Effect of different polymer molar mass on the phase behavior of carbon dioxide plus dichloromethane plus ε- caprolactone plus poly(ε-caprolactone) system

The phase behavior of the system containing carbon dioxide + dichloromethane + epsilon-caprolactone + poly(epsilon-caprolactone) was investigated in order to provide fundamental information to understand the polymerization reaction in a high-pressure system. The experiments were performed using a variable-volume view cell over the temperature range from 323.15 to 353.15 K, different mass ratios of carbon dioxide: dichloromethane: [epsilon-caprolactone + poly(epsilon-caprolactone)] (1:0.5:1, 1:1:1, and 1:2:1), different mass average molar mass of poly(epsilon-caprolactone) (14,000 and 138,840 g . mol(-1)), and different poly(epsilon-caprolactone) mass fractions (reaction conversion) from 0.0 up 15.0 wt%. Phase transitions of vapor-liquid bubble point type were verified and lower critical solution temperature (LCST) behavior phase in P-T diagrams was observed. The experimental results were modeled using the PC-SAFT EoS, providing a positive representation of the experimental phase equilibrium data. (C) 2020 Elsevier B.V. All rights reserved.