Preparation and Properties of Liquid Crystalline Polyurethanes Containing No Mesogenic Unit

Mesogen을 포함하지 않은 액정 polyurethane의 합성과 열적성질에 관한 연구

  • 이종백 (동의대학교 공과대학 화학공학과) ;
  • 최대웅 (동의대학교 공과대학 화학공학과)
  • Received : 1996.12.30
  • Accepted : 1997.03.13
  • Published : 1997.04.10

Abstract

Liquid crystalline polyurethanes were prepared from 1,4-bis(6-hydroxyhexoxy)benzene (BHB6) and 2,5-tolylene diisocyanate (2,5-TDI) solution polymerization in dimethylformamide produced intrinsic viscosities in the range 0.26 and $0.42d{\ell}/g$. The polyurethanes were investigated by DSC, Polarizing microscopy, X-ray, $^1H$-NMR and IR spectroscopy. Polyurethanes of two different molecular weights were studied in detail and these will be referred to as low molecular weight and high molecular weight. Polyurethane 2,5-TDI/BHB6 with $[{\eta}]=0.26d{\ell}/g$ prepared from BHB6 and 2,5-TDI, exhibited monotropic liquid crystallinity, although these polyurethanes contained no mesogenic core unit. For example, LCPU-L(low molecular weight) exhibited $T_{I-LC}$ of $122^{\circ}C$ $T_{LC-K}$ $89^{\circ}C$.

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