Article
  • Thermal Properties of Poly(ethylene oxide)-Poly(lactic acid) Diblock Copolymers
  • Choi SW, Shim WS, Kim SW, Lee DS
  • Poly(ethylene oxide)-Poly(lactic acid) Diblock Copolymer의 열적성질
  • 최성원, 심우선, 김성완, 이두성
Abstract
Poly(ethylene oxide)-b-poly(L-lactic acid) (PEO-PLLA), poly(ethylene oxide)-b-poly(L-lactic acid-co-glycolic acid) (PEO-P(LLA/GA)), and poly(ethylene oxide)-b-poly(DL-lactic acid-co-glycolic acid) (PEO-P(DLLA/GA)) were prepared via ring opening polymerization from poly(ethylene oxide), L- and DL-lactide, and glycolide. Their thermal properties were investigated by using DSC. As the length of PLLA, P(LLA/GA), and P(DLLS/GA) blocks increased, Tc, Tm, crystallization exotherm, and melthing endotherm of PEO blocks decreased. The Tc of PLLA block of PEO-PLLA was significantly affected by changing the molecular weight. The co-melting of PEO and PLLA occurred when the PLLA was low molecular weight. The crystallization exotherm of PEO block was not observed during cooling run of PEO-P(LLA/GA). But, thecrystallization peak and Tg of PEO blocks appeared in the second heating run due to the steric hindrance of stereo irregular P(LLA/GA) blocks. PEO-P(DLLA/GA) showed the same pattern except showing the more decreased crystallization exotherm and melthing endotherm of PEO.

Poly(ethylene oxide) (PEO)에 L-lactide(LA), DL-latide, glycolide(GA)를 개환 중합하여 PEO-PLLA, PEO-P(LLA/GA), PEO-P(DLLA/GA) diblock 공중합체들을 제조하였다. 시차주사 열분서기 (DSC)를 사용하여 공중합체의 열적 특성을 조사하였다. PLLA, P(LLA/GA), P(DLLA/GA) 블록들의 길이가 증가할수록 PEO 블록의 Tc, Tm은 낮아졌고, 결정화 별열량, 용융 흡열량이 감소하였다. PEO-PLLA 공중합체에서 PLLA의 Tc는 분자량의 변화에 따라 크게 변화하였다. 낮은 분자량의 PLLA는 용융 피이크가 PEO와 겹쳐졌다. PEO-P(LLA/GA)는 입체적으로 불규칙한 P(LLA/GA) 블록의 영향으로 PEO 블록의 결정화 발열 피이크가 냉각시에 나타나지 않고, 이차 가열곡선에서 나타났으며, Tg가 관찰되었다. P대-P(DLLA/GA)도 마찬가지로 냉각시에 PEO의 결정이 형성되지 않았고, 가열곡선에서 PEO 블록의 결정화 발열량과 용융 흡열량은 매우 감소되었다.

Keywords: poly(ethylene oxide)-b-poly(L-lactic acid) diblock copolymers; biodergradable polymer; thermal properties; stereo-regularity

References
  • 1. Schmitt EE, Polistina RAU.S. Patent, 3,297,033 (1967)
  •  
  • 2. Frazza EJ, Schimitt EE, J. Biomed. Mater. Res., 1, 43 (1971)
  •  
  • 3. Kulkarni RK, Pani KC, Nauman C, Leonard F, J. Biomed. Mater. Res., 5, 169 (1971)
  •  
  • 4. Schneider AKU.S. Patent, 3,636,956 (1975)
  •  
  • 5. Gilding DK, Reed AM, Polymer, 20, 1459 (1979)
  •  
  • 6. Jackanicz TM, Nash HA, Wise DL, Gregory JB, Contraception, 8, 277 (1973)
  •  
  • 7. Schmitt EE, Epstein MAA. Patent, 718,150 (1971)
  •  
  • 8. Hollinger JO, J. Biomed. Mater. Res., 17, 71 (1983)
  •  
  • 9. Kulkarni RK, Panl KC, Neuman C, Leonard F, J. Biomed. Mater. Res., 5, 169 (1971)
  •  
  • 10. Herold DK, Keil K, Bruns DE, Biochem. Pharmacol., 38, 73 (1989)
  •  
  • 11. Richter AW, Akerblom E, Int. Arch. Allergy Appl. Immunol., 70, 124 (1983)
  •  
  • 12. Jeong B, Bae YH, Lee DS, Kim SW, Nature, 388(6645), 860 (1997)
  •  
  • 13. Bailey FE, Koleske JVPoly(ethylene oxide), Chapter IV, Academic Press, New York, 1976 (1976)
  •  
  • 14. Jeong B, Lee DS, Shon JI, Bae YH, Kim SW, J. Polym. Sci. A: Polym. Chem.in press
  •  
  • 15. Choi SW, Choi SY, Jeong B, Kim SW, Lee DS, J. Polym. Sci. A: Polym. Chem.in press
  •  
  • 16. Fischer EW, Sterzel HJ, Wegner G, Kolloid-Z. u.Z. Polym., 251, 980 (1973)
  •  
  • 17. Grijpma DW, Pennings AJ, Macromol. Chem. Phys., 195, 1663 (1994)
  •  
  • 18. Rashkov I, Manolova N, Li SM, Espartero JL, Vert M, Macromolecules, 29(1), 50 (1996)
  •  
  • 19. Cerrai P, Tricoli M, Lelli L, Guerra GD, Sbarbati R, Guerra D, Cascone MG, Giusti PJ, Mater. Sci. Mater. Med., 5, 308 (1994)
  •  
  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2023 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 1999; 23(1): 32-41

    Published online Jan 25, 1999