Kinetics and Peculiarities of Polyamide Coatings Formation from Solutions

Abstract

Peculiarities of diffusion in 10 % methylolpolyamide (PFE) solution of various solvents (ethanol, butanol, water) and coatings formation were investigated. Dispersion and polar components of surface energy were determined (γd = 21.6 and γp = 30.8 mJ/m2) together with polymer solubility index δ for which solvents absorption method was applied. Based on the laws of thermodynamics the surface energy of solvents was determined, components of which were used to determine interphase stresses in solution γij between i and j components. Interphase stresses in their turn were used to calculate phase interaction changes when polymer solution is diluted using solvent, interaction of which with polymer solution is not known beforehand. Solvents diffusion coefficients were found and their dependences on solvent concentration were established for solvent diffusion in polymer solution. Stages of drying of the methylolpolyamide coating – free solvent evaporation, quasi-stationary and diffusion processes were established. The indices, application of which enables to forecast coating drying time, were found.