High Toughness Composite Films Produced From Zein and Bamboo Fibers Based on Incorporating Biochar: Effects of Alkali Treatment

Aiming at the problems caused by the large-scale use of non-degradable plastic films, new degradable zein composite films are developed with natural fibers based on incorporating biochar. Bamboo fibers were as raw materials to prepare biochar under 500°C and alkali treated bamboo fibers under three NaOH concentrations (2%, 4%, and 6%). The results indicate that better compatibility of zein composite films was achieved due to the reduction of polarity and the increase of roughness by alkali treatment shown in the results of XRD, FTIR, SEM, and contact angles. TGA and DSC show that adding alkali treated bamboo fibers delayed the thermal decomposition rate, increased the thermal denaturation temperature, and thereby improved the thermal properties of zein. A maximum of tensile properties with 0.19 MPa tensile strength, 4.50 MPa tensile modulus, and 331.67% elongation at break was reached at the resultant composite film of 2% concentration alkali treated bamboo fibers.