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- Abdelaziz, Omar Y., et al.
(författare)
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Recent strides toward transforming lignin into plastics and aqueous electrolytes for flow batteries
- 2024
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Ingår i: iScience. - : Elsevier Inc.. - 2589-0042. ; 27:4
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Forskningsöversikt (refereegranskat)abstract
- Lignin is an abundant polyaromatic polymer with a wide range of potential future uses. However, the conversion of lignin into valuable products comes at a cost, and medium- to high-value applications are thus appropriate. Two examples of these are polymers (e.g., as fibers, plasticizers, or additives) and flow batteries (e.g., as redox species). Both of these areas would benefit from lignin-derived molecules with potentially low molecular weight and high (electro)chemical functionality. A promising route to obtain these molecules is oxidative lignin depolymerization, as it enables the formation of targeted compounds with multiple functionalities. An application with high potential in the production of plastics is the synthesis of new sustainable polymers. Employing organic molecules, such as quinones and heterocycles, would constitute an important step toward the sustainability of aqueous flow batteries, and lignin and its derivatives are emerging as redox species, mainly due to their low cost and renewability.
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| 2. |
- Valsange, Nitin G., et al.
(författare)
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Semi-Crystalline and Amorphous Polyesters Derived from Biobased Tri-Aromatic Dicarboxylates and Containing Cleavable Acylhydrazone Units for Short-Loop Chemical Recycling
- 2024
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Ingår i: Macromolecules. - 0024-9297. ; 57:6, s. 2868-2878
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Tidskriftsartikel (refereegranskat)abstract
- Recycling polymers by site-specific scission into short-chain oligomers/polymers, followed by recoupling these to form the original polymer presents an energetically more favorable shorter-loop chemical recycling in comparison to recycling into monomers. Here, we present the synthesis and polymerization of triaromatic diesters to prepare polyesters with acylhydrazone units as weak structural links. Two diester monomers were prepared by combining methyl 5-chloromethyl-2-furoate, obtained from 5-chloromethylfurfural (CMF), with potentially biobased hydroquinone and resorcinol, respectively. The two diesters having a central phenyl ring flanked by two furan rings were polymerized with 1,6-hexanediol and 1,4-butanediol, respectively, together with controlled amounts of monofunctional ethyl levulinate to form telechelic ketone-terminated polyesters. Subsequent reactions of these telechelic polyesters with adipic dihydrazide yielded corresponding chain-extended polyesters with increased molecular weights ([η] = 0.29−0.52 dL g−1) with acylhydrazone units in the backbone. Thermogravimetric analysis showed a high thermal stability of the polyesters with thermal decomposition only above 275 °C. The polyesters containing the linear hydroquinone units were found to be semicrystalline materials with melting points at 158 and 192 °C, respectively, while those containing the kinked resorcinol units were fully amorphous with glass transition temperatures at 35 and 44 °C, respectively. Initial investigations of the chemical recyclability of the polyesters demonstrated that acylhydrazone units could be selectively cleaved to recover the original telechelic ketone-terminated polyesters, which could again be chain-extended to obtain a recycled polymer with molecular weights and properties very similar to those of the original polymer.
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