Joong Jin Han1, Sang Bok Lee2, and Kyu Yong Choi1. (1) Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, College Park, MD 20742, (2) Department of Chemistry and Biochemistry, University of Maryland, 0107 Chemistry Building, University of Maryland, College Park, MD 20742
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.