Applied Chemistry for Engineering (공업화학)

The Korean Society of Industrial and Engineering Chemistry (한국공업화학회)
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Synthesis and Properties of Liquid Crystalline Polyesters with X-shaped Mesogenic Group in Main Chain

주사슬에 X-자 모양의 메소젠기를 갖는 액정폴리에스터의 합성 및 성질

  • Park, Jong-Ryul (Division of Advanced Materials Science and Engineering, Kongju National University) ;
  • Cho, Kuk-Young (Division of Advanced Materials Science and Engineering, Kongju National University) ;
  • Bang, Moon-Soo (Division of Advanced Materials Science and Engineering, Kongju National University)
  • 박종률 (공주대학교 신소재공학부) ;
  • 조국영 (공주대학교 신소재공학부) ;
  • 방문수 (공주대학교 신소재공학부)
  • Received : 2013.09.13
  • Accepted : 2013.12.12
  • Published : 2014.02.10
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Abstract

A series of liquid crystalline polyesters containing X-shaped mesogenic groups in main chain were synthesized through the solution polymerization of 2,5-di(4-substituted benzoate)hydroquinones and 4,4'-dicarboxy-1,8-diphenoxyoctane. The structures and properties of synthesized polymers were investigated by $^1H$-NMR, FT-IR, differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), polarized optical microscopy (POM) and wide angel X-ray diffraction (WXRD). Inherent viscosities (${\eta}_{inh}$) of polymers were measured between 0.35 and 0.66 dL/g in 1,1,2,2-tetrachloroethane, and they were easily soluble in most of organic solvents used for this experiment. All polymers revealed relatively low melting transition temperature ($T_m$) and crystallinity, and also showed thermotropic nematic liquid crystallinity when they were heated to their melting temperatures. These properties of polymers were presumably due to the presence of the bulky substituting groups on the hydroquinone unit in mesogenic group.

주사슬에 X-모양의 메소젠기를 갖는 액정폴리에스터 시리즈가 단위체인 2,5-디(4-치환된 벤조에이트)하이드로퀴논과 4,4'-디카르복시-1,8-디페녹시옥테인으로부터 용액중합에 의해 합성되었다. 합성된 중합체의 구조와 물성들은 $^1H$-NMR, FT-IR, DSC, TGA, POM, WXRD를 이용하여 조사되었다. 1,1,2,2-테트라클로로에탄 내에서 측정된 중합체의 고유점성도(${\eta}_{inh}$)는 0.35~0.66 dL/g로 측정되었으며, 본 실험에서 용해도 조사에 사용된 대부분의 유기용매에 잘 용해되었다. 모든 중합체들은 비교적 낮은 용융전이온도($T_m$)와 결정성을 나타내었으며, $T_m$ 이상으로 가열했을 때 열방성 네마틱 액정성을 보였다. 중합체의 이러한 특성은 주사슬에 결합되어 있는 벌키한 4-치환된 벤조에이트기에 때문인 것으로 보인다.

Keywords

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