Lignin-derivable, thermoplastic, non-isocyanate polyurethanes with increased hydrogen-bonding content and toughness vs. petroleum-derived analogues
Date
2024-04-02
Journal Title
Journal ISSN
Volume Title
Publisher
Materials Advances
Abstract
The functionality inherent in lignin-derivable bisguaiacols/bissyringols can improve the processability and performance of the resulting polymers. Herein, non-isocyanate polyurethanes (NIPUs) were synthesized from bisguaiacols/bissyringols with varying degrees of methoxy substitution and differing bridging groups. Notably, the presence of increasing numbers of methoxy groups (0, 2, and 4) in bisphenol F (BPF)-, bisguaiacol F (BGF)-, and bissyringol F (BSF)-NIPUs led to higher percentages of hydrogen-bonded –OH/–NH groups (i.e., ∼65%, ∼85%, ∼95%, respectively). Increased hydrogen bonding between chains improved the elongation-at-break (εbreak) and toughness of lignin-derivable NIPUs over their petroleum counterparts without a reduction in Young's moduli and tensile strengths. For example, BSF-NIPU exhibited the highest εbreak ∼210% and toughness ∼62 MJ m−3, followed by BGF-NIPU (εbreak ∼185% and toughness ∼58 MJ m−3), and then BPF-NIPU (εbreak ∼140% and toughness ∼42 MJ m−3). Similar trends were found in the dimethyl-substituted analogues, particularly for the bisphenol A-NIPU and bisguaiacol A-NIPU. Importantly, the melt rheology of the lignin-derivable NIPUs was comparable to that of the petroleum-derived analogues, with a slightly lower viscosity (i.e., improved melt flow) for the bio-derivable NIPUs. These findings suggested that the added functionalities (methoxy groups) derived from lignin precursors improved thermomechanical stability while also offering increased processability. Altogether, the structure–property-processing relationships described in this work can help facilitate the development of sustainable, performance-advantaged polymers.
Description
This article was originally published in Materials Advances. The version of record is available at: https://doi.org/10.1039/D4MA00039K. © 2024 The Author(s). Published by the Royal Society of Chemistry
Keywords
industry, innovation, and infrastructure, responsible consumption and production, climate action
Citation
Mahajan, Jignesh S., Zachary R. Hinton, Eduardo Nombera Bueno, Thomas H. Epps, Iii, and LaShanda T. J. Korley. “Lignin-Derivable, Thermoplastic, Non-Isocyanate Polyurethanes with Increased Hydrogen-Bonding Content and Toughness vs. Petroleum-Derived Analogues.” Materials Advances 5, no. 9 (2024): 3950–64. https://doi.org/10.1039/D4MA00039K.