Effect of alkali and silane treatments on the surface energy and mechanical performances of Raphia vinifera fibres

Abstract

This study aimed to evaluate the influence of chemical treatment on the surface modification of Raphia vinifera Fibres (RVF). The fiber were treated with different concentrations of alkaline solution (1%, 5% and 10%) for (30 min, 60 min and 90 min) and silane (1% and 5%) at (30 min and 60 min). Thermal degradation analysis was performed by thermogravimetric analysis (TGA/TDG) and chemical functional group was assessed by Fourier transform infrared spectrometry (FTIR). The microstructure of Raphia vinifera fibers was observed by scanning electron microscopy (SEM) and cross-sectional area measurement was performed by a projection microscope (Projectina). The surface energy of treated and untreated fibers was calculated from a standard tensiometer and their mechanical properties were evaluated by tensile tests. The results reveal a modification of the chemical structure as well as the thermal degradation of the fibres after treatment with NaOH and silane. SEM shows that alkali treatment of raffia fibers induces a significant reduction (confidence level 90%) in fiber cross-section compared to untreated fiber, resulting in a change in surface roughness and the appearance of cracks. Furthermore, the use of silane and 1% NaOH treatments significantly improves the surface energy of the fibers over time, while 5% and 10% NaOH concentrations decrease the surface energy over time. Statistical analysis (MANOVA and Tukey test) of the mechanical performance results reveals a significant increase in the Young's modulus of the fibers with the treatment time and the concentration of the treated solutions (NaOH and silane). Its fibres may therefore have good potential for the production of composites.