Conditions for secondary particle formation in emulsion polymerization systems

Morrison, Bradley R. and Gilbert, Robert G. (1995). Conditions for secondary particle formation in emulsion polymerization systems. In: International Symposium on Radical Copolymers in Dispersed Media (R C D M). International Symposium on Radical Copolymers in Dispersed Media (R C D M), Lyon, Fance, (13-30). 17-22 April 1994. doi:10.1002/masy.19950920104


Author Morrison, Bradley R.
Gilbert, Robert G.
Title of paper Conditions for secondary particle formation in emulsion polymerization systems
Conference name International Symposium on Radical Copolymers in Dispersed Media (R C D M)
Conference location Lyon, Fance
Conference dates 17-22 April 1994
Proceedings title International Symposium on Radical Copolymers in Dispersed Media (R C D M)   Check publisher's open access policy
Journal name Macromolecular Symposia   Check publisher's open access policy
Place of Publication Weinheim, Germany
Publisher Wiley - V C H Verlag GmbH
Publication Year 1995
Sub-type Fully published paper
DOI 10.1002/masy.19950920104
ISSN 1022-1360
1521-3900
Volume 92
Issue 1
Start page 13
End page 30
Total pages 17
Language eng
Formatted Abstract/Summary
A simple means is deduced for determining conditions for secondary particle formation in emulsion polymerization systems in systems where the amount of added surfactant is below the cmc. A new radical formed from initiator in the aqueous phase will undergo some polymerization with aqueous-phase monomer, but must have three possible eventual fates: aqueous-phase termination, entry into a preexisting particle, or creation of a new particle. The means for determining the onset and extent of secondary nucleation is to modify HUFT theory to take into account a successful model for entry [ Macromolecules, 24, 1629 (1991)] which states that entry occurs if and only if the aqueous-phase radical has achieved a critical degree of polymerization z. Particle formation below the cmc is by homogeneous/coagulative nucleation which (if coagulation is ignored) gives an upper bound to the rate of formation of precursor particles; these are of a degree of polymerization Jcrit > z. The resulting equations are readily solved, and require only a knowledge of the aqueous-phase propagation and termination rate coefficients (the latter is very high: ca. 109 dm3 mol−1 s−1 for termination between the very small radicals), z and jcrit. Easily applied means are given for estimating all these quantities. The treatment gives good accord with experimentally observed conditions for the onset of secondary nucleation in low-surfactant systems (including taking in situ micellization into account).
Keyword Free-radical polymerization
Molecular-weight distributions
Aqueous-phase polymerization
Propagation rate coefficient
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ
Additional Notes Article first published online: 7 March 2011.

Document type: Conference Paper
Collection: Centre for Nutrition and Food Sciences Publications
 
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Created: Mon, 07 Mar 2011, 15:53:27 EST