N-isopropylacrylamide에 기초한 공중합체의 합성과 팽윤 거동에 관한 연구

Abstract

열에 민감한 poly(N-isopropylacrylamide)[poly(NIPAAm)], poly(N-isopropylacrylamide-co-acrylamide)[poly(NIPAAm-co-AAm)], poly(N-isopropylacrylamide-co-N.N-dimethylacrylamide)[poly(NIPAAm-co-DMAm)] 그리고 poly(N-isopropylacrylamide-co-N,N-diethylacrylamide)[poly(NIPAAm-co-DEAm)]을 가교제인 ethylene glycol dimethacrylate(EGDMA)와 개시제인 N,N-azobisisobutyronitrile(AIBN)을 사용하여 라디칼 중합으로 합성하였다.

공중합체의 팽윤 거동을 고분자의 친수성 및 공단량체의 조성에 따라 조사하였다. 공단량체가 더욱 친수성인 AAm과 공중합되어 있는 poly(NIPAAm-co-AAm)은 poly(NIPAAm)보다 팽윤비와 LCST가 높았으며, 단량체의 함량이 증가함에 따라 팽윤비와 LCST는 더욱 높아졌다. 반면에 단량체가 가장 소수성인 DEAm과의 공중합체 poly (NIPAAm-co-DMAm)은 팽윤비와 LCST가 가장 낮았으며, 공중합체에서 단량체 DEAm의 함량이 증가함에 따라 팽윤비와 LCST는 더욱 낮아졌다.

공중합체의 팽윤비는 공단량체의 친수성 순서와 같은 poly(NIPAAm-co-AAm)> poly(NIPAAm-co-DMAm)> poly(NIPAAm-co-DEAm)의 순이었으며, LCST 또한 같은 순서로 관찰되었다.

Thermosensitive hydrogels of poly(N-isopropylacrylamide)[poly(NIPAAm)], poly(N-isopropylacrylamide-co-acrylamide)[poly(NIPAAm-co-AAm)], poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide)[poly(NIPAAm-co-DMAm)] and poly(N-isopropylacrylamide-co-N,N-diethylacrylamide)[poly(NIPAAm-co-DEAm)] were prepared by free radical copolymerization with ethylene glycol dimethacrylate(EGDMA) as crosslinking agent.

The swelling behavior of hydrogels was investigated as a function of hydrophilicity and composition of copolymer. The swelling ratio and LCST of poly(NIPAAm-co-AAm) were much higher than that of poly(NIPAAm), and as the AAm content increased the swelling ratio and LCST were increased. On the other hand, in the poly (NIPAAm-co-DMAm) which was prepared from NIPAAm and hydrophobic comonomer, DEAm, the swelling ratio and LCST of copolymer were decreased with increasing of DEAm content.

The swelling ratio of these copolymers were poly(NIPAAm-co-AAm)> poly(NIPAAm-co-DMAm)> poly(NIPAAm-co-DEAm) in decreasing order. Also, the LCST was observed in same order.

Thermosensitive hydrogels of poly(N-isopropylacrylamide)[poly(NIPAAm)], poly(N-isopropylacrylamide-co-acrylamide)[poly(NIPAAm-co-AAm)], poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide)[poly(NIPAAm-co-DMAm)] and poly(N-isopropylacrylamide-co-N,N-diethylacrylamide)[poly(NIPAAm-co-DEAm)] were prepared by free radical copolymerization with ethylene glycol dimethacrylate(EGDMA) as crosslinking agent.

The swelling behavior of hydrogels was investigated as a function of hydrophilicity and composition of copolymer. The swelling ratio and LCST of poly(NIPAAm-co-AAm) were much higher than that of poly(NIPAAm), and as the AAm content increased the swelling ratio and LCST were increased. On the other hand, in the poly (NIPAAm-co-DMAm) which was prepared from NIPAAm and hydrophobic comonomer, DEAm, the swelling ratio and LCST of copolymer were decreased with increasing of DEAm content.

The swelling ratio of these copolymers were poly(NIPAAm-co-AAm)> poly(NIPAAm-co-DMAm)> poly(NIPAAm-co-DEAm) in decreasing order. Also, the LCST was observed in same order.