The effect of the number and nature of phenoxy group substituents on the activity and selectivity
of CpTiCl3-n(OC6H5-mXm)n/MAO catalyst systems in syndiotactic polymerization of styrene
Polimery 2002, No 1, 30
Styrene was polymerized oyer hemititanocene catalysts CpTiCl3-nYn (where Y = OC6H5-mXm; X = Me, i-Pr, t-Bu or Cl; n = 1—3; m = 1—3) activated with methylaluminoxane (MAO). Catalyst structure modifications allowed to follow the effect of steric factors and of the electron donor-acceptor properties of phenoxy ligands on the yield and selectivity of syndiotactic polymerization of styrene (Table 1). The interpretation uses Scheme 1 which shows the mechanisms believed to underlie the formation of active centers and the reaction of propagation of the polymerization.
Keywords: syndiotactic polymerization of styrene, hemititanocene catalysts, substitution of ligands, index of syndiotacticity