A Perfect Match: Fast and Truly Random Copolymerization of Glycidyl Ether Monomers to Thermoresponsive Copolymers

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• 作者：Silke Heinen ; Simon Rackow ; Andreas Schäfer ; Marie Weinhart
• 刊名：Macromolecules
• 出版年：2017
• 出版时间：January 10, 2017
• 年：2017
• 卷：50
• 期：1
• 页码：44-53
• 全文大小：501K
• ISSN：1520-5835

文摘

Thermoresponsive and highly biocompatible poly(glycidyl ether) copolymers of glycidyl methyl ether (GME) and ethyl glycidyl ether (EGE) with adjustable molecular weight and defined end groups are synthesized by a monomer-activated anionic ring-opening polymerization with NOct₄Br as initiator and i-Bu₃Al as activator. In contrast to a conventional oxyanionic (nonactivated) copolymerization, higher molecular weights and a truly random incorporation of the monomers are accomplished. The monomer reactivity ratios were determined by the Kelen–Tüdõs approach to be r_GME = 0.98 and r_EGE = 0.95. The thermoresponsive properties of these copolymers with varying molecular weight were characterized by UV–vis transmittance and dynamic light scattering. Conformational changes of the copolymer during the phase transition on the molecular level were studied by ¹H and ¹³C NMR spectroscopy in D₂O and revealed only a partial dehydration during the collapse of the copolymer affecting both side chains and polymer backbone.