Preparation,Modification And Application Of Silica Functional Material Catalyzed By Alkali And Acid

Reaction process and product of sol-gel method under different catalytic conditions have been researched.The transparent silica sol was prepared under acidic condition and the transparent films on the substrate of glass and iron with no cracks was prepared by dip-coating.The study shows that the stability of the sol affects the properties of the films.Films will not crack when the gel time could be controlled in 4-7 days by adjusting the ratio of the sol,adding amount of catalyst and reaction temperature and time.The method and effects of KH 560 on the silica sol have been studied.The results of orthogonal test and the gel time of recording show that the addition of coupling agent has a great influence on the stability of the sol.The gel time sharply reduced when the dosage of KH 560 was improper.At the same time,the infrared spectrum showed that KH 560 was successfully grafted onto the inorganic network of silicon dioxide.However,silica microspheres with different particle sizes was prepared under alkaline condition.Morphology,particle size and distribution of the product are characterized by scanning electron microscopy and dynamic light scattering.It shows that the particle size was to add with the concentration of the TEOS or NH3 increased,but decrease with the temperature increased.And it increases with increasing H2 O concentration and then descends.Monodisperse silica nanoparticles was also synthesized with a higher TEOS concentration at 60 °C and the preparation mechanism was proposed.At the last,the application of the product fabricated under the both conditions was researched.SiC/SiO₂ inorganic-inorganic core-shell composite particles was prepared by sol-gel method.The morphology was observed and the bond strength of the composite structure was discussed qualitatively.