Hemicellulose additive to chitosan-based bioplastic improved the tensile strength and allowed to control the material swelling

This study assessed bioplastics made from different mass proportions of commercial chitosan and banana plant pseudostem-derived hemicelluloses. The bioplastics were prepared by the casting method and characterized for moisture content, water solubility, opacity, water absorption, tensile strength, and thermogravimetric properties. The formulations with hemicelluloses addition showed higher moisture content and water solubility than the chitosan-only bioplastic, the maximum values of these properties (22.3 and 22.4%) were achieved when hemicelluloses were added at the proportion of 10 and 5%, respectively. A positive linear correlation (r = 0.86) was found between added hemicelluloses and opacity, with the highest opacity (1.95 mm-1) achieved in the formulation with the maximum hemicellulose incorporation. The bioplastics containing hemicelluloses exhibited lower swelling (water absorption) than that made only of chitosan, with the formulation featuring the highest hemicelluloses content showed the lowest swelling (229.2%). A negative linear correlation (r = 0.95) was observed between added hemicelluloses and swelling values. The formulation with the highest hemicelluloses content demonstrated statistically significant differences and exhibited the highest tensile strength (18.7 MPa) and Young's modulus (66.1 MPa). Thermogravimetric analysis revealed four stages of mass loss in the bioplastics. Hemicelluloses addition decreased the temperature at maximum mass loss, and the formulation with the lowest hemicelluloses content showed a higher degradation rate than the others.