Solution behavior of ionomer blends - II. Acid-base interactions in blends of poly(phenylene oxide)ionomers and poly(styrene-4-vinylpyridine)

The solution behavior of blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) ionomers (carboxylated PPO, CPPO, or sulfonated PPO, SPPO) and poly(styrene-4-vinylpyridine) (PSVP) was investigated. The reduced viscosities of both the two series of blends were higher than those of comparable blends composed of PPO and PSVP. This was 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. The existence of proton transfer between sulfonic acid and the pyridine group was confirmed by H-1 NMR studies on SPPO/4-VP blend. Moreover, the effects of functionalization level, solution concentration and cosolvent content on the strength of the acid-base interaction were discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.