A PARAMETRIC STUDY OF THE TERMINAL MALEATION OF POLYPROPYLENE THROUGHAN ALDER ENE REACTION

A study of the parameters that affect the Alder Ene reaction with resp ect to the synthesis of a terminally anhydride-functionalized polyprop ylene was carried out over a temperature range of 220-250 degrees C us ing maleic anhydride concentrations of 2-12 mol equivalence with respe ct to the vinylidene group. As previously observed, a Lewis acid (i.e. , SnCl2. 2H(2)O) had a catalytic effect on the reaction at these tempe ratures, thereby improving anhydride content in the polymer for short reaction times. Increased temperature and maleic anhydride concentrati on had a positive effect on improving the incorporation of the succiny l anhydride moiety at the terminal site in polypropylene. Lower SnCl2. 2H(2)O concentrations, likewise, improve the functionality of the pro duct. The application of a second-order kinetic model to the measured succinyl anhydride results was not valid over the entire temperature r ange studied due to side reactions, particularly vinylidene isomerizat ion, and homopolymerization of maleic anhydride. Ruthenium chloride ha s been examined as another possible catalyst candidate in the reaction and has been found to improve the level of anhydride incorporation in polypropylene compared to stannous chloride. (C) 1998 John Wiley & So ns, Inc.