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

직접 용액 축중합에 의한 직쇄형 및 스타형 폴리락트산의 합성과 물성

  • Kim, Wan Jung (Department of Chemical Engineering, Sungkyunkwan University) ;
  • Lee, Sun Young (Department of Chemical Engineering, Sungkyunkwan University) ;
  • Kim, Ji-Heung (Department of Chemical Engineering, Sungkyunkwan University) ;
  • Kim, Soo Hyun (Biomaterial Research Center, Korea Institute of Science & Technology) ;
  • Kim, Young Ha (Biomaterial Research Center, Korea Institute of Science & Technology)
  • 김완중 (성균관대학교 화학공학과) ;
  • 이선영 (성균관대학교 화학공학과) ;
  • 김지흥 (성균관대학교 화학공학과) ;
  • 김수현 (한국과학기술연구원 생체재료연구센타) ;
  • 김영하 (한국과학기술연구원 생체재료연구센타)
  • Received : 1999.07.19
  • Accepted : 1999.10.23
  • Published : 1999.11.10

Abstract

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 $SnCl_2$ 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 inherent 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.

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