High wet-toughness bioplastics from lignin-containing cellulose nanofibrils modified by maleic anhydride esterification

Bioplastics based on lignin-containing cellulose nanofibrils (LCNF) have emerged as attractive alternatives to petrochemical plastics. However, the preparation of LCNF-based bioplastics with excellent wet-mechanical properties and water stability remains challenging. This study reports a sustainable route for the preparation of LCNF-based bioplastics with excellent wet mechanical properties and water stability. First, a deep eutectic solvent was employed to pretreat the bamboo powder to partially remove lignin. Then, the pretreated bamboo powder was esterified by one-step maleic anhydride (MAH) esterification to produce maleic anhydride-esterified LCNF (MLCNF). MLCNF exhibits a high aspect ratio (337), fine diameter (4.6 nm), and high surface charge (1.67 mmol/g). These properties endow MLCNF bioplastics with excellent wet elongation at break (41 %, significantly higher than other cellulose-based bioplastics), wet tensile strength (43.5 MPa), wet toughness (9.8 MJ m −3 ), dry tensile strength (164 MPa), dry toughness (15.7 MJ m −3 ), thermal stability, hydroplastic properties, and water stability (water contact angle: 91°). This research provides a straightforward, eco-friendly, and efficient approach for developing bioplastics with excellent wet mechanical properties and water stability using renewable lignocellulosic resources, with the potential to replace petrochemical plastics.