"THERMAL STABILITY AND UV RESISTANCE OF NANOCELLULOSE/TANNIN HYBRID FILMS"

"Nanofibrillated cellulose can be used as a robust scaffold filled with tannin particles. Such reinforcement may confer particular chemical features needed for the production of hybrid films used as active packaging. Based on this hypothesis, powdered tannin particles were incorporated into nanocellulose-based films at two different weight fractions. The chemical, thermal and mechanical properties of these films were determined. Also, their resistance to UV exposure was evaluated in terms of colorimetric and mechanical characteristics. Neither chemical nor thermal noticeable adverse effects could be ascribed to the tannin insertion. On the other hand, the insertion of 1 wt% tannin induced an increase of 60% in tensile strength, although this effect was not retained after UV exposure. Meanwhile, the film that incorporated 3 wt% tannin appeared to present stable mechanical properties after UV exposure. This mechanical stability over UV exposure was not obtained with the inclusion of 1 wt% tannin content. The hybrid nanofilms acquired brown shades, which were not retained when the films were exposed to UV radiation."