Preparation And Performance Study Of Nanosized Cesium Tungsten Bronze Transparent Dispersions And Their Composite Coating Materials

Building energy consumption occupies about 30%of the total energy consumption in China.Nearly 50%Building energy consumption is lost through the glass windows and doors.So energy-saving technologies of building glass as a way to reduce building energy consumption has been widespread concern.Energy-saving glass include heat conduction-reducing glass like vacuum glass and hollow glass and radiation-reducing glass like transparent thermal insulation coating,the solar control coated glass,and low-emission glass.The transparent thermal insulation coating not only has high visible light transmittance and high near-infrared shielding performance,but also has the advantages of simple production process and low cost,which is the main direction of the development of future building glass energy saving technology.Tungsten bronze stand out from a variety of transparent thermal insulation coating with its features of environmentally friendly and high thermal insulation.However,the current preparation process of tungsten bronze transparent nano-thermal insulation coating requires toxic raw materials and high operating conditions.In this paper,we synthesized the nanosized cesium tungsten bronze in aqueous to form the transparent nanodispersion by the hydrothermal method,then the transparent thermal insulation coating was prepared by mixing the water-based resin with the cesium tungsten bronze aqueous nanodispersion.The effect of the preparing conditions and blending conditions on the morphology and dispersion of the nanoparticles and optical properties were investigated.The main conclusions of this paper are shown as follows:Cesium tungsten bronze transparent aqueous dispersions were prepared by hydrothermal methods.Influences of material concentration,mixing time,hydrothermal temperature on the morphology of cesium tungsten bronze particles and the dispersity and optical properties of cesium tungsten bronze dispersions were investigated.Suitable preparing conditions were obtained:sodium tungstate concentration of 0.3 mol/L,mol ratio of Cs to W of 0.3:1,water/ethylene glycol volume ratio of 60:15,the precursor stirring time of 1 h,the hydrothermal pH value of 2,the heating rate of 2 ?/min,the hydrothermal temperature of 230 ?,the hydrothermal time of 20 h.The prepared cesium tungsten bronze nanoparticles showed 5?20 nm primary particle size and narrow size distribution and remarkable dispersity in water phase.The prepared transparent cesium tungsten bronze aqueous dispersions showed remarkable dispersity and excellent optical properties.The visible light transmitted of cesium tungsten bronze dispersions is 75%at 500 nm and the near-infrared rejection of that is 91%at 1000 nm.The transparent nanocomposite coating with strong infrared radiation absorption had been prepared by mixing the nano-cesium tungsten bronze aqueous dispersions with water-based resin.Influences of water-base substrate material,dosage of cesium tungsten bronze and filming thickness on the mechanical properties and optical properties of the transparent composite film were investigated.The results showed that under the process conditions of that Acrylic acid as the water based resin,mass ratio of cesium tungsten bronze to Acrylic acid(CsxWO3/PA)of 7.0%and coating thickness of 6 ?m,that the prepared cesium tungsten bronze composite coating has high transparency,good near infrared shielding performance,good thermal insulation performance,high hardness,uniformly smooth surface,strong adhesion with glass,and excellent optical properties.The visible light transmitted of cesium tungsten bronze composite film is 74%at 500 nm and the near-infrared rejection of that is 90%at 1000 nm.