No abstract

Initiators for continuous activator regeneration atom transfer radical polymerization technique was first accessed to acrylonitrile by using CuBr 2 /2,2 0 -bipyridine as the catalyst, ethyl 2-bromoisobutyrate as the halogen initiator, and azobis(isobutyronitrile) as the free radical initiator. The key to success is ascribed to the facile achievement of the rapid equilibrium between active species and dormant species. Effects of ligand, catalyst concentration, free radical initiator concentration, and reaction temperature on the polymerization reaction and molecular weight (MW) as well as polydispersity index (PDI) were investigated in detail. The polymerization proceeded in a controlled/living fashion even though the concentration of copper catalyst decreased to 50 ppm, which is evident in pseudo first-order kinetics of polymerization, linear increase of molecular weight, low PDI, and high chain-end functionality of the generated polymer. V C 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: [4358][4359][4360][4361][4362][4363][4364] 2012

Zn(0)/ppm concentrations of CuBr2 from 10 to 50 ppm was firstly used to catalyze radical polymerization of acrylonitrile at ambient temperature. The polymerization displayed typical living radical polymerization (LRP) characteristics, as evidenced by pseudo first‐order kinetics of polymerization, linear increase of number‐average molecular weight, and low polydispersity index (PDI) value. Effects of solvent, copper concentration, and initiator concentration on the polymerization reaction and molecular weight as well as PDI were investigated in detail. EC excelled NMP, DMF, and DMSO in terms of rate of polymerization as well as control of molecular weight and PDI. The increase of the copper concentration from 2.5 to 50 ppm leads to a higher rate of polymerization and a better control over the polymerization reaction. 1H NMR and GPC analyses as well as chain extension reaction confirmed the very high chain‐end functionality of the resultant polymer. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

This article first reports a fast and controlled living radical polymerization (LRP) of acrylonitrile, evidenced by 81.3% monomer conversion within 40 min and well‐defined the polymers with a narrow polydispersity index (PDI) range of 1.14−1.38. This was achieved by utilizing azobis(isobutyronitrile) as radical initiator with a high concentration up to 190 mM and CuBr2 as catalyst with a very low concentration down to 50 ppm. The polymerization displayed typical LRP characteristics, including pseudo first‐order kinetics of polymerization, the linear increase of number‐average molecular weights (MWs), low PDI values. The influence of various experimental components, radical initiator concentration, catalyst concentration, and reaction temperature, on the polymerization reaction and MW as well as PDI has been investigated in detail. 1H NMR and gel permeation chromatography analyses as well as chain extension reaction confirmed the very high chain‐end functionality of the resultant polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Transition metal-catalyzed living radical polymerization (LRP) is a powerful synthetic technique for synthesizing polymeric materials with a predetermined molecular weight, a low polydispersity index (PDI), and chain end functionality. 1-8 Among the family of transition metal catalysts, copperbased complexes are extremely appealing in view of high efficiency and relatively low cost. To date, many strategies have been developed for copper-mediated LRP, for example, atom transfer radical polymerization (ATRP) and singleelectron-transfer (SET) LRP. [9][10][11]