Styrene emulsion polymerization. The effects of initiator charge

Penboss, Ian A., Napper, Donald H. and Gilbert, Robert G. (1983) Styrene emulsion polymerization. The effects of initiator charge. Journal of the Chemical Society. Faraday Transactions I, 79 1257-1271. doi:10.1039/f19837901257

Author Penboss, Ian A.
Napper, Donald H.
Gilbert, Robert G.
Title Styrene emulsion polymerization. The effects of initiator charge
Journal name Journal of the Chemical Society. Faraday Transactions I   Check publisher's open access policy
ISSN 0300-9599
Publication date 1983
Sub-type Article (original research)
DOI 10.1039/f19837901257
Volume 79
Start page 1257
End page 1271
Total pages 15
Place of publication Cambridge, United Kingdom
Publisher Royal Society of Chemistry
Language eng
Formatted abstract
The results are reported of a series of kinetic studies of the seeded emulsion polymerization of styrene, designed to investigate the effect of different initiator species on the rate coefficient for the entry of free radicals into the latex particles. The initiators employed were persulphate anions (which give negatively charge free-radical species), Fe2+/H2O2 (giving rise to neutral free-radical species) and 2,2′-azobis-(2-amidinopropane) hydrochloride (generating positively charged free-radical species). Entry rate coefficients were determined from the observed rates of approach to the steady state, making due allowance for the processes of free-radical exit, re-entry and aqueous-phase heterotermination. It was found that the efficiency of capture of aqueous-phase free radicals by the latex particles was relatively low (the rate coefficient for entry being proportional to [initiator]0.5-0.9), at least for charged initiator species; the dependence on initiating species concentration for the Fe2+/H2O2 system could not be directly determined. The dependence of the entry rate coefficient (pA) on particle number density (Nc) and initiator concentration ([I]) was fitted by a mechanism incorporating the conversion of initiating free-radical species into oligomeric free radicals, mutual aqueous-phase termination of these oligomers and entry of these oligomers into latex particles. This gives an expression for pA(Nc, [I]) containing only two rate parameters. It was found that data over wide ranges of [I] and Nc could be accurately fitted with this expression. It was thus found that the charge on the initiating species has only a weak effect on entry and mutual termination of oligomers, indicating that both processes are dominated by the hydrophobic tail of the species involved.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemistry and Molecular Biosciences
Centre for Nutrition and Food Sciences Publications
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Created: Mon, 07 Mar 2011, 15:54:59 EST