Abstract: Wood plastic biocomposites of biodegradable poly(butylene succinate) (PBS) and Padauk sawdust was successfully pre-pared by using a twin screw extruder and an injection molding machine. The effects of water absorption and sunlight exposure on some properties of the composites were investigated. Water absorption of PBS composites was found to follow the Fick’s law of diffusion, while the diffusion coefficient increased with increasing wood content. Maximum water absorption of around 4.5% was observed at 30 wt.% sawdust. Optical micrograph indicated the swelling of wood particles by around 1% – 3% after 30 days of water immersion. The tensile and flexural strengths reduced slightly both under the water immersion and sunlight exposure. After 90 days of exposure, the composites clearly looked paler than the non-weathered ones. Thermal scan indicated the re-duction of crystalline region due to the plasticization effect derived from water molecules.

Key words: wood plastic composites, Fickian diffusion, mechanical properties, biodegradable polymers, environmental deg-radation