Statistical predicting and optimization of the tensile properties of natural fiber bio-composites

This study aims to investigate the tensile strength of the polypropylene-based bio-composites reinforced with natural kenaf fibers, basalt fiber, and nanographenes. The response surface methodology was used to investigate the behavior of the bio-composites based on the weight percentage of basalt and kenaf fibers and nanographenes. The behavior of the samples was analyzed using the tensile test, and the results were interpreted using field emission scanning electron microscope images. The fracture surface of the samples indicated the fibers' breakage and their separation as well as the pullout of the fibers from the substrate as the main mechanisms in improving the behavior of the bio-composite under study. Then, the multi-objective optimization was performed by increasing the tensile strength and elastic modulus and reducing the weight of the samples, and a Pareto diagram was drawn according to the design objectives. The results showed that the bio-composite sample in the optimal status with the maximum tensile strength of 30.9481 MPa and the lowest weight includes 15% kenaf fibers and 0.862% graphene nanoparticles. Moreover, the optimal sample of the bio-composite with the highest elastic modulus of 3.5126 GPa and the minimum weight of 1.626 g consists of 15% of kenaf fiber and 1.5% of graphene nanoparticles. Twenty-seven percent reduction in composite weight by optimizing the amount of reinforcements causes the weight of the final structure to be significantly reduced in the use of these composite plates in high volumes.