(434f) Prospective Nipu and Biopu Models: A Push for Polyurethanes Sourced from Biomass

Background: The use of fossil fuel and natural gas reserves depletes nonrenewable resources while releasing emissions that directly contribute to global warming. In 2016, 2.9 million tonnes of polyurethane (PU) were produced in the United States at the expense of 1.1 million tonnes of crude oil and 1.1 million tonnes of natural gas.¹ With a 5.5 % end-of-life recycling rate, PU is recycled at less than the average recycling rate of U.S. plastics in 2015.^1,2 To enhance PU sustainability, it is necessary to advance technologies for producing this material from bio-based feedstocks and to expand methods for recycling PU monomers. Another challenge with today’s technology for manufacturing PU is the use of isocyanates, which pose a human health hazard. To alleviate issues with safety, the U.S. Environmental Protection Agency (EPA) has begun to phase out the use of isocyanates in the synthesis of PU.³ Non-isocyanate polyurethane (NIPU) materials can be synthesized from biomass^4,5 and reprocessed into secondary (2°) NIPU materials.⁶ NIPU materials eliminate the need for toxic and potentially harmful diisocyanates.⁷

Methods: Previously, our group performed a cradle-to-gate material flow analysis (MFA) of PUs in the United States¹ and a techno-economic analysis (TEA) on two NIPU materials.⁸ The studies utilized various data sources including governmental resources, industry associations, and peer-reviewed literature. The MFA study involved estimating precursor quantities based on industrial surveys and market reports, calculating energy consumption, tracking waste generation and management, and incorporating historical production data for in-use phase analysis. These data and data from a baseline MFA on NIPU production push the dynamic systems modeling for introducing NIPUs into the market of PU materials. This model is primarily informed by key economic factors affecting the PU market over a temporal horizon of 25 years (2025 – 2050). These economic factors include feedstock costs, GDP growth, cost of PU, and cost of NIPU.⁹

Results: Our research efforts are focused on analyzing prospective scenarios for the entry of NIPUs into the market for PU materials. Initially, two baseline scenario is reported: (1) for the replacement of PU monomers with bio-based polyols and diisocyanates and (2) for the substitution of all PU materials manufactured within the United States with NIPU materials. We report optimistic and pessimistic potentials for augmenting biogenic NIPUs into the PU market through the year 2050. Furthermore, our prospective MFA provides valuable insights into the changing efficacy of recycling NIPU materials over time. Overall, this research contributes to the ongoing efforts to promote environmentally conscious practices and investigate isocyanate-free methods in the plastics industry.

[1] Liang, C., Gracida-Alvarez, U.R., Gallant, E.T., Gillis, P.A., Marques, Y.A., Abramo, G.P., Hawkins, T.R. and Dunn, J.B. "Material flows of polyurethane in the United States." Environmental Science & Technology 55.20 (2021): 14215-14224.

[2] Di, J., Reck, B.K., Miatto, A. and Graedel, T.E. "United States plastics: Large flows, short lifetimes, and negligible recycling." Resources, Conservation and Recycling 167 (2021): 105440.

[3] US Environmental Protection Agency. "Methylene Diphenyl Diisocyanate (MDI) And Related Compounds Action Plan." (2011).

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[5] Wu, S.; Luo, M.; Darensbourg, D. J.; Zeng, D.; Yao, Y.; Zuo, X.; Hu, X.; Tan, D. Non-isocyanate and catalyst-free synthesis of a recyclable polythiourethane with cyclic structure. ACS Sustainable Chemistry & Engineering 2020, 8(14), 5693-5703.

[6] Zhao, L; Semetey, V. Recycling polyurethanes through transcarbamoylation. ACS omega 2021, 6(6), 4175-4183.

[7] Khatoon, H.; Iqbal, S.; Irfan, M.; Darda, A.; Rawat, N. K. A review on the production, properties and applications of non-isocyanate polyurethane: A greener perspective. Progress in Organic Coatings 2021, 154, 106124.

[8] Liang, C.; Jadidi, Y.; Chen, Y.; Gracida-Alvarez, U. R.; Torkelson, J. M.; Hawkins, T. R.; Dunn, J. B. Techno-economic Analysis and Life Cycle Assessment of Biomass-Derived Polyhydroxyurethane and Non-isocyanate Polythiourethane Production and Reprocessing. Manuscript in preparation 2024.

[9] Döhler, N.; Wellenreuther, C.; Wolf, A. Market dynamics of biodegradable bio-based plastics: Projections and linkages to European policies. EFB Bioeconomy Journal 2022, 2, 100028.