A kinetic study of butyl acrylate free radical polymerization in benzene solution

Fernández-Sanz, Marina; Madruga, Enrique López

doi:10.1002/1521-3935(20000901)201:14<1840::aid-macp1840>3.0.co;2-n

Cited by 25 publications

(34 citation statements)

References 38 publications

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“…The single‐lumped rate coefficient, θ , that controls the apparent order of rate on monomer concentration could be determined from the dependence R p = R p ([M]). Applied to rate data from the literature,5,8 this new treatment yields consistent estimates for θ (≈1 mol · L −1 ) and k p / k

_{t}^{0.5}

= 1.8 (L · mol −1 · s −1 ) 1/2 for BA polymerization at 50 °C.…”

Section: Introductionmentioning

confidence: 76%

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Effect of Intramolecular Transfer to Polymer on Stationary Free Radical Polymerization of Alkyl Acrylates, 2

Nikitin

Hutchinson

2006

Macro Theory & Simulations

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Summary: Procedures are developed to estimate kinetic rate coefficients from available rate data for the free radical solution polymerization of butyl acrylate at 50 °C. The analysis is based upon a complete mechanistic set that includes the formation of mid‐chain radicals through backbiting and their subsequent reaction, and contains no assumptions on how the rate coefficient for cross‐termination of mid‐chain and end‐chain radicals is related to the two homo‐termination rate coefficients. After a thorough statistical analysis, the results of the fitting are combined with other recent literature data to provide a complete set of individual rate coefficients for the butyl acrylate system. Monomer addition to a mid‐chain radical is estimated to be slower than addition to a chain‐end radical by a factor of more than 400. The termination of two mid‐chain radicals is estimated to be two orders of magnitude slower than termination of two end‐chain radicals, with the cross‐termination rate coefficient close to the geometric mean.Formation of a mid‐chain radical by intramolecular chain transfer to polymer by a chain‐end radical.imageFormation of a mid‐chain radical by intramolecular chain transfer to polymer by a chain‐end radical.

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_{t}^{0.5}

= 1.8 (L · mol −1 · s −1 ) 1/2 for BA polymerization at 50 °C.…”

Section: Introductionmentioning

confidence: 76%

“…Instead, the exponent m in the proportionality law R p ∝ [M] m is found to lie between 1.4 and 1.8 and to vary with monomer concentration 1–9. If first‐order behavior is assumed, then the ratio of k p / k

_{t}^{0.5}

( k p and k t are propagation and termination rate coefficients, respectively) is found to apparently vary with [M].…”

Section: Introductionmentioning

confidence: 99%

Effect of Intramolecular Transfer to Polymer on Stationary Free Radical Polymerization of Alkyl Acrylates, 2

Nikitin

Hutchinson

2006

Macro Theory & Simulations

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“…Furthermore, no temperature dependence for k t ss has been determined so far. An attempt to estimate chain-length averaged AEk , and θ 2 = (k t tt /k t ss )/(k bb /k p t ) 2 obtained by analysis of experimental rate data for stationary BA polymerization at 50°C 8,35 and by assuming the activation energy of the three termination rate coefficients to be identical and to be given by the value deduced from SP-PLP-NIR experiments. 36 Direct information on termination kinetics comes from the measurement of radical concentration vs time profiles under nonstationary but well-defined reaction conditions.…”

Section: Introductionmentioning

confidence: 99%

Termination and Transfer Kinetics of Butyl Acrylate Radical Polymerization Studied via SP-PLP-EPR

et al. 2010

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Butyl acrylate (BA) solution polymerization (1.5 M in toluene) was investigated via singlepulse pulsed laser polymerization in conjunction with electron paramagnetic resonance spectroscopy (SP-PLP-EPR) with emphasis on the termination and transfer kinetics of the system in which two distinctly different types of radicals, secondary chain-end radicals (SPRs) and midchain radicals (MCRs), are present. MCRs are produced by intramolecular hydrogen transfer (backbiting). They may react back to SPRs by monomer addition. The evolution of SPR and MCR concentrations after photoinitiation with an intense laser pulse was measured via highly time-resolved EPR at temperatures between -40 and þ60°C. At very low temperatures the MCR concentration is negligible, enabling the chain-length-dependent rate coefficient of SPR termination, k t ss (i,i), to be directly determined. At higher temperatures it was necessary to use PREDICI simulation of the radical concentration vs time traces, a process which yields the chain-length-dependent rate coefficient of SPR termination for monomeric radicals, k t ss (1,1), as well as the rate coefficients for backbiting, k bb , for monomer addition to an MCR, k p t , and for SPR-MCR cross-termination, k t st . The composite model adequately represents k t ss (i,i), with the power-law exponents R s = 0.85 ( 0.09 and R l = 0.16 ( 0.07 for shortchain and long-chain radicals, respectively, and a crossover chain length between short-chain and long-chain behavior at around i c = 30. The activation energy for both k t ss (1,1) and k t st (1,1) is found to be as one would expect for translational diffusion of small molecules.

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“…2), have been observed frequently. [11][12][13][14][15] Varying explanations for this deviation from ideal polymerization kinetics were given due to the complex kinetic situation where numerous influences like the gel effect or the chain length dependency of bimolecular termination rate coefficient, k t , need to be considered. It is, however, noteworthy to add that ideal behavior is observed in dilute solution for methacrylates (and other monomers that propagate via a tertiary radical).…”

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.

212

326

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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 kinetic study of butyl acrylate free radical polymerization in benzene solution

Cited by 25 publications

References 38 publications

Effect of Intramolecular Transfer to Polymer on Stationary Free Radical Polymerization of Alkyl Acrylates, 2

Effect of Intramolecular Transfer to Polymer on Stationary Free Radical Polymerization of Alkyl Acrylates, 2

Termination and Transfer Kinetics of Butyl Acrylate Radical Polymerization Studied via SP-PLP-EPR

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

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