Polymerization of Methyl Methacrylate with a Novel Carbon Bridged Cyclopentadienyl Chromium Complex
A new carbon bridged cyclopentadienyl chromium complex of the type [ (C5H4)C(CH3)2 CH2(C5H4N) ]CrCl2 was prepared by treatment of CrCl3•(THF) 3 in THF solution with the lithium salt of ligand with cyclopentadienyl and pyridyl group. The chromium complex was characterized by mass spectra and elemental analysis. Activated by Al(i-Bu) 3, the chromium complex displayed a very high activity for methyl methacrylate (MMA) polymerization. After 18 hours, 85.49 % MMA was converted to polymethyl methacrylate (PMMA) with a viscosity average molecular (Mv) of 328000 at 60 °C at MMA/ Al(i-Bu) 3/chromium complex of 2000:20:1 in MMA bulk. The high conversion of MMA and high molecular weight of PMMA are the cause of the unique stable active site formed by the new chromium complex and cocatalyst.
Z. Z. Cheng et al., "Polymerization of Methyl Methacrylate with a Novel Carbon Bridged Cyclopentadienyl Chromium Complex", Advanced Materials Research, Vol. 214, pp. 517-521, 2011