Abstract
Natural fibres, despite their carbon-neutral, renewable, and low-energy characteristics, are underutilized as reinforcements in polymer composites, impeding advancements in sustainable material innovation and high-performance applications across aviation, automobile, energy, and construction industries. This study investigates the mechanical, thermal, and structural enhancement of natural fibres (NF) derived from plantain pseudo-stem Fibres (PtF) and bamboo Fibres (BmF) through chemical treatments using sodium hydroxide (NaOH) and potassium permanganate (KMnO₄). NaOH treatment of the fibres was carried out using 5% solution for a duration of 1-4 hours, while for KMnO4 treatment, the fibres were soaked at different concentrations of 0.01%, 0.05% and 0.10% KMnO4 in (CH3)2CO solution for 1-3 minutes. Characterisation via X-Ray Diffractometer (XRD), Fourier Transform Infra-red spectrophotometer, Thermogravimetric analyser (TGA), Scanning Electron Microscope (SEM) and Mechanical testing revealed significant improvements in crystallinity, macromolecular, surface morphology, and tensile properties at optimal treatment conditions. Untreated fibre-reinforced polymer bio-composites were fabricated using Eco-epoxy as the polymer matrix with different fibre volume percentages (5%, 10%, 15%, and 20%) via the hand layup technique. A 15% fibre volume fraction was identified as optimal for mechanical performance. Consequently, a constant 15% volume fraction of the fibre was used to fabricate all composites throughout the investigation. Treated NF were utilised to fabricate bio-composites and hybrid nano bio-composites incorporating carbon nanotubes (CNTs). Optimal treatment time for alkaline treatment was observed at 5% for 2 hours, while for 0.05% for 3 minutes, it was the optimal treatment parameter for KMnO4. The highest values for the crystallinity index, crystallite size, and bulk density for PtF fibres were observed at a 0.05% concentration for 3 minutes, whereas for BmF, these values were observed at a 0.01% concentration for 3 minutes. FTIR analysis shows that the vibration intensity of the peaks indicates that the fibres have been successfully regulated by this...