16. The proper durability assessment criterion of wood resins

摘要

Wood and wood composites are susceptible to lose mechanical properties due to moisture exposure. Resins play an important role in determining the durability of wood based materials. Several wood resins were used in this study to bond veneers, and their performance before and after cyclic wetting and drying was observed. Various mechanical properties such as stiffness, strength and toughness were studied. Conventional methods of durability assessment in wood industry are related to modulus and ultimate load carrying capacity, while newer approaches suggest considering post-peak-load performance. The property degradation trends of solid wood as well as wood composite samples made out of the same wood species were analyzed statistically. To gain insight into the proper durability assessment criteria of wood resins, the retention percent of different properties were compared after up to 24 cycles of moisture exposure. Based on the results of this study, all properties significantly decline due to moisture exposure, however the rate of degradation considerably varies among different materials and properties. The pluses and minuses of each approach to study dry and wet durability are discussed.