Preparation And Performance Research Of Heat Insulating Materials With Composite Structures

Asbestos、rock wool、glass ceramic fiber、aluminum fibers、high silica andalumina fiber fibers are the common heat insulating materials of fiber. These materialshave the characteristics of low thermal conductivity, light density, high heat capacity, easyprocessing and forming and good mechanical properties. But a single traditional textilematerial can’t meet the requirements of fire equipment at high temperature. SiO₂aerogelhave excellent heat insulating performance.However,at ambient and highertemperatures,aerogel has poor thermal insulating property because it is highly transparentin the2-8μm wavelengthregions and the infrared electromagnetic wave can transmit in theSiO₂aerogel， therefore the radiative thermal conductivity will increase with thetemperature increasing.And SiO₂aerogel has low mechanical property,which limits itspractical use.In this paper, inorganic fabric, with high temperature resistance, was coated withmaterials,as a kind of packing, which have reflective properties.And the thermalperformance of coating fabric was explored. Fill the SiO₂aerogel, doping sunscreenagent,to3-d layer even interval fabric to form SiO₂aerogel composite material,which hasgood insulating performance and physical properties. Then the two materials werecompounded to make up composite materials with good insulating performance.This article prepared six titanium potassium whisker/basalt coating, six titaniumpotassium whisker/quartz coating, titanium dioxide/basalt coating and titaniumdioxide/quartz coating by using infrared reflective materials such as six titanium potassiumwhisker and titanium dioxide as coating packing and using inorganic fabrics such as basaltfabric and quartz fabric as base cloth. The properties of the coating fabrics weretested,such as anti-thermal radiation and heat insulation performance and mechanicalproperty.Meanwhile, the coating fabrics and aluminum foil coated fabrics were mutually combined, and the TPP value of the combined fabrics were tested.Research results show that, in the case of the same coating thickness,theanti-thermal radiation and heat insulating performance increases, the breaking strength andtear strength gradually declines decreases gradually, with the increase of functionalparticles in the coating.With the increases of functional particles in coating,the temperatureof the coating fabric’s hot surface reduced, mainly because of coating particles’ function ofinfrared radiation effect. Along with the rise of the content of functional particles,theparticles with infrared radiation effect mount up,and the coating fabric show good anti-infrared radiation. However，when the content of functional particles of coating reaches15%, temperature drop rate of the hot surface of coating fabrics keeps almost thesame.Perhaps owing to the functional particles increase, van der Waals force between themolecules increases,and cause functional particles reunion,leading to the decrease ofparticles’ reflecting action. When the content of functional particles is10%,the surfacetemperature of TiO₂coating fabric20.8%, temperature difference between hot and coldface improves by40%,relatively it declines by23.1%and improves by120%of K2Ti6O13whisker coating fabric. Therefore, the prepared coating fabrics has a good performance ofanti-thermal radiation and anti-heat radiation. The TPP test results show that the TPP valueof combined fabrics with coating fabric as outer layer is higher than that with aluminumfoil coated fabric as outer layer,and all the TPP value is greater than28,indicating thatcoating fabric has good anti-thermal radiation and anti-heat radiation performance.In the course of sol-gel,two-step acid-base catalyzed silica gels were prepared byusing of tetraethoxysiliane（TEOS）as precursor,absolute alcohol （EtOH）as solvent,hydrochloric acid an dammonia as acid and base catalyzer respectively, N, N-DMF aschemical dry control agent （DCCA）, chlorotrimethylsilane as surface modification agent,six titanium potassium whisker as the refraction agent,3-d layer even interval fabric asskeleton of composite material, to prepare dry SiO₂gel and3d interval fabric filled withSiO₂gel dopping with K2Ti6O13whisker（3d interval composite material）.. Themicrostructure and physicochemical properties of the prepared aerogels were investigatedby the menas of SEM、FTIR、XRD、TG-DTA、BET、hydrophobic performance、thermalconductivity。The thermal property and mechanical performance of the compoundmaterials were tested,such as TPP、flat pressing、side pulling and four points bending，The results shows that the SiO₂gel is basically composed of disordered amorphous silica, and the size of the particles making up SiO₂gel is about50nm. Doppingwith six titanium potassium whisker,the heat insulating performance of SiO₂gel improvessignificantly and it effectively reduces the transmissivity of infrared radiation at2-8m.Though surface modification, the contact angle of SiO₂gel is130.5288o,having excellenthydrophobic performance. Replaced by solvent, the specific surface area of SiO₂gelincreases significantly.The3d interval composite material has good heat insulatingperformance and compressive strength、bending strength and tensile strength.The composite material combined of coating material and the3d intervalationhas excellent comprehensive thermal protection performance, the TPP value reaches morethan60.