INSTYTUT TECHNOLOGII DREWNA WOOD TECHNOLOGY INSTITUTE DREWNO PRACE NAUKOWE DONIESIENIA KOMUNIKATY WOOD RESEARCH PAPERS REPORTS ANNOUNCEMENTS

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3 INSTYTUT TECHNOLOGII DREWNA WOOD TECHNOLOGY INSTITUTE DREWNO PRACE NAUKOWE DONIESIENIA KOMUNIKATY WOOD RESEARCH PAPERS REPORTS ANNOUNCEMENTS Vol. 54 POZNAŃ 2011 Nr 186

4 Wydanie publikacji dofinansowane przez Ministerstwo Nauki i Szkolnictwa Wyższego The journal is financially supported by Polish Ministry of Science and Higher Educations Recenzenci (Reviewers): prof. dr Levente Dénes, prof. dr hab. Danuta Krutul, mgr inż. Andrzej Noskowiak, dr inż. Grzegorz Pajchrowski, prof. dr hab. Stanisław Proszyk, dr hab. Grzegorz Wieloch, dr hab. Adam Wójciak Publikacje indeksowane są w bazach danych (Publications are indexed in the databases): Science Citation Index Expanded BazTech baztech.icm.edu.pl, DREWINF The Central European Journal of Social Sciences and Humanities W 2010 roku czasopismo znalazło się na tzw. Liście Filadelfijskiej (ISI Master Journal List) z obliczonym Impact Factor (IF). W 2010 roku czasopismo zostało uhonorowane Medalem im. Michała Oczapowskiego. Artykuły polskojęzyczne zawierają streszczenia w języku angielskim, a obcojęzyczne w języku polskim. Spisy treści, streszczenia i pełne teksty artykułów są dostępne na stronie In 2010 the journal was indexed on ISI Master Journal List with calculated Impact Factor (IF). In 2010 the journal was honored with Michał Oczapowski Medal. 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 Wydawca (Publisher): Instytut Technologii Drewna ul. Winiarska 1, Poznań, Polska (Poland) Adres Redakcji (Editor s address): Instytut Technologii Drewna ul. Winiarska 1, Poznań tel. +48/ , +48/ , fax +48/ , office@itd.poznan.pl Copyright by Instytut Technologii Drewna w Poznaniu Poznań 2011 ISSN Projekt okładki (Cover design): Piotr Gołębniak Redaktor (Editor): Edward Grześkowiak Skład komputerowy (Computer typesetting) oraz druk (print): Studio Poligrafia, ul. Bułgarska 10, Poznań, tel Nakład (Edition): 520 egz.

5 SPIS TREŚCI CONTENTS Prace naukowe Research papers Mariusz Jóźwiak, Juliusz Pernak, Mariusz Kot: Protic ionic liquids as a new hardener-modifier system for melamine-urea-formaldehyde adhesive resins (Protonowe ciecze jonowe jako nowe utwardzacze - modyfikatory klejowych żywic melaminowo-mocznikowo-fomaldehydowych)... Xue-Fei Zhou, Jian-Xin Qin, Shu-Rong Wang: Oxidation of a lignin model compound of benzyl-ether type linkage in water with H 2 O 2 under an oxygen atmosphere catalyzed by Co(Salen) (Utlenianie modelowego związku ligniny z typem wiązania benzylowo-eterowego w wodzie z H 2 O 2 w atmosferze tlenu katalizowane Co(Salen))... Ladislav Dzurenda, Kazimierz A. Orlowski: The effect of thermal modification of ash wood on granularity and homogeneity of sawdust in the sawing process on a sash gang saw prw 15-M in view of its technological usefulness (Wpływ modyfikacji termicznej drewna jesionowego na ziarnistość i jednorodność trocin z procesu przecinania na pilarce ramowej wielopiłowej PRW 15-M w aspekcie ich przydatności technologicznej)... Iwona Frąckowiak, Franciszek Warcok, Dorota Fuczek, Cezary Andrzejak: The influence of UF molar ratio on selected particleboard properties (Wpływ stosunku molowego żywicy UF na wybrane właściwości płyt wiórowych)... Agata Stachowiak-Wencek, Włodzimierz Prądzyński: Emission of volatile organic compounds (voc) from waterborne lacquers with different content of solids (Emisja lotnych związków organicznych (VOC) z wodorozcieńczalnych wyrobów lakierowych o zróżnicowanej zawartości ciał stałych) Doniesienia naukowe Research reports Mária Krajčovičová: Determination of bottlenecks in the production of wooden constructions (Określenie wąskich gardeł w produkcji konstrukcji drewnianych)... 65

6 Komunikaty Announcements Weronika Przybylska, Jadwiga Zabielska-Matejuk: Światowy kongres na temat cieczy jonowych Coil-4 (The 4 th congress on ionic liquids)... Kazimierz A. Orłowski: 20. Międzynarodowe seminarium mechanicznej obróbki drewna w Szwecji (20 th international wood machining seminar)... Andrzej Fojutowski, Władysław Strykowski: FTP-C7 session of the European Forest-Based Sector Technology Platform (FTP) in Warsaw (FTP-C7 Obrady Europejskiej Platformy Technologicznej Sektora Leśno-Drzewnego w Warszawie)... Ewa Ratajczak: Early stage researchers from throughout Europe presented their research in forestry-wood sciences (Młodzi naukowcy z całej Europy o wynikach własnych badań z zakresu leśnictwa i drzewnictwa)

7 Drewno. Pr. Nauk. Donies. Komunik. 2011, vol. 54, nr 186 PRACE NAUKOWE - RESEARCH PAPERS Mariusz Jóźwiak, Juliusz Pernak, Mariusz Kot 1 PROTIC IONIC LIQUIDS AS A NEW HARDENER-MODIFIER SYSTEM FOR MELAMINE-UREA-FORMALDEHYDE ADHESIVE RESINS This paper presents the results of investigations on the possibility of using protic ionic liquids as a hardener and modifier of melamine-urea-formaldehyde (MUF) adhesive resins. In research dialkylmethylammonium dodecylbenzenesulfonate base protic ionic liquids with varied amounts of carbon in alkyl group were used. The plywood manufactured using protic ionic liquids and MUF resin was characterized by a complete water resistance of glue lines, thus meeting the requirements of EN standard. Keywords: MUF adhesive resin, protic ionic liquid, modifier-hardener system, plywood Introduction For the curing of adhesive amino resins we use ammonium salts of strong inorganic acids, primarily nitrates, sulfates and chlorides (coming out of use for environmental reasons), inorganic acids (phosphoric acid) and organics (formic acid, oxalic acid), as well as acid anhydrides [Pizzi 1994]. In order to increase hydrolytic resistance of adhesive joints, melamine salts are used [Weinstabl et al. 2001; Zanetti, Pizzi 2003, 2004]. Much research on alternative hardeners that cause viscoelastic dissipation of energy of glue lines and an increase in their resistance to external factors has Mariusz Jóźwiak, Wood Technology Institute, Poznan, Poland m_jozwiak@itd.poznan.pl Juliusz PERNAK, Poznan University of Technology, Poland Juliusz.Pernak@put.poznan.pl Mariusz KOT, Poznan University of Technology,Wood Technology Institute, Poznan, Poland m_kot@itd.poznan.pl

8 6 Mariusz Jóźwiak, Juliusz Pernak, Mariusz Kot been conducted independently [Wang, Pizzi 1997; Proszyk et al. 2002; Pizzi et al. 2002; Zanetti et al. 2002; Kamoun, Pizzi, Zanetti 2003; Zanetti, Pizzi 2004]. In the Wood Technology Institute we have been studying a new generation of multitasking hardener of amino resins. Based on preliminary studies, we have found that ionic liquids can meet these expectations. Ionic liquids are chemical organic compounds composed solely of ions (cation and anion) and having a melting temperature below the boiling point of water [Deetlefs, Seddon 2010; Kichner 2009]. Ionic liquids have been applied in many fields of human activity [Rogers, Seddon 2002; Wasserscheid, Welton 2008]. They have also been broadly used in wood technology, especially in wood preservation [Han et al. 2008; Pernak et al. 2008; Stasiewicz et al. 2008; Pernak et al. 2004, 2005, 2006, 2008; Zabielska-Matejuk et al. 2004; Zabielska-Matejuk 2005]. Ionic liquids are often referred to as designed compounds, and they owe this description to the fact that they offer a possibility of modelling their properties by selecting cation and anion. This creates the possibility of obtaining compounds that, in addition to cross-linking properties, allow the adhesive bond to obtain the desired physical and mechanical properties. From this perspective, it can be interesting to apply protic ionic liquids (PILs). They are a special case of ionic liquids that are synthesised by the transfer of a proton derived from the acid to the free electron pair on the nitrogen atom present in the amine [Welton 1999]. This paper presents the results of conducted research on the usefulness of dialkylmethylammonium dodecylbenzenesulfonate base protic ionic liquids as a hardener-modifier system for melamine-urea-formaldehyde adhesive resin. Materials and methods General procedure for synthesis of protic ionic liquids All reagents were purchased from a commercial source (Sigma-Aldrich) and used as received mol of tertiary amine was dissolved in 100 cm 3 of methanol and then 0.05 mol of dodecylbenzenesulfonic acid (70%) was added. The solution was stirred at cool bath in 20 o C for 30 min. Methanol was then removed in vacuum. Next, in order to obtain hydrophobic ionic liquids, water (50 cm 3 ) was added to the raw product and then the mixture was shaken. The mixture was stirred for an additional 30 min. After the separation of phases, the organic phase was washed with 10 cm 3 of distilled, cold water until free amine was no longer detected. Water was then removed and the residue was dried at 50 o C in vacuum. In this research PILs with alkyl substituent of the following amounts of carbon were used: 4 (butyl C 4 H 9 ), 6 (hexyl C 6 H 13 ), 8 (oktyl C 8 H 17 ), 10 (decyl C 10 H 21 ). PILs were developed and synthesised in the Institute of Chemical Technology and Engineering, Poznan University of Technology.

9 Protic ionic liquids as a new hardener-modifier system for melamine-urea-formaldehyde adhesive resins 7 R = C n H 2n+1 where n = 4, 6, 8, 10 Fig 1. Reaction of synthesis of protic ionic liquids Rys.1. Reakcja syntezy protonowych cieczy jonowych MUF resin In our studies we applied MUF resins condensed on a lab scale for the molar ratio of formaldehyde : melamine : urea as follows 3.8 : 1.0 : 1.0. The condensation was a three-stage process performed at a temperature of 82 ± 2 C and 0.2 mole of urea was additionally condensed in the third stage. Condensation was carried out to water tolerance in the range of %. Polycondensate was not distilled. The synthesis details are presented hereinbefore [Jóźwiak, Proszyk, Jabłoński 2003]. The resins were stored at a temperature of 20 ± 2 C. The basic physicochemical properties of the resin were determined using the following methodologies: apparent viscosity using Emil rotational viscometer in accordance with PN-92/C-89402, content of dry mass according to DIN EN 827 (weighed sample 2.0 ± 0.1 g was dried in a thermal chamber with natural air circulation, at 120 ± 1 C for 120 ± 1 min), ph applying ph-meter with combined electrode, according to PN-ISO 1148, gel time at 100 C, according to BN 75/ , free formaldehyde content by sulphite method, according to DIN EN The MUF resin was characterised by the following basic properties: apparent viscosity of 35 mpa. s, solid content 52.3%, ph value 9.48, gel time at 100 C 103 s, and free formaldehyde content 0.76 %. Preparation of glue mixtures To arrive at the technological conditions that are necessary for the appropriate bonding of adhesives, the viscosity of polycondensate was increased by adding potato starch to the amount of 5% of solid mass of the resin, thus obtaining a viscosity of 2100 ± 100 mpa. s. The gelatinization process was carried out in a water bath at 80 ± 2 C. Then protic ionic liquids in the amount of 20% of solid mass of the resin were added. For control purposes, the glue mixtures hardened with solid NH 4 NO 3 to the amount of 3.2% of solid mass of the resin were prepared.

10 8 Mariusz Jóźwiak, Juliusz Pernak, Mariusz Kot The gel time at 100 C for the glue mixture (without starch) was determined independently according to the BN 75/ standard. Preparation and test of plywood The glue mixtures were spread in a quantity of 180 g/m 2 on the surfaces of beech veneer. Three-layered plywood in the form of mm sheets that were 1.8 mm thick (moisture content of veneer 6 ± 1% was glued after 40 min assembly time with the use of a laboratory press in the following conditions: unit pressure 1.8 MPa, temperature 125 ± 2 C and time 10 min. The plywood was prepared for selected variants (PIL-butyl and PIL-decyl) after 1 day and 30 days after application of the glue mixtures. The plywood was produced using the same pressing parameters. All plywood types were conditioned for 7 days in standard atmosphere, i.e. temperature of 23 ± 2 C and relative humidity of 50 ± 5%. Then samples were cut to determine the shear strength (R t ) of the adhesive glue line of the plywood in accordance with the EN standard. Before determining the shear strength of the bonds, the samples were subjected to hydrothermal treatments in accordance with item (24 h soaking in water at a temperature of 20 ± 3 C) and (4 h boiling in water as well as 16 h drying in air at a temperature of 60 ± 3 C and 4 h boiling in water and cooling in water to a temperature of 20 ± 3 C) of the EN314-1 standard. All the samples were tested wet in a Schopper testing machine at loads up to 500 dan. Rupture of the samples occurred within 30 ± 10 s. After shear tests, the samples were dried and the percentage share of the bond surface covered with wood fibers, i.e. wood failure (WF), was determined by comparing the pictures of bond damage with those presented in the EN standard. Results The results of research on the application of protic ionic liquids in plywood manufacturing technology are summarised in tables 1 and 2 and illustrated in fig. 2 and 3. The gel time at 100 C of the adhesive glue mixtures ranged from 287 s (PIL-butyl group) to 540 s (PIL-decyl). During the test a strong foaming of the adhesive mixtures was observed. A cured adhesive was characterised by relatively high flexibility (low hardness) compared to the control variant. Organoleptic assessment indicated that the adhesive could be modified under the influence of PIL. The gel time of PIL-cured adhesive masses was from 3 to 6 fold higher compared with the control hardener NH 4 NO 3 (gel time 96 s) used. For these reasons, the plywood pressing time was set at 10 min.

11 Protic ionic liquids as a new hardener-modifier system for melamine-urea-formaldehyde adhesive resins 9 Table 1. Shear strength and wood failure of three-layer beech plywood with MUF resin hardened with PILs with different amounts of carbon in alkyl group after tests according to EN standard Tabela 1. Wytrzymałość na ścinanie i udział ścięcia próbki w drewnie trzywarstwowych sklejek bukowych po testach według EN uzyskanych z żywicy MUF utwardzanej protonowymi cieczami jonowymi z różną liczbą atomów węgla w grupie alkilowej Shear strength and wood failure of plywood after tests according to EN Wytrzymałość na ścinanie i udział ścięcia próbki w drewnie po testach wg EN Type of test Rodzaj testu item IF-20 item AW-100 Basic statistics Statystyki podstawowe x max. x avg. x min. δ n-1 ν WF x max. x avg. x min. δ n-1 ν WF Unit Miano MPa % MPa % Hardener type Typ utwardzacza Alkyl group in PILs Grupa alkilowa w protonowej cieczy jonowej Control Kontrolny C 4 H 9 C 6 H 13 C 8 H 17 C 10 H 21 NH 4 NO x max. maximum, x avg. average, x min. minimum, δ n-1 standard deviation, ν variation coefficient, WF wood failure x max. maksimum, x avg. średnia, x min. minimum, δ n-1 odchylenie standardowe, ν współczynnik zmienności, WF zniszczenie w drewnie The effect of the size of the alkyl group in cation in PIL on the reactivity mass of the MUF adhesive resin is presented in fig. 2. It can be observed that with an increase in the number of carbon atoms in alkyl group, the reactivity of the adhesive mass decreased to increase the gel time. The relationship was linear with a high correlation coefficient (r 2 = 0.972). This phenomenon can be explained by the increase in the length of the alkyl chain which causes a decrease in proton mobility and greater steric barriers. These factors may influence a decrease in the reactivity of the adhesive mass.

12 10 Mariusz Jóźwiak, Juliusz Pernak, Mariusz Kot Table 2. The effect of assembly time on shear strength and wood failure of three-layer beech plywood with MUF resin hardened with PILs with different amounts of carbon in alkyl group after tests according to EN standard Tabela 2. Wpływ roboczego czasu klejenia na wytrzymałość na ścinanie i udział ścięcia próbki w drewnie trzywarstwowych sklejek bukowych po testach według EN uzyskanych z żywicy MUF utwardzanej protonowymi cieczami jonowymi z różną liczba atomów węgla w grupie alkilowej Shear strength and wood failure of plywood after tests according to EN Wytrzymałość na ścinanie i udział ścięcia próbki w drewnie po testach wg EN Hardener type Typ utwardzacza Alkyl group PILs Grupa alkilowa w protonowej cieczy jonowej Control Kontrolny C 4 H 9 C 10 H 21 NH 4 NO 3 Assembly time (days) Roboczy czas klejenia (dni) Type of test Rodzaj testu p AW-100 Basic statistics Statystyki podstawowe x max. x avg. x min. δ n-1 ν WF Unit Miano MPa % x max. maximum, x avg. average, x min. minimum, δ n-1 standard deviation, ν variation coefficient, WF wood failure x max. maksimum, x avg. średnia, x min. minimum, δ n-1 odchylenie standardowe, ν współczynnik zmienności, WF zniszczenie w drewnie 1 40 min 2 after 30 days waterproof plywood was not achieved po 30 dniach nie uzyskano sklejki wodoodpornej The properties of beech plywood are presented in tables 2, 3 and illustrated in fig. 3. The plywood types were characterised by very high quality waterproof glue lines. No effect of the size of the alkyl group on waterproof glue lines was observed. Rt values were similar and ranged from 2.39 MPa (PIL-butyl) to 2.73 MPa (PIL-hexyl). Slightly higher values of WF were obtained for hexyl and octyl substituents. The results were similar to those obtained using NH 4 NO 3 as a hardener (control plywood). The plywood fulfilled the requirements of the EN standard in terms of strength and water resistance of glue lines, regardless of PILs used. The effects of assembly time on the quality of beech plywood are given in table 2. We managed to obtain waterproof plywood for variants seasoned for 1 day and 30 days, produced using glue with PIL modifiers. However, in the case of control plywood we did not achieve waterproof glue lines after 30 days.

13 Protic ionic liquids as a new hardener-modifier system for melamine-urea-formaldehyde adhesive resins11 Fig. 2. Gel time at 100 C for MUF resins cured with PILs with different amounts of carbon atoms in alkyl group Rys. 2. Czas żelowania w 100 C żywic MUF utwardzanych protonowymi cieczami jonowymi z różną liczbą atomów węgla w grupie alkilowej Fig.3. Shear strength (Rt) and wood failure (WF) of three-layer beech plywood with MUF resin hardened with PILs type with different amounts of carbon in alkyl group after tests on an IF-20 and AW-100 item and according to EN standard Rys.3. Wytrzymałość na ścinanie (Rt) i udział ścięcia próbki w drewnie (WF) trzywarstwowych sklejek bukowych po testach IF-20 and AW-100 p and według EN uzyskanych z żywicy MUF utwardzanej protonowymi cieczami jonowymi z różną liczbą atomów węgla w grupie alkilowej

14 12 Mariusz Jóźwiak, Juliusz Pernak, Mariusz Kot To sum up, based on the results of the tests it can be concluded that PILs are fully useful in plywood manufacturing technologies using MUF resins. They are interesting compounds, fulfilling the function of modifier and/or hardener of MUF resin: a phenomenon which has as yet not been described in literature. The relatively low reactivity of studied PILs may be increased by the use of a combined hardener, i.e. ionic liquid/lewis acid. Gluing plywood for up to 30 days indicates a strong possibility of modelling the process and the technology of bonding. Studies have proved that there is great potential in the application of protic ionic liquid as hardeners-modifiers. It seems purposeful to conduct further research on the use of PILs in wood material technology. The method of synthesis of protic ionic liquids and their use as a modifier of adhesive amine resins has been submitted for patent protection. Summary Based on the research conducted, it was found that dialkylmethylammonium dodecylbenzenesulfonate base protic ionic liquids made a whole hardener of MUF resins that could simultaneously perform the function of a modifier, plasticizing the adhesive glue line. The plywood types obtained were characterised by very high water resistance and quality of adhesive bonding. They met the requirements of EN standard, for class 3 of gluing quality. The application of protic ionic liquids as amino resin glue hardeners would expand technological capabilities in plywood manufacturing. Acknowledgements This investigation received financial support from project POIG /08 Ionic liquids in innovative technologies connected with the processing of lignocellulosic raw materials co-financed by the European Regional Development Fund under the Innovative Economy Operational Program References Deetlefs M., Seddon K. [2010]: Assessing the greenness of some typical laboratory ionic liquid preparations. Green Chem. 12: 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: Jóźwiak M., Proszyk S., Jabłoński W. [2003]: Adhesive melamine-urea-formaldehyde resins modified with natural alkyloresorcinols. Drewno-Wood [46]: Kamoun C., Pizzi A., Zanetti M. [2003]: Upgrading melamine-urea-formaldehyde polycondensation resins with buffering additives. I. The effect of hexamine sulfate and its limits. J. Appl. Polym. Sci. [90] 1:

15 Protic ionic liquids as a new hardener-modifier system for melamine-urea-formaldehyde adhesive resins13 Kichner B. [2009]: Ionic Liquids. Springer-Verlag Berlin, Heidelberg Pernak J., Zabielska-Matejuk J., Kropacz A., Foksowicz-Flaczyk J. [2004]: Ionic liquids in wood preservation. Holzforschung 58: Pernak J., Goc I., Fojutowski A. [2005]: Protic ionic liquids with organic anion as wood preservative. Holzforschung 59: Pernak J., Śmiglak M., Griffin S. T., Hough W. L., Wilson T. B., Pernak A., Zabielska- -Matejuk J., Fojutowski A., Kita K., Rogers R. D. [2006]: Long alkyl chain quaternary ammonium-based ionic liquids and potential applications. Green Chemistry 8: 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: Pizzi A. (1994): Advanced wood adhesive technology. Marcel Dekker Inc. New York Pizzi A., Beaujean M., Zhao C., Properzi M., Huang Z. [2002]: Acetal-induced strength increases and lower resin content of MUF and other polycondensation adhesives J. Appl. Polym. Sci. [84] 13: Proszyk S., Krystofiak T., Jóźwiak M, Lis B. [2002]: Investigations on the strength and durability of glue lines from MUF adhesives at various loading. Proc. of IV th Inter. Symp. Composite wood materials. TU Zvolen: Rogers R. D., Seddon K. R. [2002]: Ionic liquids: Industrial applications for Green Chemistry. Oxford University Press, New York Stasiewicz M., Fojutowski A., Kropacz A., Pernak J. [2008]: 1-Alkoxymethyl-X-dimethylaminopyridinium-base ionic liquids in wood preservation. Holzforschung 62: Wang S., Pizzi A. [1997]: Waste nylon fibre hardeners for improved adhesives water resistance. Holz a. Rohu.Werkst. [55] : 9195 Wasserscheid P., Welton T. [2008]: Ionic liquids in synthesis, Wiley-VCH Welton T. [1999]: Room-temperature ionic liquids. Chem. Rev. 99: Weinstabl A., Binder W.H., Gruber H., Kantner W. [2001]: Melamine salts as hardeners for urea formaldehyde resins J. Appl. Polym. Sci. [81] 7: Zabielska-Matejuk J. [2005]: Antifungal properties of new quaternary ammonium compounds in relation to their surface activity. Wood Science and Technology [39]3: Zabielska-Matejuk J., Urbanik E., Pernak J. [2004]: New bis-quaternary ammonium and bis-imidazolium chloride wood preservatives. Holzforschung 58: Zanetti M., Pizzi A., Beaujean M., Pasch H., Rode K., Dalet P. [2002]: Acetals-induced strength increase of melamine-urea-formaldehyde (MUF) polycondensation adhesives. II. Solubility and colloidal state disruption J. Appl. Polym. Sci. [86] 8 : Zanetti M., Pizzi A. [2003]: Upgrading of MUF polycondensation resins by buffering additives. II. Hexamine sulfate mechanisms and alternate buffers J. Appl. Polym. Sci. [90] 1: Zanetti M., Pizzi A. [2004]: Low addition of melamine salts for improved melamine-ureaformaldehyde adhesive water resistance J. Appl. Polym. Sci. [88] 2:

16 14 Mariusz Jóźwiak, Juliusz Pernak, Mariusz Kot PROTONOWE CIECZE JONOWE JAKO NOWE UTWARDZACZE - MODYFIKATORY KLEJOWYCH ŻYWIC MELAMINOWO-MOCZNIKOWO-FOMALDEHYDOWYCH Streszczenie Do utwardzania klejowych żywic aminowych stosowane są sole amonowe silnych kwasów nieorganicznych (głównie azotany), siarczany, chlorki (wychodzące z użycia ze względów ekologicznych), kwasy nieorganiczne oraz organiczne, a także bezwodniki kwasowe. W celu zwiększenia odporności hydrolitycznej spoin klejowych stosuje się sole melaminy. W wielu ośrodkach naukowych prowadzone są badania nad uzyskaniem alternatywnych utwardzaczy, powodujących uplastycznienie i zwiększających odporność spoiny na działanie czynników zewnętrznych. W Instytucie Technologii Drewna w Poznaniu, w ramach Projektu nr POIG /074/08 Ciecze jonowe w innowacyjnych technologiach związanych z przetwarzaniem surowców lignocelulozowych, prowadzone są badania nad zastosowaniem cieczy jonowych do utwardzania modyfikacji klejowych żywic melaminowo-mocznikowo-formaldehydowych. Celem badań było sprawdzenie przydatności protonowych cieczy jonowych jako utwardzaczy modyfikatorów klejowych żywic MUF. Do badan wytypowano protonowe dodecylbenzosulfoniany dialkilometylamoniowe, zaliczane do protonowych cieczy jonowych. Poszczególne ciecze różniły się liczbą węgli w grupie alkilowej. Wytworzono trzywarstwowe sklejki bukowe utwardzane zastosowanymi protonowymi cieczami jonowymi. Na podstawie przeprowadzonych badań stwierdzono, że zastosowane protonowe ciecze jonowe stanowią pełnowartościowe utwardzacze żywic MUF, mogące wypełniać równocześnie funkcję modyfikatora - plastyfikatora spoiny klejowej. Zastosowanie protonowych cieczy jonowych jako utwardzaczy klejowych żywic aminowych poszerza możliwości technologiczne w zakresie wytwarzania sklejki. Uzyskane sklejki charakteryzowały się bardzo wysoką wodoodpornością spoin klejowych i spełniały wymagania EN Słowa kluczowe: żywica klejowa MUF, protonowa ciecz jonowa, system modyfikator-utwardzacz, sklejka

17 Drewno. Pr. Nauk. Donies. Komunik. 2011, vol. 54, nr 186 Xue-Fei Zhou, Jian-Xin Qin, Shu-Rong Wang 1 OXIDATION OF A LIGNIN MODEL COMPOUND OF BENZYL-ETHER TYPE LINKAGE IN WATER WITH H 2 O 2 UNDER AN OXYGEN ATMOSPHERE CATALYZED BY Co(Salen) The catalytic properties of Cobalt salen? complex in the oxidation of a lignin model compound [veratrylglycerol-β-guaiacyl-α,γ-dimethylether, VGD] have been investigated in order to obtain the mechanistic aspects of the reaction between Co(salen) and VGD under an oxygen atmosphere using hydrogen peroxide as an oxidant. VGD was found to undergo structural changes in response to the catalytic reaction as characterised by different analytical techniques (FT-IR, H-1 NMR and GC-MS), yielding 2-methoxy phenol and biphenyl. A mechanism for the oxidation of VGD was postulated. Keywords: catalytic oxidation, veratrylglycerol-β-guaiacyl-α,γ-dimethylether (VGD), Co(salen), FTIR, H-1 NMR, GC-MS Introduction Salen complexes are known to be an important class of coordination compounds that have been used to catalyse an extremely wide variety of reactions over the past decades since 1933 [Pfeiffer et al. 1933]. Many of these reactions are oxidations of organic substrates, based on the use of terminal oxidants such as molecular oxygen and hydrogen peroxide. Besides being environmentally more benign, the catalytic oxidation of organic compounds with O 2 and H 2 O 2 is less wasteful from an economic point of view, and is now an important reaction in both research laboratories and industry [Meyer, Limberg 2007]. Metal salen compounds Xue-Fei ZHOU, Kunming University of Science and Technology; South China University of Technology, Guangzhou; Nanjing University of Technology; Beijing University of Chemical Technology; Southwest University of Science and Technology, Mianyang, China lgdx602@tom.com Jian-Xin QIN, Kunming University of Science and Technology, China Shu-Rong WANG, Zhejiang University, Hangzhou, China. srwang@zju.edu.cn

18 16 Xue-Fei Zhou, Jian-Xin Qin, Shu-Rong Wang have been investigated as catalysts in several different reactions, for example in epoxidation, epoxide ring opening, carbonyl addition, cycloaddition and the oxidation of sulphides to sulphoxides [Larrow, Jacobsen 2004]. Previous work on Co(salen)-catalyzed O 2 -oxidation of p-substituted phenols to p-benzoquinones has been extended to include substrates that serve as models for lignin phenolic subunits [Salanti et al. 2010]. Lignin is an aromatic, amorphous, heterogeneous polymer that represents the second most abundant natural polymeric material on Earth [Lebo Jr et al. 2001]. It is known that the bulk of lignin in wood consists of nonphenolic aryl-glycerol-β-o-aryl ether units. Other units, such as phenylcoumaran (β-5), resinol (β-β), and dibenzodioxocins(5-5/β-o-4, α-o-4) are also present within the lignin macromolecule [Ralph et al. 2000]. Furthermore, lignin is usually covalently linked to carbohydrates forming a refractory lignin-carbohydrate network [Lowoko et al. 2003]. Our laboratory has been investigating the mechanism of Co(salen) catalysed oxidation of lignin using isolated lignins and some model compounds as substrates. In this context, we studied the oxidation of another lignin model compound with special linkage of benzyl-ether type (VGD) as a substrate, using Co(salen) complex as a catalyst to mimic lignin peroxidase. The mechanism of oxidation of such a lignin model compound, using Co complexes as catalysts, is largely unstudied. In the present study, the oxidation of VGD can provide us with information on the reactivity of both the model compound and lignin itself, and assist in the development of new catalysts for environmentally-friendly pulp bleaching processes. Materials and methods Synthesis of cobalt salen complex Ligand for the complex was synthesised using the standard method [Jacobsen 1993]. Cobalt complex was synthesised by refluxing an EtOH solution of the ligand and 2 eq. of Co(OAc)2 4H 2 O for 1 h (scheme 1), adding water and filtering out the product. Scheme 1 Schemat 1 The product was washed successively with water and 80% EtOH. Brownish- -black powder was then obtained under vacuum drying, yield %. Typical characteristic absorption peaks were found with FTIR as follows: C-H stretching vibration ( cm -1 ), C=N stretching vibration [1635 cm -1 ], C=C stretching

19 Oxidation of a lignin model compound of benzyl-ether type linkage in water with H 2 O vibration in aromatic ring (1610, 1577, 1498 cm -1 ), C-H bending vibration (1373 cm -1 ), C-O in Ar-O bending vibration (1284 cm -1 ), C-N stretching vibration (1200, 1149 cm -1 ), Co-N stretching vibration (568 cm -1 ), Co-O stretching vibration (470 cm -1 ). Synthesis of veratrylglycerol-β-guaiacyl-α,γ-dimethylether (VGD) Guaiacylglycerol-β-guaiacyl (GG) was basically prepared following the procedure proposed by Hosoya et al. [Hosoya et al. 1980], except for cupric bromide being used instead of Br 2 for the preparation of ω-bromo acetoguaiacone from acetoguaiacone [King, Ostrum 1964; Fukagawa et al. 1992]. GG was methylated fully with methyl iodide in anhydrous methyl sulfoxide (DMSO) in a nitrogen atmosphere according to Hakomori method [Hakomori 1964]. See scheme 2. Typical characteristic absorption. Scheme 2 Schemat 2 Peaks of VGD were found in FTIR and H-1 NMR spectra as follows (fig. 2, 3): C-H vibration in aromatic ring (3030 cm -1 ), C-H vibration in CH 3 -, CH 2 -, CH- (2937 cm -1 ), C-H vibration in -CH 2 - (2841 cm -1 ), C=C vibration in aromatic ring (1595, 1503, 1456 cm -1 ), C-H vibration in CH 3 - (1369 cm -1 ), C-O vibration in β-o-4 linkage (1258 cm -1 ), C-H stretching in aromatic ring (1147 cm -1 ), C-O- -C at α, γ-position (1076 cm -1 ), C-H stretching in aromatic ring (1031, 951, 815 cm -1 ); H-Ar ( ppm), H-β ( ppm), H-α ( ppm), 3-OCH 3 and 4-OCH 3 ( ppm), 3 -OCH3 ( ppm), H-γ ( ppm), α-och 3 and γ-och 3 ( ppm). Oxidation of VGD 30 mg of VGD, 2 mg of catalyst, and 0.48 mg of pyridine were taken in a glass reactor. 0.6 ml of 30% H 2 O 2 was added drop by drop. Enough NaOH was added to ensure ph controlled to 12.5 and heated to the reaction temperature in a water bath. The mixture was stirred under oxygen atmosphere. The reaction was carried out for 0.5 h at 90 C. At the end of the reaction, the reaction mixture was cooled to room temperature and then separated with a glass filter to obtain solid and liquid samples. The isolated solid samples were analysed by FTIR (EQUINOX55) and

20 18 Xue-Fei Zhou, Jian-Xin Qin, Shu-Rong Wang H-1 NMR (BRUKER DRX500). The liquid samples were extracted into dichloromethane. The extract was dried over Na 2 SO 4, filtered and then the solvent was evaporated under reduced pressure. The identity of the products, i.e. 2-methoxy phenol and biphenyl, present in the extract was confirmed by GC-MS (AGILENT TECHNOLOGIES GC-MS HP6890/5973MS). See table 1 and fig. 1. Table 1. Identity of the products, i.e. 2-methoxy phenol and biphenyl, by GC-MS Tabela 1. Określenie produktów, tj. 2-metoksy fenolu i bifenylu, za pomocą GC-MS No. Nr RT [min] RSI SI Name Nazwa Molecular formula Wzór cząsteczkowy Library Biblioteka Methoxy phenol C 7 H 8 O 2 Mainlib 6-Hydroxy-2',3',4'-1,1' C -biphenyl 15 H 16 O 4 Mainlib With the SI and RSI matching factors, a perfect match results in the value of As a general guide 900 or greater is an excellent match, a good match, and a fair match. Przy dobrze dobranych czynnikach SI i RSI, doskonałe dopasowanie prowadzi do wartości Ogólnie przyjmuje się, że 900 lub większa wartość oznacza doskonałe dopasowanie, dobre dopasowanie, a dostateczne dopasowanie. (a) Compound Structure Struktura związku Delta Spectrum Widmo (b) Fig. 1. MS spectra of 2-methoxy phenol (a) and biphenyl (b) Rys. 1. Widma MS 2-metoksy fenolu (a) i bifenylu (b)

21 Oxidation of a lignin model compound of benzyl-ether type linkage in water with H 2 O Result and discussion Oxidative enzymes such as lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase participate in bioconversions of lignin [Boerjan et al. 2003]. The capability of salen-type metal complexes to function as mimics for those enzymes was tested by oxidising VGD with H 2 O 2 under oxygen atmosphere catalysed by a prepared Co(salen) complex. The oxidation was carried out at a temperature of 90 C in an alkaline aqueous solution at ph The reaction was elucidated with FTIR, H-1 NMR and GC-MS techniques. The structural changes of VGD across the Co(salen) catalytic oxidation were obtained based on the data (tables 2, 3) from FTIR and H-1 NMR spectra (fig. 2, 3). The functional description in FTIR and H-1 NMR spectra was determined following the data from Hu [2003] and Toikka & Brunow [1999], respectively. Table 2. Structural changes of VGD as determined by FTIR during Co(salen) catalytic oxidation Tabela 2. Zmiany strukturalne VGD określone za pomocą FTIR podczas katalitycznego utleniania Co(salen) No. Nr Functional description Opis funkcjonalny C-H stretching in aromatic ring rozciąganie się C-H w pierścieniu aromatycznym C-H vibration in CH 3 -, CH 2 -, CHdrgania C-H w CH 3 -, CH 2 -, CH- C-H vibration in -CH 2 - drgania C-H w -CH 2 - C-O vibration in side chain C=O drgania C-O w łańcuchu bocznym C=O C=C vibration in aromatic ring drgania C=C w pierścieniu aromatycznym C-H vibration dragnia C-H C-H vibration in CH 3 - drgania C-H w CH 3 - Wavenumber Numer fali [cm -1 ] Signal changes in FTIR spectra Zmiany sygnału w widmach FTIR VGD after reaction VGD VGD po reakcji 3030 m w 2937 m n 2841 m n 1623 n m 1595, 1503, 1456 s n 1400 n s 1369 m n

22 20 Xue-Fei Zhou, Jian-Xin Qin, Shu-Rong Wang Table 2. Continued Tabela 2. Ciąg dalszy C-O vibration in β-o-4 linkage drgania C-O w wiązaniu β-o-4 C-H stretching in aromatic ring rozciąganie się C-H w pierścieniu aromatycznym C-O-C vibration at α, γ-position drgania C-O-C w pozycji α, γ C-H stretching in aromatic ring rozciąganie się C-H w pierścieniu aromatycznym C-H stretching in aromatic ring rozciąganie się C-H w pierścieniu aromatycznym C-H stretching in aromatic ring rozciąganie się C-H w pierścieniu aromatycznym 1258 m n 1147 m n 1076 m n 1031 s n 951 m n 815 w n s strong; m medium; w weak; n nondetectable s silne; m średnie; w słabe; n niewykrywalne Table 3. Structural changes of VGD as determined by H-1 NMR during Co(salen) catalytic oxidation Tabela 3. Zmiany strukturalne VGD określnone za pomocą H-1 NMR podczas katalitycznego utleniania Co(salen) No. Nr Functional description Opis funkcjonalny Chemical shift Przesunięcie chemiczne [ppm] Signal changes in spectra Zmiany sygnałow w widmach VGD VGD after reaction VGD po reakcji 1 H-Ar s m 2 H-β ns ns 3 H-α ns ns 4 3-OCH 3, 4-OCH s m 5 3 -OCH s m

23 Oxidation of a lignin model compound of benzyl-ether type linkage in water with H 2 O Table 3. Continued Tabela 3. Ciąg dalszy 6 H-γ ns ns 7 α-och 3, γ-och ns ns s strong; m medium; ns not significant s silne; m średnie; ns nieistotne (a) (b) Fig. 2. FTIR spectra of untreated sample (VGD, a) and treated sample (treated VGD, b) Rys. 2. Widma FTIR próbki niezmienionej (VGD, a) i próbki zmienionej (zmieniony VGD, b)

24 22 Xue-Fei Zhou, Jian-Xin Qin, Shu-Rong Wang Fig. 3. H-1 NMR spectra of untreated sample (VGD) and treated sample (treated VGD) Rys. 3. Widma H-1 NMR próbki niezmienionej (VGD) i próbki zmienionej (zmieniony VGD) A clear trend is observed according to the signal changes in the FTIR and H-1 NMR spectra in tables 1 and 2. The aromatic ring (3030, 1595, 1503, 1456, 1147, 1031, 951, 815 cm -1, ppm) was seriously degraded; carbonyl (C=O, 1623 cm -1 ) occurred in the aromatic side chain due to Co(salen) catalytic oxidation in the presence of H 2 O 2 under oxygen atmosphere. Similarly Kervinen found that veratryl alcohol, a lignin model compound, could be selectively oxidized to veratraldehyde with molecular oxygen in water catalyzed by Co(salen) [Kervinen 2005]. Fig. 4. Postulated mechanism for transformation of VGD catalyzed by Co(salen) Rys. 4. Postulowany mechanizm transformacji VGD katalizowanego Co(salen)

25 Oxidation of a lignin model compound of benzyl-ether type linkage in water with H 2 O Demethylation was observed during the catalytic oxidation based on the signals at 1369, 1076 cm -1 (FTIR), , ppm (H-1 NMR). The cleavage of β-o-4 linkage (1258 cm -1 ) gave 2-methoxy phenol, and C-C coupled biphenyl, a compound arising from radical coupling, was obtained as well, as detected by GC-MS analysis (table 1, fig. 1), which commonly involves the hydrogen atom abstraction by the cobalt superoxo complex [Mayer 1998; Mayer et al. 2006]. The mechanism postulated is given in fig. 4. Conclusions VGD, a lignin model compound with benzyl-ether type linkage, was found to undergo obvious changes in structure during the catalytic reaction by Co(salen) with hydrogen peroxide under oxygen atmosphere. The reaction of aromatic ring- -opening, demethylation and β-o-4 cleavage was observed, yielding 2-methoxy phenol and biphenyl. Acknowledgements The authors are grateful for the financial support of the National Natural Science Foundation of China (No , ), the Scientific Research Foundation of the Department of Education of Yunnan Province (No. 2010J059), the Open Project of the State Key Laboratory of Clean Energy Utilization of Zhejiang University (No. ZJUCEU ), the Open Project of the State Key Laboratory of Pulp and Paper Engineering of South China University of Technology (No ), the Open Project of the State Key Laboratory of Materials-Oriented Chemical Engineering of Nanjing University of Technology (No. KL10-12), the Open Project of the State Key Laboratory of Chemical Resource Engineering of Beijing University of Chemical Technology (No. CRE-2011-C-305), the Open Project of the Key Laboratory of Solid Waste Treatment and Resource Recycling of the Ministry of Education of Southwest University of Science and Technology (No. 11zxgk07), and the Analysis and Testing Foundation of Kunming University of Science and Technology. References Boerjan W., Ralph J., Baucher M. [2003]: Lignin bios. Ann. Rev. Plant Biol. 54: Fukagawa N., Meshitsuka G., Ishizu A. [1992]: 2D NMR study of residual lignin in beech Kraft pulp combined with selective cleavage with pivaloyl iodide. J. Wood Chem. Technol. 12 [4]: Hakomori S. [1964]: A rapid permethylation of glycolipid and polysaccharide catalyzed by methylsulfinyl carbanion in dimethyl sulfoide. J. Biochem. [55]: Hosoya S., Kanazawa K., Kaneko H., Nakano J. [1980]: Synthesis of gaiacylglycerol-βguaiacyl ether (in Japanese). Mokuzai. Gakkaishi 26:

26 24 Xue-Fei Zhou, Jian-Xin Qin, Shu-Rong Wang Hu Z. J. [2003]: Degradation of lignin-carbohydrate complexes catalyzed by GIF biomimetic system (in Chinese). South China University of Technology, Guangzhou Jacobsen E. N. [1993]: Catalytic Asymmetric Synthesis. VHC, New York King L. C., Ostrum G. K. [1964]: Selective bromination with copper (II) bromide. J. Org. Chem. 29: Kervinen K. [2005]: Studies on veratryl alcohol oxidation catalyzed by Co(salen) type complexes and molecular oxygen in aqueous solution. University of Helsinki Larrow J. F., Jacobsen E. N. [2004]: Asymmetric processes catalyzed by chiral (salen) metal complexes. Topics Organomet Chem. 6: Lebo Jr S. E., Gargulak J. D., McNally T. J. [2001]. Lignin. In: Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley and Sons, Hoboken Lowoko M., Henriksson G., Gellerstedt G. [2003]: New method for the quantitative preparation of lignin-carbohydrate complex from unbleached softwood kraft pulp: Lignin-polysaccharides networks I. Holzforschung 57: Mayer J. M. [1998]: Hydrogen atom abstraction by metal-oxo complexes: Understanding the analogy with organic radical reactions. Acc. Chem. Res. 31: Mayer J. M., Mader E. A., Roth J. P., Bryant J. R., Matsuo T., Dehestani A., Bales, B. C. Watson E. J., Osako T., Valliant-Saunders K., Lam W. H., Hrovat D. A., Borden W. T., Davidson E. R. [2006]: Stoichiometric oxidations of σ-bonds: Radical and possible non-radical pathways. J. Mol. Catal. A: Chem. 251 [1-2]: Meyer F., Limberg C. [2007]: Organometallic Oxidation Catalysis. Springer-Verlag, Berlin, Heidelberg Pfeiffer P., Breith E., Lübbe E., Tsumaki T. [1933]: Tricyclic ortho-condensed partial valence rings. Justus Liebig's Annalen der Chemie 503: Ralph J., Marita J., Ralph S., Hatfield R., Lu F., Ede R., Peng J., Quideau S., Helm R., Grabber J., Kim H., Jimenez-Monteon G., Zhang Y., Jung H., Landucci L., Mackay J., Sederoff R., Chapple C., Boudet A. [2000]: Solution-state NMR of lignins. In: Advances in Lignocellulosic Characterization. Argyropoulos D., Rials T., Eds.; TAPPI Press, Atlanta Salanti A., Orlandi M., Tolppa E.-L., Zoia L. [2010]: Oxidation of isoeugenol by salen complexes with bulky substituents. Int. J. Mol. Sci. 11: Toikka M., Brunow G. [1999]: Lignin-carbohydrate model compounds. Reactivity of methyl 3-O-(α-L-arabinofuranosyl)-β-D-xylopyranoside and methyl β-d-xylopyranoside towards a β-o-4-quinone methide. J. Chem. Soc., Perkin Trans. L.:

27 Oxidation of a lignin model compound of benzyl-ether type linkage in water with H 2 O UTLENIANIE MODELOWEGO ZWIĄZKU LIGNINY Z TYPEM WIĄZANIA BENZYLOWO-ETEROWEGO W WODZIE Z H 2 O 2 W ATMOSFERZE TLENU KATALIZOWANE Co(Salen) Streszczenie Zbadano katalityczne właściwości kompleksu Co(Salen) w utlenianiu modelowego związku ligniny (veratrylglycerol-β-guaiacyl-α,γ-dimetyleter, VGD) w celu określenia mechanicznych aspektów reakcji pomiędzy Co(salen) i VGD w atmosferze tlenu przy zastosowaniu nadtlenku wodoru jako utleniacza. Zaobserwowano, że w VGD zaszły zmiany strukturalne w odpowiedzi na reakcję katalityczną, co przedstawiono za pomocą różnych technik analitycznych (FTIR, H-1 NMR oraz GC-MS). W efekcie otrzymano 2-metoksy fenol i bifenyl. Słowa kluczowe: utlenianie katalityczne, veratrylglycerol-β-guaiacyl-α,γ-dimetyleter (VGD), Co(salen), FTIR, H-1 NMR, GC-MS

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29 Drewno. Pr. Nauk. Donies. Komunik. 2011, vol. 54, nr 186 Ladislav Dzurenda, Kazimierz A. Orlowski 1 THE EFFECT OF THERMAL MODIFICATION OF ASH WOOD ON GRANULARITY AND HOMOGENEITY OF SAWDUST IN THE SAWING PROCESS ON A SASH GANG SAW PRW 15-M IN VIEW OF ITS TECHNOLOGICAL USEFULNESS This paper presents the results of granulometric analyses of sawdust of unmodified and thermally- modified ash wood (Fraxinus exelsior L.) sawed on a narrow-kerf sash gang saw. The sawdust of dry thermally-modified ash produced in the sawing process on a frame sawing machine PRW15-M at a feed speed in the range of m min -1 has chip granularity ranging from 33.5 µm to 9.9 mm; whereas unmodified ash wood sawdust consists of chips in a granularity range from 35.6 µm to 13.8 mm. It was observed that thermally-modified ash sawdust is finer, with a distinctly larger share of the fraction in the granularity range a = μm and a slightly increased share of the fraction in the range a = μm. Changes in mechanical characteristics of modified wood were also observed in the technological usefulness of a part of dry sawdust chip in the granularity range a = 250 μm-2.4 mm. While the homogenous share of chips in sawdust produced in the process of sawing of dry ash wood was HSCh a = %, the demonstrated homogenous share of chips in ash sawdust formed in the process of sawing of dry thermally-modified wood was lower by 4-6 %. Keywords: ash wood, thermal modification, frame sawing machine, granulometric analysis, granularity Introduction During the sawing process of wood, chip sawdust is produced together with the main product. The shape, dimensions and amount of chips depend on the form, physical and mechanical properties of the sawed wood, as well as on the shape, dimensions, and sharpness of the cutting blade, and technical and technological Ladislav Dzurenda, Technical University in Zvolen, Slovakia dzurenda@vsld.tuzvo.sk Kazimierz A. Orlowski, Gdansk University of Technology, Poland korlowsk@pg.gda.pl

30 28 Ladislav Dzurenda, Kazimierz A. Orlowski conditions of the sawing process [Prokeš 1978; Goglia 1994; Lisičan et al. 1996; Wasielewski 1999; Orłowski 2003; Kopecký, Rousek 2007; Klement, Detvaj 2007; Dzurenda 2007]. Sawdust is characterised as poly-dispersion bulk material consisting of coarse and medium- coarse fractions [Hejma et al. 1981; Dzurenda 2009], i.e. bulk material with dimensions of grain over 0.3 mm, while the share of fine fractions with smaller dimensions of chips is not excluded. According to the classification parameters of bulk material described in STN standard, sawdust is classified as B-45UX, i.e. bulk material of fine granularity ( mm), hygroscopic, low crisp and abrasive material with a tendency to crowd. As a secondary raw material, sawdust has miscellaneous applications. For example, sawdust is one of the base materials utilised in the production of agglomerated chip materials in the range of granularity mm [Drouet 1992; Štefka 1997] and also in chemical processing of wood. Moreover, it is a valuable raw material for energy use by way of direct combustion, and possibly also for the production of dimensionally and energetically homogenised fuel, for instance briquettes (type RUF Klasik with dimensions mm) and industrial type pellets (with a cylindrical shape of Ø6-8 mm in diameter and a length of mm) [Dzurenda, Slovak 2001; Pastorek, Kara, Jevič 2004; Šooš 2005; Dobrowolska et al. 2010]. In recent years, the increasing interest in sawdust as a secondary raw material, has created the need for a proper specification of the following physical properties: granularity, geometric shapes and dimensions of sawdust chips. The aim of this work is to analyse the effect of the thermal treatment of ash wood (Fraxinus excelsior L.) on sawdust granularity in the sawing process conducted on a frame sawing machine (sash gang saw) PRW15-M, and its technological advantages in the production of agglomerated chip materials and bio-fuel (pellets and briquets). Material and methods The thermal modification of ash was performed in overheated steam in a high temperature steam dry kiln PW-10 [Hamech 2011] using a technology similar to ThermoWood technology, in the following conditions presented in fig. 1: intense heating of ash wood up to the temperature of t = 110ºC joined with drying with wet atmospheric air, overheating of wood in an environment of superheated steam at atmospheric pressure at a temperature corresponding to conditions of modifications, with lower intensity than in phase 1., and wood drying, proper process of thermal modification of ash wood at a constant temperature of t = 197ºC in an environment of superheated steam at atmospheric pressure, process duration: 4 hours,