The present work focuses on the study of the water absorption phenomenon through the pith ofRaffia viniferaalong the stem. The water absorption kinetics was studied experimentally by the gravimetric method with the discontinuous control of the sampling mass at temperature of 30°C. The samples of 70 mm × 8 mm × 4 mm were taken from twelve sampling zones of the stem ofRaffia vinifera. The result shows that the percentage of water absorption of the pith ofRaffia viniferaincreases from the periphery to the center in the radial position and from the base to the leaves in the longitudinal position. Fick’s second law was adopted for the study of the water diffusion. Eleven models were tested for the modelling of the water absorption kinetics and the model of Sikame Tagne (2014) is the optimal model. The diffusion coefficients of two stages were determined by the solution of the Fick equation in the twelve sampling zones described by Sikame Tagne et al. (2014). The diffusion coefficients decreased from the center to the periphery in the radial position and from the base to the leaves in the longitudinal position.

The study is focused on the water diffusion phenomenon through the Raffiaviniferafibre from the stem. The knowledge on the behavior of those fibres in presence of liquid during the realization of biocomposite, is necessary. The parameters like percentage of water gain at the point of saturation, modelling of the kinetic of water absorption, and the effective diffusion coefficient were the main objectives. Along a stem of raffia, twelve zones of sampling were defined. From Fick’s 2nd law of diffusion, a new model was proposed and evaluated compared to four other models at a constant temperature of 23°C. From the proposed model, the effective diffusion coefficient was deduced. The percentage of water gain was in the range of 303–662%. The proposed model fitted better to the experimental data. The estimated diffusion coefficient was evaluated during the initial phase and at the final phase. In any cross section located along the stem of Raffiavinifera, it was found that the effective diffusion coefficient increases from the periphery to the centre during the initial and final phases.

The study of the physical and mechanical properties of raffia vinifera fibers along the stem is examined in this work. In central Africa, these fibers are already being used by craftsmen in the field of textile and decoration. The cross-section of fibers is higher at the base of the stem and grows from the periphery toward the center on a transverse position. By the Archimedes method, the obtained bulk density was between 0.1288 g/cm³ and 0.2368 g/cm³ and in a transverse position, it increases from the center toward the periphery. The dynamic tensile tests were used to estimate the Young’s modulus that lies among 0.88 GPa and 7.9 GPa and the low values are at the base of the stem. The specific Young’s modulus was deduced and varied from 7.33 GPa/(g/cm³) and 66.00 GPa/(g/cm³). Finally, through the strain, the microfibril angle was found and it is oscillated from 29.81° to 48.65°.

This study focuses on the production and characterization of biodegradable handmade paper from the Sida rhombifolia plant (SRP) cellulose. Sida rhombifolia plant is a seasonal plant that grows in the equatorial and tropical climates. The studies carried out on this SRP were aimed at investigating the methods required for the production of handmade paper from SRP plant and also at determining the tensile strength. Four specimens of SRP paper of different additive labels S0 (no additive), S1 (starch and KOH), S2 (starch), and S3 (Foska liquid glue) were produced using the Kraft method. Tensile properties (stress at break, elongation at break, and Young’s modulus), the rate of water absorption, and the rate of moisture absorption were carried out. Results showed that the addition of potassium hydroxide considerably reduces Young’s modulus of SRP handmade paper (S1) while the Foska liquid glue (S3) significantly improves it. In addition, the addition of potassium hydroxide and Foska liquid substantially improves the water absorption properties of the paper S2 and S3, respectively. The adhesive liquid creates more porosity and consequently increases the absorption of water. The addition of potassium hydroxide and Foska liquid significantly embedded the rate of moisture absorption. From the results obtained, it can be concluded that the paper S3 can be used as packaging paper since it has better mechanical properties and moisture absorption.

This work focuses on the assessment of oil palm mesocarp fibers as reinforcement in a composite material with an unsaturated polyester matrix. Several volume ratios of OPMF reinforcement (0 to 15%) were used, the fibers being distributed randomly. The resulting composite was characterized on the physical and mechanical aspects. Physically, the true and apparent densities were determined as well as the porosity rate. It appears that the addition of fibers further lightens the composite and increases the porosity. The water absorption rate of the different composites samples was evaluated. The more fibers the composite contains, the higher its water absorption rate. On the mechanical aspect, the bending modulus of elasticity, bending stress at break, and breaking strain were evaluated through a three-point bending test on all combinations. The same parameters were also evaluated for certain combinations by a unidirectional tensile test. It appears from this mechanical characterization that the volume fraction of 5% reinforcement has the highest specific modulus. Impact tests were performed on samples of this combination using several sizes of reinforcing fibers. Impact resistance is enhanced as the size of the inclusion increases. The Halpin-Tsai micromechanical model for randomly distributed short fiber composites was used for the inverse approach determination of the theoretical moduli of the matrix and OPMF, then in a direct approach to determine the elastic modulus of the composite at 7.5% reinforcement.