VLE properties and the critical parameters of ternary mixture of CO2 + toluene/dichloromethane involved in the SEDS precipitation process

Abstract

The VLE properties and the critical parameters of ternary mixture of CO2 + toluene/dichloromethane involved in the SEDS precipitation process were studied. The derived VLE and the critical properties data were used to select most preferred thermodynamic conditions (optimal SEDS process parameters) for implementation of the process of supercritical dispersion of the polymer mixtures of EVCA-113/PC using Solution Enhanced Dispersion by Supercritical (SEDS) fluids method. SEDS process has been used to produce ethylene vinyl acetate copolymer (EVCA)/polycarbonate (PC) polymer mixture microparticles at operating parameters from (8 to 25) MPa in the temperature range from (313 to 323) K and at concentration of (0, 0.25, 0.50, 0.75, and 1.00) mass fraction of PC. The effect of SEDS process operating variables (temperature, pressure, and concentration) on EVCA/PC polymer mixtures microparticle sizes and their physical–mechanical properties was studied. We showed that it is possible to modify particle dimensions and physical - mechanical properties of SEDS produced EVCA/PC polymer mixtures by changing the operating parameters. SEM and DSC were used to characterize of the produced polymer mixture microparticles. The crystallization kinetics (degree of crystallinity) and phase -transformation characteristics (heat of fusion and melting temperature) of polymer mixtures obtained by melt mixing and using the SEDS method were studied. The mechanical characteristics such as tensile strength and elongation-at-break were studied as a function of process conditions (temperature, pressure, and concentration).