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);{3,5-di-Br-2-(O)C6H2CHN[2(O)C6H4]}[TiCl (C5H5)](3) bearing Schiff base ligands.All complexes were characterized by 1 HNMR 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)=2 000,Al/Cat(molar ratio)=20,T=60 ℃,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.