Preparation, characterization and antibacterial properties of cyanoethylchitosan/cellulose acetate polymer blended films

Modification of chitosan (CS) by means of blending with other polymers is a convenient method to improve its physical properties for practical utilization. The similarity of cellulose and chitosan in primary structures might facilitate the formation of homogeneous films. Mixing cyanoethylchitosan (CECS) with cellulose acetate (CA) overcomes mechanical weakness of CS films. CECS is prepared by reaction of chitosan with acrylonitrile in the vapour phase under a different reaction conditions, namely, sodium hydroxide concentration and reaction period. Blended films of CECS and CA are made by casting from dimethylformamide (DMF) followed by impregnation in water. CECS/CA films obtained are characterized by nitrogen content, tensile strength, elongation at break, FTIR and thermogravimetric analysis (TGA). Antibacterial activity of films prepared against Gram (−ve) and Gram (+ve) bacteria is measured via both disk diffusion method and bacterial count method. Blended films show good antibacterial effects toward Gram (+ve) bacteria than Gram (−ve) ones. Antibacterial activities of blended films increased by increasing the CECS percent in the blended films while the tenacity of these films gradually decreased. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) show that CECS possesses higher effect on Gram (+ve) bacteria Staphylococcus aureus than Gram (−ve) bacteria Escherichia coli. In the meantime, CECS is much more powerful in inhibition of bacteria than CS itself.