Grafting of maleic anhydride on polypropylene by reactive extrusion: Effect of maleic anhydride and peroxide concentrations on reaction yield and products characteristics

Abstract

A series of polypropylenes (PPs) grafted with maleic anhydride (MA), prepared by reactive extrusion in a twin screw extruder with different contents of peroxide and MA, was characterized. For each sample, the amount of grafted MA, the molecular weight distribution, the viscoelastic properties in small amplitude oscillatory shear and the transition temperatures and enthalpies were measured. The respective influence of initial MA and peroxide concentrations on these parameters was characterized. In particular, it was shown that the rheological properties are only controlled by the molecular weight, whatever the way it has been obtained, by varying either MA content or peroxide concentration. Moreover, it is clearly shown that the presence of MA tends to enhance the PP degradation due to the peroxide.