Hydrophobically Modified Associative Polymer Solutions: Rheology and Microstructure in the Presence of Nonionic Surfactants

English, Rob J, Laurer, J H, Spontak, R J and Khan, S A (2002) Hydrophobically Modified Associative Polymer Solutions: Rheology and Microstructure in the Presence of Nonionic Surfactants.

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Abstract

We report on the rheology and morphology of a hydrophobically modified alkali-swellable emulsion (HASE) polymer solubilized in alkaline media containing nonionic surfactants. The HASE polymer consists of complex alkylaryl hydrophobes composed of oligomeric nonylphenol condensates attached to a poly(ethyl acrylate-co-methacrylic acid) backbone. The complex linear viscoelastic response of the polymer in alkaline solution suggests an unentangled network with an appreciable fraction of microgel. The concentration and hydrophile−lipophile balance (HLB) of nonionic surfactants profoundly affect the solution rheology. A surfactant of high HLB inhibits the dynamic network connectivity of the HASE polymer, as demonstrated by reductions of both the steady-shear viscosity and the dynamic storage modulus. The shear-induced structuring previously reported for this polymer is also progressively diminished as the surfactant concentration is increased. In contrast, the addition of a low-HLB surfactant promotes system structuring, as evidenced by (i) increases in the shear viscosity and the high-frequency plateau modulus and (ii) retention of the ability to undergo shear-induced structuring. We also employ cryofracture-replication transmission electron microscopy for the first time with regard to HASE associative polymers to examine the morphological characteristics of selected systems. The morphology of the HASE polymer in both latex and solubilized form appears more complex than previously anticipated, and a reasonable interpretation of these new data is provided.

Item Type: Article
Additional Information: Copyright © 2002 American Chemical SocietyMetadata only available from this repositoryThis article was originally published in Industrial and Engineering Chemistry Research - Journal of the American Chemical Society in 2002. The full article can be found at http://dx.doi.org/10.1021/ie020409s
Keywords: alkali-swellable emulsion, alkylaryl hydrophobes, oligomeric nonylphenol condensates, cryofracture-replication transmission electron microscopy
Divisions: ?? GlyndwrUniversity ??
Depositing User: ULCC Admin
Date Deposited: 05 Oct 2011 09:14
Last Modified: 11 Dec 2017 20:06
URI: http://glyndwr.repository.guildhe.ac.uk/id/eprint/228

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