This research work was to study the effect of moisture on mechanical properties of wood/polyvinylchloride composites (WPVC). WPVC specimens in ratio of PVC and wood (100:100 by weight) were prepared by using twin screw extruder. The water conditions for WPVC specimen immersion testing were varied for temperatures of 30-70 oC and specimen immersion time of 0-120 h. The moisture effect was investigated by measuring flexural properties and hardness of WPVC as comparing with case of PVC specimen. The result suggested that flexural modulus of WPVC tended to decrease with increasing time of water immersion and then remained unchanged at immersion time of more than 72 and 48 h for water temperature of 30 and 70 oC respectively. The decrease rate in flexural modulus enhanced when water temperature increased. Flexural modulus of PVC slightly changed with increasing both immersion time and water temperature. Flexural strength for both PVC and WPVC specimens were found the change at water temperature of 70 oC only. Flexural strength of PVC tended to slightly increase with increasing immersion time whereas flexural strength of WPVC slightly decreased with increasing immersion time. Hardness of PVC specimen in cases of both water temperature of 30 and 70 oC slightly increased with increasing immersion time. For WPVC hardness tended to decrease with increasing immersion time and water temperature.

This research work was to study the chemical release of wood/polyvinylchloride composites (WPVC) affecting the physical and chemical properties of water. WPVC specimens in ratio of PVC and wood (100:100 by weight) were prepared by using twin screw extruder. The water conditions for specimen immersion testing were varied for temperatures of 30-70 oC and specimen immersion time of 0-120 h. The water quality was estimated by measuring pH electrical conductivity turbidity and color of water after immersion of WPVC specimen as comparing with case of PVC specimen. The result suggested that pH values of water slightly decreased with increasing specimen immersion time whereas the change of temperature of water did not affect the pH value. The electrical conductivity remained unchanged with increasing specimen immersion time or temperature except for immersion of WPVC specimens at 70 oC. This might be attributed the weak interfacial bonds between PVC and wood and this led to more easily release the metal ions from additives of PVC. The turbidity and color of water for case of WPVC increased with increasing specimen immersion time whereas those for case of PVC did not change. From the results of water quality testing it indicated that WPVC applications which contact with water are safety. This was because water quality after immersion of WPVC specimen is within the effluent standards of pollution control department.