Graphitic carbon-rich oil fly ash as effective reinforcements to enhance the mechanical, thermal, and radiation shielding properties of high-grade epoxy polymer

Abstract

Herein, we enhanced the epoxy resin's mechanical, thermal, and radiation shielding properties by introducing graphitic heavy oil fly ash (HOFA) to produce composite sheets at various weight fractions of HOFA, namely, 0, 10, 20, and 30 wt%. The morphology, chemical group functions, mechanical properties, thermal properties, and the X-ray and neutron shielding properties of the produced epoxy resin/HOFA composite sheets were rigorously tested. The SEM images showed a uniform distribution for the HOFA particles in the polymer matrix. The FTIR spectra revealed a new peak of C=C bounds, suggesting that the epoxy resin/HOFA composites were tightly bounded through these functional sites. The mechanical results showed that Young's modulus and stiffness were enhanced gradually by increasing the HOFA weight fraction; for instance, Young's modulus increased by ∼20% compared with neat epoxy. The hardness obtained by the nanoindentation test was also significantly enhanced by around 25% by increasing the HOFA weight fraction. The observed micro scratch confirmed these mechanical enhancements. The thermal conductivity and diffusivity were slightly increased by increasing the load of HOFA, but this was combined with an apparent increase in the value of the char yields, suggesting improvements in the thermal properties. The X-ray shielding results showed increases in the linear attenuation coefficients and decreases in the half-value layer, indicating better shielding properties; no effects were detected in the neutron shielding while HOFA addition. These results clearly demonstrated the possibility of reinforcing the epoxy resin thermal, mechanical, and radiation shielding properties using the waste HOFA material to be a valuable and economical material used in polymer composite applications, such as constructions, piping, and automobiles.