Hydroxyethyl cellulose (HEC) with hydroxyethyl group substitution degree (DS) 1.0 and molar substitution degree (MS) 2.0 was reacted with butyl glycidyl ether (BGE) to synthesize 2-hydroxy-3-butoxypropyl hydroxyethyl cellulose (H-HEC). The properties of H-HEC prepared by varying BGE concentrations were analyzed using ¹H NMR, FTIR, and UV-Vis spectrophotometer. The aqueous solution of H-HEC showed a lower critical solution temperature (LCST), indicating that H-HEC is a thermoresponsive polymer. As the concentration of reacting BGE during H-HEC synthesis increased, the MS of hydroxy-butoxypropyl group increased linearly and LCST decreased linearly. H-HEC was crosslinked with epichlorohydrin (ECH) to prepare a thermoresponsive hydrogel. Measurement of the swelling property in distilled water showed a maximum swelling ratio when H-HEC was crosslinked at a certain ECH concentration. H-HEC retained the Cellulose II crystal structure, but the hydrogel obtained by crosslinking with ECH showed no crystal structure.

히드록시에틸기의 치환도(DS)가 1.0이고 몰 치환도(MS)가 2.0인 히드록시에틸 셀룰로오스(HEC)에 부틸글리시딜에테르(BGE)를 반응시켜 2-히드록시-3-부톡시프로필 히드록시에틸 셀룰로오스(H-HEC)를 합성하였다. BGE 농도를 달리하여 제조된 H-HEC의 치환도에 따른 특성을 ¹H NMR, FTIR, UV-Vis 분광광도계 등을 이용하여 분석하였다. H-HEC의 수용액은 하한임계 용해온도(LCST)를 나타내어 H-HEC가 열감응형 고분자임을 보여주었다. H-HEC 합성시 반응시키는 BGE의 농도가 커짐에 따라 히드록시-부톡시프로필기의 몰 치환도는 직선적으로 증가하면서 LCST는 직선적으로 감소하였다. H-HEC를 에피클로로히드린(ECH)으로 가교시켜 열감응성 수화젤을 제조하였으며, 이들의 증류수에서의 팽윤성을 측정한 결과 특정 ECH 농도로 가교시킨 경우 최대팽윤비를 나타내었다. H-HEC는 셀룰로오스 II 결정구조를 유지하였지만, ECH로 가교시킨 수화젤은 결정구조를 나타내지 않았다.

Keywords: 2-hydroxy-3-butoxypropyl hydroxyethyl cellulose, butyl glycidyl ether, epichlorohydrin, hydrogel, thermoresponsive property