ON THE GLASS-TRANSITION BEHAVIOR, INTERACTION ENERGIES, AND HYDROGEN-BONDING STRENGTHS OF BINARY POLY(P-VINYLPHENOL) POLYETHER BLENDS

The miscibility behavior and the specific interactions of binary blends of poly(ethylene oxide) (PEG) and poly(vinyl methyl ether) (PVME) with poly(p-vinylphenol) (PVPh) are investigated by means of differential scanning calorimetry, analogue calorimetry, and Fourier transform infrared (FTIR) spectroscopy. The compositional variation of the glass transition temperature (T-g,) of PEO/PVPh and PVME/PVPh blends is analyzed in terms of the Kovacs free volume theory. This theoretical approach is able to reproduce the glass transition behavior of both systems quite well, although excess volume measurements of PVME/PVPh blends do not support the physical meaning assigned to the parameters in the theory. The presence of specific interactions between the PVPh and the polyethers is indicated by the large and exothermic interaction energy density obtained both from heat of mixing data using model compounds and from melting point depression data of PEO/PVPh blends. The specific nature and the average strength of the intermolecular interaction for the polymer blends and the analogue mixtures are determined by means of FTIR measurements.