The phase transition and swelling behavior of opolymeric hydrogels composed of poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide)[poly(NIPAAm-co-NIPMAAm)] in aqueous solution have been investigated. The homopolymers and their copolymers differing in the mole ratio of NIPMAAm to NIPAAm were obtained by free radical polymerization in dioxane using 2,2'-azobisisobutyronitrile (AIBN) as an initiator at 60 ℃ for 5hrs. The crosslinked copolymers were synthesized from NIPAAm and NIPMAA with crosslinkers such as ethylene glycol dimethacrylate (EGDMA) and N,N'-methylene-bisacrylamide (MBAAm) in dimethylsulfoxide (DMSO). The lower critical solution temperatures (LCSTs) of the copolymers were increased with increasing NIPMAAm content in the poly(NIPAAm-co-NIPMAAm). The swelling ratio of the copolymeric hydrogels crosslinked with MBAAm was higher than that of the hydrogels crosslinked with EGDMA. The LCSTs of the crosslinked copolymeric hydrogels were also increased with increasing NIPMAAm content in the poly (NIPAAm-co-NIPMAAm).

수용액중에서 손도에 민감한 반응을 나타내는 poly(N-isopropylacrylamide)[poly(NIPAAm)] 와 poly(N-isopropylmethacrylamide) [ipoly(NIPMAAm)]로 이루어진 공중합체의 상전이 현상과 그 수화겔의 팽윤거동에 대하여 연구하였다. PoIy(N-isopropylacrylamide- co-N-isopropy1acrylamide-co-N-isopropylmethacrylamide) [poly(NIPAAm-co-NIPMAAm -co-NIPMAAm)]는 dioxane 용매하에서 2,2'-azobisisobutyronitrile(AIBN)을 개시제로 하여 합성하였으며, 가교공중합체는 dimethylsulfoxide (DMSO) 용매하에서 가교제 ethyleneglycol dimethacrylate (EGDMA)와 N,N'-methylenebisacrylamide (MBAAm)를 이용하여 합성하였다. 공중합체내의 NIPMAAm의 양이 0wt.%에서 100wt.%로 증가함에 따라 공중합체내의 저임계용해온도 (LCST)가 29.5℃에서 48℃의 온도까지 증가하였다. 가교제의 종류에 따른 가교공중합체의 팽윤도는 친수성 가교제 MBAAm의 함량이 증가할수록 높은 팽윤도를 나타내었다. 또한 이들이 나타내는 상전이 온도는 가교공중합체내의 NIPMAAm의 양이 0wt.%에서 100 wt.%으로 증가함에 따라 32℃에서 42℃로 증가함을 확인하였다.

Keywords: Lower Critical Solution Temperature (LCST); Cloud Point; Swelling Ratio; Poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide); Phase Transition