关键词: 共聚物, 三元共混物, 相容性, Spinodal相图

Abstract: A spinodal equation based on the modified Prigogine-Flory′s equation of state theory was derived and applied to predicting the phase behavior of a ternary polymer blend comprising styrene-methyl methacrylate copolymer(SMMA),styrene-acrylonitrile copolymer(SAN)and poly methyl methacrylate(PMMA). According to Flory′s combining rules, the parameters of state equation for copolymers were evaluated from those of the constituent monomer segments, and binary segmental contact energy parameters Xij between copolymer and copolymer were computed. The numerical solution of spinodals of SMMA-PMMA-SAN at various temperatures was derived by computer programming, and confirmed by the corresponding experimental results. It was found that Flory′s equation of state theory could be successfully extended to predict the phase behavior of ternary copolymer blends by adding the term of interaction entropy parameters Q_ij evaluated from the phase diagrams of the corresponding binary blends.

Key words: Copolymer, Ternary blends, Miscibility, Spinodal phase diagram