Research On The Preparation And Properties Of Anti-ultraviolet PVA/nano-TiO₂Composite Film

At present, PE which is main packaging material is used as fruit bag.However, PE film can not completely degrade, that brings serious pollutionto the environment, and is caused by the potential harms to the ecologicalenvironment. Therefore, it is an important direction to use the greenenvironmental protection and biodegradable materials as the preparation offruit bagging. In addition, the excessive use of chlorofluorocarbons lead tothe severe destruction of Ozone layer in recent years, even appeared in theozone hole in the north and south poles. So the shielding effect greatlyweakened to the ultraviolet in atmosphere. According to reports, thesunburn is caused by ultraviolet （<380nm）, which generally leads todegenerate to the cell and stagnate to the physiological metabolism, so theUV shielding materials research has been paid more and more attention.This paper studied the preparation and performance of the anti-ultraviolet PVA/nano-TiO₂composite film. The main content of the thesisis listed as follow: nano-TiO₂graft-modified by coupling agent was used toprepare PVA/nano-TiO₂composite material and the interface structure andthe composites properties were studied. The PVA/nano-TiO₂compositefilm was formed through a solution casting method. The PVA in themembrane is comprised of PVA17-88and PVA17-99, through regulatingthe two ratio to control the amount of air permeability of compositemembrane; UV absorbers affected to the anti-ultraviolet performance ofcomposite film.The results showed that:Nano-TiO₂has better dispersion、compatibilityand interface interaction after being modified by coupling agent, whichenhanced the interaction of hydrogen bonding between the nano-TiO₂andPVA and improved the dispersibility of nano-TiO₂in PVA and theproperties of the composite fim have been improved greatly. KH550is thebest modifier of this system. Through the experiment, the two best ratio is3:7between PVA17-88and PVA17-99.The UV transmittance of thecomposite films with nano-TiO₂was lower than adding UV-531、UV-9andnano-ZnO. Along with the increase of the content of ultraviolet absorber,the UV transmittance of the compound films reduced gradually. Afteradding the inorganic UV absorbers, the Transmittance of the compound films declined, but Haze degree increased. Along with the increase of thecontent of UV absorbers, UV transmittance of composite films graduallyreduced.