The Effects Of SiO₂ Nanoparticles Addition On The Starch Films And The Mechanism Analysis

In this study, the properties of starch film improved by SiO2 Nanoparticles. And the mechanism of improving the tensility, the wearing resistance and the flexibility resistance by adding SiO2 Nanoparticles were studied through the experimental analysis in this paper.The films were added with the disperse SiO2 Nanoparticles which were mixed with starch. The mechanical properties of these films were measured using a wear tester and a universal material testing machine. Then the result showed that the mechanical properties of the film increased rapidly with the addition of the SiO2 Nanoparticles below the critical value, and then enhancement ratio decreased above the critical value. And the best mechanical properties of the film was achieved when the content of SiO2 Nanoparticles was about 3～4%.The mechanism of improving the mechanical properties of the film by adding SiO2 Nanoparticles were analyzed by the sophisticated apparatus. Such as, the microscopic view of the film was observed with Scanning Electronic Microscope, Atom Force Microscope and High Magnification Optical Microscope; The chemistry character of the film were analyzed with the Infrared Spectrum; The thermal properties were analyzed with the Differential Scanning Calorimetry and Thermogravimetry Analysis; The crystallographic structures were analyzed with the X-ray diffraction analysis. The research show than the test result was consistent with the theoretical analysis. On the base of this, the effect of SiO2 Nanoparticles'dispersion on Mechanical Property of the films had been studied.The test adopted the content of SiO2 Nanoparticles was 3% and kept the others conditions constant which included ultrasonic frequency, ultrasonic efficiency besides the disperser time was delaying, and the SiO2 Nanoparticles'diameter had been tested with the Atom Force Microscope and Transmission Electronic Microscope. The results showed that the SiO2 Nanoparticles'diameter decreased with the ultrasonic disperse time delaying. The best dispersion of SiO2 Nanoparticles was made and its diameters were kept about 60nm when the ultrasonic disperse on time was arriving about 50 minute.At the same time, mechanical properties of the films were affected by the SiO2 Nanoparticles'dispersion. In good dispersion condition, the films filled with small-size particles revealed higher mechanical properties than those filled with large-size particles.