INTERMOLECULAR COOPERATIVITY AND THE TEMPERATURE-DEPENDENCE OF SEGMENTAL RELAXATION IN SEMICRYSTALLINE POLYMERS

The effect of the presence of a crystalline phase on the temperature dependence of segmental relaxation is examined. For both an aromatic and an aliphatic polyester, for polypropylene, and for poly-(dimethylsiloxane) (PDMS), it is demonstrated that crystallinity has an insignificant effect on the temperature dependence of the segmental relaxation time when the temperature is normalized by the glass transition temperature, T(g), of the polymer. This allows the correlation between time and temperature dependencies of segmental relaxation, whereby more intermolecularly cooperative relaxations have a stronger dependence on T(g)-normalized temperature, to continue to be used to assess the intermolecular coupling strength in semicrystalline polymers.