Kinetics of N-isopropylacrylamide polymerizations in supercritical carbon dioxide fluids

详细信息    查看全文

• 作者：Yeong-Tarng Shieh ; ^{yts@nuk.edu.tw" class="auth_mail} ; Chongheng Zhao ; Tzong-Liu Wang ; Chien-Hsin Yang
• 关键词：N-isopropylacrylamide ; Supercritical carbon dioxide ; Free radical polymerization kinetics ; 2 ; 2&prime ; -Azobis(isobutyronitrile)
• 刊名：The Journal of Supercritical Fluids
• 出版年：July 2014
• 年：2014
• 卷：91
• 期：Complete
• 页码：1-6
• 全文大小：1339 K

文摘

Free-radical polymerization kinetics of N-isopropylacrylamide (NIPAAm) using 2,2′-azobis(isobutyronitrile) (AIBN) as an initiator in supercritical carbon dioxide (scCO₂) was investigated. A high-pressure differential scanning calorimeter revealed that the melting temperatures of NIPAAm and AIBN were both decreased with increasing CO₂ pressure in a linear fashion and the polymerization could occur in CO₂ at 55 °C. The polymerization kinetics of NIPAAm in scCO₂ was compared with that in methanol (MeOH). At 55 °C, the induction periods of polymerizations in scCO₂ of 27.6 MPa were much longer (up to 6 h) than those in MeOH (about 30 min) for similar feed concentrations. The monomer conversions reached and molecular weights produced were much higher in scCO₂ than in MeOH. The reaction orders for initial monomer and initiator concentrations, [NIPAAm]₀ and [AIBN]₀, in initial stage of polymerizations were respectively 1.48 and 0.79 in scCO₂ and 1.27 and 0.51 in MeOH.