Kyu Y. Choi1, Joong Jin Han2, Bo He3, and Sang Bok Lee3. (1) Chemical and Biomolecular Engineering, University of Maryland, Stadium Drive, Bldg 090, College Park, MD 20742, (2) Department of Chemical & Biomolecular Engineering, University of Maryland, Stadium Drive, Bldg 090, College Park, MD 20742, (3) Department of Chemistry, University of Maryland, Stadium Drive, Bldg 090, College Park, MD 20742
Nanofibers of syndiotactic polystyrene have been synthesized in a metallocene catalyst-anchored silica nanotube reactor (SNTR) in an porous alumina template. Very thin sPS nanofibrils (< 10 nm) grown at the catalytic sites on the pore walls aggregate to form intertwined, rope-like nanofibrils with 30-50 nm diameters, which further intertwine into even larger 200-nm diameter polymer nanofibrils. The extrusion of nanofibrils synthesized inside the SNTR was directly observed by scanning electron microscopy, and the individual SNTR containing a single polymer nanofibril was separated and observed by transmission electron microscopy. The syndiotactic polystyrene produced in the SNTR is a delta-form crystal polymer and it has very high molecular weight including a large fraction of 2,000,000 - 5,000,000 g/mol molecular weight and higher crystalline melting point than the sPS synthesized over homogeneous or silica-supported metallocene catalysts.