Artificial Dry Heat Temperature Effects on Tensile Properties of Chlorinated Poly(Vinyl Chloride)

摘要

Chlorinated-PVC (CPVC) pipes are used extensively for water supply pipes, wastewater, and gas distribution. They are desired for their quick installation, durability and strength. CPVC is a heat resistant type of plastic that welds, bends and shapes easily. Its utilization in harsh environmental conditions requires an understanding of weathering effects on its mechanical properties. In this work, the effect of dry heat on the tensile properties of CPVC is studied using artificial weathering procedures. CPVC specimens were prepared according to ASTM standard D 638 and exposed to accelerated dry heat temperature to simulate natural weathering effects of long term outdoor exposure. Tests were performed at two different temperatures of 40°C and 70°C for duration up to 3000 hours. Stress-strain curves were developed for this material and weathering effects on the tensile strength, modulus of elasticity and strain at fracture were obtained. The results of this investigation show that the ultimate tensile stress and the fracture stress exhibit a slight increase over the period of the exposure. The modulus of elasticity was not affected by the exposure while the fracture strain decreases slightly at the beginning of the exposure and remains constant for the remaining period of the exposure.