A facile preparation and characterization of a sustainable and superhydrophobic carboxymethyl cellulose/ZnO composite film

This study sought to develop a biodegradable material that can be a substitute for conventional plastics and is sustainable and eco-friendly. The research’s primary focus was the conversion of carboxymethyl cellulose (CMC) derived from agricultural waste into a bioplastic film that is satisfactory for use in packaging. The weak mechanical stability and excessive water sensitivity of CMC films limit their widespread use. To overcome these limitations, therefore, CMC films were reinforced with varying concentrations (0, 5, 10, 15, 20, and 25%) of zinc oxide nanoparticles (ZnO NPs), using a solution casting method. The films were also surface-modified by spray coating with a 1:1 composite mixture of poly(dimethylsiloxane) (PDMS) and starch. An array of analyses were used to investigate the films’ properties. Structural characterization employing Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed the successful incorporation of ZnO and uniformity of PDMS/starch coating on the films. Thermogravimetric analysis (TGA) and mechanical testing revealed that the films’ thermal and mechanical properties were improved by the incorporation of ZnO, with the film CZ₂₀-C exhibiting the highest value of tensile strength––14.029 MPa––and 27.59% elongation at break. The films exhibited excellent water resistance, as evidenced by a remarkable increase in their water contact angle to 152.04°. Furthermore, biodegradability studies demonstrated that the films degraded by 84.78% in soil within 20 days, under ambient conditions. Films with these desirable characteristics are therefore producible through the study’s facile strategy for preparing CMC-based eco-friendly composite films that have excellent potential to replace conventional plastic in the packaging industry.

Graphic abstract