Preparation and characterization of a biodegradable starch-based antibacterial film containing nanocellulose and polyhexamethylene biguanide

The starch-based composite antibacterial films were successfully prepared by the method of casting using nanocellulose as the reinforcing material and polyhexamethylene biguanide (PHMB) as the antibacterial agent. The morphology and properties of the starch-nanocellulose (S-N) films and starch-nanocellulose with PHMB (S-N-P) films were explored. When the content of nanocellulose and PHMB was 5% (wt%) and 6% (wt%), respectively, the S-N-P composite film had excellent properties. FT-IR analysis showed that both PHMB and nanocellulose molecules had successfully entered the starch matrix, forming a stable composite film. Thermogravimetric analysis of the S-N-P composite film showed that the film with PHMB added had greatly thermal stability, indicating that the S-N-P composite material with PHMB had good heat resistance. The addition of PHMB and nanocellulose can enhance the mechanical properties, indicating composite films can be used as a good food packing material. In addition, when the content of PHMB was higher than that of 6% (wt%), the S-N-P composite film shows an excellent antibacterial activity against Escherichia coli. This research provides a bright prospect in the application of food preservation by using the biodegradable antibacterial film.