Abstract
The physical ageing of poly(vinyl chloride) (PVC) is affected by the degree of crystallinity which can be induced by annealing of the sample at temperatures above T g. Differential scanning calorimetry (d.s.c.) measurements showed that the enthalpy relaxation, induced by sub- T g annealing, of PVC samples with different crystallinity increases with increasing crystallization temperature ( T c). On the other hand, the enthalpy relaxation decreases with increasing crystallization time ( t c) at a given T c. These observations cannot be attributed only to the overall crystallinity percentage, but they are attributable mainly to the entire structure of the amorphous phase which depends upon above- T g annealing conditions ( T c, t c). The assumptions of different portions of the material crystallized at different T c and of decreasing extent of disturbed regions as t c increases seem to explain well the above findings. Solvent sorption experiments served to support our suggestions resulting from d.s.c. experiments.
Published Version
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