Rutile TiO2 integrated zwitterion polyurethane composite films as an efficient photostable food packaging material

Abstract

Zwitterion polyurethanes (ZPU) are used for non-fouling and antimicrobial surfaces but their sensitive nature under ultra-violet (UV) radiations limits the requirements of engineering materials. Herein, ZPU is successfully synthesized and then prepared different TiO2/ZPU composites, aiming to increase the service life of ZPU and to form active film for food packaging applications. The thermo-mechanical results revealed that the 4% TiO2/ZPU sample exhibits better performance, as evidenced through tensile testing and surface morphology analysis. The UV–Vis spectra results indicated that the rutile TiO2 nanoparticles can enhance the UV absorption and visible light reflectance, decreasing photoaging properties of composites thereby prolonging its shelf life. Moreover, scanning electron microscopy (SEM) observation after 5 h irradiation of UV light confirmed the photostability of TiO2/ZPU composite film. Further, the antioxidant ability of ZPU is increased from 51% to 71% with TiO2. The results of antimicrobial activity of TiO2/ZPU demonstrate strong bacterial growth inhibition against E. coli that regards its suitability for food and other packaging applications. Besides, the food preservation ability is monitored by visual changes of tomato fruit. In essence, we anticipate that the TiO2/ZPU composite films possessed all expected features to be considered as photostable material for food packaging.