Simulation and model development for the equation of state of heteronuclear non-additive copolymer chains

Full Paper: Molecular dynamics simulations of hard alternating copolymer chains composed of size asymmetric nonadditive segments were performed. Different degrees of polymerization, densities, size ratios and non-additivities were used. The equation of state for these copolymers was investigated and models based on the first order thermodynamic pertubation theory (TPT1) and the polymeric analog of the Percus-Yevick approximation (PPY) were developed to predict the compressibility factor of the copolymers. The models predicted the compressibilities of the mixtures accurately at small size ratios, low degrees of polymerization and higher densities. The TPT1 model was generally more accurate in predicting the compressibility factor than the PPY model.