Catechyl lignin-reinforced mechanical performances of Poly(vinyl alcohol)-Based materials

Catechyl lignin, a unique naturally occurring biopolymer is hailed as an “idea lignin” archetype owing to its homogeneity, linearity, and acid resistance. In this study, we discover that the precipitation-induced C-lignin nanoparticles (NPs) display a crystallite structure with clear lattice spacings which has never been observed in conventional G/S-lignin NPs. Compositing C-lignin with poly (vinyl alcohol) (PVA) through casting-drying, freezing-thawing, and freezing-salting methods, results in a dazzling array of PVA-based films, soft hydrogels, and rigid hydrogels, respectively. Such compositing processes not only improve the mechanical properties by 2–6 times, but also make the resultant materials UV-blocking, fluorescence, thermostability, and water-resistance properties. This work introduces a novel sustainable building block for the fabrication of strong polymeric materials and discovers a new route for the valorization of waste biomass.