Miscibility enhancement on the immiscible binary blend of poly(vinyl phenol) and poly(acetoxy styrene) with poly(ethylene oxide)

The miscibility and hydrogen-bonding behaviors of ternary polymer blends of poly(ethylene oxide) (PEO)/ poly(vinyl phenol) (PVPh)/poly(acetoxystyrene) (PAS) were investigated by using DSC and Fourier transform infrared spectroscopy (FTIR). The PEO is miscible with both PVPh and PAS based on the observed single T-g over the entire composition range. FTIR was used to Study the hydrogen-bonding interactions between PEO with PAS and PVPh, respectively. Quantitative analyses show that the strength of hydrogen-bonding strength is of the order of the hydroxyl-ether inter-association of PVPh/PEO blend > the hydroxyl-hydroxyl self-association of pure PVPh > the hydroxyl-carbonyl inter-association PVPh/PAS blend at room temperature. Furthermore, the addition of PEO is able to enhance the I miscibility of immiscible PVPh/PAS binary blends at lower (20 wt.-%) or higher (60 and 80 wt.-%) PEO content. However, there exists a closed iminiscibility loop in the phase diagram at 40 wt.-% PEO content due to the "Delta chi" and "Delta K" effects in this hydrogen-bonded ternary polymer system. Therefore, an interesting and unusual sandwich phase diagram has been observed in this ternary polymer blend.