STEREOSELECTIVE SUBSTITUTION ON PVC USING PHASE-TRANSFER CATALYSTS

The nucleophilic substitution with sodium benzenethiolate in aqueous suspension in the presence of a phase-transfer catalyst has been studied for two samples of PVC of different tacticities. The kinetics show two well-defined periods: one period is very fast and involves low conversions that are greater as the isostatic content of PVC increases, while anothr steady period is slow and its slope seems to depend on physical features, e. g. , molecular weight and crystallinity, which would affect the accessibility of nucleophile. The evolution of unreacted syndio, iso, and heteroactic triad contents with degree of substitution has been followed by **1**3C-NMR spectroscopy. The influence of degree of substitution on both the thermal degradation rate and the evolution of UV-Visible spectra of equally degraded samples has been also studied.