Extent of intramolecular cyclization in RAFT-synthesized methacrylic branched copolymers using 13C NMR spectroscopy. Issue 7 (14th November 2014)

• Record Type: Journal Article
• Authors: Rosselgong, J.; Armes, S. P.
• Is Part Of: Polymer chemistry. Volume 6:Issue 7(2015)
• Page Start: 1143
• Page End: 1149
• Publication Date: 2014-11-14
• Subjects: Polymers -- Periodicals; Macromolecules -- Periodicals; Polymerization -- Periodicals; 547.705
• DOI: 10.1039/c4py01441c
• Languages: English
• ISSNs: 1759-9954

Abstract

Abstract : The extent of intramolecular cyclization for a series of soluble branched methacrylic copolymers is determined by 13 C NMR spectroscopy via deconvolution of oxymethylene carbon signals. Abstract : Recently, we reported using 1 H NMR spectroscopy to assess the degree of intramolecular cyclization in a series of soluble methacrylic branched copolymers (see J. Rosselgong and S. P. Armes, Macromolecules, 2012, 45, 2731–2737). The key to success in addressing this long-standing problem in polymer science was the selection of a suitable disulfide-based dimethacrylate as the branching comonomer, which was statistically copolymerized with methyl methacrylate using reversible addition-fragmentation chain transfer (RAFT) polymerization. In this earlier work, estimation of the degree of intramolecular cyclization required peak deconvolution of the relevant thiamethylene proton signals. In the present work, we show that quantitative 13 C NMR spectroscopy can also be utilized to determine the intramolecular cyclization for the same series of methacrylic copolymers via peak deconvolution of the oxymethylene carbon signals. Although this technique requires long spectral accumulation times, it offers superior resolution compared to 1 H NMR spectroscopy and hence may ultimately enable this analytical approach to be applied to less esoteric divinyl comonomers.