‘Living’ and controlled radical polymerization

Abstract

Radical polymerizations cannot truly be ‘living’ because of the inevitable termination between growing radicals. However, relatively good control of molecular weights, polydispersities and terminal functionalities can be achieved by using either unimolecular or bimolecular exchange between growing radicals and dormant chains. The dormant chains can be in the form of either covalent species or organometallic compounds. Some systems based on alkoxyamines, organochromium compounds, organoaluminum compounds and alkyl iodides were studied and are discussed in detail.

Determination of the activation rate constants of alkyl halide initiators for atom transfer radical polymerization

“…Variants of living radical polymerization (LRP) have recently been developed and made it possible to synthesize well-defined, low-polydispersity polymers under robust conditions [1][2][3][4][5][6][7][8][9][10] . The basic mechanism commonly underlying in all variants of LRP is the alternating activation-deactivation process, in which a dormant species P-X is reversibly activated to polymer radical P9 by thermal, photochemical, and/or chemical stimuli.…”

“Green” Atom Transfer Radical Polymerization: From Process Design to Preparation of Well-Defined Environmentally Friendly Polymeric Materials

“…The latter cannot terminate but can be intermittently reactivated to active radicals which, after few monomer additions, are transformed back to the dormant state. [16][17][18] In the first living radical polymerizations, reversible radical (spin) traps, such as the trityl (triphenylmethyl) radical, 19,20 were used that formed relatively labile bonds with the propagating radical. The formed compounds could be further photochemically or thermally reactivated, and the generated polymeric radicals could continue to grow in the presence of a monomer.…”

Atom transfer radical polymerization in aqueous dispersed media

“…In an ATRP, the catalyst is usually a transition metal complex, in which the ligand plays a critical role in determining the reactivity of the catalyst complex [10,[29][30][31][32][33][34]. In addition, the ligand also strongly influences the solubility of the complex, and consequently the concentration of activators and deactivators in the reaction medium [18,[35][36][37][38][39][40].…”