Orientation and relaxation study of polystyrene: Polystyrene/poly(phenylene oxide) blends

Polarization modulation infrared linear dichroism has been used to study th e molecular orientation and relaxation of polystyrene/poly(2,6-dimethyl 1,4 -phenylene oxide) (PS/PPO) miscible blends, containing up to 20% PPO, durin g and after a rapid uniaxial deformation above T-g. In general, it is found that both the PS and PPO chain orientation functions increase with stretch ing rate and PPO content, and decrease with temperature. For all blends inv estigated, between T-g + 5 and T-g + 13 degrees C, the relaxation occurs at the same rate for PS and PPO and, therefore, the relaxation times calculat ed are similar indicating, under those conditions, a strong relaxation coup ling between the two polymers at both short and long times. (C) 2000 John W iley & Sons, Inc.