Recycled polycarbonate as impact modifier in polypropylene

Abstract

© 2019 Author(s).Polypropylene (PP) is one of the most widely used commodity thermoplastics, such as in the automotive sector, in part, for being lightweight, flexible and strong, with high flexural fatigue strength. However, it displays low impact strength, which is commonly improved by adding elastomer. Elastomer, however, reduces tensile strength and stiffness. To increase impact strength without reducing tensile strength and stiffness PP was blended with recycled polycarbonate (PC) at 10, 20 and 30 wt%. Since these polymers are incompatible two compatibilizer have been tested in the blends, namely, maleic anhydride grafted PP, PPgMA, and a Lotader copolymer ethylene -co-methyl acrylate co-glycidyl methacrylate, P(E-co-MA-co-GMA). Two methods of blending have been tested: (i) tumble mixing of all components with subsequent extrusion and injection molding; and (ii) extrusion of PC/compatibilizer master-batch, with subsequent injection molding of tumble-mixed master batch plus PP. Specimens have been subjected to impact and tensile testing as well as scanning electron microscopy analysis. In terms of mechanical properties the best performance was found with the 80/20 PP/PC blend containing 10 wt% Lotader, prepared according to the first method of blending.