Process-induced morphology distribution in injection molded syndiotactic polystyrene samples

In this work, syndiotactic polystyrene was injection molded with different molding conditions. The morphology distribution inside the molded parts was analyzed by several techniques, including optical microscopy, IR spectroscopy, and X-ray diffraction. The final morphology distribution was found to be strongly affected by mold temperature and holding pressures. A peculiar morphology distribution, an alternation of several amorphous and crystalline layers, was found along the samples thickness. The experimental results were analyzed and discussed by means of a software code developed at the University of Salerno. The software implements a model for crystallinity evolution that is able to consider the effects of high cooling rates and high pressures. Furthermore, the software is able to predict the orientation evolution during the injection molding. On commenting on the differences between the experimental data and the model predictions for crystallinity and orientation, it was possible to gain some insights on the causes of the peculiar morphology distributions inside the molded samples.