Chemical changes in curing and ageing oil paints

A chemical and physical description is given of different processes in the development of an oil paint film: curing, maturing, and degradation. A transition from the initial polyester to an ionomeric system during the maturation process as a result of hydrolysis and metal carboxylate formation is proposed. Analytical results describe to what extent the transition from a polyester to a polyanionic ionomer has occurred for a number of aged paint samples. High degrees of hydrolysis (> 65%) are found in samples from 100-250-yearold paintings.