Green Composites from Carbonated Bio-based Oils and Recycled Nanofibers

The U.S. transportation system depends on vehicles to move people and products. The majority of U.S. vehicles rely on petroleum products as the primary energy source (e.g. gasoline and diesel), and are material-, energy- and emissions-intensive in their manufacturing and use. Increased adoption of clean energy technologies based on energy storage, electrification, alternative fuels and lightweight materials continues to enable modern vehicles to move with greater efficiencies and a lower carbon footprint. A further reduction in cost, petroleum use, non-renewable materials, emissions and manufacturing energy is needed to further improve the efficiency and performance of vehicles and decarbonize the U.S. transportation system. Lightweight vehicle components provide a significant opportunity to reduce recharging or fueling and facilitate the transition to a sustainable transportation system. Carbon fiber reinforced polymers are promising alternatives to metals due to their high strength-to-weight properties, but these composites are expensive, and their manufacturing involves significant energy and a large carbon footprint. Critical advancements in lightweight, high strength and eco-friendly composites are needed to reduce the energy and emissions involved in manufacturing vehicle components. A transition to green composites will require innovative approaches to employ natural or recycled materials, improve affordability, reduce and absorb CO2, and lower manufacturing energy requirements. To meet this demand, Luna Labs and the National Renewable Energy Laboratory (NREL) are developing a green composite that combines a non-isocyanate polyurethane matrix with a modified nanofiber reinforcement. The composite uses recycled or renewable feedstocks (waste fibers, bio-sourced oil, amino acids) and avoids petroleum products. The oil and amino acids derive from plants and algae, which consume CO2 during their growth, and both the nanofibers and resins consume additional CO2 in their production. The materials are easily moldable to rapidly create complex shapes under mild conditions, and the use of injection molding avoids the high temperatures and pressures used for traditional composites to further reduce the embodied energy in manufacturing. The team’s green composite can be made at low costs through the use of low loadings of the modified nanofibers and inexpensive NIPU resins (<$2.50 lb) and will be greater than 80% biodegradable to reduce end-of-life waste. The team will refine the green composite and develop prototypes to demonstrate the material’s mechanical performance and environmental durability (Phase I). A preliminary life cycle analysis will be conducted using NREL’s Materials Flows through Industry supply chain modeling tool to 1) determine the emissions and energy requirements in manufacturing and 2) prepare the team for a detailed analysis in Phase II. Finally, the team will optimize, scale-up and transition the green composite technology to the automotive industry to replace existing plastic and plastic composite vehicle components (Phase II).