Partial periodate oxidation and thermal cross-linking for the processing of thermoset all-cellulose composites

Mechanical properties, measured with 3-point bending test, together with structural and thermal observations showed a direct correlation between the DO of the specimens, the cross-linking density, the macroscopic performances and the propensity to retain water when they were heated as shown by thermogravimetric (TGA) measurements. An optimum of the properties was reached for samples having a DO in the range of 0.4-0.65, where surface oxidized cellulose nanocrystals could be cross-linked with their oxidized or un-oxidized neighbors to yield nearly transparent samples of flexural modulus as high as 7 GPa and flexural strength of 177 MPa. Such values, obtained with samples resulting from the simple oxidation followed by thermosetting process presented here, match well the physical properties of ACCs resulting from more complex preparation scheme.