Poly(ether ether ketone)-Grafted Graphene Oxide “Interconnects” Enhance Mechanical, Dynamic Mechanical, and Flame-Retardant Properties in Epoxy Laminates

Herein, the interface of epoxy and graphene oxide (GO) is tailored through hydroxylated poly(ether ether ketone) (HPEEK). The resultant modification (HPEEK-g-GO) improved the interfacial adhesion between epoxy and carbon fiber (CF) in the laminates. This strategy resulted in improved tensile strength, modulus, and storage modulus by 8, 10, and 26%, respectively, with respect to control samples (epoxy/CF laminates). The HPEEK-g-GO was thoroughly characterized using spectroscopic techniques and was infused using vacuum-enhanced resin infusion technology into the epoxy/CF laminates. To address the challenges involved with primary agglomeration, the composite formulation was subjected to mechanical stirring coupled with bath sonication throughout the mixing process. The improved structural properties in epoxy/CF laminates were attributed to HPEEK-g-GO "interconnects", which provided the necessary reinforcement owing to better interfacial adhesion with the CF mat as inferred from the fracture surface morphology assessed using SEM. In addition, the epoxy laminates containing HPEEK-g-GO also showed flame-retardant properties along with good thermal stability. The electromagnetic interference shielding capability of the modified laminates was also evaluated in the frequency range of 12-18 GHz. It was observed that the laminates exhibited a shielding effectiveness of -50 dB. Thus, this strategy offers some promise in fabricating epoxy/CF laminates with multifunctional properties through HPEEK-g-GO "interconnects".