Study On The Poly(Vinyl Alcohol)/Montmorillonite/Titanium Dioxide Composite Films

Polymer Matric Nanocomposites (PMN) have been widely studied in packagingfield in recent years because of its amazing performances in mechanical, thermal,optical, anti-aging and anti-bacterial compared to pure polymers or conventionalcomposites. In order to improve the properties of the packaging materials, thepreparation, characterization, physical-chemical properties and anti-bacterial ofPoly(Vinyl Alcohol)/Montmorillonite/Titanium Dioxide (PVA/MMT/TiO₂) compositefilms were studied in this paper, with its main working as follows:First, PVA/MMT/TiO₂ composite films were prepared directly from PVA solution,MMT aqueous suspension and TiO₂ sol by solution intercalation and sol-gel process.The fracture morphology, molecule structure and thermal properties were investigatedby SEM, FTIR and TG-DSC respectively. The SEM images showed that MMT andTiO₂ particles are well dispersed in the Poly(Vinyl Alcohol). The IR results revealedthat, net-structure was formed after MMT and TiO₂ composing with PVA, whichindicated that MMT and TiO₂ had been successfully dispersed in PVA matrix. TheTG-DSC results showed that, the thermal performances of composite films haveincreased greatly as the synergistic effect of the two inorganic particles.Second, TiO₂ mass fraction, pH, stirring time and reaction temperature werestudied to optimize the preparation conditions of the PVA/MMT/TiO₂ composite films.The mechanical test showed that, when the TiO₂ mass fraction is 1.0% and MMT massfraction is 3.0%, the tensile strength of PVA/MMT/TiO₂ composite films increased 49.46% than that of pure PVA films. The right elastic modulus and angle tearingstrength are 1.8 and 1.4 times as high as that of pure PVA films respectively. Theelongation rate decreased from 329.33% to 181.15%. The light transmittance resultsshowed that different wavelength ultraviolet radiation. transmittance kept between50%-60%, and the visible light transmittance were high. The water absorbing rateincreased firstly and then reached to 236.77%. The water vapor transmittance of thePVA/MMT/TiO₂ composite films was 3.05 g/(h·m²), and decreased 57.64% than thatof pure PVA films. The oil transmittance of the PVA/MMT/TiO₂ composite films keptin about 0.0216%.Finally, the aging and anti-bacterial properties of PVA/MMT/TiO₂ compositefilms were also studied. The results showed that, after aging, the physical-chemicalproperties of PVA/MMT/TiO₂ composite films were reduced. But its properties werealso better than others because of the synergistic effect of MMT, TiO₂ particles. Theanti-bacterial test revealed that MMT, TiO₂ particles can kill some bacterias.