Intermolecular Transfer to Polymer in the Radical Polymerization of n-Butyl Acrylate

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• 作者：Nicholas Ballard ; Shaghayegh Hamzehlou ; José M. Asua
• 刊名：Macromolecules
• 出版年：2016
• 出版时间：August 9, 2016
• 年：2016
• 卷：49
• 期：15
• 页码：5418-5426
• 全文大小：528K
• 年卷期：0
• ISSN：1520-5835

文摘

Transfer to polymer in the radical polymerization of acrylic monomers results in chain branching and has significant implications for both reaction kinetics and the microstructure of the resulting polymer. While intramolecular transfer to polymer is more prevalent than the intermolecular pathway, intermolecular transfer to polymer is of particular importance for understanding polymer microstructures. Despite this, the magnitude of the rate coefficient is uncertain, and therefore, predicting the effects of intermolecular transfer remains a challenge. Herein, we seek to provide an estimate of the rate of intermolecular transfer of butyl acrylate by conducting reversible addition–fragmentation chain transfer (RAFT) polymerizations in the presence of a low molecular weight dead polymer. In these experiments, intermolecular transfer to polymer yields a characteristic low molecular shoulder in the polymer detected by UV in the SEC. We obtain a value significantly higher than those previously estimated and discuss the implications this has on branch formation, molecular weight and gel formation in radical polymerization of acrylic monomers as well as the formation of dead chains in controlled radical polymerization.