The Measurement and Meaning of Rate Coefficients in Free-Radical Polymerizations

Heuts, Johan P. A.; Clay, Paul A.; Christie, David I.; Piton, Mark C.; Hutovic, Jelica; Kable, Scott H.; Gilbert, Robert G.

doi:10.1007/978-3-642-78759-1_17

Cited by 15 publications

(11 citation statements)

References 18 publications

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“…These problems led us to consider other methods for transfer constant measurement. Recently, Gilbert and co-workers ,− have advocated analysis of the ln chain length distribution in this context (ln CLD method), an approach also adopted by Hutchinson ,, …”

Section: Resultsmentioning

confidence: 99%

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Chain Transfer Activity of ω-Unsaturated Methyl Methacrylate Oligomers

et al. 1996

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The chain transfer activities of a series of ω-unsaturated methyl methacrylate oligomers [(dimer (1), trimer (2), tetramer (3), and a methyl methacrylate macromonomer with average chain length of 24 units (4)] have been evaluated in methyl methacrylate polymerizations over the temperature range 45−100 °C. Transfer constants were determined by analysis of the ln chain length distributions. The dimer (1) was found to be substantially less effective as a chain transfer agent than the trimer (2) or the higher macromonomers (3, 4) [C T(60 °C) 1, 0.013; 2, 0.19; 3, 0.31; 4, 0.21]. The transfer constants show only a small temperature dependence and no variation with conversion. No discernible retardation was observed in these polymerizations. A reduced yield of polymer observed at conversions >10% in bulk polymerizations of MMA carried out in the presence of 1 − 4 can be attributed to the absence of the gel (Trommsdorff) effect. The results are interpreted in terms of the addition−fragmentation mechanism for chain transfer.

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Section: Resultsmentioning

confidence: 99%

“…The method ,− , is based on the use of eqs 3 and 4 for the measurement of chain transfer constants where P i is the chain length distribution, k tr,M and k tr,T are the rate constants for chain transfer to monomer and transfer agent respectively, k p is the propagation rate constant, and i is the chain length.…”

Section: Resultsmentioning

confidence: 99%

Chain Transfer Activity of ω-Unsaturated Methyl Methacrylate Oligomers

et al. 1996

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“…. , n ) ( 6 ) for which the eii are uncorrelated with mean zero but with unequal variances var( c?) = a : , each residual is weighted by the reciprocal of the error standard deviation, i.e., wi = l / a ; .…”

Section: Data Fittingmentioning

confidence: 99%

Estimation of activation parameters for the propagation rate constant of styrene

Manders¹,

Chambard²,

Kingma³

et al. 1996

J. Polym. Sci. A Polym. Chem.

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“…The data of Heuts et al [9] are measured in the low temperature range, and it might not be permitted to extrapolate the Arrhenius equation to higher temperatures, since transfer to monomer may become more significant. The processing of the experimental data, however, is different, which leads to striking differences in the resulting propagation rate coefficients.…”

Section: Reevaluation Of Existing Datamentioning

confidence: 99%

“…Heuts et al [9] used pulsed laser polymerization (PLP) for measuring the propagation rate coefficient of butyl acrylate. The inflection point in the molar mass distribution was used as starting point for data analysis.…”

Section: Introductionmentioning

confidence: 99%

Seeded emulsion polymerization of butylacrylate: “Zero‐one or pseudo‐bulk?”

et al. 1996

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The kinetics of the emulsion polymerization of butyl acrylate at 20 "C in Smith-Ewart interval 111 were investigated using a redox initiator system peroxodisulfatebisulfite-copper. The aim of this work was to obtain more basic knowledge about the kinetic behavior of the butyl acrylate system. Monomer conversion into polymer was based on gravimetrically calibrated online densitometry. The experimentally obtained conversion versus time curves for these seeded reactions were fitted by a linear regression procedure (slope and intercept) as well as by a nonlinear regression procedure based upon zero-one kinetics. The conclusion is that the emulsion polymerization of butyl acrylate may reflect zero-one kinetics up to a particle size of approximately 130 nm. The rate coefficients for entry and exit can be obtained fairly accurately with the slope and intercept procedure and with the nonlinear regression method if the propagation rate coefficient is accurately known. However, this is not the case. Therefore the development of universal procedures for obtaining the propagation rate coefficients is essential, since this parameter is of paramount importance in all further model calculations concerning emulsion polymerization.x exp [-20 f 2 x 1 O~/ R T ] (40 "C --7 0~x 2 ) k = 107.4*0.4 P Acta Polymer., 47,441-449 (1996) 0 VCH Verlagsgesellschafi mbH, D-69451 Weinheim, 1996

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The Measurement and Meaning of Rate Coefficients in Free-Radical Polymerizations

Cited by 15 publications

References 18 publications

Chain Transfer Activity of ω-Unsaturated Methyl Methacrylate Oligomers

Chain Transfer Activity of ω-Unsaturated Methyl Methacrylate Oligomers

Estimation of activation parameters for the propagation rate constant of styrene

Seeded emulsion polymerization of butylacrylate: “Zero‐one or pseudo‐bulk?”

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