High content chitosan-based materials with high performance properties.

Chitosan is a valuable biopolymer with a great potential to be used in the design of sustainable materials. Its use typically requires converting the solid powder into a quite dilute solution by disrupting the hydrogen bonding between primary amine and hydroxyl groups. In this work we show that chitosan can be reacted with a tris-aromatic tris-epoxy monomer, generating thermoset materials. The design of the new structures adopted a strategy where the chitosan was mixed in its solid form, to avoid the use of solvents and additional processing steps. A combined polymerization mechanism was proposed, including growth chain polymerization and polyaddition. The obtained materials containing different epoxy/chitosan weight percentage ratios show outstanding properties: high glass transition ~230 °C, high Young's modulus ~2116 and 1716 MPa, tensile strength of ~35 MPa and T ~ 300 °C.