Morphology of syndiotactic polystyrene as examined by small-angle X-ray scattering

Small Angle X-Ray scattering (SAXS) studies have been carried out on injection molded syndiotactic polystyrene (SPS) at room temperature and at elevated temperatures up to 290°C. Features indicating lamellar crystallinity were weak or entirely absent at room temperature, becoming increasingly intense above the glass transition temperature (T_g) for this material. A background scattering whose intensity was roughly proportional to q^-2, where q is the scattering momentum transfer, was present throughout the temperature range. We suggest that these results indicate that SPS materials formed in this way are three-phase systems, with an amorphous phase, a crystalline phase, and a grain boundary phase.