Waste Iron Filings to Improve the Mechanical and Electrical Properties of Glass Fiber-Reinforced Epoxy (GFRE) Composites

Abstract

Several studies have been conducted to improve the mechanical and other value-added properties of glass fiber-reinforced epoxy (GFRE) composites by the addition of different fillers. In this work, waste iron filings (WIFs) obtained from the steel industry were incorporated into GFRE composite samples in varying amounts of up to 50% (%w) to improve their mechanical and electrical properties. The results showed that, with increasing WIF loading from 0 w% to 50 w%, the resultant composite density gradually increased from 1.4 to 2.1 g/cm3. Surface hardness, Young’s modulus, and tensile strength also increased significantly with the addition of up to 9 w% of WIF followed by a significant drop with more WIF addition due to agglomeration. Overall, Young’s modulus of the GFRE samples with any WIF content was higher than that of the GFRE composite with no WIF. The elongation at break results showed that the GFRE samples were less ductile upon WIF addition, which decreased from 2% to 0.6% upon loading the composite with 50% WIF. In terms of electrical conductivity, the GFRE samples with WIF content of 15% or more were electrically conductive and their electrical conductivity increased with WIF content. It was clear that more WIF was needed to establish a percolated network in the GFRE composites to render them conductive. The electrical conductivity of the GFRE samples containing 15% WIFs was around 2.9 kS/m and increased to 35 kS/m upon the addition of 50% WIFs. These novel electrically conductive GFRE composites could be promising for structural dynamic monitoring systems in the construction industry. They also support the efforts for the utilization of waste materials towards a circular economy.