Authors:M. Bakass, H. Bahaj, R. Benaddi, and C. Bayane
The objective of this article is to study an amorphous superabsorbent polymer, which is able to absorb up to 300 times its weight of water. Adsorption–desorption phenomena of water vapor on the polymer as a function of temperature showed a reversibility of the adsorption–desorption phenomena. The thermal stability of the polymer at atmospheric pressure was also studied. The kinetic study of the desorption phenomena of water vapor on the polymer according to certain physicochemical parameters was discussed. The results showed that the kinetic regime governing the desorption phenomena of water vapor on the polymer is a process limited by a mono-dimensional diffusion for low masses and by a three-dimensional diffusion for high masses.
Authors:H. Bahaj, M. Bakass, C. Bayane, J. P. Bellat, M. Benchanaa, and G. Bertrand
The adsorbed amounts of water vapor onto polyacrylic polymer (polymer ×10) were measured using a thermogravimetry method as a function of pressure at 298 and 313 K. The adsorption isotherms are categorized to type II isotherms by IUPAC classification leading to a hysteresis loop between adsorption and desorption branches. The current study was completed by the measurement of the adsorption heats at 298 K using a differential scanning calorimetry. The calorimetric curves showed two adsorption heats domains. These domains have been attributed to the adsorption of “equivalent monolayer” and the condensation of water between polymeric chains. The correlation of experimental data to some chosen theoretical models shows that the GAB model is the most adequate to describe water vapor sorption isotherms.