4 phenylene oxide)(PPO)ionomer(carboxylated PPO or sulfonated PPO)/poly(styrene-co-4 vinylpyridine)(PSVP)blends were investigated.The reduced viscosities of both the two series of blends were higher than those of comparable blends composed of PPO and PSVP.These were attributed to the acid base interactions resulting from proton transfer between the acid groups of the PPO ionomer and the vinylpyridine groups of the PSVP.