DRYING OF SOLVENT COATED POLYMER-FILMS

The ability to predict the drying behavior of coating is of great impo rtance to the coating industry. For this purpose, the model developed by Vrentas and Vrentas(19) has been used to predict the concentration profile as well as the thickness and the temperature change of the pol ymer film as a function of time. The model incorporates the coupling b etween heat and mass transfer and diffusion induced convection which o ccurs when a single layer of a binary polymer solution is dried in a c onvection heated oven. The model was solved numerically by using the f inite difference approximation and it was applied to the well characte rized polyvinylacetate(PVAC)-toluene system. The effects of operating conditions on the residual solvent level were investigated. The validi ty of the model was confirmed by using two sets of data available for the drying of polystyrene(PS)toluene and PVAC-toluene systems.