@article {1866, title = { ANTI-FUNGAL AND ANTI-TERMITE ACTIVITY OF EXTRACTIVES COMPOUNDS FROM THERMALLY MODIFIED ASH WOODS }, journal = { MADERAS-CIENCIA Y TECNOLOGIA }, volume = {22}, year = {2020}, pages = {223-240}, abstract = {

Thermal modification of wood is a promising alternative to chemical and biocidal modification processes, increasing the biological durability and dimensional stability of wood. However, the wood-decay resistance properties of heat-treated wood are still not well known. The main objective of this study was to determine the biological resistance of heat-treated ash wood, and assess the antifungal and anti-termite activity of extractive compounds from heat-treated ash woods, depending on the intensity of the modification process (2 hours at 170, 200, 215, 228 (degrees C) - steam pressure). Untreated and heat-treated wood samples were extracted with water or acetone. The extracts were then used to determine inhibition effectiveness against white-rot (Trametes versicolor) and brown-rot (Rhodonia placenta) fungi. Whatman papers impregnated with extractives were used to evaluate the inhibition of termite feeding. Lastly, the extractives were analyzed by Gas Chromatography - Mass Spectrometry (GC-MS) and compared for their level of anti-termite and antifungal activity. The results showed that the degree of antifungal activity of these extracts depended on the solvent used during the extraction process and varied depending on heat treatment intensity. The extracts were more effective against brown-rot than white-rot fungi. However, the anti-termite activity of heat-treated ash wood extracts was not really significant. A GC-MS analysis showed that the main share of the extractives in untreated wood was removed. In addition, new chemical elements were generated by the thermal degradation of wood polymers (lignin and hemicelluloses), including aliphatic acids, monosaccharides and other products resulting from their dehydration reaction. The most abundant element was syringaldehyde, from lignin derived compounds, which might explain the antifungal activities of thermally treated ash wood extracts.

}, url = {https://hal.univ-lorraine.fr/LERMAB-UL/hal-02502770}, author = {K. CONDELIER and M.F. THEVENON and R. COLLET and P. GERARDIN and S. DUMARCAY} } @article {1867, title = { Beech wood treated with polyglycerol succinate: a new effective method for its protection and stabilization }, journal = { HOLZFORSCHUNG }, volume = {74}, year = {2020}, pages = {351-361}, abstract = {

This paper deals with an original and non-biocidal chemical treatment consisting of a vacuum/pressure impregnation step of beech wood with a water-borne mixture made from heat-activated condensation of succinic anhydride (SA) and glycerol (G). Chemical structures of adducts were established using matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF) investigations. Beech wood was impregnated and cured in order to induce in situ polymerization of glycerol/succinic adducts (GSA) in the cell walls, leading to the formation of polyglycerol succinate (PGS) polyester. Various treatment conditions were investigated depending on the duration (6-72 h) and curing temperature (103-160 degrees C). Weight percent gains (WPGs) ranging between 40 and 60\% were obtained. Attenuated total reflectance-middle infrared spectroscopy (ATR-MIR) and carbon-13 nuclear magnetic resonance (C-13-NMR) spectroscopy confirmed polyester formation. A curing temperature of 160 degrees C was found to be the best condition to totally avoid polymer leaching, and brought the anti-swelling efficiency (ASE) up to 64\%. Decay resistance of PGS-treated wood against Trametes versicolor and Coniophora puteana was also strongly temperature and time dependent: performances fit with the EN113 standard requirements if a curing temperature of 160 degrees C was applied.

}, author = {C. L{\textquoteright}HOSTIS and E. FREDON and M.F. THEVENON and F.J. SANTIAGO-MEDINA and P. GERARDIN} } @article {1873, title = { Natural durability of four Tunisian Eucalyptus spp. and their respective compositions in extractives }, journal = {HOLZFORSCHUNG}, volume = {74}, year = {2020}, pages = {260-274}, abstract = {

Eucalyptus trees have been adapted to the Tunisian climate. Now, they need to be economically valued. Tunisian Eucalyptus have great technological properties allowing us to use them as wooden material. However, there is large variability in the natural durability between heartwood Eucalyptus spp. The wood sustainability assessment provides reliable parameters to predict the service life of wood-based products. This study aimed to evaluate the wood deterioration of four North Tunisian fast-growing Eucalyptus spp. (Eucalyptus maidenii, Eucalyptus saligna, Eucalyptus camaldulensis and Eucalyptus gomphocephala) exposed to basidiomycetes (Coniophora puteana and Trametes versicolor) and termite (Reticulitermes flavipes) attacks. Among the four Eucalyptus woods, Eucalyptus gomphocephala presents the highest decay and termite resistance. The four Eucalyptus wood species are classified as very durable against fungal degradation and durable against termite attacks, expect for Eucalyptus saligna which is classified as sensible against termites. The natural durability of Eucalyptus seems to be mainly caused by extractives, and a lot of compounds are involved. Antifungal and anti-termite properties of these compounds were put in perspective with the natural durability of wood. Gas chromatography-mass spectrometry (GC-MS) analyses highlighted that Eucalyptus durability is mostly governed by gallic acid, fatty acid glycerides, fatty acid esters, phenolic compounds, sitosterol, catechin and ellagic acid.

}, author = {M.T. ELAIEB and S. BEN-AYED and S. DUMARCAY and B.D.H. DE-FARIA and M.F. THEVENON and P. GERARDIN and K. CANDELIER} } @article {1800, title = { Comparison of different treatments based on glycerol or polyglycerol additives to improve properties of thermally modified wood }, journal = { EUROPEAN JOURNAL OF WOOD AND WOOD PRODUCTS }, volume = {77}, year = {2019}, pages = {799-810}, abstract = {

Impregnation of European beech (Fagus sylvatica) with 10\% w/w aqueous solution of different additives made from the reaction of glycerol or polyglycerol with glycidyl methacrylate or maleic anhydride followed by thermal modification at 150, 200 or 220 degrees C under inert conditions was investigated to evaluate potential synergies between chemical and thermal treatments. Treated and untreated wood were analysed to evaluate mass changes and bulking values after treatments, resistance of treatment to leaching, wettability, anti-swelling efficiency, modulus of elasticity (MOE), modulus of rupture (MOR), decay resistance against Coriolus versicolor and termite resistance against Reticulitermes flavipes. Results revealed that synergic effects between a combination of light chemical modification and thermal treatments can be observed at higher temperature treatments (200 and 220 degrees C), improving wood dimensional stability (approximately 80\%), decay, and termite resistance properties. However, MOE and MOR values decreased by approximately 30\% and 60\%, respectively. Treated samples resulting from the combination of chemical and thermal treatment performed at 220 degrees C present improved durability against the termites R. flavipes.

}, url = {https://hal.archives-ouvertes.fr/hal-02352486}, author = {M. MUBAROK and S. DUMARCAY and H. MILITZ and K. CANDELIER and M.F. THEVENON and P. GERARDIN} } @article {1823, title = { Improvement of Modified Wood Properties with Addition of Chestnut Tannins in Lactic Acid-Based Treatments }, journal = { JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY }, volume = {39}, year = {2019}, pages = {124-135}, abstract = {

Wood modification treatments based on lactic acid oligomers (OLA) and monomers (LA) enhance beech dimensional stability (up to 70\%) and biological resistance (less than 3\% weight loss according to EN113). Chestnut wood tannins natural biological activity might improve the modified wood durability with milder curing conditions. Treatment consisted of the impregnation of monomers or oligomers mixtures followed by curing (140 degrees C/160 degrees C for 48h). Tannins addition is almost inconsequential with oligomeric-based treatment but improved the monomeric-based treatment. In this case, modified wood biological resistance and product persistence were increased. OLA impregnated wood cured at 160 degrees C was always the best performing treatment regarding dimensional stability and durability, but the addition of tannins in LA systems conferred promising properties to wood allowing simplification of the modification process.

}, author = {C. GROSSE and M. NOEL and M.F. THEVENON and P. GERARDIN} } @article {1790, title = { Non-biocide antifungal and anti-termite wood preservation treatments based on combinations of thermal modification with different chemical additives }, journal = { EUROPEAN JOURNAL OF WOOD AND WOOD PRODUCTS }, volume = {77}, year = {2019}, pages = {1125-1136}, abstract = {

The synergic effect between a mild chemical and thermal modification of beech wood (Fagus sylvatica) has been studied. A low concentration of additives based on vinylic-polyglycerol, vinylic-glycerol, and maleic anhydride was impregnated into beech wood, followed by curing under different temperature conditions at 103, 150, 200, and 220 degrees C. The modified wood was then analyzed for its leaching resistance, dimensional stability, wettability, modulus of elasticity (MOE) and modulus of rupture (MOR) in bending, decay resistance against Trametes versicolor, and termite resistance against Reticulitermes flavipes. Results have disclosed a synergic effect of thermo-chemical wood modification under 200 and 220 degrees C curing conditions. At these curing temperatures, thermo-chemically modified beech presents improved dimensional stability (\> 60\%) and better resistance against both Trametes versicolor and Reticulitermes flavipes compared to the control. However, at the same conditions, MOE and MOR values were lowered by approximately 25\% and 60\%, respectively.

}, author = {M. MUBAROK and S. DUMARCAY and H. MILITZ and K. CANDELIER and M.F. THEVENON and P. GERARDIN} } @article {1784, title = { Optimizing Chemical Wood Modification with Oligomeric Lactic Acid by Screening of Processing Conditions }, journal = { JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY }, volume = {39}, year = {2019}, pages = {385-398}, abstract = {

When exposed to moisture, wood undergoes swelling and is susceptible to fungal degradation. Chemical modification via oligomeric lactic acid (OLA) treatment has been found to be a promising environmentally friendly solution to this disadvantage. In this study, wood was impregnated with OLA and then variously heat treated to polymerize the OLA in situ. The effect of curing temperature and time on OLA polymerization has been determined chemically. Dimensional stability was examined by water immersion and hygroscopicity measurements and biological decay resistance also evaluated. OLA impregnation followed by heat treatment enhanced wood properties. OLA cure at 160 degrees C for 48 h resulted in treated wood with greater dimensional stability and biological resistance.

}, author = {C. GROSSE and W.J. GRIGSBY and M. NOEL and A. TREU and M.F. THEVENON and P. GERARDIN} } @article {1745, title = { Improvement of beech wood properties by in situ formation of polyesters of citric and tartaric acid in combination with glycerol }, journal = { HOLZFORSCHUNG }, volume = {72}, year = {2018}, pages = {291-299}, abstract = {

Beech wood has been treated by impregnation followed by heating at various temperatures with solutions containing citric acid (CA) or tartaric acid (TA) alone or in combination with glycerol (G), i.e. with G+CA and G+TA. The resulting modified woods were tested in terms of resistance to leaching, durability and dimensional stability. These properties are improved as a function of heating temperature, which leads to higher levels of poly-esterification involving grafting onto wood simultaneously with thermal degradation of wood. Dimensional stability of all treated wood was increased, but glycerol does not have a positive effect with this regard. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy contributed to understanding the effects of the different treatments. In situ polymerization of G+TA at 140 degrees C increased the bending resistance, while G+CA polymerization does not compensate notably the mechanical weakness induced by thermal degradation of wood at higher temperatures. However, G+CA treatment is more efficient regarding leaching and decay resistance, than that with G+TA.

}, author = {C. L{\textquoteright}HOSTIS and M.F. THEVENON and E. FREDON and P. GERARDIN} } @article {1742, title = { Influence of Water and Humidity on Wood Modification with Lactic Acid }, journal = { JOURNAL OF RENEWABLE MATERIALS }, volume = {6}, year = {2018}, pages = {259-269}, abstract = {

Impregnation of dry wood with pure lactic acid oligomers (OLAs) followed by heat treatment confers promising properties to wood because of OLA\&$\#$39;s good diffusion, in-situ polymerization and persistence in cell walls. Treatment provides drastic reduction of the equilibrium moisture content, high dimensional stability and good durability. The presence of water during treatment has been evaluated. Curing of OLA impregnated dry wood in humid atmosphere leads to a strong and global degradation of the material. OLA treatment of wet wood only impacts the water leaching rate negatively. Treatment of dry wood with OLA diluted in water additionally decreases the biological resistance and is not efficient for decreasing hygroscopicity. Treatment of dry wood with lactic acid solution leads to a lower polymerization level but confers good properties.

}, author = {C. GROSSE and M. NOEL and M.F. THEVENON and L. RAUTKARI and P. GERARDIN} } @article {1688, title = { Resistance of thermally modified ash (Fraxinus excelsior L.) wood under steam pressure against rot fungi, soil-inhabiting micro-organisms and termites }, journal = { EUROPEAN JOURNAL OF WOOD AND WOOD PRODUCTS }, volume = {75}, year = {2017}, pages = {249-262}, abstract = {

Thermal modification processes have been developed to increase the biological durability and dimensional stability of wood. The aim of this paper was to study the influence of ThermoWood(A (R)) treatment intensity on improvement of wood decay resistance against soil-inhabiting micro-organisms, brown/white rots and termite exposures. All of the tests were carried out in the laboratory with two different complementary research materials. The main research material consisted of ash (Fraxinus excelsior L.) wood thermally modified at temperatures of 170, 200, 215 and 228 A degrees C. The reference materials were untreated ash and beech wood for decay resistance tests, untreated ash wood for soil bed tests and untreated ash, beech and pine wood for termite resistance tests. An agar block test was used to determine the resistance to two brown-rot and two white-rot fungi according to CEN/TS 15083-1 directives. Durability against soil-inhabiting micro-organisms was determined following the CEN/TS 15083-2 directives, by measuring the weight loss, modulus of elasticity (MOE) and modulus of rupture (MOR) after incubation periods of 24, 32 and 90 weeks. Finally, Reticulitermes santonensis species was used for determining the termite attack resistance by non-choice screening tests, with a size sample adjustment according to EN 117 standard directives on control samples and on samples which have previously been exposed to soil bed test. Thermal modification increased the biological durability of all samples. However, high thermal modification temperature above 215 A degrees C, represented by a wood mass loss (ML\%) due to thermal degradation of 20\%, was needed to reach resistance against decay comparable with the durability classes of \&$\#$39;\&$\#$39;durable\&$\#$39;\&$\#$39; or \&$\#$39;\&$\#$39;very durable\&$\#$39;\&$\#$39; in the soil bed test. The brown-rot and white-rot tests gave slightly better durability classes than the soil bed test. Whatever the heat treatment conditions are, thermally modified ash wood was not efficient against termite attack neither before nor after soft rot degradation.

}, url = {https://hal.univ-lorraine.fr/LERMAB-UL/hal-02179527}, author = {K. CANDELIER and S. HANNOUZ and M.F. THEVENON and D. GUIBAL and P. GERARDIN and M. PETRISSANS and R. COLLET} } @article {1687, title = { Tannin-boron complex as a preservative for 3-ply beech plywoods designed for humid conditions }, journal = { HOLZFORSCHUNG }, volume = {71}, year = {2017}, pages = {249-258}, abstract = {

Boric acid (BA) effectively controls wood-rotting fungi and termite attack but is readily leached out in outdoor exposure. A newly developed tannin-boron (TB) complex has been investigated to reduce BA leaching and to preserve beech plywood from biological attack. Wood veneers were impregnated with different TB solutions and then bonded with a melamine urea formaldehyde (MUF) adhesive for bond class 2 applications. The formation of a solid hydrophobic TB network on the veneer surfaces partially decreased the tensile shear strength of plywood but the prepared panels met the requirements for bond class 2. The plywood samples made from veneers treated with only BA solutions showed fair resistance against white rot fungus and termite attack, but the durability decreased even after mild leaching tests. The panels made of treated veneers with TB formulations showed instead a high resistance against biological attack after mild leaching and to some extent after severe leaching tests. This depended on the concentration of tannin and BA in the solutions. Favorable results were obtained with 20\% tannin in the formulation. The results of the termites feeding choice test were more positive than those obtained by a forced feeding test. The control samples were attacked faster and showed higher weight loss when alternative samples included TB formulations.

}, author = {D. EFHAMISISI and M.F. THEVENON and Y. HAMZEH and A. PIZZI and A. KARIMI and K. POURTAHMASI} } @article {1612, title = { Control of wood thermal treatment and its effects on decay resistance: a review }, journal = { ANNALS OF FOREST SCIENCE }, volume = {73}, year = {2016}, pages = {571-583}, abstract = {

Key message An efficient use of thermal treatment of wood requires a depth understanding of the chemical modifications induced. This is a prerequisite to avoid problems of process control, and to provide high quality treated wood with accurately assessed properties to the market. Properties and structural anatomy of thermally modified woods are slightly different than un-processed woods from a same wood species. So it is necessary to create or adapt new analytical methods to control their quality.

Heat treatment as a wood modification process is based on chemical degradation of wood polymer by heat transfer. It improves mainly the resistance of wood to decay and provides dimensional stability. These improvements, which come at the expense of a weakening of mechanical properties, have been extensively studied. Since a decade, researches focused mainly on the understanding of wood thermal degradation, on modelling, on quality prediction and quality control.

We aimed at reviewing the recent advances about (i) the analytical methods used to control thermal treatment; (ii) the effects on wood decay resistance and (iii) the advantages and drawbacks of a potential industrial use of wood heating.

We carried out a literature review of the main industrial methods used to evaluate the conferred wood properties, by thermal treatment. We used papers and reports published between 1970 and 2015, identified in the web of science data base..

Approximately 100 papers mostly published after 2000 were retrieved. They concentrated on: (i) wood mass loss due to thermal degradation determination, (ii) spectroscopic analyses of wood properties, (iii) colour measurements, (iv) chemical composition, (v) non-destructive mechanical assessments and (vi) use of industrial data.

One of most interesting property of heat-treated wood remains its decay resistance. Durability test with modified wood in laboratory are expensive and time-consuming. This review displays data from different analytical methods, such as spectroscopy, thermogravimetry, chemical analyses or mechanical tests that have the potential to be valuable indicators to assess the durability of heat treated wood at industrial scale. However, each method has its limits and drawbacks, such as the required investment for the equipment, reliability and accuracy of the results and ease of use at industrial scale.

}, url = {https://hal.archives-ouvertes.fr/hal-01532412}, author = {K. CANDELIER and M.F. THEVENON and A. PETRISSANS and S. DUMARCAY and P. GERARDIN and M. PETRISSANS} } @article {1635, title = { Induced Tannin Adhesive by Boric Acid Addition and Its Effect on Bonding Quality and Biological Performance of Poplar Plywood }, journal = { ACS SUSTAINABLE CHEMISTRY \& ENGINEERING }, volume = {4}, year = {2016}, pages = {2734-2740}, abstract = {

Quebracho tannin wood adhesive in a non formaldehyde approach has a low hardening rate and needs more pressing time than formaldehyde-based wood adhesives during wood composites production. In this study, boric acid (BA) was used to increase autocondensation rate of tannin to make poplar plywood. The main ingredients of the adhesives included quebracho tannin, NaOH, hexamine, BA and polymeric isocyanate (PMDI). Thermomechanical analysis of without BA adhesives showed that maximum modulus of elasticity increased with increasing the initial tannin concentration from 40\% to 50\% (w/w), whereas no significant effect has been found by adding PMDI. Moreover, the addition of BA lowered time and temperature of hardening and increased modulus of elasticity of the adhesive. Also, tensile shear strength increased significantly with increasing the tannin concentration and the BA content (from 2\% to 4\%). Interestingly, applied BA in the glueline not only improved bonding quality of the panels but also provided good preservative performance against fungal attack even after mild leaching test.

}, author = {D. EFHAMISISI and M.F. THEVENON and Y. HAMZEH and A.N. KARIMI and A. PIZZI and K. POURTAHMASI} } @article {1191, title = {Accelerated autocondensation of quebracho tannin by boric acid to make poplar plywood. }, journal = {J. Forest and Wood Products (Iran)}, year = {2014}, month = {2014}, author = {D. EFHAMISISI and Y. HAMZEH and M.F. THEVENON and A. KARIMI and A. PIZZI and K. POURTAHMASI} } @article {1207, title = {Hydrogel-based boron salt formulations for wood preservation. }, journal = {Wood Sciences Technology}, year = {2014}, month = {2014}, author = {F. OBOUNOU-AKONG and P. GERARDIN and M.F. THEVENON and C. GERARDIN-CHARBONNIER} } @article {524, title = {Efficacy of tannin in fixing boron in wood: fungal and termite resistance}, journal = {Bioresources}, volume = {7}, year = {2012}, month = {2012}, chapter = {1238-1252}, author = {G. TONDI and S. WIELAND and N. LEMENAGER and A. PETUTSCHNIGG and A. PIZZI and M.F. THEVENON} } @article {1146, title = {Tannin-boron preservatives for wood buildings: mechanical and fire properties. }, journal = {Eur. J. Wood Wood products}, volume = {70}, year = {2012}, month = {2012}, chapter = {689}, author = {G. TONDI and S. WIELAND and T. WIMMER and M.F. THEVENON and A. PIZZI and A. PETUTSCHNIGG} }