Compatibilization and toughening of immiscible ternary blends of polyamide 6, polypropylene (or a propylene-Ethylene copolymer), and polystyrene

摘要

In this work, typical ternary blends of three versatile polymers-polyamide 6, a propylene-ethylene copolymer (co-PP), and polystyrene-were studied. As a compatibilizer, co-PP with randomly dispersed minor ethylene units was multimonomer-melt-grafted in the presence of maleic anhydride, styrene, and dicumyl peroxide. The influence of the ethylene content in co-PP and the blend composition on the performance was investigated. Scanning electron microscopy images showed an obvious decrease in the droplet size of the dispersed phase with increases in the compatibilizer content and number of ethylene units in co-PP. Peaks of tan δ/temperature curves approaching the glass-transition temperatures of the components were observed with dynamic mechanical thermal analysis. The improved mechanical properties implied good compatibility of the components in the blends. Significant toughening was achieved when the concentration of co-PP was increased from 15 to 25 wt %: the elongation at break of the compatibilized blends increased dozens of times in comparison with the elongation at break of the uncompatibilized blends. The introduction of the multimonomer-melt-grafted co-PP was shown to be an effective approach for improving immiscible multipolymer blends and to have practical potential.