Evaluating physico-mechanical properties of NaOH-treated natural fibres: Effects of polyolefin

The bottle gourd plant fibres (BGPF) and okra fibres were processed and refined (w/w 6 % NaOH) before being incorporated with polyolefin (polypropylene) for composite fabrication using a blending technique. The polyolefin matrix is used to develop composites with 5 % okra fibres and varying percentages (25, 30, 35 and 40 %) of BGPF. The results indicated that the "35 % BGPF +5 % okra +60 % polypropylene" composition achieved remarkable mechanical properties with tensile strength (26.95 MPa), tensile modulus (3.16 GPa), decreased elongation at break (1.71 %), bending strength (52.53 MPa), bending modulus (3.45 GPa), impact strength (14.25 kJ/m²⁾, and hardness (69 D-shore). Moreover, these composites absorbed minimal water when a specific portion was submerged. The scanning electron microscopy (SEM) test on the composites revealed good fibre adhesion and adherence content between BGPF and okra fibres. Additionally, the thermo-gravimetric analysis and differential scanning calorimetry exhibited weight loss of composites during maximum cellulose degradation (80 %) at 483 °C. In the composites of the fibre-PP matrix, two distinct physical changes were observed indicating glass transition and degradation. However, the mechanical properties decreased after soil degradation. Thus, remarkable properties were achieved for the fibres-fibres and fibres-polyolefin (polypropylene) interfacial interactions.