Fabrication of MA-EPDM grafted MWCNTs by reactive extrusion for enhanced interfacial adhesion and mechanical properties of PP/MA-EPDM composite

Abstract

Maleic anhydride modified ethylene-propylene-diene tripolymer (MA-EPDM) is an efficient toughening agent for other polymers such as polypropylene (PP). However, the rubber toughened plastics always exhibit a trade-off between stiffness and toughness. In this study, PP/MA-EPDM blend had functionalized multi-walled carbon nanotubes (MWCNTs) incorporated for reinforcement of both stiffness and toughness. PP and MA-EPDM were melt-extruded with amine group functionalized MWCNTs. During the extrusion, MA-EPDM was grafted to the MWCNTs by the reaction between MA and amine groups (MWCNTs-g-MA-EPDM), resulting in the fabrication of PP/MA-EPDM/MWCNTs-g-MA-EPDM composite. The MWCNTs-g-MA-EPDM were extracted from the composite by dissolving and removing PP and unreacted MA-EPDM using a solvent to characterize resulting properties. The interfacial adhesion of MWCNTs-g-MA-EPDM to PP and MA-EPDM blend was characterized by using a drop-on-fiber method. The MWCNTs-g-MA-EPDM exhibited enhanced interfacial adhesion and better MWCNT dispersion in the composite compared to the pristine MWCNTs. As a result, the PP/MA-EPDM/MWCNTs-g-MA-EPDM composite exhibited the highest tensile strength, tensile modulus and impact strength of the composites examined.