKATY – ANNOUNCEMENTS
Grzegorz PAJCHROWSKI1
11. ŚWIATOWA KONFERENCJA INŻYNIERII DREWNA
W czerwcu 2010 roku we Włoszech odbyła się międzynarodowa konferencja poświęcona inżynierii drewna, w której udział wzięło ponad 650 uczestników z całego świata. Liczne referaty oraz postery prezentowały szeroki zakres prac teoretycznych i eksperymentalnych związanych z drewnianymi elementami konstrukcyjnymi, połączeniami, a także całymi konstrukcjami i budowlami.
Słowa kluczowe: inżynieria drewna, łączniki, drewno konstrukcyjne, klasyfikacja, konferencja
W dniach 20–24 czerwca 2010 roku w miejscowości Riva del Garda we Włoszech odbyła się konferencja poświęcona inżynierii drewna pod nazwą World
Conference on Timber Engineering (http://www.wcte2010.org).
W wydarzeniu tym udział wzięło ponad 650 uczestników z całego świata.
Większość z nich pochodziła z krajów europejskich, natomiast najliczniejszą
grupę narodowościową stanowili Japończycy.
Wśród uczestników byli architekci, inżynierowie, naukowcy i inni specjaliści zajmujący się drewnem inżynierskim.
Polska była reprezentowana przez specjalistów Politechniki Wrocławskiej
oraz Instytutu Technologii Drewna w Poznaniu. W konferencji uczestniczyło
również kilkoro Polaków pracujących w zagranicznych jednostkach badawczych.
Delegacja Politechniki Wrocławskiej przedstawiła własne dokonania w zakresie stosowania numerycznych analiz drewnianych belek zbrojonych polimeGrzegorz PAJCHROWSKI, Instytut Technologii Drewna, Poznań, Polska
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Grzegorz PAJCHROWSKI
rami wzmocnionymi włóknem węglowym (CFRP), a także w zakresie wyznaczania parametrów drgań swobodnych belek z różnych gatunków drewna.
Delegacja Instytutu Technologii Drewna omówiła dotychczasowe działania
podejmowane przez Instytut w zakresie klasyfikacji drewna konstrukcyjnego,
dzięki którym polskim klasom sortowania wizualnego przyporządkowano europejskie klasy wytrzymałościowe według normy EN 338.
Prezentowane podczas sesji tematycznych referaty oraz postery obejmowały
bardzo szeroki zakres zagadnień. Najczęściej poruszane tematy były związane
z takimi zagadnieniami jak: łączniki, klasyfikacja drewna konstrukcyjnego, połączenia klinowe i drewno klejone warstwowo oraz konstrukcje drewniane w
rejonach sejsmicznych.
Ze względu na fakt, iż połączenia elementów drewnianych są najsłabszymi
punktami powstających konstrukcji, łącznikom i ich właściwościom wytrzymałościowym poświęcono najwięcej uwagi. Wystąpienia prelegentów dotyczyły
przede wszystkim badań wytrzymałości różnego rodzaju połączeń, poszukiwań
nowych rozwiązań oraz wzmocnień i modyfikacji połączeń obecnie stosowanych.
Odrębną grupę tematyczną stanowiły połączenia klinowe i drewno klejone
warstwowo. Również w tej dziedzinie poszukuje się nowych rozwiązań w celu
poprawy właściwości wytrzymałościowych.
Kilka wystąpień nawiązujących do klasyfikacji drewna konstrukcyjnego dotyczyło różnych aspektów badań wytrzymałościowych konkretnych gatunków
pochodzących z określonego obszaru wzrostu. Ponadto dokonano analizy metod
sortowania drewna zawartych w obowiązujących normach (nie tylko europejskich) i zaproponowano ulepszenia oraz nowe modele pozwalające na uzyskanie
większej ilości sortowanego materiału w wyższych klasach wytrzymałościowych.
Z racji licznego uczestnictwa Japończyków, sporo prezentacji dotyczyło stosowania konstrukcji drewnianych w rejonach sejsmicznych. Były to zarówno
wyniki badań czysto teoretycznych, jaki i analizy skutków rzeczywistych trzęsień ziemi. Podobne omówienia dotyczyły konstrukcji drewnianych w rejonach
narażonych na działanie huraganów.
Ważnym aspektem badań w obszarach różnych zastosowań drewna staje się
szeroko pojęte oddziaływanie na środowisko. Tak jak w wielu innych dziedzinach, obok uwarunkowań ekonomicznych, coraz większą uwagę zwraca się na
aspekty środowiskowe związane z powstawaniem, eksploatacją i późniejszym
zagospodarowaniem odpadów dla drewnianych elementów, konstrukcji i całych
budowli. Jako jeden z przykładów przedstawiono porównawcze badania środowiskowej oceny cyklu życia dla elementów konstrukcyjnych wykonanych
w różnych technologiach.
Bardzo interesujące prezentacje znalazły się w grupie tematycznej dotyczącej dróg i konstrukcji hydrotechnicznych. Uczestnicy konferencji mieli możli-
11. Światowa Konferencja Inżynierii Drewna
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wość poznania konstrukcji mostów zbudowanych w technologii łączenia drewna
z betonem, gdzie elementy drewniane stanowią część konstrukcyjną mostu,
natomiast elementy betonowe część nawierzchniową.
Wśród uczestników konferencji nie brakowało również osób, których badania dotyczyły zagadnień związanych z bezpieczeństwem pożarowym, architekturą i projektowaniem, a także dziedzictwem kulturowym w postaci zabytkowych budowli drewnianych.
Konferencja była znakomitym miejscem wymiany doświadczeń i dyskusji,
a także prezentacji wyników badań naukowych oraz najnowszych osiągnięć
technicznych i konstrukcyjnych.
Kolejna konferencja z tego cyklu odbędzie się w lipcu 2012 roku w Auckland, w Nowej Zelandii (http://www.wcte2012.com).
11th WORLD CONFERENCE ON TIMBER ENGINEERING
Summary
11th World Conference on Timber Engineering was held in Riva del Garda in Italy in June
2010. The conference was attended by over 650 participants from around the world. Poland
was represented by Wroclaw University of Technology and Wood Technology Institute in
Poznan. Numerous papers and posters presented a very wide range of theoretical and experimental work related to the wooden structural elements, joints, and the whole structures and
buildings.
Keywords: timber engineering, joints, structural timber, grading, conference

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