Modeling phase behavior of poly(lactic acid) in supercritical fluids

Poly (lactic acid) (PLA) is typical biocompatible polymer, and is widely used in drug delivery application. For the production of polymeric microspheres loaded with the pharmaceutical, the supercritical fluid technology using carbon difoxide (CO2) is favor because of non-toxic nature. In this work, the phase behaviors of PLA in various supercritical solvents such as dimethyl ether (DME), CO2, chlorodifluoromethane (HCFC-22), difluoromethane, trifluoromethane (HFC-23), 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane are described by PC-SAFT model. One binary interaction parameter without considering temperature-dependency is used over a wide range of temperature and pressure. CO2 shows the poorest solubility, while HCFC-22 and DME show the highest solubility. The predicted cloud-point pressure shows the increasing tendency with an increase of PLA's molecular weight. In addition, the pressure-temperature isopleths for the dl-PLA/CO2 solutions with DME, HCFC-22, and HFC-23 as a cosolvent are investigated. The predicted results for three ternary systems with PC-SAFT model show a good agreement with experimental data. (C) 2018 Elsevier Ltd. All rights reserved.