The Research On SiO₂ Nanoparticls Modified Starch

In order to improve the deficient sizing properties of the traditional starch, the starch was modified by SiO₂ Nanoparticles, which own the special structure and performance. Also, the interaction mechanism of the effect of SiO₂ Nanoparticles on the properties of starch film and the sizing performance of starch was investigated.The dispersion method,the sort and consistency of the dispersants were optimized by experiments. It is an effective method that 3% sodium hexametahposphate was added as a dispersant using ultrasonic wave cleaner to disperse the SiO₂ Nanoparticles. And the dispersion properties were analyzed with the dispersion efficiency,particle diameter in the dispersed liquid and the surface traits of the dispersed liquid. At the same time, its stability was discussed.The certain proportion dispersed SiO₂ was added into the starch films to prepare the SiO₂ nanoparticles modified starch. The mechanical properties of these films were measured by a wear tester and a universal material testing machine. The influences of SiO₂ Nanoparticles quality fraction and the its dispersion time on the mechanical properties of the films were analyzed by the Atom Force Microscope, Scanning Electronic Microscope, and High Magnification Optical Microscope and so on. The results showed that the best mechanical properties of composite film were achieved when the quality fraction of SiO₂ Nanoparticles for the 3 to 4 percent was in the composite sizing and ultrasonic intermittently dispersed 50 minutes.Using the self-made SiO₂ Nanoparticles/starch slashed the cotton yarn and T/C yarn by a sizing machine, each performance of the slashed yarns systematically was tested and the influence of the SiO₂ Nanoparticles on the performance of the slashed yarns was analyzed by the Scanning Electronic Microscope, the High Magnification Optical Microscope and so on. The results showed that the slashed yarns had the best performances when the SiO₂ Nanoparticles content was 3% to 4% and the cotton yarn gained the advantage over the T/C yarns.The physical and chemical structure of the SiO₂ Nanoparticles/starch films was analyzed by investigating the influence of SiO₂ Nanoparticles on the acting force between the starch molecules and fiber molecules, and the thermal properties,thermal stability of the films. The mechanism about SiO₂ Nanoparticles modified starch was also discussedIt showed that SiO₂ Nanoparticles modified starch mainly may due to its super surface activity, unique three-dimensional network structure and the small size effect and macro-quantum tunneling effect, which made its surface active hydroxyl easily combined with the hydroxyl existed in the starch and fibre surface. It increased acting force existed in the starch intermolecular, interfibrous, starch and fibre midst, which improved effectively the performance of starch and cellulose fibre and enhanced cohesive strength of the glue starch film,its cohesion and adhesive force significantly. It also improved the starch film forming and its adhesiveness effectively. It played an active part in starch sizing improvement and the slashed yarn's performance when an adequate quality of SiO₂ Nanoparticles dispersed uniformly in the starch.