화학공학소재연구정보센터
Applied Chemistry for Engineering, Vol.28, No.2, 237-244, April, 2017
직접중축합법에 의한 하이퍼브랜치 액정 폴리에스터의 합성 및 성질
Synthesis and Properties of Hyperbranched Liquid Crystalline Polyesters by Direct Polycondensation
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초록
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), 열중량분석(TGA), 편광현미경(POM)에 의하여 조사되었다. 합성된 고분자들의 고유점성도(ηinh)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 80~120 ℃의 유리전이온도(Tg)를 보여주었으며, 실험에 사용된 대부분의 유기용매에 잘 용해되었다. 메소젠기로써 콜레스테릴기를 갖는 하이퍼브랜치 고분자들만이 액정상을 나타내었다.
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 (ηinh) 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 °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.
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