In a remarkable breakthrough that bridges environmental sustainability with advanced materials science, researchers have developed a novel method to fabricate high-performance carbon fibers using a combination of coal and waste plastics. Carbon fibers (CFs), renowned for their strength, light weight, and versatility, serve critical roles across industries such as aerospace, automotive manufacturing, and renewable energy sectors. Traditionally, the production of carbon fibers relies on polyacrylonitrile (PAN), an expensive synthetic polymer, which significantly contributes to the high overall cost of these materials. However, this new approach uses abundant and inexpensive feedstocks, promising to revolutionize CF manufacturing while addressing pressing ecological issues tied to waste and fossil fuel consumption.
The study centers on converting two problematic materials—coal and waste plastics—into a valuable resource for carbon fiber production. Coal, a fossil fuel that has faced increasing scrutiny due to its environmental footprint, can be liquefied into a polyaromatic mixture amenable to being spun into fibers. Simultaneously, waste plastics, which pose major global pollution challenges, especially in land and marine environments, are hydrogenolyzed to create a solvent that substitutes traditional petroleum or coal-derived solvents used in coal liquefaction. This substitution not only cuts costs but offers a sustainable solution to plastic waste, avoiding the need for complex and energy-intensive solvent recycling.
Dr. Eric Eddings of the University of Utah highlights the ingenuity of this strategy, emphasizing that “utilizing hydrogenolyzed waste plastics as the solvent enables us to bypass the expensive and environmentally detrimental recycling process usually associated with coal liquefaction solvents.” This insight is instrumental in both simplifying the process and embedding circular economy principles within the production of high-value materials. By integrating the solvent directly into the coal liquefaction mix, the researchers effectively render the plastic-derived solvent a constituent of the final carbon fiber product.
The experimental foundation of this work involved using high-density polyethylene (HDPE)—a common plastic in packaging and containers—as the model feedstock for the solvent. After hydrogenolysis, the derived plastic solvent was combined with Utah Sufco coal at an equal mass ratio. The subsequent liquefaction yielded fractions of varying molecular weights, with the heaviest fractions presenting the ideal structure and carbon content for transformation into mesophase pitch materials. These mesophase coal-plastic liquids (MCPLs) serve as precursors for spinable fibers essential for carbon fiber fabrication.
Thermal treatments enacted on these fractions allowed precise control of mesophase content, a critical parameter influencing the molecular orientation and performance characteristics of the resulting fibers. By optimizing the stabilization temperature and extending the carbonization period at 1500°C, the team succeeded in producing carbon fibers with diameters as small as 10.8 μm, exhibiting mechanical properties on par with general-purpose carbon fibers. Subsequent graphitization at 2800°C further refined the fiber structure, boosting Young’s modulus to an impressive 759 GPa and tensile strength to 4.03 GPa—metrics aligning with high-performance carbon fibers used in cutting-edge applications.
Professor Maohong Fan from the University of Wyoming underscored the transformative potential of the findings: “This research not only proves the feasibility of using plastic-derived liquids as solvents for coal liquefaction but also demonstrates that the resultant heavier fractions can be spun and converted into superior carbon fibers.” This dual utility—waste valorization and material performance—positions the technology as a compelling alternative to current industry standards.
Crucially, the environmental implications extend beyond material innovation. The development addresses significant pollution concerns by providing a sustainable outlet for plastic waste conversion and by leveraging coal in a cleaner, more efficient manner. The approach departs from conventional processes reliant on petroleum-based solvents, which bear heavy carbon footprints and complicate waste streams. Utilizing waste plastics in solvent roles repurposes problematic refuse while diminishing fossil fuel dependency within the carbon fiber production pipeline.
Looking ahead, the research team is poised to broaden their investigations by incorporating heterogeneous, real-world plastic waste streams into the solvent production protocol. They aim to explore lower temperature and hydrogen pressure conditions during liquefaction to further enhance process sustainability and cost-effectiveness. Additionally, they plan to test an array of coal types to ascertain the universality of the technique across coal sources varying in rank and composition.
The far-reaching applications of these cost-effective and high-performance carbon fibers span numerous sectors. Lightweight yet strong carbon fiber components could accelerate innovation and energy efficiency in automotive and aerospace designs while enabling the production of durable sporting goods and larger-scale products such as wind turbine blades. Lowering material costs without sacrificing mechanical integrity directly propels the adoption of carbon fiber composites across industries striving for carbon neutrality and advanced material efficiency.
The collaborative effort unites expert scientists from the University of Wyoming and the University of Utah. First author Zhe Chen and colleagues Tongtong Wang, Sean Tang, Sabin Gautam, Nilay Saha, Piumi Samarawickrama, So Tie, along with corresponding authors Maohong Fan, Wenjia Wang, and Eric Eddings, combine expertise in coal chemistry, polymer processing, and materials science to drive this forward-looking research. The project receives support from the United States Department of Energy, reflecting the strategic importance of sustainable materials development within national energy initiatives.
In summary, this innovative technique for carbon fiber fabrication represents a significant leap forward, uniting waste management innovation with industry-level material production. By transforming coal and plastic waste into a valuable, high-performance product, the work heralds a paradigm shift in resource utilization, economic viability, and environmental stewardship. The published findings in the journal Industrial Chemistry & Materials, dated October 3, 2025, mark a promising step towards industrial scalability and broader adoption of these transformative carbon fiber technologies.
Subject of Research: Production of high-performance carbon fibers from coal and waste plastics by using plastic-derived solvents for coal liquefaction.
Article Title: High-performance carbon fibers fabricated from coal and waste plastics
News Publication Date: October 3, 2025
Web References:
Industrial Chemistry & Materials Journal
DOI: 10.1039/D5IM00110B
Image Credits: Industrial Chemistry & Materials
Keywords
Carbon fibers, coal liquefaction, waste plastics, hydrogenolysis, solvent replacement, high-performance materials, sustainability, polyaromatic compounds, mesophase pitch, carbonization, graphitization, environmental technology
