A mechanistic perspective on atom transfer radical polymerization

Abstract

Since its invention 25 years ago, atom transfer radical polymerization has become one of the most dominant methods in controlled radical polymerization. This rise in importance is due in large part to increases in scope, reduced catalyst loading and improved oxygen tolerance. These developments have been in turn underpinned by an improved understanding of the mechanism, kinetics and structure-reactivity trends. This mini-review outlines these mechanistic developments with a particular emphasis on the relationship between structure and activity in both the catalyst and alkyl halide substrate, and their implications for future catalyst design.

Photo‐Iniferter RAFT Polymerization

“…[ 21 ] Here, the radical species, necessary for polymerization are generated by homolytic bond cleavage (NMP) [ 22 ] or by a redox process (ATRP). [ 23 ] RAFT polymerization on the other hand relies on a degenerative chain transfer mechanism of growing chains. In contrast to other RDRP techniques the conventional RAFT process does not produce radicals but must be fueled by an exogenous radical source (such as a thermal initiator).…”

Delayed Gelation Kinetics of In‐Situ Polymerized Gel Based on the Mechanism of Living/Controlled Radical Polymerization

“…Then, the active Fe(II)/L complex formed by the reduction reaction can capture halogen atoms of dormant species and regenerate radical species, thereby triggering a new polymerization cycle [31] . These repeated activation/deactivation cycles in the polymerization process ensure that the concentration of active free radicals is always at a low level, to achieve the purpose of delaying the reaction rate [32] . Finally, the polymerization is terminated when the acrylamide monomer is exhausted.…”

“…[31] These repeated activation/deactivation cycles in the polymerization process ensure that the concentration of active free radicals is always at a low level, to achieve the purpose of delaying the reaction rate. [32] Finally, the polymerization is terminated when the acrylamide monomer is exhausted. The fundamental cause of the controllable polymerization of acrylamide lies in the low concentration of propagating radicals.…”

Computational design of next generation atom transfer radical polymerization ligands

“…Thus, for example, Me 6 TREN is significantly more effective than Et 6 TREN. 18 Additionally, the energy barrier will be smaller if the ligand conformational changes throughout the process are minimised.…”