Research On Graphene Oxide/Polyvinyl Alcohol To Improve Barrier Properties Of PLA Film

With the increasing of white pollution and constantly consumption of non-renewable resources, like oil, preparation of new type of biodegradable packaging materials has become the hotspot in packaging field to replace the traditional packaging materials. Polylactic acid film is a kind of biodegradable and environmentally friendly aliphatic polyester polymer materials, but the barrier property is poorer, restricting the applications in the field of packaging. Graphene oxide is a single layer of graphite oxide layer, preparing by mechanical stirring and ultrasonic dissection. The structure of graphene oxide is similar to graphene, having plane and two-dimensional layered structure. Graphene oxide layer structure has excellent gas barrier performance, therefore graphene oxide layer be able to effectively improve membrane performance, through the deposition on the polylactic acid.In this paper, we use the hydrogen bonding interaction between graphene oxide and PVA molecules through the self-assembly layer by layer on the polylactic acid film, to improving the barrier property of the polylactic acid film.By improving the Hummers method, we can preparation stable dispersed graphite oxide in water solution. Using the hydrogen bonding interaction between graphene oxide and PVA molecules through the self-assembly layer by layer on the polylactic acid film, to preparing multila yer block structure of(GO/PVA)n. Through the FT-IR, XRD, TEM and AFM succeeded in characterization of graphene oxide that we prepare by ourselves. By contact Angle test, AFM and ultraviolet spectrum, tracking shows that the multilayer structure of(GO/PVA)n has been formed on the surface of the polylactic acid film. By blocking performance tests show that the multilayer structure of(GO/PVA)n has very obvious effect on Oxygen barrier property. When the number of layer is 40, the concentration of GO is 1mg/ml and the concentration of PVA is 1wt%, the Oxygen barrier property of the polylactic acid film was the lowest, reduced by 99.58% compared with the original film; and the light performance was reduced by 54.84% compared with the original film; At the same time the polylactic acid film has good mechanical properties. Unlike oxygen barrier property, When the number of layer is 40, the concentration of GO is 0.5mg/ml and the concentration of PVA is 1wt%, the water vapor transmittance of the polylactic acid film was the lowest, reduced by about 42.31% compared with the original film.In order to further improve the water vapor barrier properties of the polylactic acid film, the FAS was carried out on the assembly polylactic acid film surface modification after we have the basis of previous research. After surface modification, we are able to effectively reduce the water vapor transmittance, by reducing the adsorption of water molecules on the polylactic acid film surface. Through the image of AFM and the surface contact Angle, we can observe that the surface roughness and the contact Angle are increased, the contact Angle increased from the original 48.1 ° to 94.5 °, increasing the surface hydrophobic. When the number of layer is 40、the concentration of GO is 0.5mg/ml and the concentration of PVA is 1wt%, the water vapor transmittance of the modified polylactic acid membrane film was the lowest, reduced by about 56.07%compared with the original film, further increased by about 13.76%.