The Research Of Nano-calcium Silicate Hydrate Modified Thermal Insulation Coatings

With the development of society,the use of architectural glass ceilings is getting more and more,in summer,the glass ceiling can not only pass a lot of ultraviolet and sunlight,but also contribute to the high temperature of internal space,the use of thermal insulation coating can be helpful to the above problems.However,the surface of the glass is extremely smooth.Most of the basic fillers other than the heat-insulating filler used in the thermal-insulating coatings are traditional fillers,such as heavy calcium powder,which have insufficient adhesion to the glass surface and are easily peeled off after raining,and it is harmful to appearance and use.In order to solve the above problems,the thesis has been prepared a thermal insulation coating that is excellent in basic performance and meets the requirements for thermal insulation performance,which has significiance for optimizing the performance of the coating and reduces the energy consumption of the building.In the present thesis,C-S-H powder were synthesized via dynamic hydrothermal treatment.Nano silica and rounded quartz powder were used as siliceous materials and lime was used as calcareous materials.These powders were used XRD,TEM and DSC-TG to characterize performances.The nano-C-S-H modified thermal insulation coating was prepared by the matrix of pure acrylic emulsion,the heat-insulating functional fillers of SiO₂ aerogels,infrared ceramic powder,HGM and the foundation filler of nano-C-S-H powder.Then the thermal insulation performance and basic properties of the coating were investigated.Finally,the modification mechanism of the nano-C-S-H powder was investigated.Research indicates:Under the process parameters of C/S molar ratio of 1,constant temperature of 120℃and constant temperature time of 10 h,nano-C-S-H powder A（siliceous raw material:nano silica）and B（siliceous material:quartz sand）can be prepared by dynamic hydrothermal treatment.Powder A has a specific surface area of 165.74 m²/g,a particle size of about 50-100 nm.While powder B has a specific surface area of 11.07 m²/g,a particle size of 50²00 nm and a lower reaction level.Using the powder as foundation filler,the ratio of nano-C-S-H modified thermal insulation coating was determined by experiment with Design Expert software:pure propylene emulsion content was 37.6%,nano C-S-H powder content was 18.9%,the SiO₂ aerogel content was 3.0%,the infrared ceramic powder content was 3.3%,the HGM content was 2.1%,and the water content was 30.7%.Then the nano-C-S-H modified thermal insulation coating was prepared.Nano-C-S-H has a significant effect on the improvement of the basic properties of thermal insulation coatings.In addition,the improvement effect of A powder is better than that of B powder.The nano-C-S-H modified thermal insulation coating（A）has a water resistance of 403h and an alkali resistance of 243h,which is much higher than the national superior product standard.Simultaneously,the adhesive force of thermal insulation coating achieved secondary level,and the washing resistance is 3200 times.In comparision to titanium dioxide thermal insulation coating,the water resistance and the alkali resistance is 3⁴ times,and the washing resistance is about 2 times.The thermal insulation temperature difference of the nano-C-S-H thermal insulation coating（A）is 10.3°C,the thermal conductivity of thermal insulation coating（A）is0.147W/（m·K）,which indicated that the coating has greatinsulting properties.The contrast ratio is 63.2%,so the thermal insulation coating are light-admitting.SEM analyses showed that the nano-C-S-H modified thermal insulation coating has a compact structure,and the thermal insulation component is uniformly distributed inside the coating substrate.The modification mechanism of the nano-C-S-H powder is:During the film formation process,the specific surface energy of the powder is released gradually,to enhance the binding force with the organic polymer chain.The nano-C-S-H powder has a small particle size and great particle grading,which can make the coating more compact and firm.The nano-C-S-H modified thermal insulation coating prepared in this experiment has obvious improvement in basic properties such as adhesion and scrub resistance,and has heat-insulating and light-admitting property,which is suitable for use on the roof of the architectural glass.