Syndiotactic polystyrene nanofibrils in silica nanotube reactors: understanding of synthesis with ultrahigh molecular weight.
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.
Choi
Kyu Yong
KY
Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, USA. choi@umd.edu
Han
Joong Jin
JJ
He
Bo
B
Lee
Sang Bok
SB
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
D008567:Membranes, Artificial; D009942:Organometallic Compounds; D011137:Polystyrenes; D012822:Silicon Dioxide; D014025:Titanium; D000537:Aluminum Oxide