UV-functional flexible nanocomposite film with high lignin-cellulose nanocrystals content

Lignin-cellulose nanocrystals (L-CNCs) can be used as UV-functional fillers in polyvinyl alcohol (PVA) films for various applications. However, agglomeration of particles restricts their addition to 20 wt% in the polymer matrix due to the reduction in mechanical properties. In this work, a new method is proposed to produce a flexible UV-protective composite film with a superior amount of L-CNCs (>76 wt%), where cellulose nanocrystals (CNCs) were used as a co-reinforcing agent (20%) and amount of synthetic polymer was very low, i.e., 5% PVA. Hemp hurd, a naturally abundant waste resource, was used for both L-CNCs and CNCs extraction. The addition of CNCs showed a synergistic effect with LCNCs, improving the UV-shielding ability of the film at 300-400 nm light wavelength. The resultant films were flexible, and showed similar elongation behaviour to PVA, yet had a high modulus. The initial results showed improvement in the shelf-life of raspberries with a high amount of L-CNCs film, which indicated the potential of the bio-based nanocomposite film as a sustainable alternative to commercial petroleum-based plastics.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study proposes a new method to enhance the performance of polyvinyl alcohol films by adding lignin-cellulose nanocrystals (L-CNCs) as UV-functional fillers. The addition of cellulose nanocrystals (CNCs) improves the UV-shielding ability of the film and enhances its flexibility and modulus. Preliminary results show that films with a high amount of L-CNCs can improve the shelf-life of raspberries.