Dynamic‐mechanical study of the secondary transition of poly(vinyl chloride)

Abstract
The influence of crystallinity, thermal history, plasticization, copolymerization, and chemical modifications on the dynamic‐mechanical properties of poly(vinyl chloride) has been studied by means of a free‐oscillation torsional pendulum. It was found that the secondary dispersion maximum is not affected by free volume, crystallinity, or head‐to‐head microstructure, but is modified by post‐chlorination, copolymerization, and plasticization. These results show that the molecular motions responsible for the PVC β peak are not influenced by local differences in the distribution of the Cl atoms along the chain, so that they seem to be largely of a cooperative type.