Phase Behavior for Poly(vinylacetate) + Carbon Dioxide + Cosolvent Ternary Systems

Abstract

Experimental cloud point and bubble point data of ternary mixtures for poly(vinylacetate) (PVAc) and cosolvents in carbon dioxide (CO2) are studied using the supercritical CO2 phase behavior device. The cloud point and bubble point pressures are determined by measuring the resistance variation of photoresistance. Acetate acid and ethyl acetate have been selected as the cosolvents. These systems show phase behavior over a temperature range of 308.2–338.2 K and pressure of up to 50 MPa. The transition point pressure increases as the temperature increases. The transition point isopleths for the PVAc + CO2 + cosolvent ternary systems show upper critical solution pressure types. The cloud point and bubble point curves for the PVAc + CO2 + cosolvent systems decrease rapidly as the cosolvent concentration increases. When the mass ratio of PVAc and cosolvents is fixed at 1:7, the transition point pressures increase as CO2 increases. Compared with acetic acid and ethyl acetate, the transition point pressures of th...