Physically Cross-linked nanocellulose composites tailored from base bath and ferric (III) ion: Mechanical, water resistance and thermal property

Abstract

The development of sustainable composites from wood derived cellulose nanocrystals (CNCs) and degradable poly(vinyl alcohol)-PVA polymer is a promising strategy to resolve the issue of plastic pollution, which is also consistent with the current carbon neutrality and sustainable development tendency. However, the strong intra- or inter-molecular hydrogen bonding interactions of CNCs endow it with poor processability, resulting in the composites with unsatisfied comprehensive performance. Therefore, a novel method developed from base bath solutions and ferric (III) ion was reported to construct the physical cross-linking (e.g., hydrogen bonding and coordination interactions) to improve the water resistance, thermal and mechanical performance of PVA/CNC composites. For the comparison with the counterparts without cross-linking, the Young’s modulus and tensile strength of physically cross-linked PVA/CNC composites were obviously increased. Meanwhile, the thermal and water resistance property of physically cross-linked composites was also obviously improved owing to the physical interactions, e.g., hydrogen bonding and ferric (III) ion-carboxyl group coordination interactions. The results above provided the basis for the further exploration of direct ink writing 3D/4D printing sustainable nanocellulose composites.