Esterification modified corn starch composite with chitosan and PVP for enhanced mechanical properties and antimicrobial freshness preservation of starch-based films

Traditional plastic packaging films may bring convenience to people, but may also bring fossil energy shortage and pollution problems. Thus, it is of great research significance to use renewable resources to develop biodegradable green packaging materials instead of traditional petroleum-based film materials. In this study, aryl esterified starch was prepared by graft modification of corn starch using acryloyl esterification. Then ES/CS/PVP composite film materials were prepared by introducing chitosan and polyvinylpyrrolidone (PVP) from esterified starch. Chitosan and PVP were introduced to greatly improve the antimicrobial and mechanical properties of the composite film. And the chemical structure and microscopic morphology of ES/CS/PVP were characterised by FT-IR, XRD, SEM and XPS. The results showed that the ES/CS/PVP composite film had excellent tensile properties and good antimicrobial freshness preservation properties. The maximum tensile strength reached 51.69 MPa and the water vapour permeability was 4.76 × 10−5 g/mm∙d. The results of antimicrobial freshness preservation experiments show that the composite film has excellent antimicrobial freshness preservation performance, enough to keep cherries with good freshness in 6 days.