MELTING BEHAVIOR OF HIGH-PERFORMANCE COMPOSITE MATRIX POLYMERS - POLY(PHENYLENE SULFIDE)

We have been studying crystallization and melting behavior of high performance semicrystalline polymers to increase our understanding of the effects of processing on microstructure. Questions on development of morphology center around whether single or dual populations of crystals exist after melt processing, and how these crystals melt creating the multiple endotherms usually observed. We have used differential scanning calorimetry (DSC) to examine endothermic response in poly(phenylene sulfide), PPS, after various processing treatments. These include isothermal melt crystallization and crystallization from the rubbery amorphous state. For the first time, we report endothermic response of solution crystallized mats of single crystals. Our results on melt crystallized PPS are explained by a model in which different crystal populations exist in the material at room temperature prior to DSC scanning. Ability of the material to reorganize during the scan depends upon the initial state of perfection of the crystals. Copyright © 1990 Society of Plastics Engineers