Polymer(Korea), Vol.19, No.3, 359-367, May, 1995
폴리스티렌이 그라프트된 액정 공중합체의 합성
Synthesis of Liquid Crystalline Copolyester Grafted with Polystyrene
초록
폴리스티렌 (PS)과 액정 중합체의 블렌드시 상용화제로의 응용을 목적으로, 한쪽 말단에 두개의 hydroxy기를 갖는 polystyrene macromonomer (PSM)와 terephthaloyl chloride (TPC), 4,4'-dihydroxy-α,ω-diphenoxydecane (DHDP)을 반응시켜 PS가 그라프트된 폴리에스테르 액정 중합체 (LCP-g-PS)를 합성하였다. 수평균분자량이 6,000인 PSM을 사용하여 PS의 함량을 0, 25, 50, 75, 85, 그리고 100 wt%인 그라프트 공중합체들을 합성하였으여, 이들의 열적 성질을 시차 열분석과 열중량 분석으로 조사하고 편광 현미경을 이용하여 이들의 광학적 성질을 관찰하였다. PSM이 도입된 그라프트 공중합체의 대부분에서 액정성이 관찰되었으나 PSM함량이 85 wt%에 이르면 메소상을 형성하지 못하였다. 용융 온도와 등방성화 온도는 PSM의 함량이 증가할수록 저하되었으며, 열안정성도 감소하였다.
Thermotropic liquid crystalline copolyesters (LCP-g-PS) were synthesized by solution polycondensation of diol-terminated polystyrene macromonomer (PSM) and 4,4'-dihydroxy-α,ω-diphenoxydecane (DHDP) with terephthaloyl chloride (TPC). The molecular weight of PSM was 6,000 and the content of styrene grafts in graft copolyester was varied. These liquid crystalline polymers were prepared to be used as a fiber-reinforcing material for flexible chain thermoplastics like polystyrene. The thermal properties of the polymers were investigated by differential scanning calorimetry and thermogravimetry. A polarizing microscope equipped with a hot stage was used for the determination of the LC texture. The thermal behaviors indicated that the majority of the prepared graft copolyesters exhibited LC originated from LC main chain. The melting temperature decreased with increasing styrene macromonomer content. The clearing temperature were not observed for the graft copolymer with the grafts content of over 75 wt%. Thermal stability of the polymers decreased with increase of polystyrene grafts content.
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