• Journal of Industrial Technology
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• v.18
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• pp.277-287
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• 1998

In this work continuous thermodynamics was adopted for describing the influence of copolymer polydispersity on phase separations in random copolymer solutions. Continuous themodynamic frameworks were formulated using the Flory-Huggin's excess Gibbs free energy model in which the concentration- and temperature-depentent terms of interaction parameter x were modified. Cloud-point curves and coexistence curves of poly(ethylene-vinylactate)/methylacetate solutions and poly(ehtylene-vinylacetate)/ethylacetate solutions were measured, and experimental data were fitted with theoretical relations formulated in this work. Calculated could-point curves were more good ageeable with experimental data than the modified Flory-Huggins's relations. Coexistence curves which were evaluated by using parameters of x estimated from experimental cloud-point curves, were found to coincide with experimental data.