Development of citric acid crosslinked biodegradable chitosan/hydroxyethyl cellulose/organo-modified nanoclay composite films as sustainable food packaging materials

Chitosan/hydroxyethyl cellulose-based sustainable food packaging composite films (CS/HEC/NC) crosslinked with citric acid (CA) and containing organophilic nanoclay were prepared using the solvent casting method. The physical, thermal, mechanical and barrier properties of as-synthesized composite films were evaluated toward their use as an alternative to petroleum-based polymers. A considerable improvement was observed in surface hydrophobicity, water resistance, barrier properties, tensile strength, and thermal stability of the composite films with increasing nanoclay ratio. CS/HEC/NC3 film loaded with 5 wt% nanoclay exhibited the best physical properties with percent enhancements of 22.94°C, 52.56% and 36.53° in maximum degradation temperature, tensile strength, and water contact angle, respectively, over the neat CS/HEC film. In addition, low permeabilities against water vapor (1.240 × 10−11 gs−1m−1Pa−1) and oxygen (1.12 × 10−16 m3s−1m−1Pa−1), and also strong antibacterial activity against Staphylococcus aureus and Escherichia coli were obtained for this film. The food preservation effects of CS/HEC/NC composite films against cherry tomatoes were also studied, and less than 20% mass loss was achieved in five weeks. Consequently, CS/HEC/NC composite films can be considered competitive packaging materials with great potential to improve safety and quality and extend the shelf life of packaged foods.