A titration microcalorimetry study of the interactions between poly(vinyl alcohol) and coating colour minerals

The interaction between poly(vinyl alcohol) (PVA), and coating colour miner als has been studied with titration microcalorimetry and adsorption measure ments. The adsorption of a partially hydrolysed PVA on non-dispersed and di spersed minerals, as well as on mineral mixtures was investigated at low so lid contents (5% w/w). Commercial grades of calcium carbonate and clay were used with non-dispersed minerals as references. The results of the microcalorimetric measurements indicated that there was quite a strong interaction between PVA and the commercial grade of clay, th e reference clay showed a fairly weak interaction with PVA. A relatively we ak interaction was found between PVA and both the calcium carbonate.. This was interpreted as an indication that the interaction is very dependent on the surface chemical properties. In mixtures of clay and calcium carbonate, the clay had more influence on the strength of interaction at low amounts of added PVA, whereas the level of calcium carbonate had more influence on the total adsorbed amount. Increasing the amount of sodium polyacrylate in the pre-dispersing of the mixtures did not affect the adsorbed amount of PV A.