Toughening of poly(2,6-dimethyl-1,4-phenylene oxide)/nylon 6 alloys with functionalized elastomers via reactive compatibilization: morphology, mechanical properties, and rheology

Blends of poly(2,6-dimethyl-1,4-phenylene oxide)/nylon 6 alloys based on ethylene-propylene-diene elastomer (EPDM) grafted with maleic anhydride (MA) (EPDM-g-MA), EPDM grafted with glycidyl methacrylate (EPDM-g-GMA), and styrene-ethylene-butadiene-styrene block copolymer grafted with MA (SEBS-g-MA) were prepared via melt extruction, and morphology, mechanical properties, and rheology were studied. The compatibilizing effects of functionalized elastomers on the PPO/nylon 6 alloys were proved by DSC analysis and confirmed by the significant improvement in the notched Izod impact strength. Toughening was resulted from the smaller particle size and finer dispersion of EPDM in the PPO/nylon 6 matrix as well as a novel network structure of SEBS-g-MA domain in matrix. The notched Izod impact strength of the blends exhibited an optimum value when the extent of MA or GMA graft ratio of EPDM varied, which was an order of magnitude higher than the non-toughened alloys. The morphology revealed that the size of EPDM particles decreased with an increase in graft ratio of MA or GMA onto EPDM. Rheology investigation indicated that the MA or GMA moieties on EPDM reacted with the amine groups of nylon 6, which increased the molecular weight and the degree of branching, and thus resulted in an increase in the viscosity of the blends. This proved the reactive compatibilization between functionalized EPDM and PPO/nylon 6 matrix.