Biobased Carbon Fibers and High-Performance Thermosetting Resins for Use in U.S. Department of Defense Applications

Current constituent materials used to produce composites for the military are often made from both fibers and resins that are derived from petrochemical feedstocks. The use of biological resources to make advanced fibers and high-performance thermosetting resins will help reduce the dependence of military composites on the volatile cost of petroleum, thereby helping to reduce the cost of composite materials for the Department of Defense. In addition, the processes used to make these fibers and resins from biological sources should have reduced environmental effects. To this end, we have developed carbon fibers based on lignin and carbohydrate and lignin-derived thermosetting resins. We have used both bacterial and chemical decomposition of lignin to make tractable structures that are capable of fiber spinning. Current efforts have been successful in stabilizing and carbonizing the fibers, but the resulting properties need to be improved using some newly developed chemical routes and by improving processing. Unsaturated polyester, vinyl ester, and epoxy resin thermosets have been developed. So far, the unsaturated polyesters and epoxies have fairly poor properties, but we have developed materials with the highest-ever recorded glass transition temperature for a vinyl ester.