COMPOSITE COATINGS WITH CERAMIC MICROSPHERES AS INSULATING MATERIALS FOR TRANSPORT MEANS

The paper presents the structure and the influence of the chemical composition and structure on the insulating properties of a polymer-ceramic microspheres hybrid composite used as insulating materials in infrastructure of transport and means of transport. The composite matrix is an acrylic resin and ceramic microspheres with the pressure of 13 Pa are the reinforcement. A content of about 44 microspheres in a 1 mm-thick coating has a major impact on the thermal insulating properties of the coating. The coefficient of heat conduction depends from the temperature and is lower at lower temperatures. This is the reason why these coatings are used as an insulator in technical means of transport requiring cooling (refrigerators and ice vehicles) and in the aviation industry to protect the interior of the plane against low temperatures during flights at high altitudes. Microscopic examinations were performed, the stereological features of the coating were examined and a equivalent model of the resistance of thermal transmittance through the coating have was developed. The equivalent coefficient of thermal conductivity of the composite, calculated on the basis of a formula taking into account the volume shares of the components and their thermal properties, is greater than the coefficient of ceramic spheres with their volume fraction amounting to 80%. This is caused by the fact that the formula does not take into account the stereological properties of spheres in the composite, i.e. the distribution pattern and number per unit of thickness of the coating.