Methyl methacrylate bulk polymerization by schiff base-titanium complexes/Al(i-Bu)3

Substituted salicyladimine ligand (1) was prepared by schiff base condensation, and its sodium salts reacted with TiCl4 and CpTiCl3, giving the novel Titanium complexes {3,5-di-Br-2-(O)C6H2CHN [2(O)C6H4]}TiCl2(2); and {3,5-di-Br-2-(O)C6H2CHN [2(O)C6H4]} [TiCl(C5H5)](3) bearing Schiff base ligands. All complexes were characterized by 1HNMR and element analysis. In combination with Al(i-Bu)3, both 2/Al(i-Bu)3 (A) and 3/Al(i-Bu)3 (B) were active to initiate methyl methacrylate (MMA) polymerization. The influence of reaction parameters such as Al/Cat molar ratio, MMA/Cat molar ratio, time and temperature on polymerization have been examined in detail. The polymerization conversion of A and B reached 62%. Under the polymerization condition (MMA/Cat(molar ratio)=2000, Al/Cat(molar ratio)=20, T=60°C, t=15 h) of A system, Mη and MWD of PMMA reached 3.6 × 105 and 2.14 respectively. Under the same polymerization condition, B system, Mη and MWD of PMMA reached 4.3 × 105 and 2.44, respectively. From IR analysis, the syndiotactic content of PMMA obtained by A and B were about 85% and 86% respectively.