Coexistence Curves of Polystyrene in Cyclohexane near the Critical Double Point in Composition-Pressure Space

Solvent H/D isotope effects on miscibility and Θ-temperature in the polystyrene–cyclohexane system

“…In the case of the polystyrene-cyclohexane system both cases have been found (see Table 4), depending on the molecular weight and pressure ranges, dT c /dP is negative or positive. 25,[31][32][33][34] Although some data are limited to low pressure only, p < 100 bar, 31 it is possible to estimate dT c /dP with rather good accuracy over a fairly broad range of molecular weights from 3.7 Â 10 4 to 1.56 Â 10 6 and pressure up to 500 bar. The low pressure data set reported by Saeki et al 31 has been treated in the following way.…”

“…This procedure also seems to be risky for M w ¼ 67.0 Â 10 4 and 145.0 Â 10 4 because of the expected change of sign of dT c /dP. For other polystyrene fractions being considered [32][33][34] the measurements span over a broad pressure range, mostly up to 500 bar and the necessary UCST could be interpolated using 2 nd order fits. UCSTs reported by Wolf and Gerrissen 32 for pressure up to 300 bar were extrapolated to somewhat higher values.…”