| Carbon foam with its low density, excellent thermal properties, good dimensional stability, good thermal shock resistance, processing, and good formability is as an excellent heat-resistant material. In the aspects of thermal materials, filters, electrode material, catalyst carriers, aerospace and other fields it has broad application prospects. The aerogels with ultra-low-density, low thermal conductivity properties, is a great potential for super-insulation material. But as the infrared radiation aerogels completely "transparent", it can not be directly used as insulation material, limiting its practical application.To this end, we plan to fill the the SiO2 aerogels in the internal void of the non-graphitized carbon foam. Compounding two or more insulation materials in accordance with their own characters, exploring a more comprehensive performance, superior, economical and versatile composite insulation material, this is an important trend in the development of insulation materials.In recent years it developed a new carbon foam preparation, that organic polymers as the carbon source, carbon foam is prepared by using the template to better control the product's structure and morphology. We use furfuryl alcohol as carbon, polyurethane foam as templates, obtaining non-graphitized carbon foam though high-temperature carbonization. The product has the properties as three-dimensional mesh opening structure, regular pore structure showing pentagonal dodecahedron shape, pore size distribution in the 500μm-600μm, the very low density (0.02-0.04g/cm3) and high porosity (95～98%). And we investigated the product structure and properties influence with the end of carbonization temperature and time, and impregnated amount by orthogonal design template types in the present experimental conditions. Finally we get the optimum preparation parameters of carbon foams. The RVC we obtained is amorphous carbon structure in which carbon atoms in the aromatic plane is completely irregular turbulent structure form X-ray diffraction (XRD) and Raman spectroscopy (Raman) analysis. As the temperature rised and holding time increased the degree of carbonization of carbon foam goes up and graphite-like microcrystalline grows up from the internal of cell wall structure making the carbon structure more regular. Mechanical properties and thermal insulation performance of the products were tested. It indicates that the compression failure mechanism is brittle fracture pressure loss. The product has good performance in the thermal insulation, temperature reached nearly 400℃on hot surface, grim remains in the near 80℃.We prepared SiO2 aerogels by sol-gel process with TEOS as silica source, distilled water as raw materials, ethanol as solvent, hydrochloric acid and ammonia as catalyst. With the carbon foam to be impregnated in sol-phase of SiO2 aerogels and after drying, we get SiO2/RVC insulation composite material. We analyze the phase composition of SiO2 aerogels by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD), test the physical and mechanical properties, discuss the reaction mechanism of the sol system and the mechanism of composite insulation of SiO2/RVC insulation composite material. Conclude that the density and compressive strength are dependent on the physical properties of carbon foam skeleton, the density and compression strength of SiO2/RVC are a growing trend with the carbon foam substrate carbonization temperature rising. The thermal insulation properties of SiO2/RVC is better than pure RVC, and high temperature insulation advantages become more pronounced. |
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