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The structural similarities between lignin-derivable bisguaiacols and petroleum-derived bisphenol A/F (BPA/BPF) suggest that bisguaiacols could be ideal biobased alternatives to BPA/BPF in non-isocyanate polyurethane (NIPU) thermosets. Herein, bisguaiacol/bisphenol-derived cyclic carbonates with variations in methoxy content and bridging-carbon substitution were cured with two triamines of different chain lengths, and the impact of these differences on the thermomechanical properties of NIPU networks was examined. The methoxy groups present in the lignin-derivable cyclic carbonates led to thermosets with significantly improved toughness (∼49–59 MJ m −3 ) and elongation at break ( ε b ∼195–278%) vs. the BPA/BPF-based benchmarks (toughness ∼ 26–35 MJ m −3 , ε b ∼ 86–166%). Furthermore, the addition of dimethyl substitution on the bridging carbon resulted in increased yield strength ( σ y ) – from ∼28 MPa for networks with unsubstituted bridging carbons to ∼45 MPa for the dimethyl-substituted materials. These enhancements to mechanical properties were achieved while retaining essential thermoset properties, such as application-relevant moduli and thermal stabilities. Finally, the triamine crosslinkers provided substantial tunability of thermomechanical properties and produced NIPUs that ranged from rigid materials with a high yield strength ( σ y ∼ 65–88 MPa) to flexible and tough networks. Overall, the structure-property relationships presented highlight a promising framework for the design of versatile, bio-derivable, NIPU thermosets.
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This content will become publicly available on August 27, 2026
Lignin-derivable, thermally healable thiol-acrylate vitrimers with improved mechanical performance and reprocessability via transesterification
The development of vitrimers with dynamic covalent bonds enables reprocessability in crosslinked networks, offering a sustainable alternative to conventional thermosets. In this work, a thiol-acrylate vitrimer was synthesized from lignin-derivable (bis)phenols (guaiacol and bisguaiacol F) and compared to a control derived from petroleum-based precursors (phenol and bisphenol F) to investigate the effect of structural differences on network properties and thermal reprocessing. The presence of methoxy groups in the lignin-derivable vitrimer promoted intermolecular interactions by serving as additional hydrogen bonding acceptors during curing, leading to a denser network, as evidenced by a higher rubbery storage modulus (∼2.4 MPa vs. ∼1.4 MPa) and glass transition temperature (∼34 °C vs. ∼28 °C). The lignin-derivable vitrimer exhibited a slightly higher elongation-at-break (∼170% vs. ∼130%) and improved mechanical robustness, including a nearly two-fold increase in Young's modulus (∼6.9 MPa vs. ∼3.4 MPa) and toughness (∼750 kJ m−3vs. ∼390 kJ m−3). The similar stress relaxation behavior and activation energy of viscous flow indicated comparable bond exchange dynamics between the two vitrimers, while the lignin-derivable system demonstrated higher thermal healing efficiency with improved recovery of tensile properties after reprocessing. These findings highlight the potential of lignin-based aromatics in designing mechanically robust and sustainable vitrimers, aligning with efforts to develop renewable and reprocessable polymeric materials.
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- Award ID(s):
- 1934887
- PAR ID:
- 10659432
- Publisher / Repository:
- RSC Sustainability
- Date Published:
- Journal Name:
- RSC Sustainability
- Volume:
- 3
- Issue:
- 9
- ISSN:
- 2753-8125
- Page Range / eLocation ID:
- 4067 to 4078
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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