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Ability of nitrones of various structures to control the radical polymerization of styrene mediated by in situ formed nitroxides

“…Importantly, the styrene polymerization rate, R p , in the presence of PBN type of nitrones is much higher than the styrene thermal polymerization rate, R th , which emphasizes the decisive effect of the alkoxyamine concentration on the polymerization kinetics. This study shows good improvements in terms of rate of polymerization and polydispersity indices compared to previous works [39][40][41] in which nitrone and initiator are directly reacted in the presence of styrene.…”

“…These two compounds are well known spin-trapping agents [27][28][29][30][31][32][33][34] that react with radicals with formation of nitroxide (Scheme 1). Later on, Grishin et al reported on the controlled radical polymerization of methylmethacrylate (MMA) [34][35][36], n-butylmethacrylate (BMA), n-butylacrylate (nBuA) [37][38], styrene (S) [39], and styrene/acrylonitrile (SAN) [40] initiated by traditional free radical initiators in the presence of C-phenyl-N-tert-butylnitrone (PBN) or N,α-diphenylnitrone (DPN). Molecular weight distribution was, however, broad (1.3≤M w /M n ≤3.65), and synthesis of block copolymers was not reported.…”

Synthesis of di-and triblock-copolymers of vinylic monomers in the presence of high molecular weight nitroxyl radicals formed in situ from N-tert-butyl-C-phenylnitrone

“…A reduction of the active chain fraction and, therefore, an increase in the "dead" polymer fraction in dicate that during polymerization of styrene in the pres ence of 0.08 mol.% BPN, a common bimolecular chain termination occurs together with transformation accord ing to the nitroxide mediated radical polymerization mechanism (see Scheme 2). This agrees with the reported data 19 and confirms the suggestion on an increase in poly dispersity during polymerization progress exactly due to the side reaction of bimolecular termination. Comparative analysis of the MMD curves for the block copolymers initiated by polystyrene with various yield indicates different extent of the block copolymer ization control by macromolecular nitroxyls formed from BPN.…”

In situ nitroxide‐mediated polymerization of styrene promoted by the N‐tert‐butyl‐α‐isopropylnitrone/bpo pair: ESR investigations

“…This might be a limitation for implementation of NMP in industry, especially when process costs are the main criteria to be considered. Therefore, few research groups, both in academia and industry, have contemplated in situ NMP processes,2 thus the direct formation of NMP regulators (nitroxides and alkoxyamines) within the polymerization medium from hopefully cheap (and ideally commercially available) precursors, including nitrones,16, 19–29 nitroso compounds,12, 30, 31 sodium nitrite,11, 32, 33 nitric oxide,12 secondary amines,24, 34, 35 and hydroxylamines 36. In addition to a low cost, these precursors must provide the radical polymerization with a degree of control comparable to preformed nitroxides or alkoxyamines.…”