Modeling the thermodynamic behavior of copolymers using equation of state

Abstract

A simplified procedure with minimum input information for calculating an analytical equation of state for copolymer melts from density and surface tension at the room temperature, as scaling constants, is presented. The second virial coefficients are calculated from a two-parameter corresponding states correlation, which is constructed with two constants as scaling parameters, i.e., the molar density (ρ r) and surface tension at room temperature (γ r). This new correlation has been applied to the Tao–Mason equation of state to calculate the volumetric behavior of copolymer melts including poly(ethylene-co-propylene), poly(ethylene-co-vinyl acetate), poly(ethylene-co-metacrylic acid), poly(ethylene-co-acrylic acid), poly(ethylene-co-vinyl alcohol), poly(styrene-co-acrylonitrile), and poly(acrylonitrile-co-butadiene). The experimental specific volumes were correlated satisfactorily with our procedure and average absolute deviation percent for 7,431 data point is within 0.93 %.