Determination of the effective diffusion coefficient during the drying of paint and varnish films applied on fir wood

[Display omitted] •The effective diffusion coefficient was determined.•The duration of the drying process were calculated.•Many models were tested for fitting the drying kinetics.•The films obtained after the drying process were characterized. The development of the civil and industrial building sector lead to an increase in the demand of lacquers and paints. Wood is one of the long-lasting building materials, for which the demand for exterior landscaping and internal finishes is very high and ever-growing. The drying process is an essential step in obtaining a paint film which shall protect the wood. In this paper, we shall use for the first time the derivatograph to analyse the drying process, respectively, the forming process of the actual film on a series of commercial lacquers and paints deposited directly on fir wood support. Many kinetic drying models were tested. The effective diffusion coefficients and the duration of the drying process were calculated. The use of classical models from literature emphasized the difficulty of modelling the drying of certain paint films, due to their complex composition. The films obtained after the drying process were characterized.