Preparation And Characterization Of Building Waterborne Thermal Insulation Coating Using Composite Technology

With the development of economy, energy and environmental issues have become increasingly prominent. Since the "Eleventh Five-Year Plan", China has continually introduced a series of energy-saving and environment-rescue policies and measures. As one of the most popular and focused topics in energy efficiency and energy conservation fields in recent years, thermal insulation and heat preservation technology adopts a set of integrated principles, such as decrease of heat transfer, reduction of sunlight absorption and decline of the intrusion of external solar energy, in an attempt to achieve thermal retardation purpose. At present, the external wall thermal insulation coatings have been more and more frequently studied for energy-saving goals. However, the key issue restricting the applications of such coatings is the unsatisfactory thermal insulation results on its own in practice. It is believed that the composite technique of thermal insulation coatings is one of the major measures to solve this problem.In the present study, a paste method was used to prepare coating composites. The cordierite and zirconia were selected as the filler materials, due to their physical and chemical stability and low price, to give the function of near infrared radiation. Titanium dioxide was used as pigments based on its excellent chemical stability and widely commercial availability. The external wall thermal insulation coating composed with laboratory self-made micro-encapsulated phase change materials (MPCMs), cordierite powders having nano-szied zirconia deposited on the surface and hollow microspheres was also prepared and investigated in term of its heat preservation effect. The MPCMs were characterized by using scanning electronic microscopy (SEM), laser particle size analyzer and Differential Scanning Calorimetr (DSC). The relevant results indicate that the self-made MPCMs have the spherical-like morphology, uniform particle size distribution and outstanding engery (thermal) storage performance. Morphology of the cordierite powders with nano-szied zirconia deposits on the surface was also analyzed by using SEM. The SEM observation shows that a layer of zirconia spheres has been formed on surface of the cordierite. The zirconia layer dose not come off the surface of cordierite even under high power ultrasonic condition. Such phenomena further variy a good combination between zirconia and cordierite.The relationships between the contents of zirconia, cordierite, titanium dioxide and hollow microspheres within the coating composites and their thermal insulation performances were primarily investigated, respectively. In addition, the thermal insulation performance of the coating composites with multiple fillers involving self-made MPCMs, cordierite powders with nano-szied zirconia deposited on the surface and hollow microspheres were systemically studied by comparing with those of the coatings composed with the single filler on their own. The relevant research outcomes show that the coating composite with a multiple fillers system, i.e. a mixture of zirconia and cordierite and titanium dioxide pigments in a ratio of 2:1, gives the best thermal insulation performance. Addition of 10 wt% of hollow microspheres as the single function filer for the coating composite results in a prime thermal insulation performance. The coating composite films with a thickness of 2mm individually composed with self-made MPCMs or cordierite powders with nano-szied zirconia deposited on the surface give a temperature difference more than 15℃compared to the blank coating film under a controlled heating system. It was also found that the ordierite powders with nano-szied zirconia deposited on the surface can be employed as an ideal function fillers, as it gives the coating composites a relatively better thermal insulation performance compare to their physical mixture.The current study also explored the potential applications of magnesium hydroxide (Mg(OH)2) within the exterior wall coatings to give the functions of flame retardancy and smoke suppression. Research shows that when the content of Mg(OH)2 within the coatings reaches 30wt%, a obvious flame retarding and smoke suppressing effect can be achieved. And reduction of the thermal insulation performance of such a coating can be kept within 2℃.