직접 용액 축중합에 의한 직쇄형 및 스타형 폴리락트산의 합성과 물성

김완중; 이선영; 김치흥; 김수현; 김영하

Journal of the Korean Industrial and Engineering Chemistry, Vol.10, No.7, 1028-1034, November, 1999

Export Citation

직접 용액 축중합에 의한 직쇄형 및 스타형 폴리락트산의 합성과 물성

Synthesis and Properties of Linear and Star-shaped poly(L-lactic acid)s by Direct Solution Polycondensation

김완중, 이선영, 김치흥, 김수현, 김영하

초록

p-Xylene을 용매로 사용하고, 몇 가지 다른 종류의 촉매를 사용하여 직접 축중합에 의해 직쇄형 폴리락트산 합성 실험을 하였다. 그 중 우수한 활성을 보인 촉매는 주석(Tin)계 촉매이었다. 촉매의 양과 용매의 양을 변화시켜 중합반응을 한 결과, 촉매 0.2g (0.5 wt % 모노머), 용매 100mL수준에서 보다 높은 분자량의 중합체를 얻을 수 있었으며, 이때 대수점성도 η_inh 는 0.72 dL/g(중량평균분자량(GPC)=70500)이었다. 직접중합 반응 시스템에서 분자량을 더욱 향상시키기 위해 branching 모노머로서 다가알콜인 dipentaerythritol(dipet)또는 Pentaerythritol(pet)을 소량 도입하여 스타형 폴리락트산을 합성하였으며, 직쇄형에 비해 분자량 분포가 좁고, 향상된 분자량(최고 η_inh= 1.14,M_w = 143,200)을 얻을 수 있었다. Dipet의 함량이 0.05~0.2 wt %일 때 보다 높은 분자량의 폴리락트산을 얻을 수 있었으며, 얻어진 중합체의 열적성질은 직쇄형에 비해 큰 차이가 없었다. 얻어진 고분자량의 중합체로부터 투명하고 강인한 필름을 성형할 수 있었다.

Poly(lactic acid) is expected to be one of the most promising biodegradable polymers. However, the high molecular weight polymer could be obtained by ring-opening polymerization process conventionally, which raises the production cost and decreases the final yield. In this study, linear and star-shaped poly(L-lactic acid)s were prepared by direct solution polycondensation method and their physical and thermal properties were examined. Tin compounds were found to be effective catalyst for the preparation of high molecular weight polymers. When 0.2g (0.5 wt % of monomer) of SnCl₂ and 100 mL of p-xylene were used, the polymer yield and molecular weight were relatively high. As a means to obtain higher molecular weight polymer easily in the direct polycondensation system, dipentaerythritol(dipet) or pentaerythritol(pet) was introduced as a multifunctional branching monomer to provide a star-shaped poly(lactic acid). Moderately high molecular weight polymers with the ihgerent viscosity values up to 1.14 dL/g(weight-average molecular weight of about 140000 by GPC) were obtained and could be cast strong and transparent films.

Keywords:poly(lactic acid);direct solution polycondensation;star-shape

[References]

Ratner BD, Hoffman AS, Schoen FJ, Lemons JE, "Biomaterials Science," Ch. 2, Academic Press (1996)
Hiltunen K, Harkonen M, Seppala JV, Vaananen T, Macromolecules, 29(27), 8677 (1996)
Ajioka M, Enomoto K, Suzuki K, Yamaguchi A, J. Environ. Polym. Degrad., 3, 4 (1995)
Sinclair RG, U.S. Patent, 5,180,765 (1993)
Seppala JV, PCT WO 96/31552 (1996)
Doi Y, Polym. Prepr. Jpn., 46, 6 (1997)
Enomoto K, U.S. Patent, 5,310,865 (1994)
Nieuwenhuis J, Clinical Mater., 10, 59 (1992)
Kim YH, U.S. Patent, 5,434,241 (1995)
Shin GI, Kim JH, Kim SH, Kim YH, Korea Polym. J., 5(1), 19 (1997)
Odian G, "Principles of Polymerization," 3rd Ed., Ch. 2, John Wiley & Sons, Inc. (1991)
Arvanitoyannis I, Nakayama A, Kawasaki N, Yamamoto N, Polymer, 36(15), 2947 (1995)
Eenink MJD, Thesis, University of Twente, The Netherlands, Ch 5 (1987)
Gogolewski S, Pennings AJ, J. Appl. Polym. Sci., 28, 1045 (1983)

[Referenced By]

[1] Ratner BD, Hoffman AS, Schoen FJ, Lemons JE, "Biomaterials Science," Ch. 2, Academic Press (1996)

[2] Hiltunen K, Harkonen M, Seppala JV, Vaananen T, Macromolecules, 29(27), 8677 (1996)

[3] Ajioka M, Enomoto K, Suzuki K, Yamaguchi A, J. Environ. Polym. Degrad., 3, 4 (1995)

[4] Sinclair RG, U.S. Patent, 5,180,765 (1993)

[5] Seppala JV, PCT WO 96/31552 (1996)

[6] Doi Y, Polym. Prepr. Jpn., 46, 6 (1997)

[7] Enomoto K, U.S. Patent, 5,310,865 (1994)

[8] Nieuwenhuis J, Clinical Mater., 10, 59 (1992)

[9] Kim YH, U.S. Patent, 5,434,241 (1995)

[10] Shin GI, Kim JH, Kim SH, Kim YH, Korea Polym. J., 5(1), 19 (1997)

[11] Odian G, "Principles of Polymerization," 3rd Ed., Ch. 2, John Wiley & Sons, Inc. (1991)

[12] Arvanitoyannis I, Nakayama A, Kawasaki N, Yamamoto N, Polymer, 36(15), 2947 (1995)

[13] Eenink MJD, Thesis, University of Twente, The Netherlands, Ch 5 (1987)

[14] Gogolewski S, Pennings AJ, J. Appl. Polym. Sci., 28, 1045 (1983)