Electrochemical activation of polymer chains mediated with radical transfer reactions

2020 ◽  
Vol 56 (17) ◽  
pp. 2626-2629 ◽  
Author(s):  
Yu-Ling Chang ◽  
Tzu-Chien Wei ◽  
Ying-Ling Liu
Keyword(s):  
Polymer Chains ◽  
Transfer Reactions ◽  
Electrochemical Activation ◽  
Polymer Reactions ◽  
Radical Transfer

Electrochemical activation of polymer chains mediated with radical transfer reactions for polymer reactions and functionalization.

Radical transfer reactions in polymers

1999 ◽  
Vol 55 (5-6) ◽  
pp. 599-603 ◽  
Author(s):  
Clemens von Sonntag ◽  
Eberhard Bothe ◽  
Piotr Ulanski ◽  
Amitava Adhikary
Keyword(s):  
Transfer Reactions ◽  
Radical Transfer

Characterizations of radicals formed in radical polymerizations and transfer reactions by electron spin resonance spectroscopy

2018 ◽  
Vol 90 (8) ◽  
pp. 1237-1254 ◽  
Author(s):  
Atsushi Kajiwara
Keyword(s):  
Electron Spin Resonance ◽  
Radical Polymerization ◽  
Electron Spin ◽  
Transfer Reactions ◽  
Resonance Spectroscopy ◽  
Spin Resonance ◽  
Radical Transfer ◽  
Radical Polymerizations ◽  
Chain Lengths

Abstract Electron spin resonance (ESR, aka electron paramagnetic resonance, EPR) investigations have been conducted on radicals formed during radical polymerizations and provide a detailed characterization of the active radical species. Active propagating radicals can be observed during actual radical polymerizations by ESR/EPR. The chain lengths of the observed radicals were estimated by a combination of atom transfer radical polymerization (ATRP) and ESR/EPR. The structures of the chain end radicals were determined by analysis of the ESR/EPR spectra. An increase in the dihedral angles between terminal p-orbital of radical and Cβ–H bonds was observed with increasing chain lengths of methacrylate polymers. Radical transfer reactions were observed during radical polymerization of acrylates. A combination of ATRP and ESR/EPR clarified a 1,5-hydrogen shift mechanism of the radical transfer reactions using model adamantyl acrylate radicals. Penultimate unit effects were also observed. Time-resolved ESR/EPR (TR ESR) spectroscopy clarified the initiation processes of an alternating copolymerization of styrene with maleic anhydride and the copolymerization of styrene with 1,3-butadiene. Several unsolved problems in conventional radical polymerization processes have been clarified using combinations of ATRP with ESR/EPR and TR ESR. Characterization of the radicals in radical polymerizations using various ESR techniques would definitely provide interesting and useful information on conventional radical polymerizations.

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