Effect of different peroxide initiators on the reaction extrusion of polypropylene-graft-cardanol and its compatibilization on PP/PC

Abstract

Polypropylene-graft-cardanol (CAPP) was prepared by reactive extrusion in the presence of three kinds of initiators: dicumyl peroxide (DCP), benzoyl peroxide (BPO) and di-tert-butyl peroxide (dTBP). The effects of initiator type on grafting degree, melt flow index (MFI), isothermal crystallization and capillary rheological properties were investigated. CAPP with an improved level of grafting and stabilized value of MFI was obtained in the presence of DCP. The cardanol grafted onto polyproplylene (PP) afforded an “impurity” for the formation of a crystallization nucleus and spherulite growth during the crystallization process. On the other hand, the shear stress and viscosity of CAPPs were lower than PP because the cardanol grafted onto PP broadened the distance between the molecules. In particular, the shear stress and viscosity of CAPP using DCP as the initiator was lower than that of CAPP by using BPO or dTBP attributed to the optimum initiation of DCP. The effect of CAPP using DCP as the initiator on the compatibilization of PP and bisphenol-A polycarbonate (PC) was investigated with a mechanical properties test and scanning electron microscopy (SEM). It could be found that the CAPP enhanced the interfacial adhesion between PP/PC and improved the mechanical properties.