Abstract

The theory is proposed as a result of this work that under “static” conditions, latex destabilization proceeds through a time-dependent localized polymer-particle dehydration. This dehydration apparently occurs in two stages. In the initial stage more or less reversible aggregates are formed. This creaming is accompanied by a perceptible increase in viscosity. In the second stage the aggregates are further dehydrated and coalescence occurs. This latter process is irreversible. Evidence is presented to support the argument that the prime requirement for the dehydration and, consequently, for the destabilization of high-stability latex is the presence of a static latex surface in contact with an unsaturated gas phase. Three factors involved here are (1) surface area, (2) surface agitation, and (3) the degree of saturation of the gas phase in contact with the surface. In addition, it is shown that particle growth precedes the destabilization and that stability is influenced by a number of other factors, including (1) temperature, (2) polymer concentration, and (3) polymer-particle size, which contribute, either directly or indirectly, to the dehydration process.