Interdiffusion in blends of deuterated polystyrene and poly(alpha-methylstyrene)

The differing glass transitions between deuterated polystyrene and poly(alp ha-methylstyrene) are shown to have a profound effect on their interdiffusi on coefficient. We have measured the interdiffusion coefficient as a functi on of concentration and temperature for two blends. The results can be inte rpreted in terms of the 'fast' theory of interdiffusion with the temperatur e dependence obtained from a Williams-Landel-Ferry (WLF) treatment. The int radiffusion coefficients of the two polymers have also been deduced by this analysis. It is found that the deuterated polystyrene has a much more conc entration-dependent intradiffusion coefficient than the poly(alpha-methylst yrene). Thermodynamic slowing down is also observed in one blend. (C) 1999 Elsevier Science Ltd. All rights reserved.