Five innovative North American university R&D projects highlight composite materials as agents of change.
Across the global composites industry, businesses are constantly searching for innovative ways to improve the structures we make and how we make them. But much of the innovation we see today doesn’t start in a corporate meeting room – it starts at the research and development level at universities all over the world.
In North America, a lot of that research is focused on sustainability, including the development of biodegradable car parts, eco-friendly pavement that absorbs stormwater runoff and thermoplastic composite-reinforced concrete to make our infrastructure greener. Researchers are also looking for ways to make composite structures smarter through 4-D printing and magnetism. Here are five projects Composites Manufacturing has its eye on this year.
Cellulosic Composites for Cars
Project: Flax-reinforced thermoplastics
School: University of Southern Mississippi
Location: Hattiesburg, Miss.
Principal Investigator: Joshua Otaigbe, Ph.D.
Over the past decade, one of the global automotive industry’s biggest concerns has been increasingly stringent fuel economy standards. As a result, the composites industry has seen increased interest from OEMs that are looking to make vehicles lighter and therefore more efficient. However, some experts anticipate that decades from now, OEMs will need to push the envelope even further with parts that are not only lightweight, but also biodegradable.
“We need to be concerned about what happens with the material that you use in cars after their service life,” says Joshua Otaigbe, Ph.D., a professor in the School of Polymers and High Performance Materials at the University of Southern Mississippi. “So if you have biodegradable components, they’ll get a useful life. Those materials can either be recycled, or they can biodegrade without harming the environment.”
Last summer, thanks to a $50,000 grant from the National Science Foundation’s I-Corps program, Otaigbe and doctoral student Shahab Rahimi developed a cellulose-reinforced Nylon 6 nanocomposite that is not only biodegradable, but also 15 percent lighter than GFRP while maintaining comparable mechanical strength and stiffness. The researchers say the material could be applied to roofs, door panels and interior parts in automobiles, as well as rear decks, sidewalls and fenders in trucks and trailers.
Typically, cellulose-based nanocomposites are made with wood particles instead of actual fibers. Those particles, according to Otaigbe, can help save money but make nanocomposite manufacturing inefficient, as cellulose has many inherent chemical properties that stifle polymerization.
Instead, Otaigbe chose to extract flax fibers, which are a lot stiffer and stronger than wood particles, from wooden signs provided by Oregon State University. He then placed them in a mold injected with Nylon 6 and an aminopropyltriethoxysilane (APS) catalyzing agent. With actual fibers in the polymer matrix, he and Rahimi could shape the material without having to melt it. Otaigbe says the low viscosity of the thermoplastic polymer also helped facilitate the chemical reaction. After one to two minutes at 150 C, the composite is fully cured. That temperature is important, according to Otaigbe, because cellulose-based composite materials can lose their flexural and tensile strength if heated above 190 C.