Effects of moisture on the durability of a wood/thermoplastic composite

The effects of simulated marine environments on the performance of wood/thermoplastic composites under quasi-static and fatigue lending is investigated. The material under consideration consists of wood flour embedded in a thermoplastic matrix. The effects of additives and processing methods were included in the durability study. Moisture sorption studies are presented for these formulations and are found to compare favorably with a linear Fickian diffusion model. Qualitative and quantitative evidence of hygrothermal damage was nevertheless consistently observed. The combination of Fickian diffusion and damage is explained from moisture-induced swelling considerations of the constituents. The influence of marine environments on fatigue response was examined by immersing the coupons in seawater during the fatigue test. The synergistic effects of moisture and fatigue are discussed.