Papers by Keyword: Silica Sphere

Abstract: Silica sphere has wide applications not only in the field of physical chemistry dealing with dynamic behavior and stability of particulate systems, but also in industries including catalysts, ceramics, pigments, pharmacy, etc. However, the control on the particle size is a key factor in the preparation process of silica sphere. In this paper, silica sphere with uniform sphere morphology and amorphous structure was prepared by a sol-gel method, and the control of particle size was emphatically studied. The results showed that the particle size of the as-prepared silica sphere was obviously influenced by the raw materials concentration. The average size of the product increased from 0.66 μm to 0.90 μm when ethanol concentration increased from 7.14M to 9.55M, increased from 0.50 μm to 0.90 μm with the increase of ammonia concentration in the range of 1.88M to 2.36M, and increased from 0.47 to 0.90 μm while tetraethoxysilane concentration increased from 0.08M to 0.11M. Further study indicated that the silica particle size was also influenced by reaction temperature, it increased with the increase of temperature from 26°C to 28°C, and decreased with the further increase of temperature in the scope of 28°C to 32°C.

Abstract: A neotype of silica microspheres were synthesized with chloropropyltrimethoxysilane (WD30) and tetraethoxysilane (TEOS) by sol-gel method. And the thermal properties of the filler both in nitrogen and in air condition were studied by means of thermogravimetric analysis. The morphology of the filler was measured by TEM. The so synthesized spheres were added into the silicone rubber whose mechanical strength was increased greatly. The molecular structure of the filler and the silicone rubber were characterized by FTIR. The possible strengthen mechanism of the filler was discussed. The neotype silica sphere researched in this paper could react with the PDMS chains which perfects the vulcanization of the silicone rubber. This kind of silica sphere exhibits many merits for usage as filler.

Abstract: A new kind of silica microspheres were first synthesized with chloropropyltrimethoxysilane (WD30) and tetraethoxysilane (TEOS) by sol-gel method. And hybrid membrane was prepared by incorporating the as prepared filler into polydimethylsiloxane (PDMS). The IR, swelling density(Dsw) and mechanical properties of these composites membranes were studied by means of IR analysis and tensile testing. The experimental results showed that both mechanical properties of these composites were significantly improved by using the as-synthesized filler. The filler synthesized in this research not only increased the volume and reduce the cost of HPDMS, but also reacted with the PDMS. The vulcanztion density was increasedwith the interaction between the filler and the PDMS chains. This new kind of silica microspheres is an effective reinforcement filler for PDMS composite.

Abstract: A neotype of silica microspheres were synthesized with dodecyltrimethoxysilane (WD10) and tetraethoxysilane (TEOS) by sol-gel method. The molecular structure was characterized by FTIR. The morphology of the filler was measured by TEM. And the properties of the filler such as thermal property and bulk density were studied by means of thermogravimetric analysis and densimeter. The effect of the schemes was dicussed. This kind of silica sphere exhibits many merits for usage as filler.

Abstract: A new kind of silica microspheres were first synthesized with dodecyltrimethoxysilane (WD10) and tetraethoxysilane (TEOS) by sol-gel method. And hybrid membrane was prepared by incorporating the as prepared filler into polydimethylsiloxane (PDMS). Thermal degradation and mechanical properties of these composites membranes were studied by means of thermogravimetric analysis and tensile testing. The experimental results showed that both mechanical properties and thermal stabilities of these composites were significantly improved by using the as-synthesized filler.

Abstract: The novelty of the current work lies in the simple synthesis of a new class of monodisperse, luminescent silica spheres produced upon calcination of hybrid amine-functionalized silica spheres which can known the role of ethylenediamine (en) on the morphology and luminescence properties of the resultant silica spheres.

Abstract: Monodispersed silica spheres have attracted much attention because of their widely applications in the areas of catalysis, adsorption, chromatography packing materials and advanced ceramics. This paper focused on its application as a packing material of function coatings for space applications. Nanosized monodispersed silica spheres can be fabricated by Stöber method. However, microsized monodispersed silica spheres are not easy obtained. In this paper monodispersed silica spheres with the size between 200nm to 2000nm were fabricated by hydrolysis of tetraethoxy silane (TEOS) in isopropyl alcohol solvent and using ammonia as catalyst through multi-step growth method. The influence of silica seed number density and TEOS concentration on monodispersity and size of silica sphere were studied. The result shows that monodispersed silica spheres could be obtained through control the concentration of TEOS and the silica seed number density during every growth step. The diameter of monodispersed silica spheres increased with the steps of growth.