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Core–shell and gradient morphology polymer particles analyzed by X-ray photoelectron spectroscopy: effect of monomer feed order

Citation

Jasinski, F and Teo, VL and Kuchel, RP and Mballa, MM and Thickett, SC and Brinkhuis, RHG and Weaver, W and Zetterlund, PB, Core-shell and gradient morphology polymer particles analyzed by X-ray photoelectron spectroscopy: effect of monomer feed order, Journal of Polymer Science. Part A: Polymer Chemistry, 55, (15) pp. 2513-2526. ISSN 0887-624X (2017) [Refereed Article]

Copyright Statement

VC 2017 Wiley Periodicals

DOI: doi:10.1002/pola.28644

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 Details

Item Type:Refereed Article
Keywords:emulsion polymerization, nanoparticles, gradient morphology, thermodynamics, core-shell
Research Division:Chemical Sciences
Research Group:Macromolecular and Materials Chemistry
Research Field:Synthesis of Materials
Objective Division:Manufacturing
Objective Group:Industrial Chemicals and Related Products
Objective Field:Plastics in Primary Forms
Author:Thickett, SC (Dr Stuart Thickett)
ID Code:117599
Year Published:2017
Deposited By:Chemistry
Deposited On:2017-06-20
Last Modified:2017-12-13
Downloads:0

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