Development of beech wood thermo-chemical modification treatments based on different vinylic derivatives of glycerol and polyglycerol
M Mubarok, S Dumarcay, H Militz, K Candelier, M-F Thevenon, P Gerardin
In this study, a combination between chemical and thermal wood modification has been investigated. Seven types of a low concentration of 10% aqueous additive solution of vinylicglycerol [glycerol-maleic anhydride (Gly-MA), glycidyl methacrylate (GM), and Glycerol methacrylate-maleic anhydride (GM/MA(2eq))], vinylicpolyglycerol [polyglycerol-maleic anhydride (PG-MA), polyglycerol methacrylate (PGM), and polyglycerol methacrylate-maleic anhydride (PGM/MA(3eq))], and maleic anhydride (MA) were impregnated into European beech wood (Fagus sylvatica), known for its low dimensional stability and poor natural durability. Varied with different curing temperatures at 103, 150, 200, and 220oC under inert condition, the modified wood and control were then characterized for their physical, mechanical, decay, and termite resistance properties. We found that, at the same initial weight percent gain (WPG) value (8 – 11%), mass changes (∆m) after thermal treatment, bulking (B), weight loss due to leaching (WLL), swelling (S), wettability, modulus of elasticity (MOE), and modulus of rupture (MOR) values of the additive-treated wood decreased as the curing temperature increased. In contrast, anti-swelling efficiency (ASE), decay resistance against Coriolus versicolor, and termite resistance against Reticulitermes flavipes values of additive-treated wood increased considerably for some treatments as the curing temperature increased, with better results at 200 and 220oC. In other words, the study has disclosed that the addition of some selected additives combined with thermal treatment can improve wood decay resistance and termite resistance better than untreated wood or wood with only thermally modified treatment.