Use of composite materials for construction of Department of Defense (DoD) weapons platforms will approach 200 million pounds per year. Vinyl ester resin (VER) is a low-cost resin that can be processed at ambient temperature using vacuum-assisted resin transfer molding (VARTM) into massive carbon-fiber-reinforced composite structures such as ship hulls and transportation vehicles. Since VER production is highly dependent on oil, it is subject to fluctuating prices and limitations in supply. The continued viability of this strategic DoD weapons material is further jeopardized by the manufacture use of hazardous materials, epichlorohydrin and styrene.
The objective of this limited scope SERDP project was to demonstrate feasibility of producing a sustainable, environmentally safe vinyl ester resin for military structural composite weapons systems starting with low-cost lignin and glycerin waste streams.
The synthesis of vinyl ester resin from lignin was conducted in four consecutive chemical reaction steps:
Published procedures were used for each step, in order to minimize danger, risk and time.
During this project, the presence of phenol in lignin hydrolysis reaction products was confirmed at 5-10% yield. Substituted phenolics guaicol and catechol were also produced that can subsequently be converted to phenol to increase yield. Synthesis of bisphenol A from authentic phenol was achieved in >90% yield. Glycidyl methacrylate was synthesized via direct reaction of glycidol with methacrylic acid in >90% yield. Reaction of bisphenol A with glycidyl methacrylate produced vinyl ester resin in >95% yield. Environmental safety in each step was assured through use of approved equipment and safe working practices. Phase I results indicated that feasibility had been demonstrated and that work should continue to refine each intermediate step, scale up to larger quantities, and produce carbon-fiber reinforced vinyl ester resin composite components for military weapons.
This successful program can provide a sustainable, environmentally safe source of vinyl ester resin monomer and other valuable chemical starting materials, starting from inexpensive, nonpetroleum waste streams of lignin and glycerin. This can enhance the independence of the United States from foreign oil.