An interdisciplinary team of top researchers at Mississippi State University in Starkville, Mississippi, is studying ways to better protect airplanes from lightning strikes and spacecraft from micrometeoroid orbital debris.
The research group is closely looking at ways to grow aerospace applications of graphene in composite materials. Bringing together faculty, graduate students and undergraduates from the university’s departments of Chemistry, Chemical Engineering, Electrical Engineering and Aerospace Engineering, the team works to understand graphene and its effects on composite materials from the molecular- to macro-structural length levels.
MSU Professor of Aerospace and Computational Engineering Thomas Lacy said graphene’s ability to efficiently conduct electricity can enhance the uses of multifunctional composite materials in aircraft. Lacy is a Georgia Institute of Technology doctoral graduate who is a Fellow of the American Society of Mechanical Engineers and an Associate Fellow of the American Institute of Aeronautics and Astronautics. He currently is serving as president of the American Society for Composites.
“We will bond a really thin graphene layer on top of a typical carbon fiber/epoxy composite used for aircraft wings and bodies. When subjected to a simulated laboratory lightning strike, the graphene layer reduces damage to the underlying composite,” Lacy said. “The basic idea is that a graphene coating layer will conduct away the heat and electricity in ways that don’t lead to explosive damage.”
The team’s work largely is funded through external research grants from private companies such as Boeing and public agencies such as the Department of Energy, NASA and the National Science Foundation.
Lacy credits the work of MSU Emeritus Professor of Organic Chemistry Charles Pittman, Professor of Chemistry Steven Gwaltney and Assistant Professor of Chemical Engineering Santanu Kundu with helping him understand graphene at the molecular level. Professor of Electrical Engineering Mike Mazzola also is a core member of the group.
Kundu, an NSF Early Career Award recipient and Clemson University doctoral graduate, is one of the few people in Mississippi with the ability to make graphene platelets, which are nanosized sheets of carbon one atom thick, to enhance composite materials. During a two-to-three-day process, Kundu is able to turn pieces of graphite into graphene by placing them in an organic liquid where ultrasonication, followed by centrifugation, eventually separates the graphene.
“I am a chemical engineer, so I know how to make graphene and how to characterize it, but I may not be able to incorporate it into engineering composite structures without Dr. Lacy’s help,” Kundu said. “If I have a chemistry problem, I know I can go to Dr. Pittman for a solution.”
Pittman and other researchers use electron microscopy to examine dispersion of the nanometer-thin material. Chemists and chemical engineers are able to modify and tailor the surface chemistry of the graphene so it is less self-attractive and also promote graphene’s attractive interactions with matrix polymers and resins when dispersed into these materials.
“Graphene is tremendously strong for its weight,” Pittman said. “It’s far stronger than steel in terms of strength per unit weight. That’s why we like it. You want to lower the weight of aircraft so you can put more people in, fly it farther and get better fuel economy.”
Pittman is a 1964 doctoral graduate of Pennsylvania State University and did postdoctoral studies at Dow Chemical Co. and Case Western Reserve University. He joined MSU’s faculty in 1983 and founded and served for many years as the research director of the University/Industry Chemical Research Center. Pittman has published more than 800 research papers, chapters, patents and 17 books.
Gwaltney has collaborated with Lacy and Pittman on molecular dynamics simulations of graphene and graphene oxide interactions with solvents, liquid resins and cured resin matrices. He predicts adhesive interactions to graphene and corresponding mechanical properties. Gwaltney is a doctoral graduate of the University of Florida and conducted postdoctoral studies at the University of California at Berkeley.
Mazzola provides the expertise to conduct laboratory generated lightning strikes on sample plane parts in the university’s High Voltage Laboratory. In the lab, researchers can see how materials react to receiving over 200,000 amps of electricity in only 15-100 microseconds. Mazzola is holder of the Jack Hatcher Chair for Entrepreneurship at MSU and is a doctoral graduate of Old Dominion University in Norfolk, Virginia.
Graphene has potential applications in increasing the stealth capabilities of military aircraft. The material may be used in high-temperature regions such as jet engines to conduct heat away from hotspots, and it has potential applications in protecting space vehicles.
“We’ve studied graphene as an outer ballistic protection layer for space structures to mitigate micro-meteoroid orbital debris,” Lacy said. “You get tiny pieces of space dust or orbital debris that are moving 70 kilometers per second. Lightweight graphene layers can be used to help break up the projectile and you can try to trap the resulting high-energy debris cloud.”
Lacy emphasized that working across disciplines in a way that Pittman often describes as “operating in their discomfort zone” strengthens the scientific process.
“So an aerospace engineer like me works with a polymer/organic chemist, chemical engineer and electrical engineer in ways that cross-pollinate and grow a level of understanding and allow us to interact and exchange ideas. It leads to very good science,” Lacy said.
In addition to working across disciplines at MSU, the group also is collaborating with researchers from the University of Mississippi, Jackson State University and University of Southern Mississippi. UM Professor of Civil Engineering Ahmed Al-Ostaz also makes graphene paper, which he has supplied to the MSU team.
“We’re putting together a Mississippi materials consortium, and graphene is an important part of that,” Lacy said. “We’re always on the lookout to involve other researchers and capabilities in ways that lead to new discovery.”
Feature story, photos and video provided by Mississippi State University.