Eco-friendly methylcellulose/zinc alginate film with multi-function properties: thermal stability, flame retardancy...

The purpose of this study was to synthesize crosslinked films from methylcellulose (MC) and sodium alginate (SA) using a straightforward ion exchange technique in a ZnCl₂ coagulation bath. The resulting MC/ZA blend films exhibited significant improvements in thermal stability, with a measured increase of 191 °C in degradation temperature compared to MC film. The introduction of zinc ion (Zn²⁺) enhanced the flame retardancy of MC/ZA film, achieving a 92.4 % reduction in flammability. The microstructure of the MC/ZA blend film displayed a relatively smooth surface, indicating better biocompatibility between MC and ZA. Additionally, the barrier property of the MC/ZA film was improved, with a 35 % reduction in permeability to water vapor, and the mechanical properties were strengthened, showing a slightly reduction of 5 % in tensile strength. Furthermore, the MC/ZA blend film demonstrated enhanced antibacterial effectiveness, with a 99.99 % of S. aureus and E. coli, implying their suitability for packaging applications involving high oil content foods.