Scalable fabrication of a tough and recyclable spore-bearing biocomposite thermoplastic polyurethane

Journal Article · 23 January 2025 · Chemical Engineering Journal

DOI: https://doi.org/10.1016/j.cej.2025.159863 · OSTI ID:2506950

Kim, Han Sol  ^[1]; White, Evan M. ^[2]; Crane, Grant ^[2]; Patel, Kush ^[2]; Noh, Myung Hyun  ^[1]; Rahman, Md Arifur ^[3]; Feist, Adam M.  ^[1]; Locklin, Jason J. ^[2]; Pokorski, Jonathan K.  ^[1]

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1. University of California San Diego, La Jolla, CA (United States)
2. University of Georgia, Athens, GA (United States)
3. BASF Corporation, Wyandotte, MI (United States)

Thermoplastic polyurethanes (TPUs) are a class of versatile thermoplastic elastomers, but most of their products lack a proper recycling strategy or have no end-of-life solutions. To pursue a sustainable end-of-life solution for TPU-based products, self-disintegrating biocomposite TPUs have recently been developed by embedding spores of TPU-degrading bacteria into TPUs via melt extrusion. Herein, we improve upon spore-bearing biocomposites and demonstrate industrially relevant manufacturing conditions for fabricating biocomposite TPUs. To minimize the coloration of biocomposite TPUs, spore production was modified. The innate brown color of the resulting materials was diminished by reducing FeSO₄ in sporulation media, generating white spores without compromising spore productivity, viability, morphology or heat-shock tolerance. Biocomposite TPUs containing white spores displayed a 45 % increase in toughness compared to TPUs without spores, while retaining ∼ 90 % spore viability post processing. Furthermore, biocomposite TPU fabrication was demonstrated using a scalable continuous extruder followed by injection molding. Biocomposite TPUs generated by these industry-relevant processes exhibited comparable toughness improvement and spore viability to biocomposite TPU prepared using a lab scale microcompounder, while enhancing productivity by 30-fold. Finally, spore addition significantly improved the recyclability of biocomposite TPUs, enabling 80 % toughness retention after 5 rounds of iterative melt processing. Additionally, no negative effect on the lifespan of the generated TPUs was observed over 1 year of storage. Overall, this study confirms that spore-bearing biocomposite TPUs are promising for practical applications, offering an accessible method to enhance toughness and sustainability of commercial TPUs through the incorporation of spore-based living fillers.

• Research Organization: University of California San Diego, La Jolla, CA (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Materials & Manufacturing Technologies Office (AMMTO)
• Grant/Contract Number: EE0009296
• OSTI ID: 2506950
• Journal Information: Chemical Engineering Journal, Journal Name: Chemical Engineering Journal Vol. 505; ISSN 1385-8947
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English