Influence of the physical characteristics of the polymer on the glass transition of various chemically modified PVCs

Vinylchloride–vinylthiocresol and vinylchloride–vinylthionaphthol copolymers of various compositions were prepared by the substitution reaction of PVC with sodium thiocresol and sodium thionaphthol, respectively, in different solvents and at different temperatures. The variation of the glass transition temperature of these copolymers with chemical com‐position does not follow the Flory–Fox equation, but is found to depend on the solvent and the temperature at which the copolymer is obtained. The comonomer sequence distribution and stereosequence content of the above copolymers, and those of vinylchloride–vinyl‐thiobenzene copolymer, were determined by 1H‐ and 13C‐NMR spectroscopy. The depen‐dence of comonomer distribution and stereoregularity content with chemical composition for the three series of copolymers, prepared in different solvents and temperatures, are similar. The Tg deviations for the three series of copolymers were attributed to the con‐tribution of physical characteristics of the PVC structure, originating from polymer–solvent interactions.