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Synthesis and Characterization of Liquid Crystalline Polyurethanes Containing Aromatic Ring Moiety

방향족 고리를 갖는 액정폴리우레탄의 합성 및 특성

  • Lee, Jong-Baek (Department of Chemical Engineering, Dongeui University)
  • 이종백 (동의대학교 화학공학과)
  • Received : 2013.02.25
  • Accepted : 2013.04.02
  • Published : 2013.06.30

Abstract

Polyurethanes containing no mesogenic unit were prepared by polyaddition reaction of homo- and copolyurethanes based on para-type 1,4-phenylene diisocyanate (1,4-PDI), 2,6-bis($\omega$-hydroxypentoxy)naphthalene (BHN5) with 1,4-bis($\omega$-hydroxypentoxy)benzene (BHB5). All copolyurethanes showed monotropic liquid crystallinity, when measurements were performed under shearing. For example, a polyurethane Poly(50/50, mol%) with $[\eta]$=0.32 dL/g exhibited liquid crystallinity in the temperature range from $223^{\circ}C$ to $211^{\circ}C$ in the cooling stage. In contrast, two homopolyurethanes exhibited no explicit mesomorphic behavior, which was observed by DSC (Differental Scanning calorimeter) and measurement and polarized microscopic observation. The mesomorphic behavior of synthesized polyurethane was identified and characterized by differential scanning calorimetry, polarized optical microscope and X-ray.

Acknowledgement

Supported by : 동의대학교

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