Characterization of the Neuropeltis acuminatas liana fiber treated as composite reinforcement

Abstract

Treatment of plant fibers with sodium hydroxide (NaOH) is an effective solution to dissolve their non-cellulosic substances and reduce their sensitivity to moisture or water, and to improve fiber-matrix adhesion in composites. The presence of these non-cellulosic substances in Neuropeltis acuminatas (NA) fibers still limits their use in biocomposite development. In this study, tropical fibers extracted by wet retting from the bark of NA lianas native to Cameroon, were treated for the first time with NaOH solution at weight concentrations of 3%, 5% and 8%. Thermal, FTIR, and SEM analyses reveal that NaOH treatment is effective in removing non-cellulosic substances, resulting in thermal stability up to 230.3 °C, allowable friction capacity (1.25<Sq/Sa=1.27<1.31) for the fiber-matrix bond, and a reduction in water absorption rate up to 74.7%. Tensile tests were performed on both raw and treated fibers, and the results showed that the fiber treated with 5% NaOH had higher tensile strength (321 MPa) and tensile stiffness (8.4 GPa). A large variability of mechanical properties with fiber diameter was observed. The two-parameter Weibull model was used to quantify the degree of dispersion of the mechanical properties of the fibers. A low dispersion for the fibers treated at 5% was observed, compared to those treated at 3% and 8%. These results compared to plant fibers from the literature show that it is relevant to recommend for NA fibers a surface treatment with 5% NaOH for the reinforcement of composites.

Keywords

• Neuropeltis acuminatas
• Surface treatment
• Plant fibers
• Surface analysis
• Weibull model