Latex thickening: Interactions between aqueous polymeric dispersions and solutions

Abstract

Latex thickening—the process of increasing the viscosity of a polymer emulsion by addition of a water‐soluble polymer —has been studied by rheological measurements and by the examination of other colloidal properties. For the systems studied, which represent a range of polymers in both the dispersion and solution phases, the flow curves were represented over a wide range of shear rate by the equation, S = K(τ − τ0)2, where S is shear stress, τ is shear rate, and K and τ0 are constants, of which the latter is considered to be a yield stress. Aside from the generality of the mathematical function, the behavior of various latex‐thickener pairs is extremely specific to the pair involved. Additional data on latex creaming and on the influence of the thickener and latex concentrations confirms the specificity. The available data indicate that latex thickening is not simply an enhancement of the viscosity of the aqueous phase by the thickener, but that in addition to this the ability of the thickener to flocculate or deflocculate the latex is an important part of the mechanism of thickening. These colloidal interactions change, often precipitously, with minor changes in the polymers, the latex emulsifier, and the concentrations of the components.

Preparation of the Pb(Mg1/3Nb2/3)O3 films by aqueous tape casting

“…Based on the previous study of Brown and Garrett, B-60A is an emulsion containing acrylic copolymer and nonionic emulsifier. 20 Nahass et al 21 reported that Rhoplex B-60A is likely a copolymer between methyl methacylate and another acrylic monomer such as ethyl acrylate. 21 Similarly, Ushifusa and Cima determined the isoelectric point of B-60A at about pH 2 in absence of any electrolyte.…”

Structure and flow behavior of crosslinked ethyl acrylate-methacrylic acid copolymer dispersion particles

“…Among them, dispersions of acrylate copolymers prepared by emulsion copolymerization of monomers carrying carboxylic groups are well known as effective thickening agents for setting up optimum flow properties of various latex materials [1,2]. On alkalinization of originally acid dispersion, electrical charges of ionized carboxylic groups on polymer chains give rise to Coulombic interactions leading to an extension of the particle double layer, swelling of copolymer particles or, if the content of carboxylic groups is large, dissolution of particles to a polyeletrolyte solution.…”