Bio-based Materials Friendlier to the Environment
July 11, 2007
By Dave Davison
ARL Public Affairs Office
ADELPHI, Md. - Army Research Lab researchers have come up with a method to produce environmentally friendly composites using bio-based materials such as soybean oil to replace petroleum-based resins in composites.
The demand for composites is rising in the military and commercial sector due to the need for low-cost and lightweight materials. Petroleum-based vinyl ester resins are used to produce composites because of low-cost compared to epoxy resins. However, these resins contain large amounts of styrene, which is a suspected carcinogen and a hazardous air pollutant, and styrene emissions are released during all stages of composite manufacture and during fielding of parts. Furthermore, the Environmental Protection Agency recently enacted strict standards further limiting styrene emissions from composite manufacture which means that reducing the emissions from composite structures is critical to meeting DoD environmental regulations.
Two ARL researchers, John La Scala and Dr. James Sands, of Weapons and Materials Research Directorate, are working with Drexel University and have come up with solutions for making resins that comply with emissions requirements by using resins based on environmentally friendly materials, such as soybean oils. These resins reduce the use of petroleum materials and reduce emissions to values below what is required by the new regulations. The composites perform approximately equal to their petroleum-based counterparts and reduce styrene emissions by 20 to 78 percent.
"This means that Soldiers working to repair vehicles can work more safely," LaScala said. "It also means that military repair shops can meet EPA standards without emission control systems that can easily cost $1 million per installation."
The bio-based composites have wide application in military and commercial vehicles, aircraft and ships. The new technologies support the 2002 Federal Farm Bill, which mandates that federal agencies establish preferred procurement for bio-based products, according to a paper prepared by Sands.
The research team has applied for two patents for the new resin systems. The technology has also been licensed for commercial development.