Miscibility and volume changes of mixing in the polystyrene/poly(2‐chlorostyrene) blend system

Abstract The specific volume‐temperature relationships of polystyrene, poly(2‐chlorostyrene), and their polymer blends as well as the volume change of mixing Δ v m of the blends were obtained in the liquid state by dilatometry. The equation of state parameter and the molecular parameter of each homopolymer and blends were determined according to the lattice fluid theory of Sanchez and Lacombe. The experimental Δ v m obtained agreed quite well with that predicted from theory, and the enthalpy of mixing Δ H m was also predicted using the pair molecular parameter. These two values were negative, indicative of miscibility of polystyrene and poly(2‐chlorostyrene) in the liquid state. The absolute values of Δ v m and Δ H m were about twice those for polystyrene and poly(phenylene oxide) blend, suggesting a specific interaction between the two polymers.