Polymerization with Borane Chemistry. Tributylborane/ p -Quinone System as a New Method of Reversible-Deactivation Radic
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Article www.springer.com/13233 pISSN 1598-5032 eISSN 2092-7673
Polymerization with Borane Chemistry. Tributylborane/p-Quinone System as a New Method of Reversible-Deactivation Radical Copolymerization for Styrene and Methyl Acrylate Dmitrii Ludin*,1 Yulia Voitovich2,3 Evgenia Salomatina3 Yulia Kuznetsova3 Ivan Grishin3 Igor Fedushkin1,4 Sergey Zaitsev3
1
Research educational center “Chemistry of molecules and materials”, Minin University, 7 Minin square, Nizhny Novgorod, 603005, Russian Federation 2 Imagerie Moléculaire et Stratégies Théranostiques, Université Clermont Auvergne, INSERM, 58 Rue Montalembert, Clermont-Ferrand, 63005, France 3 Chemistry department, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin avenue, Nizhny Novgorod, 603950, Russian Federation 4 G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Science (RAS), 49 Tropinina street, Nizhny Novgorod, 603137, Russian Federation Received December 29, 2019 / Revised April 1, 2020 / Accepted April 8, 2020
Abstract: We report a reversible-deactivation radical copolymerization of styrene and methyl acrylate in the presence of tributylborane and different p-quinones. p-Quinones, such as 1,4-naphthoquinone, 2,3-dimethyl-1,4-benzoquinone, 2,5-ditert-1,4-butylbenzoquinone, and duroquinone, with addition of a catalytic amount of tributylborane, allow for the control over styrene/methyl acrylate copolymerization. The process proceeds in a controlled manner via a reversible homolytic dissociation of the active macromolecules with terminal aryloxyboron-groups. The rate of styrene/methyl acrylate copolymerization depends on the inhibition constants of quinones. The molecular weight and molecular weight distribution of copolymers are directly dependent on the inhibitory abilities of the quinones. 1,4-Naphthoquinone and 2,3-dimethyl-1,4-benzoquinone act as the most effective mediators of chain propagation. Matrixassisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) results showed that the macromolecules contained internal fragments of p-quinone. Also, of the terminal aryloxyboron-groups were detected in the mass spectra. On realization of the “living” mechanism of copolymerization, the structure of copolymers obtained at high conversions can be considered as similar to the gradient structure. Stereo-regularity of the copolymers differed from the conventional radical copolymerization. The glass-transition temperature (Tg) of the gradient copolymer differed from Tg of the random compositional heterogeneous copolymer. The effect of the macromolecular structure on the mechanical properties of the copolymers was studied. Keywords: alkylborane, p-quinone, reversible-deactivation radical polymerization, styrene, alkyl acrylate.
1. Introduction The effect of trialkylboranes on the process of radical polymerization has been studied for over 60 years. During this time, various initiating and regulatory systems for radical polymerization were proposed and developed. The first among others is the alkylborane/
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