Emulsion polymerization in a hybrid carbon dioxide aqueous medium

Quadir, M.A., Snook, R., Gilbert, R.G. and DeSimone, J.M. (1997) Emulsion polymerization in a hybrid carbon dioxide aqueous medium. Macromolecules, 30 20: 6015-6023. doi:10.1021/ma970259a


Author Quadir, M.A.
Snook, R.
Gilbert, R.G.
DeSimone, J.M.
Title Emulsion polymerization in a hybrid carbon dioxide aqueous medium
Journal name Macromolecules   Check publisher's open access policy
ISSN 0024-9297
1520-5835
Publication date 1997-10
Sub-type Article (original research)
DOI 10.1021/ma970259a
Volume 30
Issue 20
Start page 6015
End page 6023
Total pages 9
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Formatted abstract
The development of a new reaction medium is reported, based on a biphasic mixture of carbon dioxide and water for emulsion polymerizations: a surfactant-free aqueous emulsion polymerization of methyl methacrylate using potassium persulfate under a varying head pressure of CO2 (0-350 bar) at 75 °C. The resulting polymer is a stable latex with particles of submicron size. The effect of CO2 on polymerization is relatively small, until there is a significant change at high CO2 pressure. This is seen by examining the molecular weight distribution in the form of the log(number distribution), P(M) (readily obtained by GPC). At pressures of 140 bar and below, the P(M) show the form expected for chain-stopping events dominated by transfer and by diffusion-controlled termination. At 280 bar, In P(M) is significantly steeper than its lower-pressure counterpart at relatively low conversion (45%). This is attributed to swelling by supercritical CO2 reducing the viscosity of the particles, allowing more rapid termination.
Keyword Free-radical polymerizations
Molecular-weight distributions
Termination rate-processes
Methyl-methacrylate
Coagulative nucleation
Kinetics
Styrene
Entry
Size
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, 15:56:14 EST