Elastomers and Composites

  • 제40권3호
  • /
  • Pages.212-221
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  • 2005
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  • 2092-9676(pISSN)
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  • 2288-7725(eISSN)
한국고무학회 (The Rubber Society of Korea)
권호 표지

분자량이 메소겐기를 포함한 폴리우레탄의 열적거동에 미치는 영향

Effect of Molecular Weight on Thermal Behavior of Polyurthanes Containing Mesogen Unit

  • 홍성철 (세종대학교 나노공학과) ;
  • 이무영 (KRI Inc. 광기능성재료 연구실) ;
  • 남병욱 (한국기술교육대학 응용화학과) ;
  • 이상원 (숭실대학교 환경화학공학과)
  • Hong, Sung-Chul (Department of Nano Science and Technology, Sejong University) ;
  • Lee, Woo-Young (Photofunctional Materials Research Laboratory, KRI Inc., Kyoto Research Park) ;
  • Nam, Byeong-Uk (Department of Applied Chemical Engineering, Korea University of Technology and Education) ;
  • Lee, Sang-Won (Departtment of Chemical/Environmental Engineering, Soongsil University)
  • 발행 : 2005.09.30
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초록

유연사슬길이가 6인 4,4'-bis(6-hydroxy hexoxy)biphenyl (BP-6)의 메소겐 디올을 합성하였고, 이것을 4,4'-diphenylmethane diisocyanate (MDI)와 용액축중합하여 폴리우레탄 (MPU-6)을 합성하였다. 합성된 MPU-6는 $0.23{\sim}0.56 dL/g$의 고유점도를 보였다. MPU-6는 X-ray, 편광현미경으로부터는 액정을 형성할 수 있었으나, DSC로 분석 시에는 액정거동을 관찰할 수 없는 '가상액정'의 거동을 보였다. 또한 MPU-6의 분자량이 낮을수록 결정화 속도와 결정화 온도가 높음을 알 수 있었으며 이는 분자량이 낮을수록 고분자의 mobility가 증가함으로써 메소겐기의 배향이 용이하고, 이것이 기핵으로 작용하였기 때문으로 생각된다.

Polyurethanes containing mesogen unit (MPU-6) were prepared from 4,4'-diphenylmethane diisocyanate (MDI) and 4,4'-bis(6-hydroxy hexoxy)biphenyl (BP-6) having flexible chain composed of 6 carbons. Intrinsic viscosities of MPU-6s were in the range of $0.23{\sim}0.56 dL/g$. The mesomorphic behaviors of MPU-6 were observed in X-ray and polarizing microscopy analysis. However, MPU-6s demonstrated a 'virtual liquid crystal' behavior, which did not exhibit mesophase on slow heating and slow cooling. MPU-6 having lower molecular weight exhibited higher crystallization rate and melting crystallization temperature due to increased mobility of polymer chains. The increased mobility of polymer chains facilitate the orientation of mesogen units that may act as a nucleating agent.

키워드

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