Synergistic effects of ethylene propylene diene copolymer and carbon nanofiber on the thermo-mechanical properties of polypropylene/high-density polyethylene composites

Abstract

Ethylene–propylene–diene copolymer (EPDM) modified polypropylene (PP)/high-density polyethylene (HDPE) ternary blends and their composites with carbon nanofibers (CNF) were prepared. The PP/HDPE binary blends containing 80/20 concentration was used for the preparation of ternary blends and composites. The amount of EPDM in the ternary blend was 2, 4.8, 9.1, 13 and 16.6 wt%. The best mechanical properties were obtained for the ternary blends containing 13 wt% EPDM. These blends were further modified with CNF of varying concentrations from 0.043 to 1.7 wt%. The mechanical properties of the ternary composites especially with higher concentrations of CNF show a synergistic effect with good improvements in impact strength, tensile strength, tensile elongation, and tensile toughness. The DMA studies validate the homogeneity of the ternary composites. The DSC studies reveal better miscibility/compatibility of the PP/HDPE blends in the presence of EPDM and CNF. The thermal stability of the ternary composites was enhanced due to the better stability of EPDM and the uniform dispersion of the fillers in the polymer matrix. The contact angle values were improved with the addition of EPDM, however, for the ternary composites, only marginal variations in contact angle were observed.