Effect of ultra-high pressure treatment on the functional properties of poly (lactic acid)/ZnO nanocomposite food packaging film.

BACKGROUND At present, our living environment is increasingly polluted by petroleum-based plastics and there is an increasing demand for biodegradable food packaging. In this study, the effect of different ultra-high pressure (UHP) treatment (0, 200, and 400 MPa) on the microstructure, thermal property, barrier property, and mechanical property of poly (lactic acid) (PLA)/ZnO nanocomposite films was studied. RESULTS The film-forming solution was processed by UHP technology. The crystallinity, strength, and stiffness of the composite film after UHP treatment increased. In addition, the barrier property analysis showed that the UHP treatment significantly (p<0.05) reduced the oxygen permeability (OP) and water vapor permeability (WVP) coefficient of the PLA/ZnO nanocomposite film. Furthermore, the WVP value of the 400 MPa treated film (50 g kg-1 nano-ZnO content) was the lowest and reduced by 47.3% compared with that of pure PLA film. The improvement in these properties might be due to the interaction between nano-ZnO and PLA matrix promoted by UHP treatment. CONCLUSION Therefore, the application of UHP technology on the film forming solution could improve the crystallinity and functional properties of the nanocomposite film, and has great potential in producing food packaging films with ideal functions. This article is protected by copyright. All rights reserved.