Drawing by solid‐state coextrusion of blends of atactic and isotactic polystyrene with poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Atactic polystyrene (aPS)/poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) and isotactic polystyrene (iPS)/PPO compatible blends of varied composition were subjected to solid‐state coextrusion. The efficiency of drawing, orientation, and crystallinity development were studied as a function of composition and draw ratio. The efficiency of drawing, as measured by elastic recovery, is high for coextrusion at temperatures ≲40°C above the glass transition temperature of the particular blend. The maximum attainable draw ratio for the blends decreased with increasing PPO concentration; the highest blend draw ratio attained was 6.5 for 25 wt % PPO. The orientation on drawing, as measured by birefringence, increased with draw but decreased with increasing PPO component at the same draw ratio. When PPO was <50% in iPS/PPO blends, iPS crystallized on draw. The morphology of drawn blends was studied by electron microscopy and wide‐angle x‐ray scattering.