Polymerization of Butyl Methacrylate Catalyzed by Salicylaldehyde-Imine Zirconium /Al(i-Bu)3 System

A new kind of zirconium(Zr) complex containing ligand of salicylaldehyde-imine was successfully synthesized with ZrCl4·2THF and salicylaldehyde-imine as raw materials. The ligand was characterized by means of 1HNMR, IR, and GC-MS, and Zr complex was characterized by means of 1HNMR and IR, respectively. The Zr complex, combined with co-catalyst of Al(i-Bu)3, was explored to be effective catalytic system for the polymerization of butyl methacrylate(BMA), to prepare poly-n-butyl methacrylate (PBMA), which was characterized by IR, 13C-NMR and GPC. Compared with other double-component (MAO/Cat, AlEt3/Cat) catalytic systems, catalytic system of Al(i-Bu)3 and the Zr complex provided the best catalytic activity under the same conditions. The influence of polymerization parameters, such as molar ratio of Al(i-Bu)3/Cat and BMA/Cat, polymerization temperature and polymerization time, was studied with Zr complex/Al(i-Bu)3 system. With increasing polymerization time from 4 to 24 hour, the monomer conversion increased from 40.14% to 96.56%. Viscosity-average molecular weight (Mv) of PBMA, detected by the viscosity methodology, increased from 12.67×104 Da to 44.97×104 Da and lower molecular weight distribution was obtained. According to these results, the Zr complex contained ligand of salicylaldehyde-imine was a kind of readily, long lifetime and high activity catalyst for BMA polymerization.