University Lab Creates Epoxy-Graphene Composite

Led by scientists at Rice University, researchers have created an epoxy-graphene foam compound that is tough and conductive without adding significant weight. The material is suitable for applications like electromagnetic shielding. Photo courtesy of Rouzbeh Shahsavari Group/Rice University.

Scientists at Rice University (Houston, Texas, USA) have developed a composite that combines epoxy with an “ultrastiff” graphene foam. This epoxy composite features the conductive properties of epoxy with the durability of graphene, an allotrope (or thickened form) of carbon.

The epoxy-graphene composite was created in the lab of Rice chemistry professor James Tour using a blend of polyacrylonitrile (PAN), a powdered polymer resin, and nickel powder. The compound’s creators followed a four-step process: first, the materials were cold-pressed to make them dense; second, the PAN was heated n a furnace in order to turn it into graphene; third, the product is chemically treated to remove the nickel; and fourth, a vacuum is used to pull the epoxy into a porous material.

As a result, “the graphene form is a single piece of few-layer graphene,” explains Tour. “When the epoxy infiltrates the foam and then hardens, any bending in the epoxy in one place will stress the monolith at many other locations due to the embedded graphene scaffolding. This ultimately stiffens the entire structure."

According to the researchers, the composite is marginally denser but with an electrical conductivity of 14 siemens per centimeter and seven times the compressive strength of pure epoxy. Although the university would not release a commercial version of the invention, Tour envisions that the process for creating the compound could be scaled for industrial purposes. “One just needs a furnace large enough to produce the ultimate part,” he says.

Tour created the epoxy compound in collaboration with Rice materials scientists Pulickel Ajayan, Rouzbeh Shahsavari, and Jun Lou and Yan Zhao of Beihang University in Beijing, China. The research team was supported by the Air Force Office of Scientific Research Council, and their results were published in ACS Nano, a peer-reviewed journal published by the American Chemical Society. 

Source: Rice University - Materials Science and Engineering,