A Study of the Effect of Sodium Hydroxide and Sodium Lauryl Sulfate Surface Treatments on Natural Fibers

Abstract

Due to its accessibility, environmental friendliness, renewability, CO2-neutrality, flexibility, low density, and low cost, natural fibre (NF) can have a significant impact on the area of fibre reinforced polymer composite (FRPC) as a reinforcing material. Banana fiber (BF)/calotropis gigantea fiber (CGF) could be a potential candidate for synthetic FRPC replacement. Plant derive banana and calotropis gigantea fibers are valuable NFs that are abundantly available in Bangladesh. The purpose of this research is to examine the influences of sodium hydroxide (NaOH) and sodium lauryl sulfate (SLS) and joint NaOH and SLS modification on the physical, mechanical and morphological features of BF and CGF were observed with the aim of improving their interfacial bonding with polylactic acid (PLA) matrix. Physical tests indicate that SLS-treated fibers provide the lowest fiber diameter. Droplet tests indicate that the interfacial shear strength (IFSS) of NaOH and SLS-treated BF and CGF has improved whereas SLS-treated fibers exhibit maximum IFSS. Impurities were removed from the fiber surface by modification of the fiber with NaOH and SLS which was confirmed by scanning electron microscopy (SEM). Morphological studies of treated BF and CGF by SEM indicate that SLS treated fibers have fewer impurities and lignin and hemicellulose were removed compared to NaOH treatment. Tensile test data show that the maximum improvement in tensile strength and tensile modulus of BF treated with SLS has been observed over those of untreated, alkaline and NaOH-SLS treated BF. It is expected that fiber modification will help in the development of high performance BF and CGF strengthened thermoplastic composites for engineering applications.