Thermal, mechanical, and morphological characterization studies of poly(2,6-dimethyl-1,4-phenylene oxide) blends with polystyrene and brominated polystyrene

The miscibility of the binary and ternary blends of poly(2,6-dimethyl-1,4-p henylene oxide), brominated polystyrene, and polystyrene was investigated u sing a differential scanning calorimeter. The morphology of these blends wa s characterized by scanning electron microscopy. These studies revealed a c lose relation between the blend structure and its mechanical properties. Th e compatibilizing effect of poly(2,6-dimethyl-1,4-phenylene oxide) on the m iscibility of the polystyrene/brominated polystyrene blends was examined. I t was found that poly(2,6-dimethyl-1,4-phenylene oxide), which was miscible with polystyrene and partially miscible with brominated polystyrene, compa tibilizes these two immiscible polymers if its contention exceeds 33 wt 9b. Upon the addition of poly(2,6-dimethyl-1,4-phenylene oxide) to the immisci ble blends of polystyrene/brominated polystyrene, we observed a change in t he morphology of the mixtures. An improvement in the mechanical properties was noticed. (C) 2000 John Wiley & Sons, Inc.