Moisture-triggered release of self-produced ClO2 gas from microcapsule antibacterial film system
In this study, a novel chlorine dioxide (ClO 2 ) microcapsule with a performance of moisture-triggered release was fabricated followed by the mixing with polylactic acid (PLA) for the preparation of an antibacterial packaging film. ClO 2 microcapsules were first prepared by encapsulating stable ClO 2 solution (NaClO 2 as the main component) in a PLA shell, and the resulting microcapsules together with tartaric acid were applied as antibacterial components for antimicrobial PLA film using solvent casting method. The impact of ClO 2 microcapsules on the antimicrobial effectiveness, oxygen and water vapor barrier properties, mechanical behavior, and thermal stability of PLA films was investigated. The results showed that the addition of ClO 2 microcapsules at a concentration of 20% imparted PLA films excellent antimicrobial properties with a growth inhibition of Escherichia coli and Staphylococcus aureus by 4.95 log CFU/mL and the antibacterial rate was 99%. Furthermore, the tensile strength of the films with ClO 2 microcapsules at a concentration of 20% was 21.20 MPa, which was 19% higher than that of the PLA film without microcapsules. The oxygen and water vapor transmission rates reached 2800 cm 3 m −2 24 h −1 and 20.00 g m −2 24 h −1 , respectively, and the barrier properties were improved by 20 and 36.14%. Thermogravimetric analysis showed that the generated film was stable before 193 °C. Scanning electron microscopy analysis confirmed a good compatibility between the ClO 2 microcapsules and the PLA matrix, and the emerged voids indicated the generation of ClO 2 and its release from the antimicrobial film. An obvious sustained release of ClO 2 from the antimicrobial film completed until 240 h. The release behavior fitted the logistic model, and the release mechanism followed the S model. This study may provide a feasible approach for the development of food packaging materials with efficient antibacterial activity and sustained-release performance.
危险品化学品经营许可证（带存储）