Effects of Tacticity and Molecular Weight of Poly(N-isopropylacrylamide) on Its Glass Transition Temperature

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• 作者：Chandra Sekhar Biswas ; Vijay Kumar Patel ; Niraj Kumar Vishwakarma ; Vimal K. Tiwari ; Biswajit Maiti ; Pralay Maiti ; Masami Kamigaito ; Yoshio Okamoto ; Biswajit Ray
• 刊名：Macromolecules
• 出版年：2011
• 出版时间：July 26, 2011
• 年：2011
• 卷：44
• 期：14
• 页码：5822-5824
• 全文大小：677K
• 年卷期：v.44,no.14(July 26, 2011)
• ISSN：1520-5835

文摘

A series of high molecular weight poly(N-isopropylacrylamide) (PNIPAM)s with low polydispersity (M_n = 7.0 脳 10⁴ to 10.2脳 10⁴ g mol^鈥?, PDI = 1.23鈥?.35) having different isotacticity [meso diad (m) = 47鈥?8%]] was successfully synthesized using the reversible addition鈥揻ragmentation chain transfer (RAFT) polymerization method in the presence of different concentrations of Y(OTf)₃ Lewis acid. Measurement of the glass transition temperature (T_g) of this high molecular weight isotactic PNIPAM series and the low molecular weight PNIPAM series (M_n = 3.5 脳 10⁴ to 4.0 脳 10⁴ g mol^鈥?, PDI = 1.2鈥?.3) having different isotacticity [meso diad (m) = 45鈥?2%)] reported earlier by us (Ray et al. Polym. J. 2005, 37, 234) showed that T_g of PNIPAM decreases with increase in its meso diad content (m %) and decrease in its molecular weight.