Alkali lignin mediated chitin self-assembly for constructing a fully naturally resourced bioplastic

Exploring green and sustainable alternative materials to address the growing environmental issue caused by petroleum-based plastics has led to increasing attention for the development of degradable bio-based plastics. The synthesis of bioplastics with high strength and toughness still faces a big challenge. Herein, we report a full noncovalent mediated self-assembly strategy for simultaneously improving the strength and toughness of chitinbased bioplastics via plane hot-pressing. The alkali lignin (AL) is introduced to enhance the strength and toughness of the chitinous bioplastics via forming multiple noncovalent interactions with chitin chains. The incorporated dense noncovalent networks and the pressure induced orientated nanofibers significantly enhanced the mechanical properties of the chitinous bioplastic, achieving a tensile strength of 159.0 +/- 2.1 MPa and Young's modulus of 8.4 +/- 0.2 GPa at 58 % relative humidity. The alkali lignin improved the moisture stability of the chitinous bioplastic. Moreover, the chitinous bioplastics exhibited superior welding ability, solvent resistance, good UV shielding capability and biodegradability in nature, which demonstrates the developed fabrication design of chitinous bioplastics provides a promising concept for preparing the alternative materials to replace traditional plastics.