A study of chemical release of wook/PVC composites affecting on the physical and chemical water qualities

Abstract

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.