Mechanical Properties of Natural Fibre-Reinforced Polymer Composites with Carbon Nanofillers: Experimental and Mesoscale Modelling

Incorporating carbon nanotubes (CNTs) or graphene nanoplatelets (GNPs) into thermoplastic composites enhances electrical and thermal conductivity, as well as fire resistance, but may impair mechanical performance. To address this challenge and develop multifunctional yet mechanically robust materials, Kenaf fibre-reinforced high-density polyethylene (HDPE) composites have been developed using a microwave-assisted compression moulding technique, incorporating 5% weight fraction of CNTs and GNPs. Addition of nanofillers resulted in up to a 30% reduction in energy consumption and a 12.5% reduction in processing time. The reinforcing effect of CNTs due to their high strength and aspect ratio enhanced bonding and mechanical performance, with tensile strength increasing by 11% and hardness by 17%. To complement the experimental findings and support future design optimisation, this study also introduces a novel, simplified two-step finite element method-based mesoscale model for predicting composite’s anisotropic properties. Employment of the cohesive zone model accounts for imperfect bonding between CNTs and the HDPE matrix. Simulations reveal that at a maximum fibre content of 29%, the in-plane elastic modulus is 3.6 times that of the pure matrix. This study demonstrates the potential of these nanofillers reinforced natural fibre composites for lightweight aerospace and automotive applications, offering enhanced performance while contributing to environmental sustainability.