Surface Modification Of Titanium Dioxide And Photocatalytic Activity Of Its Coating Film

BOPP film has the advantages of high mechanical strength,non-toxicity,light weight andgood printing performance.It is widely used in the packaging areas offood,cigarettes,candy and others.TiO2 has the pHotocatalytic antibacterial effect which can prolong the shelf life of the food by coating on the BOPP.In recent years,the amount of long-distance transporting fruit and seafood is increasing.The requirements ofpackaging,storage and transportationdemand even higher.This paper systematically studiedthe preparation of titanium dioxide coating film andaimed at the development of effective antibacterial preservative films.In order to prevent the agglomeration of nanometer titanium dioxide in the polyvinyl alcohol solution,we choosed different coupling agents to modified the titanium dioxide.The optimum conditions will be obtained by characterization of lipopHilicity,particle size and Zeta potential.And the structure and properties of the coupling TiO2 will be characterized by transmission electron microscopy and infrared spectroscopy.In the second section,the modified titanium dioxide was dispersed in polyvinyl alcohol and coated on the BOPP film.The pHysical properties of the films were analyzed by micro-gloss meter,friction coefficient tester and haze meter.The pHotocatalytic performance of the coating films were analyzed by antibacterial and pHotodegradation experiments.The preservation effect was tested by the king banana and mango.The result shows that the titanate coupling agent NZD-101 is better than silane coupling agent KH-550in the aspect of titanium dioxide dispersion.The best mass ratio of NZD-101and titanium dioxide powder is 0.3.And in this ratio,TiO2 has good lipopHilicity,particle size and Zeta potential.The 1%TiO2 coating films had a 7.2%increasing of tensile strength,and other performances also improved such as the surface friction performance,permeability and oxygen permeability.The 2%TiO2 coating films had a sterilization rate of 99.2%and best methyl orange pHotodegradation effects,indicating that this ratio has good pHotocatalytic performance.In the fruit preservation,2%TiO2 coating films effectively reduced the browning of banana and mango,and the occurrence of mango anthracnose.And the shelf life of bananas and was lengthened from 3 days to 7 days.The mango also lengthened from 6 days to 13 days.It can be seen that titanium dioxide coating films had good mechanical properties and pHotocatalytic performance,and couldimprove the shelf life of fruit.The Titanium dioxide coating film has great prospects in the food packaging.