A Decrease in Effective Acrylate Propagation Rate Constants Caused by Intramolecular Chain Transfer

Plessis, Christophe; Arzamendi, Gurutze; Leiza, José R.; Schoonbrood, Harold A. S.; Charmot, Dominique; Asúa, José M.

doi:10.1021/ma991205z

Cited by 185 publications

(267 citation statements)

References 28 publications

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“…It is assumed that the polymer chain grows at a constant rate c add , without any delay, its full length at a time t being c add t. It can, however, form branches [15,16] as illustrated in figure 4. The branching occurs with a rate c branch , but can only happen after a linear segment contains at least three monomers [17]. In other words, a branching event should be preceded by at least n 0 = 3 attachments of monomers.…”

Section: Linear Growth With Branching: Growth-induced Delaymentioning

confidence: 99%

Non-Markovian models of the growth of a polymer chain

et al. 2015

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Using simple exactly solvable models, we show that event-dependent time delays may lead to significant non-Poisson effects in the statistics of polymer chain growth. The results are confirmed by stochastic simulation of various growth scenarios. Our interest in mathematical aspects of non-Markovian growth arises from recent successful application of delayed probability density functions in stochastic modelling of controlled radical polymerization.

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Section: Linear Growth With Branching: Growth-induced Delaymentioning

confidence: 99%

Non-Markovian models of the growth of a polymer chain

et al. 2015

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“…For simplicity, intermolecular chain transfer to polymer is neglected since literature reports indicate that LCBs barely contribute to the total branching content. [15,[19][20][21][22][23] Similarly, termination by disproportionation [65,66] and addition reactions involving macromonomers are neglected in a first approximation. [67] The ATRP catalyst and initiator are the same as those used by Ahmad et al [32] in their experimental study of the bulk normal ATRP of nBuA at 378 K, i.e., CuBr/PMDETA and methyl 2-bromopropionate (MBrP).…”

Section: Kinetic Modelmentioning

confidence: 99%

“…However, several kinetic studies have indicated that the contribution of LCBs to the total amount of branches is very low, especially at low to intermediate conversions. [15,[19][20][21][22][23] In contrast to RP of ethylene and vinyl acetate in which the occurrence of chain transfer to polymer reactions is a long-standing fact that has been well documented since its discovery more than a half century ago, [24][25][26][27][28] the importance of branching in acrylate RP has only emerged in the early nineties by the detection of quaternary carbons via 13 C NMR spectroscopy. [29][30][31] Interestingly, Ahmad et al [32] have recently reported that the branching level of poly(nbutyl acrylate) can be reduced significantly by performing a CRP instead of an FRP.…”

Section: Introductionmentioning

confidence: 99%

Computer‐Aided Optimization of Conditions for Fast and Controlled ICAR ATRP of n‐Butyl Acrylate

Porras

D’hooge

Reyniers

et al. 2013

Macro Theory & Simulations

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The potential of initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP) for the synthesis of well‐defined poly(n‐butyl acrylate) is analyzed by means of simulations. The kinetic model accounts for reactivity differences between secondary and tertiary macrospecies and considers the possible influence of diffusional limitations. CuBr2 is used as transition metal salt and the commercially available N,N,N′,N″,N″‐pentamethyldiethylenetriamine as ligand. For targeted chain lengths (TCLs) up to 1000, the ICAR ATRP can be performed relatively quickly, and with ppm levels of ATRP catalyst. For moderate TCLs, slightly higher ppm levels are required if excellent control over chain length is also desired. In all cases, limited loss of end‐group functionality (EGF) results. magnified image

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“…[24][25][26] Although, not unlike the discussion about the monomer reaction order x, other factors such as transfer to monomer were discussed, 24 Asua and coworkers soon made the connection to the transfer to polymer reactions. [27][28][29][30][31][32] No reliable k p data for conditions under which polymerizations usually are applied are available, 33 and only rate coefficients that are extrapolated from the low-temperature polymerization data are in use. However, this extrapolation can only be seen as an approximation for the propagation rate coefficient of the SPR species, and the effective propagation rate is much lower due to the significantly reduced activity of the MCRs.…”

Section: Introductionmentioning

confidence: 99%

The role of mid‐chain radicals in acrylate free radical polymerization: Branching and scission

Junkers

Barner‐Kowollik

2008

J. Polym. Sci. A Polym. Chem.

209

319

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The past 5 years have seen a significant increase in the understanding of the fate of so‐called mid‐chain radicals (MCR), which are formed during the free radical polymerization of monomers that form highly reactive propagating radicals and contain an easily abstractable hydrogen atom. Among these monomers, acrylates are, beside ethylene, among the most prominent. Typically, a secondary propagating acrylate‐type macroradical (SPR) can easily transfer its radical functionality via a six‐membered transition state to a position within the polymer chain (in a so‐called backbiting reaction), creating a tertiary MCR. Alternatively, the radical function can be transferred intramolecularly to any position within the chain (also forming an MCR) or intermolecularly to another polymer strand. This article aims at providing a comprehensive overview of the up‐to‐date knowledge about the rates at which MCRs are formed, their secondary reactions as well as the consequences of their occurrence under variable reaction conditions. We explore the latest aspects of their detection (via electron spin resonance spectroscopy) as well as the characterization of the polymer structures to which they lead (via high resolution mass spectrometry). The presence of MCRs leads to the formation of branched polymers and the partial formation of polymer networks. They also limit the measurement of kinetic parameters (such as the SPR propagation rate coefficient) with conventional methods. However, their occurrence can also be used as a synthetic handle, for example, the high‐temperature preparation of macromonomers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7585–7605, 2008

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A Decrease in Effective Acrylate Propagation Rate Constants Caused by Intramolecular Chain Transfer

Cited by 185 publications

References 28 publications

Non-Markovian models of the growth of a polymer chain

Non-Markovian models of the growth of a polymer chain

Computer‐Aided Optimization of Conditions for Fast and Controlled ICAR ATRP of n‐Butyl Acrylate

The role of mid‐chain radicals in acrylate free radical polymerization: Branching and scission

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