Research On Preparation And Performance Of Transparent Heat-insulation Nanocomposite Coatings

Low-carbon economy becomes a global focus, and energy-saving materials arewelcomed greatly. Building energy efficiency in light transmission and thermalinsulation properties of glass is a key problem in using the large area of windows andtransparent roof of the building, car windows and other occasions. The solar heatradiation will lead to the increase of air conditioning energy consumption, resulting inconsiderable waste of energy. As the requirements for energy sources andenvironments enhanced ceaselessly, heat-insulating glass that can be used for differentapplications is universally demanded. The existing heat-insulating glass has the defectson faulty performance, complex process and high cost.Having high transparency in visible light and effective infrared-insulatingperformance, nano-meter tin antimony oxide (ATO) is an ideal heat-insulating material.The preparation of transparent and heat-insulating coating made from nano-ATO cansolve the aforementioned problems, and it has the advantages of simpler process andlower cost. So this kind of coating has extremely high practical application value andwide market prospects.At first, the stable ATO nanofluid was prepared. The influence of pH value,different kinds of dispersants and their concentration and different dispersing methodson the nano-particle dispersion stability was studied. The results indicate that thenanofluids reach its iso-electric point when pH=3.3and the stability of the nanofluidsis enhanced remarkably in alkaline system. The results indicate that the ATO nanofluidis most stable with1.5wt%P30as dispersant. The optimum dispersing method iscombination of both ultrasonic treatment for10min and milling dispersion for15h.A transparent coating with good heat-insulation property had been prepared bymixing ATO nanofluids with polymeric film-former, thickening agent and other assistant agents. The influence of different film-formers, mass fraction of nano ATO,coating thickness and curing procedure on coating mechanical properties, opticalproperties and insulation effect is investigated. Results show that the optimum filmformer is waterborne polyurethane. For coatings with ATO nanoparticles mass fractionof9%and thickness of40μm, the average transmittance of visible region was70%,while that of near-infrared region (900~2500nm) dropped to about45%. The optimumcuring procedure is drying for3h at80℃, resulting in pencil hardness of2H andadhesion force of level1. Result of the heat-insulation effect determined underself-made testing devices indicates that the coatings have good heat-insulation effects.It is expected that the contradictory of light transmission and heat insulation can besolved by applying nano-ATO to prepare coatings. It does not require expensive,large-scale investment in equipment. Furthermore, the preparation and constructionprocesses are simple, which can effectively reduce the production costs. The productshave advantage in marketing and are highly valuable in applications.