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Supporting Effects of Methylaluminoxane on the Living Polymerization of Propylene with a Chelating (Diamide)dimethyltitanium Complex
Author(s) -
Hagimoto Hitoshi,
Shiono Takeshi,
Ikeda Tomiki
Publication year - 2004
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200350079
Subject(s) - methylaluminoxane , polymerization , crystallography , metal , analytical chemistry (journal) , propylene oxide , materials science , physics , stereochemistry , chemistry , polymer , metallocene , nuclear magnetic resonance , organic chemistry , metallurgy , ethylene oxide , copolymer
Summary: Modified methylaluminoxane (MMAO), from which free AlMe 3 and Al( i Bu) 3 were reduced to ca. 0.1 mol‐%, was supported on metal oxides, such as anhydrous silica gel, alumina, or magnesia; the metal oxide‐supported MMAO prepared were used as cocatalysts for propylene polymerization combined with a chelating (diamide)dimethyltitanium complex. The systems conducted living polymerization of propylene at 0 °C regardless of the support for MMAO. The propagation rate constants ( k p ) of these systems and the molecular weight distribution ( $\overline M _{\rm w} {\rm /}\overline M _{\rm n}$ ) of the produced polymer depended on the metal oxide employed. The XPS analysis of the supported MMAOs suggested that the k p value increased with the Lewis acidity of MMAO on the support and the broadening $\overline M _{\rm w} {\rm /}\overline M _{\rm n}$ was ascribed to the distribution of k p caused by the heterogeneity of the supported cocatalyst.Plots of \overline M _{\rm n} and \overline M _{\rm w} {\rm /}\overline M _{\rm n} against polymerization time in propylene polymerization with [ArN(CH 2 ) 3 NAr]TiMe 2 : MMAO/SiO 2 system, \overline M _{\rm n} (•), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (○); MMAO/Al 2 O 3 system, \overline M _{\rm n} (▴), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (▵); MMAO/MgO system, \overline M _{\rm n} (▪), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (□); corresponding homogeneous system, \overline M _{\rm n} (▾), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (▿).