Thermally reversible nanocellulose hydrogels synthesized via the furan/maleimide Diels-Alder click reaction in water

The study deals with the synthesis of thermally reversible hydrogels from modified cellulose nanofibers via the Diels-Alder click reaction in an aqueous medium. Never-dried cellulose fibres derived from hardwood were submitted to shearing and surface TEMPO-oxidation before being modified with furfurylamine. The ensuing pendant furan moieties were reacted with a water-soluble bismaleimide via Diels-Alder coupling at 65 degrees C to produce a hydrogel, whose deconstruction was induced by the corresponding retro-Diels-Alder reaction carried out at 95 degrees C. Differential scanning calorimetry and rheological measurement were used to characterize the hydrogels. These aqueous cellulosic materials should provide original applications in such areas as strong paper-based artefacts and biocompatible gels. (C) 2019 Elsevier B.V. All rights reserved.