SBIR Phase II: Sustainable Performance Composites for Energy Efficient Transportation Applications

This Small Business Innovation Research Phase II project seeks to improve and expand the technology of recyclable thermosets by creating a new class of higher temperature performance, multivalent polyamines that retain a cleavable bond. If successful, this effort will lead to a new class of high-performance composite resins which can be recycled. Increased emphasis on energy efficiency is driving the adoption of lightweight, thermoset composites in the transportation sector. But the intractability of traditional thermosets limits the value and therefore adoption of recycled composites. Industry composites recycling experts estimate the overall scrap cost for the composites industry is between $500 and $750 million a year. Post-manufacturing scrap can account for up to 50 percent of the input materials. Carbon fiber composites for automotive applications represent an emerging and high-growth potential area for epoxy thermosets. A small volume, composite car line represents roughly 400 metric tons of polyamine curing agent. In the Phase II effort, novel, recyclable polyamine structures will be designed and synthesized, and further formulated with various epoxy resins to meet the glass transition temperature (Tg) requirements for transportation composites manufacturing. Doing so will help composite manufacturers lower costs and meet regulatory compliance for recyclability and manufacturing waste disposal. The intellectual merit of this project will be an expanded knowledge base and chemistry platform for synthesizing and formulating recyclable thermoset resins. Multivalent amines, by nature, provide higher structural rigidity of a matrix. Multivalency, by nature, translates to an overall higher cross-link density of a thermoset epoxy material. For example, composites of higher glass transition temperature, and faster cure speed can be achieved. New multivalent structures will complement the initial generation of recyclable aliphatic diamines, and enable applications previously unattainable by recyclable aliphatic structures alone, such as transportation composites. Pre-screened target cyclic scaffolds have been identified and targeted for synthesis. Successfully synthesized molecules will be further screened for physical properties and recyclability. Candidate molecules will then be formulated into full resin systems and optimized for a high-pressure resin transfer molding (HP-RTM) process, to meet the processing and cost needs of automotive manufacturers. Partners in the automotive industries will aid in testing and evaluating the performance of the formulated material. By creating new recyclable molecules that "mimic" other major industrial classes beyond aliphatic amines, the addressable market for these materials will be expanded and the adoption of recyclable thermoset composites will be accelerated.