It has been reported that, while polystyrene (PS) is not miscible with poly(ethylene oxide) (PEO), styrene ionomers show very high miscibility with this material at low ethylene oxide contents (10 wt%) and high, thought not complete, miscibility at higher loading levels. Fourier-transform infrared (FTIR) spectroscopy was used to examine the specific interactions contributing to the miscibility of the blends of styrene-sodium methacrylate copolymers (S-NaMA) and PEO. The blends of styrene-methacrylic acid copolymer (SMAA) and PEO were also studied to be compared with the above ionomer blends. From the shift in the frequencies corresponding to carboxylate ion and ether group stretching vibrations of those blends, it was found that there was an important specific interaction involving ion-dipole bonding between ionic group in styrene ionomer and ether group in PEO. Asymmetric stretching vibration frequency of $COO^-$ group was increased as the fractional amount of PEO in the blend was increased, while symmetric stretching frequency was decreased. It was also found that the vibration frquencies remained almost constant when the PEO contents in the blend reached a certain value. The transition value of the fraction of PEO from which the vibration frequencies remained constant was increased as the contents of ionic group in ionomer were increased. The stretching vibration frequency of ether group in the ionomer/PEO blend was increased as the PEO contents in the blend were increased. It was also found that the glass transition temperature of the styrene ionomer was decreased dramatically with increasing PEO contents and that the glass transition temperature of the PEO rose appreciably with increasing styrene ionomer contents. From the comparison between the interactions in S-NaMA/PEO and SMAA/PEO blends, it was concluded that hydrogen bonding was stronger than ion-dipole interaction in these blends.
