DSC evaluation of binder content in latex paints

The estimate by differential scanning calorimetry of the enthalpy of therma l decomposition of the organic fraction in a complex material can be used, in proper conditions, for evaluating the concentration of the organic compo nents. The application of this technique of thermal analysis to latex paint s aimed at identification of binder content is discussed in this paper. On the one hand it gives good results on binder content estimate; on the other hand it highlights some aspects of the thermal decomposition of polymers e nclosed in an inorganic matrix. The phenomena of thermal decomposition are studied for the main components of latex paints, i.e. for polymers, and for complete paint formulations. The materials considered include widely used binders for the manufacture of latex paints such as vinyl acetate/Versatate copolymers and styrene/acrylic copolymers, rheology modifiers such as cell ulose ethers and other standard components of latex paints. Formulations re presenting typical latex paints with different binder content and simplifie d polymer/filler systems are considered. Although decomposition paths are v ery different for different polymers and for the same polymer in different concentrations, the overall heat output is consistent and proportional to t he amount of polymer in the sample. Therefore identification by DSC measure ments of the binder content in a latex paint appears as a feasible techniqu e. (C) 1998 Elsevier Science S.A. All rights reserved.