Coexistence curve for polystyrene–cyclohexane near the critical point

Publisher Website
Google Scholar
Abstract
The coexistence curves for the system polystyrene–cyclohexane have been determined with a specially designed differential refractometer, which determines concentrations of the two coexisting phases with a precision of ± 0.01%. The plots of the coexistence curve data represented by log(X+−Xc) and log(Xc−X−) versus the reduced temperature ε = (Tc−T)/Tc yield largely curved lines. The shape of the coexistence curve very near the critical point, however, is asymptotically symmetric. The coexistence curve obtained with an over‐all concentration at the critical concentration is represented by the relation X+−X− = Bεβ with β=0.348 and B=0.97 in the temperature region of Tc −TB vary only slightly depending on the over‐all concentration. Although the data give a curved diameter, a precision of the present experiment is not sufficient to determine the asymptotic behavior of the diameter.