A kinetic study of free‐radical copolymerization of butyl acrylate with methyl methacrylate in solution

Madruga, Enrique López; Fernández‐García, Marta

doi:10.1002/macp.1996.021971120

Cited by 56 publications

(65 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, the values determined for k bb are composite numbers including the k tr,intra contribution. From a pure technical point of view, extremely high resolutions can be obtained, methods based on 13 C NMR spectroscopy can in principle distinguish between long and short chain branching 90 and thus provide access to separate values for k tr,intra and k bb . ).…”

Section: Chain-end Termination Rate Coefficient (Secondary Radicals)mentioning

confidence: 99%

“…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%

“…In 1998, Ahmad et al 16 used 13 C NMR to characterize polyBA synthesized from emulsion polymerization. From the abundance of quaternary carbons they deduced the branching frequency and concluded that the origin of these branches must be inter-and more notably intramolecular transfer to polymer reactions [17][18][19] giving a late confirmation for the backbiting theory.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Junkers

Barner‐Kowollik

2008

J. Polym. Sci. A Polym. Chem.

213

326

View full text Add to dashboard Cite

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

show abstract

Section: Chain-end Termination Rate Coefficient (Secondary Radicals)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Junkers

Barner‐Kowollik

2008

J. Polym. Sci. A Polym. Chem.

213

326

View full text Add to dashboard Cite

show abstract

“…In effect, it is purported 4 • 5 that the observed value of the bimolecular termination rate constant k 1 (for homopolymerization) is in fact a weighted sum of the individual termination rate constants of each monomer involved in the reaction: where (8) Here w;* is the concentration of radicals of length i, D; is the rate coefficient for the diffusion of the chain end of a macroradical of length i, and Pspin and a are the spin probability that forbids a certain fraction of radical-radical encounters and a capture radius, respectively. At the risk of oversimplifying this analysis, what this means is that if the hypothesis that reactivity is independent of chain length is not entirely valid for the monomer in question, or there is a large disparity in chain lengths in the system, then the termination constant (and chain length ... ) will be diffusion controlled even in dilute solutions.…”

Section: Resultsmentioning

confidence: 99%

“…For different monomers, but in a similar system, Madruga and Fernandez-Garcia 8 showed that the reactivity ratios and rate constants of the system BuA-MMA (methyl methacrylate) varied as a function of the concentration of solvent (benzene). Semchikov et a/.…”

mentioning

confidence: 99%

Effect of Solvent on the Rate Constants in Solution Polymerization III. Butyl Acrylate/Vinyl Acetate

McKenna

Heredia

1999

Polym J

View full text Add to dashboard Cite

ABSTRACT:An experimental and modelling study has been carried out to explore the kinetics of the copolymerization of butyl acrylate and vinyl acetate (BuA-V Ac) in solution. A series of batch free radical copolymerization experiments has been carried out using the system BuA-VAc in an ethyl acetate (EAc) solvent. Experimental data were obtained from gravimetric and NMR measurements. The pseudo-homopolymerization constants identified in Parts I and II of this work (McKenna et a/., J. Polym. Sci., Polym. chem., in press) were used along with literature values for the propagation rate constants and reactivity ratios to model the different reactions presented here. It was found that the reactivity ratios of Dube and Penlidis [Polymer, 36, 587 (1995) With the exception of Parts 1 and 2 1 • 2 of this work, and the study published by Dube and Penlidis, 3 recent studies on the solution copolymerization of butyl acrylate (BuA) and vinyl acetate (V Ac) are scarce. And, as we have pointed out in the previous articles, even when data are available there seems to be a rather wide dispersion in reported values of the homopolymerization kinetic constants for propagation and termination, kP and k 1 • This dispersion might in part be attributable to a lack of correlation of data with reaction conditions.In a batch reactor, and in the absence of any gel effect, monomer conversion in a homopolymerization as a function of time is given by:Iff, kd and t are known, then it is possible to estimate the value of kp/k(l_: 5 by regressing the ln(l-x) as a function ofj(t) = -kdt/2)). As can be seen in Figure 1, the lumped rate constant kP/k 1°· 5 of BuA is a function of the initial monomer concentration, even though this quantity does not appear in eq I. Very similar results were observed for VAc.Note that as shown in ref 1 and 2, the values of kp/ kt 5 varied by approximately a factor of 2 over the range of concentrations studied. This means that regardless of the cause of this variation (it was proposed that chain transfer reactions were in part responsible), the radical concentration in the systems studied changed very little, and when they did change, it was not particularly rapid. Furthermore, it can also be seen from Figure 1, and from all of the curves presented in the first 2 parts of this series that the ln(1-x) is a strongly linear function of fit). This clearly demonstrates that it is reasonable to invoke the quasi-steady state assumption (QSSA) in the derivation of the equations used to analyse kp/k1°· 5 • t To whom correspondence should be addressed.Recent works have discussed the possibility that diffusion of macroradicals (i.e., chain length) might indeed be important even at low conversions in some case. 4 • 5 And since overall chain length is controlled to a large extent by monomer concentration, it is not surprising that in such a case the observed value of the rate constants should vary with the initial monomer concentration. This variation was therefore attributed, at least in part, to the fact there is a great deal of...

show abstract

High-temperature solution polymerization of butyl acrylate/methyl methacrylate: Reactivity ratio estimation

Hakim

Verhoeven

McManus

et al. 2000

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

Solution copolymerizations of butyl acrylate/methyl methacrylate in toluene were performed over an expanded temperature range (60 -140°C) compared to more typical ranges that do not exceed 80°C. From a large amount of data collected independently at two laboratories, reactivity ratios were estimated at five different temperatures. The reactivity ratios were estimated from low conversion copolymer composition data using both the error-in-variables model method and a nonlinear parameter estimation based on the integrated copolymer composition equation. Using all of the available data, temperature-dependent expressions were developed for the reactivity ratios and compared to previously published bulk copolymerization values. No significant differences appeared to exist between the bulk and solution polymerization reactivity ratios. Furthermore, the copolymer composition data conformed to the MayoLewis kinetic model over the entire temperature range.

show abstract

A kinetic study of free‐radical copolymerization of butyl acrylate with methyl methacrylate in solution

Cited by 56 publications

References 24 publications

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

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

Effect of Solvent on the Rate Constants in Solution Polymerization III. Butyl Acrylate/Vinyl Acetate

High-temperature solution polymerization of butyl acrylate/methyl methacrylate: Reactivity ratio estimation

Contact Info

Product

Resources

About