Improved flame retardancy and mechanical properties of bacterial cellulose fabrics via solvent exchange and entrapment of zein and gluten

This study aimed to improve the flame retardancy and mechanical properties of bacterial cellulose (BC) by introducing cereal proteins, namely zein and gluten. The production conditions were determined by observing residual masses of samples at 1000 ℃ using thermogravimetric analysis (TGA). According to the TGA results, the optimized production conditions for the BCs with zein and gluten were combined solvent exchange and entrapment of 20 weight% (wt.%) of zein, and entrapment of 40 wt.% of gluten, respectively. Surface characterization of BC prepared with zein and gluten under the optimal conditions confirmed that the cereal proteins were incorporated into the BC nanostructures via solvent exchange and/or entrapment and the original chemical and crystal structures of BC were not significantly changed. Limiting oxygen index (LOI) analysis confirmed that cereal proteins improved the flame retardancy of BC. In particular, the LOI of BC entrapped with gluten was 50%, which was better than that of cowhide leather. Char morphology analysis confirmed that the as-produced BCs with cereal proteins exhibited condensed-phase flame-retardant mechanism by forming intumescent chars. Analysis of the mechanical properties confirmed that compared with cowhide leather, as-produced BCs with cereal proteins possessed high tensile strength and dimensional stability, making them suitable leather substitutes.