Nano-Silica Modification Of Polypropylene On Reducing Residual Solvents

Research about reducing residual solvent of food flexible packaging hasrecently become a hot spot with more and more attention and requirement onfood security. Polypropylene membrane, as a widely used food packagingmaterial, has the function of low temperature resistant, high stiffness, high heatresistance, corrosion resistance and excellent optical property. Polypropylenemembrane was modified by nano-silica in this paper, to obtain a newcomposites material and improve its crystallinity on the premise of keepingpolypropylene membrane’s thermodynamic properties, barrier properties,printability. The free volume between molecular chains could be decreasedand the solvent from printing ink could hardly residue and migrate on thesurface of modified polypropylene membrane. As a result, we can achieve ourspurpose of reducing residual solvent. This was the innovation of this paper andprevious studies have shown that this method is entirely feasible with highscientific value.Modified polypropylene membrane was prepared with nano-silica contentof0、0.02%、0.03%、0.06%、0.09%, respectively. Its microstructure,thermodynamic properties, barrier properties, printability, free volume andsolvent residual were studied.Results show that the grain size in modified polypropylene membranedecrease and crystallinity increase. Intensive analysis had been done on thedata of free volume and solvent residual and we found that the adding ofnano-silica can effectively reduce the free volume, and decrease theadsorption and diffusion of solvent on the surface of membrane, so to achieveour aim of reducing residual solvent in packaging material.