Lignin-derivable, thermoplastic, non-isocyanate polyurethanes with increased hydrogen-bonding content and toughness vs. petroleum-derived analogues.
Mater Adv
; 5(9): 3950-3964, 2024 May 07.
Article
em En
| MEDLINE
| ID: mdl-38721262
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., â¼65%, â¼85%, â¼95%, 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 â¼210% and toughness â¼62 MJ m-3, followed by BGF-NIPU (εbreak â¼185% and toughness â¼58 MJ m-3), and then BPF-NIPU (εbreak â¼140% and toughness â¼42 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.
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MEDLINE
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En
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Mater Adv
Ano de publicação:
2024
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Article