title: Syndiotactic polystyrene nanofibrils in silica nanotube reactors: understanding of synthesis with ultrahigh molecular weight.
abstract: Nanofibrils of ultrahigh molecular weight syndiotactic polystyrene (sPS) have been synthesized in a silica nanotube reactor (SNTR) using a metallocene catalyst in conjunction with methylaluminoxane cocatalyst. 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 sPS synthesized in the SNTR has ultrahigh molecular weight (Mw = 928,000 g/mol) with a large fraction of 2 000,000-5,000,000 g/mol molecular weight polymers.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, USA. choi@umd.edu
authors.forename: Kyu Yong
authors.initials: KY
authors.lastname: Choi
authors.forename: Joong Jin
authors.initials: JJ
authors.lastname: Han
authors.forename: Bo
authors.initials: B
authors.lastname: He
authors.forename: Sang Bok
authors.initials: SB
authors.lastname: Lee
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D002384:Catalysis; D008567:Membranes, Artificial; D008970:Molecular Weight; D049329:Nanostructures / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D010316:Particle Size; D011137:Polystyrenes / Q000138:chemical synthesis* / Q000737:chemistry*; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry
chemical_list: D008567:Membranes, Artificial; D009942:Organometallic Compounds; D011137:Polystyrenes; D012822:Silicon Dioxide; D014025:Titanium; D000537:Aluminum Oxide