Robust mechanical and water responsive mechanically adaptive property of physically cross-linked sustainable nanocellulose composites

Abstract

The development of wood derived cellulose nanocrystal (CNCs) based sustainable composites is potential to address the plastic pollution issue. However, because of strong hydrogen bonding interactions inside the CNCs, it is still challenging to obtain composites with satisfied comprehensive performance via the incorporation of CNCs into poly (vinyl alcohol) (PVA) matrix directly, so two strategies combined with dopamine modification, base bath solution and ferric (III) ion treatment were reported to tailor the comprehensive performance of PVA/CNC composites. The comparative study indicated that both of physically cross-linked PDA@CNC/PVA and PVA/CNC composites have obvious improvement in term of mechanical and water resistance property owing to the multiple physical interactions, e.g., hydrogen bonding and ferric ion-carboxyl group coordination interactions as well as catechol group and ferric ion coordination interactions. In addition, the physical performance (water resistance and mechanical property) of cross-linked PVA/CNC composites is more better than that of cross-linked PDA@CNC/PVA composites. Besides, physically cross-linked PVA/CNC composites also showed the water responsive mechanically adaptive property. This work provides the foundation for the further development of direct ink writing four-dimensional printing of physically cross-linked PVA/CNC sustainable composites.

Keywords

• Nanocellulose
• Nanocomposites
• Mechanical property
• Reinforcements
• Physical cross-linking