Coexistence curves of polymer solutions

Abstract

The asymptotic method was applied to polymer solutions to obtain their coexistence curves. The configurational partition function of the lattice model was much improved by introducing free volumes into consideration. Consequently, there were two kinds of coexistence curves which depend not only on the molecular weight but also on coordination number z, one corresponding to the upper critical solution temperature and the other to the lower critical solution temperature. The agreement of them with the experimental results is good. The comparison of the present theory with existing theories was also discussed.