INFLUENCES OF POLYMERIZATION TEMPERATURE ON SOME STRUCTURES AND PROPERTIES OF POLY(VINYL CHLORIDE) RESIN

Poly (vinyl chloride) (PVC) resins were synthesized at different polym erization temperatures(T) by suspension process. The average molecular weight ((M) over bar), syndiotacticity, crystallinity and glass trans ition temperature (T-g) of PVC resin were characterized by GPC, C-13 N MR and DSC methods. The results showed that (M) over bar decreased as T increased, the logarithmic values of (M) over bar were proportional to the reciprocal of T, the syndiotacticity, crystallinity and T-g inc reased with decreasing of T, the calculated crystallinity based on the syndiotacticity approached to the experimental value in the case of t he value of the minimum sequence length for syndiotactic chain segment contributing to the crystallites was 6.