SiO_2气凝胶复合型隔热涂层的制备及性能研究

Preparation and Properties of SiO_2 Aerogel Composite Thermal Insulation Coatings

目的探究SiO_2气凝胶在复合隔热涂料中的应用,从隔热机理出发,通过降低复合隔热涂层的导热系数,提高反射率、辐射率等方式,使涂层达到隔热降温的目的。方法首先通过单掺实验确定各填料的含量,并采用紫外/可见光/近红外分光光度计、红外辐射率测量仪和自制的测试隔热装置等,分析涂层的发射率、辐射率和隔热性能,最后通过正交实验方法得到最优涂层配方。结果 SiO_2气凝胶能显著降低涂层的导热系数,在此基础上,添加钛白粉、空心玻璃微珠、红外陶瓷粉等颜填料,能有效提高涂层的反射率和辐射率,从而进一步增强了涂层的隔热效果。分别添加质量分数为5%的SiO_2气凝胶、5%的钛白粉、5%的空心玻璃微珠和10%的红外陶瓷粉时,复合隔热涂层具有最优的隔热性能。SiO_2气凝胶复合型隔热涂层的干膜厚度为60μm时,与未涂覆的空白样板对比,温度最高可降低14.8℃。结论 SiO_2气凝胶复合型隔热涂层具有优异的隔热性能,并且具有薄层、轻质、环保等优点,具有一定的实际应用价值。

The work aims to explore application of SiO2 aerogel in composite thermal insulation coating, and achieve heat insulation by reducing thermal conductivity of composite heat insulation coating, improving reflectivity and emissivity based on mechanism of thermal insulation. First of all, content of each filler was determined by performing single-doped experiment, and ultraviolet/visible/near infrared spectrophotometer, infrared emissivity measuring instrument and homemade testing insulation device were used to analyze emissivity, radiation rate and heat insulation performance of the coating. Finally, optimal formula of thermal insulation coating was obtained in orthogonal experiment method. SiO2 aerogel could reduce thermal conductivity of the coating, on this basis, adding pigments such as titanium dioxide, hollow glass microspheres and far-infrared ceramic powder could improve the reflectivity and radiance of the coating, and further enhance the effect of heat insulation. The composite thermal insulation coating exhibited best thermal insulation performance when 5% （mass fraction） of SiO2 aerogel, 5% of titanium dioxide, 5% of the hollow glass microspheres and 10% of far-infrared ceramic powder were added. Compared to that of uncoated blank sample, the temperature could be reduced by up to 14.8 ℃ when dry film thickness of SiO2 aerogel composite heat insulation coating was 60 μm. SiO2 aerogel composite thermal insulation coating has excellent thermal insulation performance, and features in thinness, light weight and environmental protection, and is of certain value of practical application.