Abstract

Thermal stabilization studies of poly(vinyl chloride) (PVC) in the presence of lead, cadmium, barium, calcium and zinc carboxylates of Balanites aegyptiaca seed oil (BSO) were carried out in air and under nitrogen atmosphere in the temperature range 170-190 ºC. The stabilizing effects of the metal carboxylates were assessed by measurements of the time for degradation to attain 1% conversion, t_DH and the corresponding rate of degradation, R_DH. Kinetic parameters determined under nitrogen were higher than those determined in air indicating that PVC degraded less in air within the temperature range employed. All metal carboxylates stabilized PVC under the conditions employed for the study and showed a relative order of stabilization of Cd-BSO > Ba-BSO > Pb-BSO > Ca-BSO > Zn-BSO. At higher temperature (190 ºC) deleterious effect of Zn-BSO manifested after prolonged heating. This is corroborated by data obtained from measurements of intrinsic viscosity of degraded PVC samples and thermogravimetric analysis. Synergistic effect was not exhibited by the compositions of binary mixtures of Ca/Zn carboxylates investigated while Ba/Cd carboxylates at 1: 9 ratio exhibited synergistic effect on PVC stabilization.

This work is licensed under a Creative Commons Attribution 4.0 License.