| Summary: | 碩士 === 中興大學 === 森林學系所 === 103 === The purpose of this study was to evaluate the physical-mechanical performance and termite resistance of modified laminted veneer lumber (LVL), including boric acid treatment, low molecular weight phenol formaldehyde resin treatment, furfurylation, heat-treated method and biological repellent treatment. Optimized processes to improve the termite resistance of LVL was also investigated.
Results indicated that veneer of boric acid treatment has termites resistance while its retention reach 3 kg/m3, and its density, equilibrium moisture content, hygroscopicity, bending strength and compressive strength were increased, but the bonding shear strength was decreased.The way of adding boric acid to the adhesives was no significant difference for density, equilibrium moisture content and bending strength, however, the bonding shear and compressive strength were decreased, and the termite resistance was less than the boric acid treated-veneer. Retention of veneer impregnated with phenol formaldehyde resin (PF) and furfuryl alcohol (FA) were 148.2 kg/m3 and 7.5 kg/m3, respectively. Both of these two treatments have improved the properties with regard equilibrium moisture content (EMC), hygroscopicity, bending strength, compressive strength and resistance against termites. No significant difference was found on improving termite resistance with heat-treated LVL. In addition, the bending and bonding strength of LVL were decreased. However, the EMC, hygroscopicity and compressive strength of LVL were improved after heat treatment. The type of LVL treatment was better than the type of veneer treatment in strength remaining. Well termite resistance was found by adding 1% biological repellent to LVL and not affect its physical properties, dimensional stability and mechanical properties.
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