Effect of solid polymer interaction on transition temperature and diffusion coefficients

It has been shown that a nonreinforcing solid such as titanium dioxide can radically alter the glass transition temperature of the model polymer, poly(vinyl chloride–vinyl acetate) copolymer after being mechanically incorporated within it. The Tg values were either higher or lower than that of the original unfilled polymer, depending on the volume fraction of the solid. The magnitude of these changes is in some cases as great as 49°C. This phenomenon was explained on the basis of adsorption of the acetate radicals on the surface of the solid and the breaking of interchain hydrogen bonds. The changes in segmental mobility of the polymer as indicated by the variation in Tg were also verified by gaseous diffusion studies.