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

• Published in: Reactive & functional polymers Vol. 104; pp. 1 - 8
• Main Authors: Narumi, Atsushi, Hasegawa, Shuhei, Yanagisawa, Ryo, Tomiyama, Miho, Yamada, Masatsugu, Binder, Wolfgang H., Kikuchi, Moriya, Kawaguchi, Seigou
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2016
• Subjects: Crossovers; Cyclic initiator; Focusing; Initiators; Lasers; Macrocyclic polymer; Molecular weight; Nitroxide-mediated controlled radical polymerization (NMP); Polymerization; Radicals; Ring-closing metathesis (RCM) reaction; SEC–MALS measurement; Structural analysis; Macrocyclic polymer; Nitroxide-mediated controlled radical polymerization (NMP); Cyclic initiator; Ring-closing metathesis (RCM) reaction; SEC–MALS measurement
• ISSN: 1381-5148
• DOI: 10.1016/j.reactfunctpolym.2016.04.013

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〉z1/2) 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 13–40wt% of the final polymer 2 could be identified as the ring species in the Mw range of 1×105–5×105gmol−1.