Stabilising effect of derivatives of jatropha seed oil on the thermal degradation of poly(vinyl chloride)

Abstract

Nonoxidative and oxidative degradation studies on poly(vinyl chloride) were carried out at various temperatures in the presence of Jatropha seed oil, epoxidised Jatropha seed oil and metal soaps of the oils. The rate of dehydrochlorination at 1% conversion, the time required for degradation to attain 1% dehydrochlorination and changes in intrinsic viscosity, UV absorption spectra and levels of unsaturation in the degraded polymer samples have been used to assess the effects of the derivatives of Jatropha seed oil on the susceptibility of the polymer to degradation. Although the values of the rate of dehydrochlorination at 1% conversion were about the same order of magnitude (10 −2% min −1), it was found that in the presence of the derivatives of Jatropha seed oil, particularly the metal soaps of epoxidised Jatropha seed oil, the values of the rate of dehydrochlorination were relatively lower and the time required for degradation to attain 1% conversion considerably higher than the values obtained in the absence of the additives. The data from solution viscosity measurements and from the estimates of the number of double bonds formed in the degraded polymer samples indicate that the metal soaps of Jatropha seed oil and of its epoxides exert a stabilising effect on the nonoxidative and oxidative degradation of poly(vinyl chloride).