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Dimethylsilylbis(1‐indenyl) zirconium dichloride/methylaluminoxane catalyst supported on nanosized silica for propylene polymerization
Author(s) -
Li KuoTseng,
Ko FuSheng
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.27152
Subject(s) - catalysis , polymerization , materials science , methylaluminoxane , metallocene , monomer , polymer , polymer chemistry , post metallocene catalyst , polypropylene , chemical engineering , zirconium , particle (ecology) , coordination polymerization , molar mass distribution , solution polymerization , chemistry , composite material , organic chemistry , oceanography , engineering , metallurgy , geology
A dimethylsilylene‐bridged metallocene complex, (CH 3 ) 2 Si(Ind) 2 ZrCl 2 , was supported on a nanosized silica particle, whose surface area was mostly external. The resulting catalyst was used to catalyze the polymerization of propylene to polypropylene. Under identical reaction conditions, a nanosized catalyst exhibited much better polymerization activity than a microsized catalyst. At the optimum polymerization temperature of 55°C, the former had 80% higher activity than the latter. In addition, the nanosized catalyst produced a polymer with a greater molecular weight, a narrower molecular weight distribution, and a higher melting point in comparison with the microsized catalyst. The nanosized catalyst's superiority was ascribed to the higher monomer concentration at its external active sites (which were free from internal diffusion resistance) and was also attributed to its much larger surface area. Electron microscopy results showed that the nanosized catalyst produced polymer particles of similar sizes and shapes, indicating that each nanosized catalyst particle had uniform polymerization activity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008