Fibrillar Morphology of Syndiotactic Polystyrene Synthesized Over Heterogeneous Metallocene Catalyst

The morphologies of semi-crystalline syndiotactic polystyrene (sPS) polymerized over heterogenized metallocene catalysts have been investigated. It has been observed that sPS grows in fibrillar morphology with its diameter of about 30-50 nm. When silica-supported catalyst is used, the fragmentation of original silica support material takes place as confirmed by energy dispersive X-ray (EDX) spectroscopy. The polymer fibrils grow at the solid catalyst surface and intertwine quickly to larger nanofibrils. When the polymerization occurs in a confined geometry such as silica nanotube reactor (SNTR), these nanofibrils intertwine further to larger size and extrude out from the pores. The crystalline structure of the sPS analyzed by X-ray diffraction was of the d-form. Our experimental results show that the intrinsic morphology of sPS synthesized over heterogeneous metallocene catalysts is a fibrillar morphology because of rapid crystallization and the intercalation of solvent or monomer molecules between the polymer chain segments.