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Abstract

The synthesis of composite latex particles possessing core–shell and gradient morphologies, respectively, using seeded starve-fed semibatch emulsion polymerization of styrene (St) and methyl methacrylate (MMA) is presented. The focus is on the effect of the monomer feed order on the particle morphology development. The particle morphology is assessed using a novel approach which entails comparing the experimental surface composition as a function of polymerization time (particle growth) obtained by X-ray photoelectron spectroscopy with the predicted surface composition using a mass balance mathematical model. Both types of composite latexes (core–shell and gradient) feature changes with polymerization time in the oxygen/carbon surface composition which enables one to track the morphology development. Differential scanning calorimetry is also implemented to analyze the extent of phase separation. The monomer feed order is shown to play a crucial role—under the present conditions, gradient and core–shell particles are obtained if the feed order is St/MMA (St fed first), but not if the feed order is reversed. These findings illustrate that thermodynamic factors are important, given that thermodynamically it is more favorable for MMA-rich chains to occupy the oil–water interface to reduce the interfacial tension. Systems where St is the second stage monomer lead to mixed structures rather than the targeted core–shell or gradient morphology with St-rich chains at the particle surface.

Item Type:	Article
Authors/Creators:	Jasinski, F and Teo, VL and Kuchel, RP and Mballa, MM and Thickett, SC and Brinkhuis, RHG and Weaver, W and Zetterlund, PB
Keywords:	latex, core-shell, emulsion polymerization, nanoparticles, gradient morphology, thermodynamics, XPS
Journal or Publication Title:	Journal of Polymer Science. Part A: Polymer Chemistry
Publisher:	John Wiley & Sons Inc
ISSN:	0887-624X
DOI / ID Number:	https://doi.org/10.1002/pola.28644
Copyright Information:	VC 2017 Wiley Periodicals
Related URLs:	Google Scholar: Thickett, SC UTAS Profile: Thickett, SC
Item Statistics:	View statistics for this item

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