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

Abstract

Acrylonitrile (AN) was polymerized by initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP). The effect of the ligand, tris(2‐pyridylmethyl)amine (TPMA) and N,N,N',N'‐tetrakis(2‐pyridylmethyl)ethylenediamine (TPEN), in the Cu‐based catalyst, the amount of catalyst, several alkyl halide initiators, targeted degree of polymerization, and amount of azobisisobutyronitrile (AIBN) added were studied. It was determined that the best conditions utilized 50 ppm of CuBr2/TPMA as the catalyst and 2‐bromopropionitrile (BPN) as the initiator. This combination resulted in 46% conversion in 10 h and polyacrylonitrile (PAN) with the narrowest molecular weight distribution (Mw/Mn = 1.11–1.21). Excellent control was maintained after lowering the catalyst loading to 10 ppm, with 56% conversion in 10 h, experimental molecular weight closely matching the theoretical value, and low dispersity (Mw/Mn < 1.30). Catalyst loadings as low as 1 ppm still provided well‐controlled polymerizations of AN by ICAR ATRP, with 65% conversion in 10 h and PAN with relatively low dispersity (Mw/Mn = 1.41). High chain end functionality (CEF) was confirmed via 1H NMR analysis, for short PAN chains, and via clean chain extensions with n‐butyl acrylate (BA). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1961–1968

Copolymer‐Derived N/B Co‐Doped Nanocarbons with Controlled Porosity and Highly Active Surface

“…PAN is a popular nanocarbon precursor because of its thermal‐induced graphitization properties . Well‐defined PAN‐Br macroinitiator was synthesized by ICAR ATRP with <100 ppm of Cu catalyst as described in previous studies …”

“…PAN was synthesized by initiators for continuous activator regeneration (ICAR) ATRP using a reported technique . In a typical procedure for the synthesis of PAN 64 ‐Br, 50 mg of AIBN (0.31 mmol, 0.1 equiv.…”

ICAR ATRP in PEG with Low Concentration of Cu(II) Catalyst: A Versatile Method for Synthesis of Block Copolymer Nanoassemblies under Dispersion Polymerization

“…However, the Cu I /ligand catalyst system is insoluble in some organic solvents and is also vulnerable to be oxidized, which make a barrier for application of the normal ATRP in PISA. Recently, ATRP techniques employing the Cu II /ligand catalyst, typically initiators for continuous activator regeneration (ICAR) ATRP, have been achieved. In comparison, the Cu II /ligand catalyst is stable under atmosphere conditions and is soluble in most of polar solvents, which therefore affords great convenience in synthesis of block copolymer nanoassemblies when they are adopted in PISA.…”

Surface-grafted polyacrylonitrile brushes with aggregation-induced emission properties

“…normal ATRP conditions). [29][30][31][32][33][34][35][36] In order to facilitate polymerization of AN under low-catalyst-concentration ATRP techniques, such as ARGET (activators regenerated by electron transfer), 39 ICAR (initiators for continuous activator regeneration) 40 or SARA (supplemental activator reducing agent), 41 more active initiators, namely 2-bromopropionitrile (BPN) or ethyl 2-bro-mophenyl acetate (EBPA) need to be employed. Recently, EBPA initiators were used in metal-free ATRP of AN, 42 as well as to improve the initiation efficiency in SI-ATRP of methyl methacrylate.…”