Applied Chemistry for Engineering (공업화학)

The Korean Society of Industrial and Engineering Chemistry (한국공업화학회)
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Synthesis and Properties of Hyperbranched Liquid Crystalline Polyesters by Direct Polycondensation

직접중축합법에 의한 하이퍼브랜치 액정 폴리에스터의 합성 및 성질

  • Park, Jong-Ryul (Division of Advanced Materials Science and Engineering, Kongju National University,) ;
  • Kim, Hye-Mi (Division of Advanced Materials Science and Engineering, Kongju National University,) ;
  • Yoon, Doo-Soo (Department of Bioenvironmental & Chemical Engineering, Chosun College of Science & Technology) ;
  • Sohn, Jeong Sun (College of General Education Division of Undeclared Majors, Chosun University) ;
  • Bang, Moon-Soo (Division of Advanced Materials Science and Engineering, Kongju National University,)
  • 박종률 (공주대학교 신소재공학부) ;
  • 김혜미 (공주대학교 신소재공학부) ;
  • 윤두수 (조선이공대학교 생명환경화공과) ;
  • 손정선 (조선대학교 기초교육대학 자유전공학부) ;
  • 방문수 (공주대학교 신소재공학부)
  • Received : 2017.01.16
  • Accepted : 2017.02.27
  • Published : 2017.04.10
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Abstract

Hyperbranched liquid crystalline polymers with azomesogenic and cholesteryl groups in their terminal positions were designed and synthesized by direct polycondensation reaction. The chemical structures and thermal and mesomorphic properties of the synthesized polymers were investigated by FT-IR, $^1H-NMR$, differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), and polarizing optical microscopy (POM). The inherent viscosities (${\eta}_{inh}$) of the polymers were measured to be between 0.30 and 0.50 dL/g in phenol/p-chlorophenol/1,1,2,2-tetrachloroethane (25/40/35 = w/w/w). The degree of branching (DB) in these polymers ranged from 0.37 to 0.75; they, as amorphous polymer, showed glass transition temperatures ranging from 80 to $120^{\circ}C$; the polymers readily dissolved in most of the organic solvents used in the experiments. Only hyperbranched polymers with a cholesteryl group as their mesogenic group showed liquid crystalline phases.

분자의 말단에 아조메소젠기와 콜레스테릴기를 갖는 하이퍼브랜치 액정 고분자가 설계되어 직접중축합 반응에 의해 합성되었다. 합성된 고분자들의 화학구조와 열적 성질 및 액정성은 FT-IR, $^1H-NMR$, 시차주사열량분석(DSC), 열중량 분석(TGA), 편광현미경(POM)에 의하여 조사되었다. 합성된 고분자들의 고유점성도(${\eta}_{inh}$)는 페놀/p-클로로페놀/1,1,2,2-테트라클로로에테인(25/40/35 = w/w/w) 내에서 0.30~0.50 dL/g으로 측정되었고, 가지화도(DB)는 0.37~0.75의 범위를 나타내었다. 고분자들은 모두 비결정성으로써 $80{\sim}120^{\circ}C$의 유리전이온도($T_g$)를 보여주었으며, 실험에 사용된 대부분의 유기용매에 잘 용해되었다. 메소젠기로써 콜레스테릴기를 갖는 하이퍼브랜치 고분자들만이 액정상을 나타내었다.

Keywords

References

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