Effect of microwave-reduced graphene oxide on the mechanical, thermal, and physical properties of banana fiber reinforced epoxy composites

Abstract

This study presents a comprehensive investigation into enhancing the mechanical and thermal performance of banana fiber-reinforced epoxy composites through the incorporation of microwave-reduced graphene oxide (rGO) as a nanofiller. Graphene oxide (GO) was synthesized from graphite powder via the improved Hummers’ method. Its successful synthesis and subsequent reduction to rGO were confirmed by Fourier-transform infrared (FT-IR) and Raman spectroscopy. Raman analysis revealed a characteristic increase in the defect ratio (ID/IG) from 0.12 for pristine graphite to 0.896 for GO, and further to 0.963 for rGO. This trend indicates the formation of numerous, smaller sp² domains upon reduction, a key factor for effective reinforcement. Composite laminates were fabricated by hand lay-up with rGO loadings of 0, 0.1, 0.2, and 0.5 wt.%. Mechanical and thermal properties were analyzed. The results demonstrated that the effect of rGO is highly dependent on concentration. For tensile properties, the optimal performance was achieved at 0.2 wt.% rGO, while flexural properties were maximized at 0.5 wt.%. Physical property analysis revealed a decrease in composite density with increasing reinforcement content, a trend attributed to the inherent porosity (lumen) of the banana fibers themselves. Optical microscopy images confirmed the homogeneous distribution of fibers in the matrix, a key factor for composite performance. This research highlights the complex role of rGO in natural fiber composites and underscores the importance of optimizing filler content for specific application requirements.