Preparation and Properties of Cellulose/Chitosan Transparent Films

Cellulose films with antimicrobial activity and high gas barrier properties are successfully prepared by a facile surface coating chitosan approach. The cellulose wet film was prepared from an ionic liquid (IL), 1-allyl-3-methylimidazolium chloride (AmimC1) by coagulating in water. After that, the cellulose film was immersed in the chitosan-acetic acid solution with different concentrations for 2 h, and then dried in air for 24 h. Via this method, most chitosan was distributed in the surface of cellulose film, which was demonstrated by SEM-EDX, and the film had good hydrophobicity and antimicrobial activity. Scanning electron microscope images indicate that the thickness of chitosan layer on the cellulose films is in the range of 1. 31 mu m to 4. 07 pm, which can be controlled by the concentration of chitosan. FTIR and TG results demonstrate that there is hydrogen bond interaction between cellulose and chitosan. Besides this, SEM images displayed a homogenous and smooth morphology, indicating a good compatibility between cellulose and chitosan. The optical transmittance of the blend films was maintained well compared with the cellulose film reaching 80% transmittance at 600 similar to 800 nm owing to the low thickness of chitosan layer. Due to the interaction between chitosan and cellulose, the blend films have good mechanical properties, their tensile strengths are greater than 110 MPa. Their oxygen permeability results showed that the blend films had high gas barrier capacity, exceeding the ideal commercial oxygen barrier material ethylene-vinyl acetate copolymer (EVA). The cellulose/chitosan blend films showed effective antimicrobial capability against Staphylococcus aureus examined by the antimicrobial test. The obtained results indicate that the cellulose/chitosan blend films may be suitable for use in the food packaging fields.