Polymer-supported titanium catalysts for syndiotactic polymerization of styrene

Poly(styrene-co-acrylamide)(PSAm)-titanium complexes (PSAm · Ti) were prepared and characterized. It is found that the coordination number of acrylamide (Am) to Ti in the complexes is strongly dependent on Am content in PSAm, but not on Am]/Ti] ratio in the feed. The infrared and x-ray photoelectron spectra suggest that the polymer-supported complexes possess the structure The catalytic behavior of the complexes in styrene polymerization is described. The catalytic activity is markedly affected by Al]/Ti] ratio in the complexes. ¹³C NMR, IR, and DSC data indicate that the polystyrene obtained with PSAm · Ti/MAO (MAO = methylaluminoxane) is highly syndiotactic. Use of Et₃Al and i-Bu₃Al in place of MAO gives atactic polystyrene. The activities of the various aluminum compounds used as the cocatalysts decrease in the order: MAO > Et₃Al > i-Bu₃Al. The polymer-supported complexes show relatively high activity even after the complexes had been exposed to air for 19 h or higher polymerization temperature. © 1996 John Wiley & Sons, Inc.