The present work focuses on the study of the water absorption phenomenon in Rhecktophyllum camerunense (RC). Indeed the diffusive behavior of RC natural fiber was investigated. The fibers samples of 0.1g were submitted to hygro-thermal ageing in an environmental enclosure of 23%, 54% and 75% relative humidities at 23°C. Periodic gravimetric measurements were achieved on the specimens in order to follow their kinetics adsorption. The results show that the kinetic adsorption is rapid at the first hours no matter the relative humidity and begin saturation at the seventh hour. The maximum moisture content increases with the relative humidity. Predictive Fick´s Law was used to modelling experimental data. The curve of all humidities obeys to the Fick’s model and the diffusion coefficients have been deduced. We observe that the diffusion coefficient is an increasing linear function of the relative humidity. Others parameters have been also calculated.

Keywords: Rhecktophyllum camerunense, diffusion, moisture, Fick’s law