Papers by Keyword: Aerogel

Abstract: The technology of producing nano material by diisopropylamine as a replaced drying solvent has been studied．The products of Al(OH)₃ and SiO₂ are found to be amorphous aerogel．The nano particle of TiO₂ produced by it is found to be smaller than that produced by n-butyl alcohol as a replaced drying Solvent．

Abstract: Attapulgite fiber-aerogel composite was synthesized using sol-gel technology combining with surface modification and conventional drying to overcome the brittle disadvantage of traditional aerogel. Attapulgite fiber was added in the process of sol into gel, in order to enhance the mechanical property of SiO2 aerogel. Hydrophobic and low density fiber-aerogel composites were obtained in this experiment. Investigation of the removal of attapulgite reinforced SiO2 aerogel to TPH in water under low temperature was also carried out. The results showed that the attapulgite fiber-aerogel composites we obtained in this study had good performances of mechanical and hydrophobic properties; the removal rate of aerogel to TPH was 91.02% under the temperature of 10°C.

Abstract: The technology of using diisopropylamine as a replaced drying solvent preparing for nano material has been studied．The products of Al（OH）3 and SiO2 are found to be amorphous aerogel

Abstract: Using sodium tungsten and industrial water glass as raw materials, SiO₂-WO₃ composite aerogels were prepared by ambient pressure drying process. The hexamethyldisilazane(HMDSZ)/hexamethyldisiloxane(HMDSO)/hexane mixing solution was used to modify the sol-gel-derived SiO₂-WO₃ wet gel. The microstructure, morphology and pore characteristics of the obtained SiO₂-WO₃ composite aerogels were investigated by XRD, SEM, FTIR and BET N2 adsorption-desorption analysis. The adsorption/photocatalytic degradation for Rhodamine B of SiO₂-WO₃ composite aerogel was investigated. The results indicate that mesoporous SiO₂-WO₃ composite aerogel with specific surface area 660.8 m²/g and pore volume 1.94 cm³/g could be prepared by using HMDSZ/HMDSO/hexane mixing solution to modify the wet gel. The obtained SiO₂-WO₃ composite aerogels have good adsorption/photocatalytic degradation for Rhodamine B than that of pure WO₃ aerogel.

Abstract: In this paper, TiO₂-SiO₂ composite aerogels were prepared via ambient pressure drying by sol-gel and sol pre-modification method. The pre-modification solution consists of hexamethyldisiloxane (HMDSO) as buffering agent, trimethylchlorosilane (TMCS) as modifier and hexane as organic solvent. The pore structure of TiO₂-SiO₂ composite aerogels was characterized by N₂ adsorption-desorption method. The effects of HMDSO/TMCS volume ratio on the pore structure and properties of TiO₂-SiO₂ composite aerogel were studied. The results indicate that the pre-modification of TiO₂-SiO₂ composite sol by adding HMDSO/TMCS/Hexane solution could shorten the preparation period. Increasing the amount of HMDSO is favorable for obtaining TiO₂-SiO₂ composite aerogel with higher specific surface area and pore volume. The best volume ratio of HMDSO/TMCS/composite sol for preparing mesoporous TiO₂-SiO₂ composite aerogels were 12:6:120 and 12:12:120, with which the specific surface area and pore volume of the obtained TiO₂-SiO₂ composite aerogel are 425.2～645.4 m²/g and 0.80～2.85 m³/g, respectively.

Abstract: The zinc-based aerogel was synthesized via a sol-gel route that it was processed using Zinc chloride as precursor, polyacrylic acid as the template and propylene oxide as the gelation agent. The Zn-based aerogel is formed the length and cross-link of the zinc chloride hydroxide chain, owing to a dominant influence of PAA on the nucleation and growth position of sol nucleus. Nevertheless, ZnO aerogel was prepared with the method that the zinc-based aerogel was calcined at 400°C. Consequently, the R_WP value was in reasonable 7.35% according to X-ray diffraction pattern (XRD) refinement. The crystal system of the ZnO aerogel was monoclinic.

Abstract: The hydrophobic aerogel heating-insulating composite ceramic was fabricated in the way of constant pressure. The properties of the ceramic were attributed through FT-IR and energy spectrum. The microstructure and phase transformation of the insulation composites ceramic was characterized by scanning electron microscopy. The results show that after compositing with aerogel the coefficient of heat conductivity of the heat-insulating ceramic decreases forty-sixty percent and the compressive strength increases a hundred percent. There is little change to the tensile-strength. The holes of the ceramic are full of aero gel particles whose grain size is ten-twenty μm and the distribution of pore size is ten-seventy nm. After heating at 400°C for 12 minutes by quartz lamp on the surface of the ceramic which the thick of it is 8mm, the temperature of the other side increases 10°C .When the thick of the ceramic is 16mm, the temperature of the other side remains unchanged. The ceramic has excellent heating-insulting property.

Abstract: In order to get the perfect thermal protection materials and configuration of the electronic memory the relationship between the object temperature and time during heat transfer and the basic principles of heat and mass transfer for was analyzed. Several kinds of thermal protection structures and materials were simulated by ANSYS 10.0 and validated by experiments. The results demonstrated that nanometer aerogel is a kind of materials when placing it between memory and protective layer, 5 mm thick, makes sure the electronic memory works two hours normally in the environment at 125°C.

Abstract: Aerogel is a highly porous material. It has the best thermal insulation properties in all solid-state materials. This paper carried out a preliminary study to see the influence on efficiency of flat-plate collector used aerogel. Keeping the other parts of flat-plate collector unchange, the aerogel layer is placed between the transparent cover and absorber plate. Through specific calculation, analysed thermal efficiency of this model of flat-plate collector, and compared with the ordinary glass model. The results show that aerogel can greatly improve collector efficiency , as table 1 show the efficiency of aerogel model is 1.66 times higher than ordinary model.

Abstract: This article examines a new lightweight, slim, high energy efficient, light-transmitting, self-supporting envelope system, providing for seamless, free-form designs for use in architectural projects. The system exploits vacuum insulation panel technology. The research was based on envelope components already existing on the market and patents and prototypes built by independent laboratories, especially components implemented with silica gel insulation, as this is the most effective transparent thermal insulation there is today. The tests run on these materials revealed that there is not one that has all the features required of the new envelope model, although some do have properties that could be exploited to generate this envelope, namely, the vacuum chamber of vacuum insulation panels, the use of monolithic aerogel as insulation in some prototypes, and reinforced polyester barriers. These three design components have been combined and tested to design a new, variable geometry, energy-saving envelope system that also solves many of the problems that other studies ascribe to the use of vacuum insulation panels.