Temperature- and pressure-dependent composition fluctuations in a polybutadiene/polystyrene polymer blend and diblock copolymer

摘要

The phase diagram, the Flory-Huggins parameter Gamma and the Ginzburg parameter Gi of a polybutadiene/polystyrene blend and diblock copolymer were determined by small-angle neutron scattering in the pressure range of 0.1 and 200MPa. Both systems show qualitatively the same pressure dependence. The enthalpic and entropic terms of Gamma are larger in blends. In the diblock copolymer a constant order-disorder temperature was observed which could be explained by a compensation effect between Gamma and Gi. [References: 17]