Seeded Semibatch Emulsion Polymerization of<i>n</i>-Butyl Acrylate. Kinetics and Structural Properties

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

doi:10.1021/ma992053a

Cited by 170 publications

(261 citation statements)

References 29 publications

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“…2 Because most of the branches are formed by backbiting, in the homopolymerization of acrylate monomers the formation of branches can be described by Scheme 1. The propagating secondary radical, R 2 * , undergoes intramolecular chain transfer to polymer via a six membered ring transition state and subsequent propagation from the formed tertiary radical, R 3 Branching fraction= …”

Section: 18mentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12] Transfer to polymer in acrylic monomers has been shown to be mainly due to intramolecular transfer via a six membered ring transition state, resulting in a mid chain radical. [13][14][15][16][17] In general, for most polymerizations which are conducted at a temperature of <100°C , the most likely fate of the midchain radical is propagation, leading to the formation of quaternary carbons that are a fingerprint of this process and can be detected by 13 C NMR.…”

Section: Introductionmentioning

confidence: 99%

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Impact of Competitive Processes on Controlled Radical Polymerization

et al. 2014

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The kinetics of radical polymerization have been systematically studied for nearly a century and in general are well understood. However, in the light of recent developments in controlled radical polymerization many kinetic anomalies have arisen. These unexpected results have been largely considered separate and various, as yet inconclusive, debates as to the cause of these anomalies 1 are ongoing. Herein we present a new theory on the cause of changes in kinetics under controlled radical polymerization conditions. We show that where the fast, intermittent deactivation of radical species takes place, changes in the relative rates of the competitive reactions that exist in radical polymerization can occur. To highlight the applicability of the model we demonstrate that the model explains well the reduction in branching in acrylic polymers in RAFT polymerization.We further show that such a theory may explain various phenomena in controlled radical polymerization and may be exploited to design precise macromolecular architectures.

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Section: 18mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impact of Competitive Processes on Controlled Radical Polymerization

et al. 2014

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“…As long as the reaction rate of short-chain branching is much smaller than the propagation reaction, which is usually the case for FRPs, the effect of backbiting on the formed MWD, as well as the radius of gyration, would not be significant. Although it has been reported that the frequency of short-chain branching is greater than that of long-chain branching, especially for acrylic monomers [2,3], the backbiting reaction is neglected in the present theoretical investigation in which the effects of polymerization process on the MWD and the 3D size distribution are highlighted.…”

Section: Introductionmentioning

confidence: 97%

Effect of Chain Transfer to Polymer in Conventional and Living Emulsion Polymerization Process

Tobita

2018

Processes

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Abstract:Emulsion polymerization process provides a unique polymerization locus that has a confined tiny space with a higher polymer concentration, compared with the corresponding bulk polymerization, especially for the ab initio emulsion polymerization. Assuming the ideal polymerization kinetics and a constant polymer/monomer ratio, the effect of such a unique reaction environment is explored for both conventional and living free-radical polymerization (FRP), which involves chain transfer to the polymer, forming polymers with long-chain branches. Monte Carlo simulation is applied to investigate detailed branched polymer architecture, including the mean-square radius of gyration of each polymer molecule, 0 . The conventional FRP shows a very broad molecular weight distribution (MWD), with the high molecular weight region conforming to the power law distribution. The MWD is much broader than the random branched polymers, having the same primary chain length distribution. The expected 0 for a given MW is much smaller than the random branched polymers. On the other hand, the living FRP shows a much narrower MWD compared with the corresponding random branched polymers. Interestingly, the expected 0 for a given MW is essentially the same as that for the random branched polymers. Emulsion polymerization process affects branched polymer architecture quite differently for the conventional and living FRP.

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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
¹
,
Barner‐Kowollik
²

2008
J. Polym. Sci. A Polym. Chem.
213
4
326
1
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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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Seeded Semibatch Emulsion Polymerization ofn-Butyl Acrylate. Kinetics and Structural Properties

Cited by 170 publications

References 29 publications

Impact of Competitive Processes on Controlled Radical Polymerization

Impact of Competitive Processes on Controlled Radical Polymerization

Effect of Chain Transfer to Polymer in Conventional and Living Emulsion Polymerization Process

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

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