Effect of nano-CaCO3 on polymorphic behavior in syndiotactic polystyrene for non-isothermal crystallization

Syndiotactic polystyrene (sPS)/nano-CaCO3 composites were prepared on a twin screw extruder for the first time. Differential scanning calorimeter and wide-angle X-ray diffraction were used to investigate the effect of maximum melting temperature (Tmax) and the content of nano-CaCO3 on the crystal forms and melting behavior of sPS for non-isothermal crystallization. The results indicated that the increasing Tmax decreases the crystallization temperature of sPS and facilitates the formation of β-crystal. The addition of nano-CaCO3 changes the melting behavior and crystal form of melt-crystallized sPS and facilitates the formation of β-crystal. The increase in the content of nano-CaCO3 decreases crystallization temperature of sPS and increases the content of β-crystal, which was similar to the effect of increasing Tmax. Pure β-crystal in sPS/nano-CaCO3 composites can be obtained at lower melting temperature due to the effect of nano-CaCO3.