Abstract

Three differently treated samples of bovine hide powder were subjected to adsorption/desorption kinetics from 5 to 95% relative humidity in a thermogravimetric balance equipped with a controlled humidity chamber. As hygroscopic specimens take a very long time to reach equilibrium, testing times were shortened and kinetic models based on the experimental results were developed to calculate the adsorption at equilibrium, the time of half adsorption/desorption, the rate of half adsorption and the apparent coefficient of diffusion. The strong relationship between the time of half adsorption and the apparent coefficient of diffusion suggests that the rate of moisture adsorption is determined by the rate of diffusion inside the sample.