High-Performance Fiber-Reinforced Vitrimer Composites through Compression Molding

Carbon-fiber-reinforced-composites have excellent strength-to-weight ratio and represent the most promising next generation of light-weight materials that can replace currently used aluminum alloys and steel in mainstream auto-industry. However, their production cost is almost 10 times higher than that of the metals, mainly due to long production cycle time and difficulty in recycling and reuse. Besides the high cost, the waste disposal of non-degradable polymer matrix would cause a significant environmental concern. In this work, high-performance vitrimers with heat-driven malleability, repairability and full recyclability will be used as the polymer matrix. Fast compression molding conditions (minutes or even a minute) will be applied to fabricate carbon- fiber-reinforced composites through the fusion of vitrimer particles with carbon fibers integrated. At the end of service life, the vitrimers will be fully depolymerized into soluble oligomers/monomers, releasing full-length carbon fibers. All the chemical components and carbon fibers will be reused in the production of new generations of polymers and composites, thus realizing closed-loop recycling. In phase I, we will (1) develop high-performance imine/aminal hybrid vitrimers with Young’s moduli > 10 GPa and Tg > 200 oC; (2) demonstrate the feasibility of using compression molding approach to fabricate carbon-fiber reinforced composite through particle-fusion process at a pressure < 20 MPa, temperature < 300 °C (3) investigate the reprocessibility, repairability, and recyclability of such composites; (4) develop a computational modeling tool to predict the mechanical properties of fused vitrimers to guide their further development.The proposed vitrimers will provide excellent mechanical and thermal properties, fast curing time, easy reshaping and reprocessing, repairability, and closed-loop recycling. Such vitrimer-based carbon fiber-reinforced composites with high strength-to-weight ratio have a huge market not only in auto industry but also in manufacturing of aircraft, marine, wind energy, armor, and prosthetic devices. In Phase II and Phase III, we will seek large scale production of such vitrimers and their fiber-reinforced composites. We will partner with established companies in auto-industry and wind turbine manufacturing to carry out our commercialization plan.