Effect Of Different Peroxide Initiators On The Reaction Extrusion Of Polypropylene-graft-Cardanol

The polypropylene (PP) had become one of the most widely used commercial polymers because it had many advantages. On the other hand, PP was known to have some disadvantages which limited its application. An effective approach to improve such disadvantages was by melting a graft of appropriate monomer onto PP in the presence of an initiator. In this study, the polypropylene-graft-cardanol (CAPP) was prepared by reactive extrusion in the presence of three kinds of initiator as dicumyl peroxide (DCP), benzoyl peroxide (BPO) and di-tert-butyl peroxide (dTBP). The effects of initiator type on grafting degree, melt flow rate (MFR), capillary rheological properties, dynamic rheological properties, isothermal crystallization behavior and mechanical properties were investigated. To the end, the CAPP by using DCP was employed, acting at the interface to raise the phase adhension between the non-polar crystal PP and polarity amorphous PC blend. It was investigated by mechanical properties test, scanning electron microscopy (SEM) and rotational rheometer.The test results implied that the CAPP with improved level of grafting was obtained in the presence of DCP and the grafting degree reached optimal value when the concentration of DCP was0.2%. Accordingly, the MFR of CAPP by using DCP was bigger and changed much with the change of DCP concentration due to the more strong degradation of DCP. On the one hand, the shear stress and viscosity of CAPPs were lower than PP because the degradation of initiator. Moreover, at the same shear rate, the shear stress and viscosity of CAPP by using DCP as initiator was lower than that of CAPP by using BPO or dTBP attributed to the optimum degradation of DCP. In the same way, the storage modulus and loss modulus (dynamic modulus) of CAPP by using DCP as initiator was lower than that of CAPP by using BPO or dTBP. On the other hand, the cardanol grafted onto PP afforded "impurity" for the formation of crystallization nucleus and the spherulite growth during the crystallization process. Besides, the more cardanol grafted onto PP, the effect of "impurity" was stronger. In addition, the cardanol graft on PP had an obvious influence on the mechanical property of PP, particularly, the impact strength of CAPP by using DCP increases153%than PP. To the end, the CAPP by using DCP played a role of compatibilizer that raised the phase adhension between the non-polar crystal PP and polarity amorphous PC and obviously improved the mechanical properties.