Radical copolymerization of N-isopropylactylamide(NIPAAM) with methylmethacrylate(MMA) was carried out in 1,4-dioxane using 2,2''-azobisisobutyronitrile (AIBN). To investigate the reactivity ratios of NIPAAM and MMA at different reaction temperatures, the copolymerization was allowed to proceed to low conversion(less than 10wt%), and the reaction temperatures were 50, 60, and 70℃. The monomer reactivity ratios of NIPAAM and MMA were estimated by the graphical methods according to the Finemann-Ross equation. The γ₁ and γ₂ values for NIPAAM-MMA were 0.259 and 2.782 at 50 ℃, 0.271 and 2.819 at 60℃, and 0.286 and 2.915 at 70℃, respectively. As the reaction temperature increased, the γ₁ and γ₂ values increased. THe activation energy difference was estimated by comparing the reactivity ratios at different reaction temperatures.

자유 라디칼 개시제인 2,2''-azobisisobutyronitrile(AIBN)을 사용하여 1,4-dioxane용매하에서 N-isopropylacrylamide(NIPAAM)와 methyl methacrylate(MMA)를 공중합하였다. 온도에 따른 NIPAAM과 MMA의 반응성비를 알아보기 위해 각각 50, 60, 70°C에서 중합하여 전환율이 10wt%이하가 되도록 반응을 정지시켰다. 단량체 반응성빈는 Finemann-Ross법으로 구하였으며, 그 값은 50°C에서는 γ₁=0.259, γ₂=2,782, 60°C에서는 γ₁=0.271, γ₂=2.819, 그리고 70℃에서는 γ₁=0.286, γ₂=2.915로 나타나, 반응온도가 높아질수록 γ₁, γ₂값이 증가함을 알 수 있었다. 또한 반응온도와 반응성비와의 관계에서 활성화에너지의 차를 구할 수 있었으며, 그 결과 반응성비는 온도 의존성이 있는 것으로 나타났다.

Keywords: reactivity ratio; radical copolymerization; N-isopropylacrylamide; methyl methacrylate; activation energy