Thermal characterization, melting behaviors, dynamic mechanical properties, and morphology in the polymorphism of syndiotactic polystyrene and poly(2,6-dimethyl-1,4-phenylene oxide)

The thermal characterization, melting behaviors, dynamic mechanical properties, and morphology of syndiotactic polystyrene and its blends with poly(2,6-dimethyl-1,4-diphenylene oxide) were examined by differential scanning calorimetry, dynamical mechanical analyzer, and scanning electron microscope. With differential scanning calorimetry and scanning electron microscope results, two melting endothermic peaks and blending morphology were observed. We suggest that the lower melting endothermic peak is due to the melt of syndiotactic polystyrene, however, the higher melting endothermic peak comes from the melt of recrystallized syndiotactic polystyrene crystals during the differential scanning calorimetry scan. With dynamical mechanical analyzer results, we find that addition of poly(2,6-dimethyl-1,4-diphenylene oxide) into syndiotactic polystyrene can increase the soft temperature and toughness. Moreover, the experimental results also reveal that crystallization of syndiotactic polystyrene in the syndiotactic polystyrene/poly(2,6-dimethyl-1,4-diphenylene oxide) blend is impeded in the presence of poly(2,6-dimethyl-1,4-diphenylene oxide) and the melting behaviors of syndiotactic polystyrene/poly(2,6-dimethyl-1,4-diphenylene oxide) blends are homogeneous.