Effect of biomass-derived carbon nanosphere on mechanical properties of polypropylene/empty fruit bunch fibre composites

Natural fibre-reinforced polymer composites have gained significant attention as sustainable alternatives to conventional synthetic materials. This study investigates the mechanical properties enhancement of polypropylene (PP) composites through hybrid reinforcement using oil palm empty fruit bunch (EFB) fibres and carbon nanospheres (CNS) derived from sago bark waste. The CNS was synthesized via pyrolysis at 500°C under nitrogen atmosphere and characterized using TEM, XRD and FTIR which reveals spherical nanoparticles with diameters ranging from 15 to 50 nm and partially crystalline structure. PP composites were fabricated with varying EFB fibre content (0–50 wt%) and CNS loading (0–1.5 wt%) using twin-screw extrusion followed by injection molding. FTIR analysis confirmed successful interfacial interactions between PP matrix, EFB fibres, and CNS through peak shifts and intensity modifications. Thermal analysis demonstrated improved thermal stability with 20°C higher degradation onset temperature for the nanocomposite. Mechanical testing revealed that the optimal composition of 20 wt% EFB fibre with 1 wt% CNS achieved remarkable property enhancements compared to neat PP/EFB composite in which the tensile strength increased by 17%, flexural strength improved by 20% and impact strength enhanced by 32%. An artificial neural network (ANN) model was developed to predict mechanical properties and achieve excellent correlation (R = 0.985) between predicted and experimental values, enabling efficient optimization of composite formulations. This research demonstrates a viable approach for converting agricultural waste into high-performance composites with enhanced mechanical properties suitable for automotive components and consumer product applications.