The effect of intermolecular forces on the glass transition of solute-polymer blends .2. Extension to different solutes

The effects of intermolecular forces on the glass transition temperature (T-g) of various dye solutes in numerous polymer matrices have been investigated. The T(g)s of these dye-polymer blends were found to depend on the polymer T-g, the dye T-g, their relative concentrations and the dye-polymer affinity. Attempts have been made to correlate increases in T-g with dye-polymer affinity using solubility parameters as a predictive tool. Poor correlations were obtained using global solubility parameters. Excellent correlations were made between elevation in T-g and enhanced dye-polymer affinity using averaged polar/hydrogen bonding solubility parameters. For all dye solutes, the T-g was low when there was a large mismatch in solubility parameters, increased as dye and polymer became more compatible and was at a maximum when the solubility parameters of both components were equal. The results also indicate that longer range polar and hydrogen bonding forces have a controlling influence on T-g. (C) 1997 Elsevier Science Ltd.