Ultra-High Loading of Coal-Derived Flash Graphene Additives in Epoxy Composites

Graphene has proved to be an exceptional reinforcing additive for composites, but the high cost of its synthesis has largely prevented its addition on industrial scales. Flash Joule heating provides a rapid, bulk-scale method for graphene synthesis from coal materials, such as metallurgical coke (MC), into metallurgical coke-derived flash graphene (MCFG). Here, this work investigates the properties of graphene-epoxy composites in a higher nanofiller content regime than has previously been reported in literature. Composites with 20 to 50 wt% loading of MCFG are prepared by combining MCFG with diglycidyl ether bisphenol A epoxy precursor (DGEBA) and 1,5-diamino-2-methylpentane. With a 1:2 ratio of MCFG:DGEBA, the Young's modulus increases by 92% and with a 1:3 ratio, hardness increases by 140%. At a 1:4 ratio of MCFG:DGEBA, compressive strength and maximum strain increase by 145% and 61%, respectively. At a 1:3 ratio of MCFG:DGEBA, toughness increases by 496%. Finally, at a 1:1 ratio of MCFG:DGEBA, GHG emissions, water consumption, and energy consumption are reduced by 33%, 47%, and 34%, respectively. As the cost of FG plummets, since it can be produced from very low cost materials like MC, in milliseconds with no solvent or water, the prospects are promising for its high-loading use in composites.

Automated summary

Graphene has been proven to be a valuable additive for composites, but its expensive synthesis has hindered its industrial application. However, a method called Flash Joule heating can rapidly synthesize graphene from coal materials like metallurgical coke. This study investigates the properties of graphene-epoxy composites with higher nanofiller content than previously reported. The results show that these composites exhibit improved mechanical properties and reduced environmental impact.