Reduction of solvent content in toluene–neoprene adhesives and in acetone–polyurethane adhesives

The desorption of toluene in a polychloroprene (neoprene)-toluene adhesive and in a commercial neoprene adhesive was studied in air at three different temperatures by monitoring the weight loss vs time. Similarly, the desorption of acetone in a polyurethane adhesive and in a commercial adhesive was also considered. The experimental weight variations are correlated with the solution of the second Fick law at non-steady state. As the volume is highly reduced when the solvent is evaporated from the solvent-polymer mixture, the correlations obtained are discussed on the basis of the variation of the diffusivity with the solvent concentration, assuming that the product of the diffusivity and the polymer volume fraction to the power 2 is approximately constant. Apparent activation energies were obtained for the four adhesives used.