Morphology of the nanocellulose produced by periodate oxidation and reductive treatment of cellulose fibers

Nanocellulose with a morphology ranging from long flexible to rod-like fibrils were produced via periodate oxidation route followed by reductive treatment with NaBH₄ of never-dried eucalyptus pulp. The effect of the aldehyde content on the size and morphology of the resulting nanocellulose was studied by preparing three samples with 450, 830 and 1480 µmol g⁻¹ aldehyde content. The change in particle size after the oxidation and reduction was monitored by dynamic light scattering and the morphology of the nanocellulose was characterized by transmission electron microscopy. It was shown that the length of the cellulose fibrils significantly decreased with increasing oxidation. Depending on the aldehyde content, elementary nanofibrils or bundles of nanofibrils with a length from 100 nm up to several µm were obtained after the reduction process. The reinforcing potential of the nanocellulose was also investigated by dynamic thermomechanical analysis of nanocomposite films with different nanocellulose contents.