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. 2026 Sep 17;11(38):57370–57377. doi: 10.1021/acsomega.6c05696

Theoretical Study on the Reaction Mechanism of Closed-Loop Recyclability of a Biomass-Derived Epoxy Resin Thermoset by Methanolysis

Yang Du †, Hui Zhang †,*, Xia Du †, Zhuohua Sun ‡, Yan Shang †, Jun You †,*, Xuan Wang †
PMCID: PMC13629027  PMID: 42825077

Abstract

Epoxy resin thermosets (ERTs) represent a significant category of polymeric materials. However, ERTs have high cross-linking and are difficult to decompose, leading to unacceptable environmental pollution. It is evident that there is a critical need for the development of inherently recyclable ERTs derived from renewable resources. In addition, the feasibility of related reaction mechanisms of the recyclable routes needs to be investigated. In this work, the potential energy surface information for 13 reaction channels was obtained using density functional theory at the B3LYP/6-311+G­(d,p) level based on electronic structure calculations. The curing, methanolysis, and acetolysis routes were identified. The influence of heteroatom electron effects was evaluated. The calculation results show that the reaction Gibbs free energy barrier during the curing process of the DGF/MBCA ERT material is about 0.64 eV higher than that during the methanolysis process, successfully elucidating the experimental phenomenon of high-temperature curing and low-temperature methanolysis. The reaction Gibbs free energy barriers of nucleophilic substitution for the thiophene-like are both lower than those for the furan-like due to the higher conjugation degree of furan-like pentagonal rings. The elucidated reaction mechanism of the recyclable process involves lignin- or lignocellulosic-derived ERT raw materials.

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graphic file with name ao6c05696_0006.webp

1. Introduction

Epoxy resin thermosets (ERTs) constitute a prominent class of polymeric materials, distinguished by their exceptional thermal stability and durability, and are employed across a wide range of industrial applications. , However, the general non-recyclability of cured ERTs, which is attributable to their highly cross-linked nature, gives rise to unacceptable environmental challenges. , Meanwhile, bisphenol A (2,2′-di (4-hydroxyphenyl) propane), a necessary raw material commonly used in the production of ERTs, has also been found to have endocrine-disrupting properties. It is therefore of the utmost importance to identify suitable replacements, ideally derived from renewable resources. − The most reasonable source of renewable phenolic precursors extracted from biomass at present is lignocyte-derived platform chemicals. −

The development of circular strategies for ERTs, in particular, closed-loop recycling approaches, necessitates a meticulous design for molecular structures. This innovative design should employ biomass-derivable building blocks, exhibit optimal thermal and mechanical performance, and impart intrinsic ERT recyclability.

At present, dynamic covalent polymer networks (DCPNs) have attracted attention due to their unique roles in chemical recovery and self-healing, applied in the field of energy and electronic devices to discover/design functional properties that classical thermoplastic and thermosetting polymers cannot provide. Especially, ERTs are typically demonstrated for fossil-based building blocks by polymer programming. − Recently, renewable building blocks such as vanillin, 2,5-furandicarboxylic acid (DMFD), and soybean oil have been employed to introduce cleavable/dynamically linked imines, aldehydes, and esters into ERTs. Simultaneously, Hong and co-workers developed a bio-based, multicleavable epoxy thermoset capable of undergoing catalyst-free chemical recycling to monomers under mild alkaline conditions. The recovered components not only facilitate the synthesis of high-performance regenerated thermosets but also enable selective matrix removal in carbon fiber composites, highlighting a promising pathway toward sustainable closed-loop systems. However, only a few of these materials are entirely based on biomass. Although substantial advancements have been achieved in the degradation and dissolution of insoluble ERT materials, and their reuse has been successfully demonstrated during the vitrification process, the complete recovery of the original monomers still poses a significant challenge. Nevertheless, in addition to partial degradation, the development of closed-loop recycling methods is of particular importance for the realization of effective recycling strategies in the context of ERTs. The closed-loop strategy of fossil-based thermosetting materials has always been a cutting-edge research topic in the field of materials science. This study mainly focuses on two aspects: structural redesign and recycling of existing thermosetting materials. At the same time, extensive research has been conducted in the field of catalysis, dedicated to challenging catalytic deconstruction of typical materials in this field, such as bisphenol A-based materials, involving the cleavage and activation of recalcitrant C–N/C–O bonds. − Notwithstanding these significant developments, a genuinely closed-loop strategy based exclusively on biological ERTs remains to be validated. Wu and co-workers used a judicious combination of building blocks derived entirely from lignocellulosic biomass to synthesize ERTs with excellent thermal and mechanical performance and inherent recyclability. Specifically, the ERTs prepared from dimethyl ester of DMFD, 4,4′-methylenebis (cyclohexylamine) (MBCA), and glycidol display excellent thermal-mechanical properties, even surpassing their reference counterpart made from BPA. Due to its unique chemical structure and morphology, the material can promote its own low-temperature depolymerization in methanol, without the addition of any catalyst. This process leads to full solubilization of the material and excellent recovery of the original furan building block, DMFD.

Despite recent experimental demonstrations by Wu et al. on the closed-loop recyclability of biomass-derived epoxy-amine thermosetting resins, the underlying reaction mechanisms remain elusive due to heavy reliance on macroscopic characterization. Specifically, the potential energy surface (PES) profiles and heteroatom electronic effects that dictate molecular-level reaction kinetics have yet to be clarified. To bridge this gap, this study conducted comprehensive density functional theory (DFT) calculations at the B3LYP/6-311+G­(d,p) level, systematically evaluating 16 reaction channels across the curing, methanolysis, and acetylation pathways. We theoretically investigated the reaction process of recycling ERT materials starting from the dimethyl ester of 2,5-furandicarboxylic acid (DMFD) undergoing three reaction routes (curing, methanolysis, and acetolysis). In the curing route, DMFD reacts with 2-chloromethyloxirane (CMO) and then undergoes an esterification reaction with MBCA to form the ERT materials. In the methanolysis route, the ERT material degrades by the methanolysis reaction to obtain DMFD. In the acetolysis route, the ERT material undergoes an acetolysis reaction with acetate anions under acidic conditions to obtain MBCA closed-loop recyclability. On this basis, we designed additional thiophene-like ERTs and evaluated the electronic effects of the heteroatoms in comparison to furan-like ERTs. The key innovation of this study lies in the quantitative evaluation of the Gibbs free energy barriers, which elucidates the microscopic kinetic drivers behind the experimental observation of low-temperature recyclability, thereby offering a theoretical foundation for the rational design of next-generation recyclable thermosets. −

2. Computational Methods

In this work, we employ the density functional theory (DFT) method to conduct a theoretical investigation of the recycling reaction process of furan-like and thiophene-like ERT materials. The optimization of the geometry structure and the calculation of the frequency of all stationary points (optimized configurations of reactants, transition states, and products in Supporting Information Materials) were accomplished at the B3LYP/6-311+G­(d,p) level, which has been demonstrated to be a reasonable and suitable approach for the present study. In accordance with the tenets of the Intrinsic Reaction Coordinates (IRC) theory, the Potential Minimum Energy Path (MEP) was derived with a gradient step size of 0.05 (amu)1/2 Bohr. The first and second energy derivatives were obtained to calculate the curvature of the reaction path and the generalized vibration frequency along the MEP, and the potential energy surface information on the 13 reaction channels was obtained. The solvation effect was assessed with the SMD continuum solvation model. The reaction channels and transition states are abbreviated to the corresponding R and TS, respectively. All theoretical calculations in this study were performed using the GAUSSIAN 09 software package.

3. Results and Discussion

3.1. Stationary Point Geometries

Table shows the molecular names, formulas, and corresponding abbreviations of key molecules of the recycling reaction process of furan- and thiophene-like ERT materials. Figure shows the recycling reaction process of two reactants of ERT materials, commencing with the dimethyl ester of 2,5-furandicarboxylic acid (DMFD or DMTD) and MBCA, encompassing three reaction routes, which are curing (route 1), methanolysis (route 2), and acetolysis (route 3). The key reaction channels of the recycling reaction process of thiophene-like ERT materials have been investigated. Table lists the reaction equations of the 13 reaction channels; the labels of the 13 reaction channels aligned with the transition states are consistent. Figure displays the optimized geometric structures of the reactants, transition states, and products of the 13 reaction channels at the B3LYP/6-311+G­(d,p) level. Figure depicts a schematic diagram of the synthesis and recycling of furan-like ERTs. Then, taking furan compounds as an example, we describe the three reaction routes mentioned above.

1. Molecular Formulas, the Molecular Names, and the Corresponding Abbreviations of the Studied Molecules.

3.1.

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1.

1

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Recycling of two types of ERT raw materials derived from lignin.

2. Optimized Key Bond Lengths (in Angstroms) and the Calculated Frequencies (Freq) (in cm–1), Together with the Calculated Reaction Gibbs Free Energies at 298 K (ΔG) and the Gibbs Free Potential Barrier Heights (ΔG ≠) (in eV).

3.1.

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2.

2

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Optimized geometric structures of the 13 transition states.

3.

3

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Schematic representations of ERT synthesis and recycling.

There, route 1 is the curing process; DMFD derived from lignin biomass undergoes addition reactions to generate 2,5-furandicarboxylic acid (FDCA) and remove the methoxy group under alkaline conditions. FDCA exists in the form of an oxygen anion under alkaline conditions, reacts with two molecules of 2-(chloroethyl) oxirane (CMO), resulting in the production of diglycidyl ester of 2,5-furandicarboxylic acid (DGF), and further undergoes esterification with MBCA to open the epoxy ring of DGF and form C–N covalent bonds and obtain the ERT material (RTS1-RTS7). Route 2 is the methanolysis process; the obtained ERT material underwent a methanolysis reaction in the presence of methanol, resulting in the production of DMFD, and DMFD is one of the raw materials for the ERT material. The closed-loop recycling target for one of the raw materials was achieved (RTS8). Route 3 is the acetolysis process, and the ERT materials react with acetate anions to obtain MBCA under acidic conditions. In this way, the other raw material involved in the synthesis of ERT materials is also recycled. The goal of the closed-loop recycling of the other raw materials has been achieved (RTS9).

Table also lists the optimized bond lengths of the breaking bonds (b) and forming bonds (f) of the 13 transition states, and the corresponding bond lengths of the reactants and products of the equilibrium geometries. The 13 transition states have been confirmed by normal-mode analysis to exhibit a single imaginary frequency, which corresponds to the stretching modes of the coupling between breaking and forming bonds. From Table , it can be seen that the transition state structures of the nucleophilic substitution reaction channels (TS5, TS5-1, TS6, and TS6-1) exhibit a common character. For the structures of TS5, TS5-1, TS6, and TS6-1, the C–Cl breaking bonds exhibit an increase of approximately 31.98, 32.21, 32.47, and 31.93%, respectively, in comparison to the equilibrium bond lengths. Additionally, the C–O forming bonds demonstrate a stretching of approximately 44.33, 44.64, 43.19, and 43.57%, respectively, over the equilibrium bond lengths. The elongation of the breaking bond is less than that of the forming bond, indicating that TS5, TS5-1, TS6, and TS6-1 are all reactant-like. Consequently, the four reaction channels will proceed via “early” transition states, which is consistent with Hammond’s hypothesis applied to an exothermic reaction.

3.2. Energetics

Table also lists the reaction Gibbs free energy (ΔG) and reaction Gibbs free energy barrier (ΔG ≠) at 298 K of the 13 reaction channels at the B3LYP/6-311+G­(d,p) level. The recycling reaction process of two reactants of ERT materials is divided into three reaction routes, which are the curing route, methanolysis route, and acetolysis route. ,

3.2.1. Curing Route

The first route is the curing process: hydroxyl addition to the C of the carbonyl group on DMFD under alkaline conditions removes methoxy groups and forms FDCA via TS1-TS4. FDCA loses H+ under alkaline conditions and becomes an oxygen anion, nucleophilic substitution reaction with two CMOs to produce DGF (TS5 and TS6), which undergoes an esterification reaction with MBCA to open the epoxy ring and form the ERT material (TS7). The excellent thermal and mechanical properties of the ERT materials (DGF/MBCA) have been experimentally proven. The removal of methoxy groups is easier because the reaction Gibbs free energy barrier ΔG ≠ TS2 is only 0.28 eV. The reaction Gibbs free energy barriers of reaction channel RTS1 are more advantageous than those of reaction channel RTS3. Because of the formation of carboxylate anions under alkaline conditions, resulting in an increase in electron cloud density on the furan ring, and the electropositivity of the acyl C at the αposition decreases, the reaction Gibbs free energy barriers of reaction channel RTS3 increase. For reaction channels of thiophene-like ERT materials, the reaction Gibbs free energy barriers ΔG ≠ TS5‑1 and ΔG ≠ TS6‑1 are lower than those of furan-like materials, with 0.08 and 0.09 eV, respectively. Because larger conjugated systems are formed between the above-mentioned carboxylate anions with pentagonal rings. The degree of conjugation between the O atoms and other atoms on the pentagonal rings is higher than that of the S atoms. The conjugation degree is higher; the electronegativity of the O on the carboxylate anion is lower, and the nucleophilicity is weaker. The reaction activity of nucleophilic substitution is lower. Thus, the reaction Gibbs free energy barrier of TS5-1 is lower than that of TS5.

3.2.2. Methanolysis Route

The second route is the methanolysis process, in which the C–O bond of the acyl group on DGF/MBCA breaks under the action of methanol, and one molecule of methanol provides one methoxy group, decomposing DGF/MBCA into one of the reactants (DMFD). As can be seen in Table , the reaction Gibbs free energy barrier of the ring-opening esterification reaction RTS7 via TS7 and the methanolysis reaction RTS8 via TS8 in Table are 2.89 and 2.25 eV, respectively. Interestingly, Wu and his co-worker found that the methanolysis reaction here only requires a low temperature of 70 °C to occur, while a higher temperature of 170 °C is required for ring opening. Coincidentally, the reaction Gibbs free energy barrier of DGF with MBCA for the ring-opening esterification reaction is about 0.64 eV higher than that of the methanolysis reaction of DGF/MBCA ERTs. This calculated result successfully explains the experimental phenomenon of low-temperature methanolysis and high-temperature curing discovered by Wu and co-workers. One of the products of the methanolysis reaction is DMFD, which is one of the reactants. DMFD derived from lignin achieves the goal of closed-loop recycling. A similar case is also seen in the study of thiophene, the reaction Gibbs free energy barrier for the ring-opening esterification reaction via TS7-1 is 2.91 eV, which is much higher than the methanolysis reaction via TS8-1 by about 0.65 eV. At the same time, we found that the reaction Gibbs free energy barriers for thiophene-like ERTs to form during the curing process and methanolysis process were higher than those for furan-like ERTs, such as ΔG ≠ TS7‑1 2.91 eV > ΔG ≠ TS7 2.89 eV and ΔG ≠ TS8‑1 2.26 eV > ΔG ≠ TS8 2.25 eV.

3.2.3. Acetolysis Route

The third route is the acetolysis process. One of the products of the methanolysis reaction is DMFD derived from lignin after the methanolysis reaction of the ERTs material; the other product converts to the N+ ion form under acidic conditions, and further, the other product in N+ ion form undergoes an acetolysis reaction with the acetate anion to product MBCA via TS9, which is the other reactant. MBCA derived from lignocellulose achieves the goal of closed-loop recycling.

4. Conclusion

Here, at the B3LYP/6-311+G­(d,p) level, the DFT method was used to reveal the reaction mechanism of the curing route, the methanolysis route, and the acetylation routes. It has been proved that a wise combination of lignocellulosic- and lignin-derived building blocks can produce fully bio-based, high-performance ERTs that are suitable for low-temperature methanolysis. Our calculated results of furan-like successfully explain this experimental phenomenon with a higher reaction Gibbs free energy barrier of the curing process (ΔG ≠ TS7 = 2.89 eV) and a lower reaction Gibbs free energy barrier of methanolysis (ΔG ≠ TS8 = 2.25 eV). For the nucleophilic substitution reaction, the reaction channels of thiophene-like are more thermodynamically and kinetically favorable than the furan-like, due to the of conjugation degree of O atoms with other atoms on the pentagonal rings is stronger than that of the S atoms, the lower electronegativity of the O on carboxylate anion result in the lower reactivity of nucleophilic substitution in the reaction channel RTS5. The development of inherently recyclable and high-performance ERTs entirely from renewable resources are a very ideal research goal; revealing the reaction mechanism of the recycling process of the ERT materials in detail is crucial for further structural and molecular design of these ERT-type materials.

Supplementary Material

ao6c05696_si_001.pdf (223.9KB, pdf)

Acknowledgments

All authors contributed to the study conceptualization. Y.D. conducted the investigation and visualization. H.Z. and Z.S. are responsible for funding acquisition, project administration, writingreview and editing. X.D. and Y.S. are responsible for formal analysis and methodology. X.W. conducted supervision and validation. J.Y. is responsible for data curation, resources, and software. The original draft of the manuscript was written by Y.D., and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. All authors read and approved the final manuscript.

Ethics approval and consent to participate: not applicable. All data generated or analyzed during this study are included in this published article and its Supporting Information files.

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.6c05696.

  • Optimized standard orientations of stationary points of the 13 reaction channels at the B3LYP/6-311+G­(d,p) level (PDF)

This work is supported by the Key Project of the Joint Fund for Regional Innovation and Development of the National Natural Science Foundation of China (U20A20307) and the National Natural Science Foundation of China (22378024).

The authors declare no competing financial interest.

References

  1. Jin F. L., Li X., Park S. J.. Synthesis and application of epoxy resins: A review. J. Ind. Eng. Chem. 2015;29:1–11. doi: 10.1016/j.jiec.2015.03.026. [DOI] [Google Scholar]
  2. Pascault, J. P. ; Williams, R. . Overview of thermosets: Present and future. Thermosets Structure, Properties, and Applications; Elsevier: Amsterdam, 2018, 3–34. [Google Scholar]
  3. May, C. A. Epoxy Resins, Chemistry and Technology; Routledge: London, 2018. [Google Scholar]
  4. MacLeod M., Arp H. P. H., Tekman M. B., Jahnke A.. The global threat from plastic pollution. Science. 2021;373:61–65. doi: 10.1126/science.abg5433. [DOI] [PubMed] [Google Scholar]
  5. Mahajan J. S., O’Dea R. M., Norris J. B., Korley L. T., Epps T. H.. Aromatics from lignocellulosic biomass: a platform for high-performance thermosets. ACS Sustainable Chem. Eng. 2020;8:15072–15096. doi: 10.1021/acssuschemeng.0c04817. [DOI] [Google Scholar]
  6. Vom Saal F. S., Vandenberg L. N.. Update on the health efects of bisphenol A: overwhelming evidence of harm. Endocrinology. 2021;162:171. doi: 10.1210/endocr/bqaa171. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Cywar R. M., Rorrer N. A., Hoyt C. B., Beckham G. T., Chen Y. X.. Bio-based polymers with performance-advantaged properties. Nat. Rev. Mater. 2022;7:83–103. doi: 10.1038/s41578-021-00363-3. [DOI] [Google Scholar]
  8. Meylemans H. A., Groshens T. J., Harvey B. G.. Synthesis of renewable bisphenols from creosol. ChemSusChem. 2012;5:206–210. doi: 10.1002/cssc.201100402. [DOI] [PubMed] [Google Scholar]
  9. Sun Z. H., Bottari G., Afanasenko A., Stuart M. C. A., Deuss P. J., Fridrich B., Barta K.. Complete lignocellulose conversion with integrated catalyst recycling yielding valuable aromatics and fuels. Nat. Catal. 2018;1:82–92. doi: 10.1038/s41929-017-0007-z. [DOI] [Google Scholar]
  10. Sun Z. H., Fridrich B., Santi de A., Elangovan S., Barta K.. Bright Side of Lignin Depolymerization: Toward New Platform Chemicals. Chem. Rev. 2018;118:614–678. doi: 10.1021/acs.chemrev.7b00588. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Zhang B. W., Qiang G. R., Barta K., Sun Z. H.. Bio-based polymers from lignin. Innovation Mater. 2024;2:100062. doi: 10.59717/j.xinn-mater.2024.100062. [DOI] [Google Scholar]
  12. Long T. E.. Toward recyclable thermosets. Science. 2014;344:706–707. doi: 10.1126/science.1254401. [DOI] [PubMed] [Google Scholar]
  13. García F., Smulders M. M. J.. Dynamic covalent polymers. J. Polym. Sci., Polym. Chem. 2016;54:3551–3577. doi: 10.1002/pola.28260. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Fortman D. J., Brutman J. P., De Hoe G. X., Snyder R. L., Dichtel W. R., Hillmyer M. A.. Approaches to sustainable and continually recyclable cross-linked polymers. ACS Sustainable Chem. Eng. 2018;6:11145–11159. doi: 10.1021/acssuschemeng.8b02355. [DOI] [Google Scholar]
  15. Shieh P., Zhang W. X., Husted K. E. L., Kristufek S. L., Xiong B. Y., Lundberg D. J., Lem J., Veysset D., Sun Y. C., Nelson K. A.. et al. Cleavable comonomers enable degradable, recyclable thermoset plastics. Nature. 2020;583:542–547. doi: 10.1038/s41586-020-2495-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Zheng N., Xu Y., Zhao Q., Xie T.. Dynamic covalent polymer networks: a molecular platform for designing functions beyond chemical recycling and self-healing. Chem. Rev. 2021;121:1716–1745. doi: 10.1021/acs.chemrev.0c00938. [DOI] [PubMed] [Google Scholar]
  17. Wang B. B., Ma S. Q., Li Q., Zhang H., Liu J. J., Wang R., Chen Z. Q., Xu X. W., Wang S., Lu N.. et al. Facile synthesis of “digestible”, rigid-and-flexible, bio-based building block for high-performance degradable thermosetting plastics. Green Chem. 2020;22:1275–1290. doi: 10.1039/C9GC04020J. [DOI] [Google Scholar]
  18. Chen X. C., Chen S. F., Xu Z. J., Zhang J. H., Miao M. H., Zhang D. H.. Degradable and recyclable bio-based thermoset epoxy resins. Green Chem. 2020;22:4187–4198. doi: 10.1039/D0GC01250E. [DOI] [Google Scholar]
  19. Zhang W. X., Gao F., Chen X. J., Shen L., Chen Y. J., Lin Y. J.. Recyclable, Degradable, and Fully Bio-Based Covalent Adaptable Polymer Networks Enabled by a Dynamic Diacetal Motif. ACS Sustainable Chem. Eng. 2023;11:3065–3073. doi: 10.1021/acssuschemeng.2c06870. [DOI] [Google Scholar]
  20. Hong Y., Lee J., Cho Y., Oh D., Goh M.. High-Density Cleavable Epoxy Networks for Rapid Chemical Recycling to Monomer Recovery under Mild Conditions. Macromolecules. 2026;59:7102–7122. doi: 10.1021/acs.macromol.6c00907. [DOI] [Google Scholar]
  21. Liu Y. L., Yu Z., Wang B. B., Li P. Y., Zhu J., Ma S. Q.. Closed-loop chemical recycling of thermosetting polymers and their applications: A review. Green Chem. 2022;24:5691–5708. doi: 10.1039/D2GC00368F. [DOI] [Google Scholar]
  22. Christensen P. R., Scheuermann A. M., Loeffler K. E., Helms B. A.. Closed-loop recycling of plastics enabled by dynamic covalent diketoenamine bonds. Nat. Chem. 2019;11:442–448. doi: 10.1038/s41557-019-0249-2. [DOI] [PubMed] [Google Scholar]
  23. Lei Z. P., Chen H. X., Luo C. Q., Rong Y. C., Hu Y. M., Jin Y. H., Long R., Yu K., Zhang W.. Recyclable and malleable thermosets enabled by activating dormant dynamic linkages. Nat. Chem. 2022;14:1399–1404. doi: 10.1038/s41557-022-01046-4. [DOI] [PubMed] [Google Scholar]
  24. Li J., Xu P. L., Zhu Y. K., Ding J. P., Xue L. X., Wang Y. Z.. A promising strategy for chemical recycling of carbon fiber/thermoset composites: self-accelerating decomposition in a mild oxidative system. Green Chem. 2012;14:3260–3263. doi: 10.1039/c2gc36294e. [DOI] [Google Scholar]
  25. Deng T. S., Liu Y., Cui X. J., Yang Y. X., Jia S. Y., Wang Y. X., Lu C. X., Li D. B., Cai R., Hou X. L.. Cleavage of C-N bonds in carbon fiber/epoxy resin composites. Green Chem. 2015;17:2141–2145. doi: 10.1039/C4GC02512A. [DOI] [Google Scholar]
  26. Navarro C. A., Ma Y. J., Michael K. H., Breunig H. M., Nutt S. R., Williams T. J.. Catalytic, aerobic depolymerization of epoxy thermoset composites. Green Chem. 2021;23:6356–6360. doi: 10.1039/D1GC01970H. [DOI] [Google Scholar]
  27. Ahrens A., Bonde A., Sun H. W., Wittig N. K., Hammershoj H. C. D., Batista G. M. F., Sommerfeldt A., Frolich S., Birkedal H., Skrydstrup T.. Catalytic disconnection of C-O bonds in epoxy resins and composites. Nature. 2023;617:730–737. doi: 10.1038/s41586-023-05944-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Wu X. Y., Hartmann P., Berne D., De Bruyn M., Cuminet F., Wang Z. W., Zechner J. M., Boese A. D., Placet V., Caillol S.. et al. Closed-loop recyclability of a biomass-derived epoxy-amine thermoset by methanolysis. Science. 2024;384:eadj9989. doi: 10.1126/science.adj9989. [DOI] [PubMed] [Google Scholar]
  29. Han W., Zhang H., Du X., Shang Y., Du Y., Yang H. D., Wang X., Chen Q. G., Li Z. S.. Structural design of a new XLPE Insulation material without cross-linking by-products and theoretical study on the reaction mechanism: An alternative to peroxide crosslinking. Mater. Today Commun. 2023;36:106483. doi: 10.1016/j.mtcomm.2023.106483. [DOI] [Google Scholar]
  30. Du Y., Zhang H., Han W., Du X., Shang Y., Yang H. D., Wang X., Chen Q. G., Li Z. S.. The network construction of a new byproduct-free XLPE-based insulation using a click chemistry-type reaction and a theoretical study of the reaction mechanism. Polymers. 2024;16(24):3536. doi: 10.3390/polym16243536. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Du Y., Han W., Zhang H., Du X., You J., Shang Y., Wang X., Chen Q. G., Li Z. S.. Theoretical study on the design of a new byproduct free XLPE-based insulation functional network based on click chemistry: a viable alternative to peroxide cross-linking. Int. J. Quantum Chem. 2026;126(4):e70159. doi: 10.1002/qua.70159. [DOI] [Google Scholar]
  32. Parr, R. G. ; Yang, W. . Density-functional theory of atoms and molecules; Oxford University Press: New York, 1989. ;. 10.1063/1.3160670. [DOI] [Google Scholar]
  33. Lee C., Yang W., Parr R. G.. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B:Condens. Matter. 1988;37:785–789. doi: 10.1103/PhysRevB.37.785. [DOI] [PubMed] [Google Scholar]
  34. Hratchian H. P., Schlegel H. B.. Accurate reaction paths using a Hessian based predictor-corrector integrator. J. Chem. Phys. 2004;120:9918–9924. doi: 10.1063/1.1724823. [DOI] [PubMed] [Google Scholar]
  35. Frisch, M. J. ; Trucks, G. W. ; Schlegel, H. B. ; Scuseria, G. E. ; Robb, M. A. ; Cheeseman, J. R. ; Scalmani, G. ; Barone, V. ; Mennucci, B. ; Petersson, G. A. ; et al. Revision A.02; Gaussian Inc.: Wallingford CT, 2009. [Google Scholar]
  36. Hammond G. S.. A correlation of reaction rates. J. Am. Chem. Soc. 1955;77:334–338. doi: 10.1021/ja01607a027. [DOI] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

ao6c05696_si_001.pdf (223.9KB, pdf)

Data Availability Statement

Ethics approval and consent to participate: not applicable. All data generated or analyzed during this study are included in this published article and its Supporting Information files.

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