STUDY OF THE SURFACE–BULK PROPERTIES OF AN ACRYLIC DISPERSION IN THE PRESENCE OF AN AMINE-CONTAINING SURFACTANT

Abstract

Introduction. Waterborne coating materials based on polymer dispersions are regarded as a priority direction in coating technology due to reduced environmental impact and increasingly stringent requirements for production and application safety. However, aqueous acrylic dispersions retain technological limitations associated with film formation, interfacial interactions, and resistance to moisture exposure. One promising approach to improving performance is the incorporation of amine-containing surfactants capable of regulating charge–associative processes and the structure of the interfacial layer. The aim of this study was to determine the effect of an amine-containing additive on the surface–bulk properties of an aqueous acrylic dispersion and to identify the factors governing changes in interfacial activity and structural organization within the bulk phase. The research objectives included a comparative analysis of the “water–additive” system and the “acrylic dispersion–water–additive” system, as well as an examination of the mechanisms responsible for the redistribution of protonated and less ionized forms of the additive between the bulk phase and the phase boundary. Methods. Interfacial characteristics were evaluated using an ACAM series instrument equipped with video recording of the droplet profile and calculation of interfacial parameters by drop shape analysis based on the Young–Laplace equation. Bulk properties were monitored by conductometry (specific electrical conductivity) and potentiometry with pH measurements while varying the content of the amine-containing additive polyethylene polyamine. Results and discussion. It was shown that in an aqueous medium the additive exhibits limited interfacial activity. In the presence of an acrylic dispersion, the interfacial effect is enhanced, indicating the involvement of the additive in specific interactions with functional groups of the film-forming polymer and a change in its distribution between the surface and the bulk phase. Conclusion. The results obtained substantiate the use of polyethylene polyamine as a tool for controlling interfacial and bulk processes in aqueous acrylic dispersions and may be applied in the development of waterborne coating systems.