In this study, we reported a method to prepare a
lignin based cryogel by cross-linking deep eutectic solvent (DES) extracted lignin and formaldehyde as an alternative to replace resorcinol-formaldehyde (RF) based aerogel. The resulting lignin-formaldehyde cryogel has a highly porous structure (172.8 m2/g surface area) with a high dimension stability. We found that the hydroxyl group and carbonyl group of DES lignin provide reactive sites to cross-link with formaldehyde through electrophilic addition and aldol condensation reaction. We also found that using choline chloridelactic acid (ChCl-Lac) DES as a solvent during the lignin-formaldehyde cryogel formation is critical to prevent the shrinkage of the final cyrogel. The ensuing lignin-formaldehyde cryogel has promising properties such as high thermostability, low thermal conductivity, and good fire retardancy.
Revised: April 24, 2019 |
Published: January 8, 2019
Citation
Lin K., R. Ma, P. Wang, J. Xin, J. Zhang, M.P. Wolcott, and X. Zhang. 2019.Deep Eutectic Solvent Assisted Facile Synthesis of Lignin-Based Cryogel.Macromolecules 52, no. 1:227-235.PNNL-SA-142367.doi:10.1021/acs.macromol.8b02279