Ring expansion-controlled radical polymerization: Synthesis of cyclic polymers and ring component quantification based on SEC-MALS analysis

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• 作者：Atsushi Narumi^a ; ^{narumi@yz.yamagata-u.ac.jp" class="auth_mail" title="E-mail the corresponding author} ; Shuhei Hasegawa^a ; Ryo Yanagisawa^a ; Miho Tomiyama^b ; Masatsugu Yamada^b ; Wolfgang H. Binder^c ; Moriya Kikuchi^b ; Seigou Kawaguchi^a
• 关键词：Macrocyclic polymer ; Nitroxide-mediated controlled radical polymerization (NMP) ; Cyclic initiator ; Ring-closing metathesis (RCM) reaction ; SEC&ndash ; MALS measurement
• 刊名：Reactive and Functional Polymers
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：104
• 期：Complete
• 页码：1-8
• 全文大小：1465 K

文摘

We report a ring expansion vinyl polymerization producing cyclic polymers using a tetra(oxyethylene) (TOE)-tethered cyclic initiator for the nitroxide-mediated controlled radical polymerization (NMP). Styrene (St) was polymerized with the cyclic NMP initiator 1 in the bulk to produce polymer 2. Structural analyses of 2 were performed by a size exclusion chromatograph equipped with a multiangle laser light scattering (SEC–MALS) detector, focusing on the relationships between the z-averaged root-mean-square radii of gyration (〈S²〉_z^1/2) versus the molecular weights. The results proved that 2 would consist of ring components as a result of the ring expansion polymerizations and radical ring crossover reactions together with ring-opened linear components, in which the amount of ring components increased with the increasing molecular weights. The data also enabled the quantification that approximately 13–40 wt% of the final polymer 2 could be identified as the ring species in the M_w range of 1 × 10⁵–5 × 10⁵ g mol^− 1.