Copper‐mediated initiators for continuous activator regeneration atom transfer radical polymerization of acrylonitrile

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

“Nascent” Cu(0) nanoparticles‐mediated single electron transfer living radical polymerization of acrylonitrile at ambient temperature

“…The molecular weight was determined to be about 2010 by comparing the peak intensity ratios between the methylene protons in main‐chain repeated units (d) and the methine proton at the ω‐end (g), which approached the theoretical one ( M n,th = 1692). The results prove that the EBiB moiety was successfully attached to the PAN chain ends, and the PAN obtained possessed high chain‐capped fidelity 21, 22, 61…”

“…Matyjaszewski's and Chen's groups successively reported controlled synthesis of polyacrylonitrile (PAN) via 25–75 ppm concentrations of copper or iron‐mediated ARGET ATRP with tin(II) 2‐ethylhexanoate, glucose, and ascorbic acid as reducing agents 19, 20. More recently, our group also first used ICAR ATRP to yield well‐defined PAN with a low concentration of copper catalyst (50 ppm) 21, 22. In general, these cases were carried out under relatively high temperature, which means the enhancement of possible undesirable side reactions and energy consumption.…”

Synthesis of well-defined polyacrylonitrile by ICARATRP with low concentrations of catalyst

“…Procedures employing lower catalyst concentrations for PAN synthesis, including activators regenerated by electron transfer (ARGET), initiators for continuous activator regeneration (ICAR), and supplemental activators and reducing agents (SARA) ATRP ‐ were previously used. For example, the synthesis of PAN by ARGET ATRP resulted in high MW PAN ( M n = 161,300) with a narrow MWD ( M w / M n = 1.18) .…”

The X-ray investigation of the macro-stresses and design for its realization (laboratory practicum)

“…Currently, a large number of catalytic systems and compositions for homopolymerization of AN under the ATRP scheme using copper, iron, and derivatives of a number of other metals are known [37][38][39][40]. At the same time, it is possible to synthesize PAN with a narrow molecular-mass distribution (MMD) in a wide range of molecular weights (M w /M n <1.2).…”