VINYL PLASTICS Epoxidised soybean oil has a stabilising effect on PVC, extending useful life. As PVC ages, hydrogen chloride is released, accelerating deterioration. Epoxidised fatty acids minimise autocatalytic deterioration by scavenging the acid. Recent research at the University of Delaware (USA) used soybean oil directly to make a cheap and renewable composite materials for replacing poly-vinyl plastics to build cars.