Analysis of emulsion paints

Abstract

This report discusses the analytical work performed at different laboratories during the course of a cooperative project initiated by the working party on Supported Polymer Films (SPF) of the Macromolecular Division of IUPAC. Both paint manufacturing laboratories and independent research institutes participated. By means of a combination of traditional approaches and modern analytical equipment, three typical white emulsion paints have been analysed for pigments and extenders, binders, co-solvents, coalescing agents, plasticizers and additives. The dry paints were investigated by thermogravimetry (TG). The combined pigment and extender fractions were separated and identified by infrared (IR) analysis. X-ray diffraction and energy-dispersive X-ray fluorescence (EDXRF). Quantifications were performed by atomic absorption spectroscopy (AAS) and IR. In addition, the white pigment, titanium dioxide, was determined by titration and EDXRF. The isolated binder fractions were characterised by IR spectroscopy. The binders still in the wet paint were further dissolved and identified by carbon-13 nuclear magnetic resonance ( 13C NMR) spectroscopy. Co-solvents and coalescing agents were determined quantitatively by gas chromatography (GC), either by direct injection of the paint sample or following silylation. Investigations of different extraction approaches towards dry as well as wet paint samples (mainly by IR) allowed information to be obtained on various ionic and non-ionic additives.