Small-angle neutron scattering studies of inhomogeneities in latex particles from emulsion homopolymerizations

Mills, M.F., Gilbert, R.G., Napper, D.H., Rennie, A.R. and Ottewill, R.H. (1993) Small-angle neutron scattering studies of inhomogeneities in latex particles from emulsion homopolymerizations. Macromolecules, 26 14: 3553-3562. doi:10.1021/ma00066a013


Author Mills, M.F.
Gilbert, R.G.
Napper, D.H.
Rennie, A.R.
Ottewill, R.H.
Title Small-angle neutron scattering studies of inhomogeneities in latex particles from emulsion homopolymerizations
Journal name Macromolecules   Check publisher's open access policy
ISSN 0024-9297
1520-5835
Publication date 1993-07
Sub-type Article (original research)
DOI 10.1021/ma00066a013
Volume 26
Issue 14
Start page 3553
End page 3562
Total pages 10
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Abstract Small-angle neutron scattering experiments were carried out to examine the extent of monomer/ polymer spatial inhomogeneities in latex particles formed in an emulsion homopolymerization, using contrast variation and isotopic labeling systems to look at the morphology of swollen and two-stage latices. Samples covered a range of molecular weights including systems where the radius of gyration of the polymer chains was both comparable to and smaller than the particle size. The experiments were designed to test separately inhomogeneities arising from two different effects: (1) the "repulsive wall" (thermodynamic) effect arising from the decrease in entropy of a polymer chain confined near the surface of a particle (the experiments here examined polymer distribution in polystyrene particles swollen with toluene); (2) "surface anchoring" (largely kinetic) arising mainly because, with a water-soluble initiator, free radicals enter latex particles at the surface (here experiments examined the distribution of newly formed polymer in seeded growth; related to this are inhomogeneities arising from finite rates of diffusion of monomer and of polymer). Results support the conclusion that repulsive wall effects do not give rise to significant nonuniformities but that inhomogeneities may arise in the final product where the polymer chain dimensions are substantially less than the particle radius. The latter conclusion is consistent with predictions of the surface anchoring model.
Keyword Polystyrene latexes
Polymerization
Styrene
Morphology
Resolution
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, 15:53:14 EST