TERMINAL FUNCTIONALIZATION OF POLYPROPYLENE VIA THE ALDER ENE REACTION

A terminally anhydride functionalized polypropylene was synthesized vi a the Alder Ene reaction from a low molecular weight amorphous polypro pylene. A Lewis acid, SnCl2 . 2H(2)O, was found to catalyse the reacti on, thereby improving anhydride content in the polymer for reaction co nditions comparable to those in an extrusion environment, i.e, elevate d temperature and short residence time. The reaction was carried out a t 230 degrees C for 5 min in the presence of TEMPO, which acted as a f ree radical trap, preventing maleic anhydride from being grafted onto the backbone of the polypropylene. The product was characterized by se veral techniques, including FTi.r. and n.m.r., to provide evidence of the anhydride location on the chain. Several runs of varying catalyst concentration have shown that an optimum in anhydride incorporation on to the polypropylene exists. Examination of the system kinetics has sh own that the overall order of the reaction remains second-order despit e the presence of a catalyst. (C) 1997 Elsevier Science Ltd.