Multifunctional Bioplastics Inspired by Wood Composition: Effect of Hydrolyzed Lignin Addition to Xylan-Cellulose Matrices

Multifunctional bioplastics have been prepared by amorphous reassembly of cellulose, hemicelluloses (xylan), and hydrolyzed lignin. For this, the biopolymers were dissolved in a trifluoroacetic acid-trifluoroacetic anhydride mixture and blended in different percentages, simulating those found in natural woods. Free-standing and flexible films were obtained after the complete evaporation of the solvents. By varying xylan and hydrolyzed lignin contents, the physical properties were easily tuned. In particular, higher proportions of hydrolyzed lignin improved hydrodynamics, oxygen barrier, grease resistance, antioxidant, and antibacterial properties, whereas a higher xylan content was related to more ductile mechanical behavior, comparable to synthetic and bio-based polymers commonly used for packaging applications. In addition, these bioplastics showed high biodegradation rates in seawater. Such new polymeric materials are presented as alternatives to common man-made petroleum-based plastics used for food packaging.