Effects of Blending On the Polymorphic Behavior of Melt-Crystallized Syndiotactic Polystyrene

The complex polymorphic behavior of syndiotactic polystyrene (s-PS) in melt-crystallized samples is altered by blending with poly (2,6-dimethyl-1,4-diphenylene oxide) (PPO). In particular, to render the beta form in these blends, starting with samples containing the alpha or gamma forms, requires much lower temperatures and shorter melting times than for pure s-PS. On the basis of the results, it is suggested that this phenomenon is due to more rapid loss of the memory of the alpha form, for the same temperature and time, in the melt in the presence of PPO molecules.