Molecular dynamics study on the dissolution behaviors of poly(vinyl acetate)‐polyether block copolymers in supercritical CO2

Abstract

AbstractPoly(vinyl acetate) (PVAc) could be dissolved in CO2 at a high pressure, which limits its application. In this work, the PVAc‐polyether block copolymers were constructed by introducing the CO2‐philic blocks poly(propylene oxide) (PPO) and poly(ethylene oxide) (PEO) into the PVAc molecules to increase the solubility of these polymers in supercritical CO2 (scCO2). The dissolution behaviors of PVAc‐polyether copolymers with different structures in scCO2 were investigated by the molecular dynamic simulation methods. First, the cohesive energy and solubility parameters of PVAc, PVAc‐PEO, and PVAc‐PPO copolymers were analyzed. Moreover, the mechanism of PVAc‐polyether copolymers dissolving in CO2 was investigated. The results show that PVAc‐PPO molecules have a higher solubility in CO2 because they have lower polymer–polymer and higher polymer‐CO2 interactions than PVAc and PVAc‐PEO. Among the three structures of PVAc‐PPO molecules, PVAc‐PPO‐PVAc (VPV) has a highest solubility in CO2. Therefore, the molecular composition and structure have greatly influences on the interactions of polymer and CO2.