Exploring Fiber-Reinforced Polymer Composites at the University of Maine
Fiber reinforced polymer (FPR) composites are materials made by combining a polymer matrix with reinforcing fibers such as glass, carbon, wood, basalt or aramid. These composites have properties that offer high strength to weight ratio, high durability and resistance to corrosion, wear, impact and fire making them ideal for construction, aerospace, automotive and marine applications. (Rajak et al., 2019)
Composites R&D at the University of Maine
The Advanced Structures and Composites Center (ASCC) at the University of Maine (UMaine) is known for its work in innovative infrastructure solutions while aiming to further the circular economy and decarbonization of the manufacturing process. Key technologies include using large-format extrusion-based additive manufacturing to create the BioHome3D (Figure 1), the G-Beam composite bridge girder, thermoplastic composite rebar, and the VolturnUS floating offshore wind platform technologies. The Transportation Infrastructure Durability Center of the ASCC is focused on enhancing the durability and sustainability of transportation infrastructure and is supporting research on LCA of composites. On Oct 29, 2024, the ASCC broke ground on the Green Energy and Materials: Factory of the Future, which will focus on “revolutionizing manufacturing through AI-enabled, large-scale bio-based advanced manufacturing” and prepare the workforce for such revolution.
Figure 1: BioHome3D, a 600-square-foot prototype house features 3D-printed floors, walls and roof of wood fibers and bio-resins.
Composites LCA research at UMaine
Assistant Prof. Reed Miller joined UMaine in 2023 with a joint appointment in Civil & Environmental Engineering and the ASCC. He is bringing his background in LCA from the Yale Center of Industrial Ecology and MIT Material Systems Lab to assess the impacts of FRP composites and explore opportunities for circular economy and strategic material selection. Miller is collaborating with EarthShift Global to create an online microcredential introducing the fundamentals of LCA and EPDs.
Miller’s graduate students, Pratibha Sapkota, Josephine Adu-Gyamfi, and Fatemeh Kiani Salmi, are working to characterize the variability of cradle-to-gate environmental impacts of common composite feedstocks in published LCA studies. The feedstocks include ABS, aPLA and PETG polymers and reinforcing fibers made of carbon, wood flour, and glass. Comparing the carbon footprint of virgin and recycled feedstocks in Figure 2, there is a statistically significant difference between virgin and recycled carbon fiber, but not glass fiber; however, these statistical tests are influenced by the number of data points captured in the studies reviewed. It’s clear that virgin carbon fiber has a much larger impact than glass fiber, but carbon fiber is also a higher performance material necessary for some applications.
Figure 2: Comparison of cradle-to-gate carbon footprint of fibers from LCA studies
Thermoplastic composite rebar
Sapkota is also studying novel thermoplastic composite rebar. Thermoplastic rebar is made from unidirectional composite tapes through a pultrusion process (Figure 3). It is corrosion resistant, lightweight, bendable on-site and can be recycled. These features make it especially suitable for harsh environments, such as marine or chemical industries, and reduce the need for maintenance. Sapkota is collaborating with A+ Composites to gather the life cycle inventory of unidirectional composite tapes production. The environmental performance of thermoplastic rebar will then be compared to that of conventional rebars such as steel, stainless steel, and epoxy-coated steel. Additionally, a case study involving concrete bridge deck will be carried out in collaboration with Maine DOT. This study will assess the mass and impact of different rebar types used in the bridge design to ensure the results reflect real-world applications.
Figure 3: Continuous forming pultrusion machine for thermoplastic composite rebar
Wind blade recycling prize
Miller and colleagues recently won Phase 1 and Phase 2 prizes from the Department of Energy to recycle end of life wind turbine blades into FRP composites feedstocks for large-format extrusion-based additive manufacturing (Figure 4). This builds on past research in printing and several rounds of recycling precast concrete formwork (Schweizer et al. 2024). The team has formed a company, Circular Composite Technologies, to commercialize and scale the process.
Figure 4: Wind Turbine Materials Recycling Prize entry from UMaine researchers
Going forward
In 2025, Miller’s group is set to expand both in terms of graduate students and LCA projects. Next on the list is the G-Beam bridge girder, which features a FRP lamina composed of glass, carbon fiber, foam core, and resin, making it lightweight and easy to transport.
References:
Rajak, D. K., Pagar, D. D., Menezes, P. L., & Linul, E. (2019). Fiber-Reinforced Polymer Composites: Manufacturing, Properties, and Applications. Polymers, 11(10), Article 10. https://doi.org/10.3390/polym1...
Schweizer, K., S. Bhandari, R.A. Lopez-Anido, M. Korey, and H. Tekinalp. 2024. Recycling Large-Format 3D Printed Polymer Composite Formworks Used for Casting Precast Concrete – Technical Feasibility and Challenges. Journal of Composites for Construction 28(6): 04024061.