Diels-Alder-Chitosan based dissociative covalent adaptable networks.

For the first time, Diels-Alder and retro Diels-Alder reactions were evidenced by 1H NMR spectroscopy and DSC on chitosan based systems. At first, preliminary studies led to structural identification and better understanding of the Diels-Alder reaction. Then, chitosan of 30,000 g/mol and 150,000 g/mol were modified by furfuryl glycidyl ether with 20% substitution degree. The resulting products were cross-linked with bis and trismaleimide crosslinkers to produce films possessing interesting mechanical properties. Unprecedented for chitosan-based films, DMA measurement highlighted retro Diels-Alder between 110 and 130 °C. Films showed interesting hydrophobicity and fat absorption. They also exhibited resistance in acidic media whereas crude chitosan films were dissolved.