Mechanical and biological durability properties against soft-rot and subterranean termite in the field (grave-yard test) of beech wood impregnated with different derivatives of glycerol or polyglycerol and maleic anhydride followed by thermal modification in an opened or in a closed system
M Mubarok, H Militz, S Dumarcay, I W Darmawan, Y S Hadi, P Gerardin
This paper presents mechanical and biological durability properties in soil beg test (soft-rot test) and field test (grave-yard test) against subterranean termite of the wood modified with an aqueous vinylic derivative of glycerol/polyglycerol or maleic anhydride cured in an opened or in a closed system. Wood modification was performed through impregnation of European beech (Fagus sylvatica) with aqueous solution of polyglycerol maleate, glycerol maleate, or maleic anhydride at 10 or 20% w/w concentration, followed with curing under oven heating (OHT) at 120°C, 150°C, or 220°C in opened system or under heat pressurised steam (HPS) at 150°C in closed system. The modified woods were then characterized for their weight percent gain and mass losses after curing process, mechanical properties [modulus of elasticity (MOE), modulus of rupture (MOR), work to maximum load in bending (WMLB)], and biological durability properties against soft-rotting micro fungi in soil beg test and against subterranean termite (grave-yard test) in a tropical country. Results have revealed that almost all modified wood presented higher MOE values than untreated wood, however, MOR and WMLB decreased up to 27% and 87%, respectively. Biological durability in the soil beg test against soft-rot indicated that almost all modified wood were specified as durable to very durable wood. However, among the treatments, the wood modified with polyglycerol maleate/glycerol maleate/maleic anhydride at 20% under OHT 150°C or the wood modified at lower additive concentration (10%) under OHT 220°C presented significantly better durability against subterranean termite within a period of 328 days in the field.
Keywords: chemical modification, closed system, Fagus sylvatica, field test, glycerol, grave-yard test, maleic anhydride, mechanical properties, opened system, soft-rot test, termite resistance, thermal treatment, polyglycerol