COMPARISON OF THE STABILIZING EFFICIENCIES OF METAL CARBOXYLATE AND TIN STABILIZERS OF PVC

摘要

In order to obtain detailed understanding of the mechanism and action of PVC stabilizers, a new exact method has been developed for the determination of the stabilizing efficiency of these compounds. This is based on the separation of the direct chemical stabilization, i. e. blocking according to the reversible blocking mechanism of PVC stabilization, and the HCl-scavenging capacity of stabilizers. This new method has been applied to investigate the stabilizing efficiency of different stabilizers, such as metal carboxylates and tin compounds. In this study, the stabilizing efficiencies of these stabilizers will be compared by carrying out PVC degradation under inert and oxidative conditions. The stabilizing efficiencies allowed setting an efficiency order for a variety of stabilizers. These studies also led to surprising findings for thermooxidative stabilization under the applied conditions.