ALDER-ENE FUNCTIONALIZATION OF POLYPROPYLENE THROUGH REACTIVE EXTRUSION

A commercial isotactic polypropylene was degraded to increase its term inal vinylidene group concentration, and it was subsequently functiona lized with maleic anhydride through the Alder Ene reaction at temperat ures above 200 degrees C in a co-rotating twin screw extruder. Charact erization of the maleated product by Fourier transform infrared spectr oscopy, H-1 NMR, differential scanning calorimetry, and gel permeation chromatography showed the anhydride group to be terminally attached, and the degree of functionalization was determined by infrared analysi s. Increased temperature and maleic anhydride concentration, as well a s improved mixing in the extruder, were found to improve the extent of the reaction. The catalytic contribution of Lewis acid species was ev aluated, and ruthenium chloride was found to increase the extent of th e reaction by 16% in comparison with stannous chloride as a catalyst i n the Alder Ene reaction. (C) 1999 John Wiley & Sons, Inc.