고압상태에서 이산화탄소가 포함된 이성분계 혼합용매에 대한 Poly(L-lactide)와 Polycaprolactone의 상거동

Abstract

We measured cloud points using the high-pressure variable volume cell apparatus for poly(L-lactide)(L-PLA) and polycaprolactone(PCL) in various solvents. The solvents used for dissolving poly(L-lactide) and polycaprolactone were HCFC-22(chlorodifluoromethane) and DME(dimethylether), HCFC-22+CO2, and DME+CO2. In case of L-PLA, it was dissolved well in HCFC-22 in the pressure range 4.0-15.0 MPa and the temperature range 344-393 K, and exhibited LCST(lower critical solution temperature) behavior in HCFC-22 and HCFC-22+CO2. In case of polycaprolactone, it was dissolved well in DME and HCFC-22 in the pressure range 13-37 MPa and 3-27 MPa respectively, in the range 310-415 K, and also exhibited LCST behavior in DME, HCFC-22, HCFC-22+CO2, and DME+CO2. The cloud point pressure of both poly(L-lactide) and polycaprolactone increased proportionally to the amount of CO2 added at the same temperature. According to these results, it was known that CO2 could be used as an anti-solvent, and the cloud point of poly(L-lactide) and polycaprolactone could be controlled by changing the concentration of CO2.