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Korean Chemical Engineering Research,
Vol.42, No.3, 311-317, 2004
Vol.42, No.3, 311-317, 2004
고압상태의 다양한 용매내에서 poly(L-lactide)와 polycaprolactone의 상거동
Phase Behavior of Poly(L-lactide) and Polycaprolactone in Various Solvents at High Pressure
Variable volume view cell이 장착된 상평형 장치를 사용하여 고압 상태의 다양한 용매내에서 생분해성 고분자인 poly(L-lactide)(PLA)와 polycaprolactone(PCL)의 cloud point를 측정하였으며, 이 때 사용된 용매는 HCFC-22, HFC-23, HFC-32, HFC-125, HFC-143a, HFC-152a, HFC-227a, DME(dimethylether)였다. Poly(L-lactide)의 경우, DME와 HCFC-22에 대해 25.0 MPa 이하의 압력에서 잘 용해되었고 HFC-23, HFC-32, HFC-152a에 대해 53.2-116.02 MPa범위의 압력에서 용해되었다. 이들 용매내에서 Poly(L-lactide)은 분자량의 변화 (M.W.=80,000, 110,000, 230,000)에 따른 cloud point를 측정하였다. 그러나 HFC-125, HFC-143a, HFC-227ea에 대해서는 온도 413.15 K와 압력 160 MPa까지의 범위에서도 용해되지 않았다. Poly(L-lactide)의 cloud point는 HCFC-22, HFC-23, DME를 용매로 사용한 경우에 LCST(lower critical solution temperature)형태의 상거동을 나타내었으며, HFC-32과 HFC-152a를 용매로 사용한 경우에는 UCST(upper critical solution temperature)형태의 상거동을 나타내었다. Polycaprolactone의 경우, HCFC-22, HFC-143a, DME에 대해서는 36.9 MPa이하에서 비교적 잘 용해되었고 HFC-152a에 대해 126.31-151.45 MPa의 범위에서 용해되었으며 HFC-32, HFC-125, HFC-227ea에서는 413.15 K와 압력 160 MPa까지의 범위에서도 용해되지 않았다. Polycaprolactone의 cloud point는 HCFC-22, HFC-143a, DME를 용매로 사용했을 경우에 LCST형태의 상거동을 나타내었으며, HFC-152a를 용매로 사용했을 때에는 UCST형태의 상거동을 나타내었다.
Cloud points of poly(L-lactide) and polycaprolactone in chlorodifluoromethane(HCFC-22), trifluoromethane(HFC-23), difluoroethane(HFC-32), pentafluoroethane(HFC-125), 1,1,1-trifluoroethane(HFC-143a), 1,1-difluoroethane(HFC-152a), 1,1,1,2,3,3,3-heptafluoropropane(HFC-227ea) and dimethylether(DME) at high pressure were measured using the variable volume cell apparatus for. L-PLA was dissolved well in DME and HCFC-22 below 25.0 MPa, and dissolved in HFC-23, HFC-32, and HFC-152a in the range of 53.2-116.02 MPa but, it was not dissolved in HFC-125, HFC-143a, and HFC-227ea even at 413.15 K and 160 MPa. The cloud point of L-PLA was measured with L-PLA molecular weight(M.W.=80,000, 110,000, 230,000). The cloud point of L-PLA exhibited LCST(lower critical solution temperature) behavior in DME, HCFC-22, and HFC-23 and exhibited UCST(upper critical solution temperature) behavior in HFC-32 and HFC-152a. On the other hand, polycaprolactone(PCL), it was dissolved well in HCFC-22, HFC-143a, and DME below 36.9 MPa, and dissolved in HFC-152a in the range of 126.31-151.45 MPa but, was not dissolved in HFC-23, HFC-32, HFC-125, HFC-134a, and HFC-227ea even at 413.15 K and 160 MPa. Cloud point of L-PCL exhibited LCST behavior in HFC-143a, and exhibited UCST behavior in HFC-152a.
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