| There are existing problems with the high energy consumption and low energy efficiency in our country. Compared to developed countries with the similar climate, per unit area of the residential building energy consumption in our country is three times than theirs. Energy conservation in building is an indispensable energy-saving way as the important part of sustainable development of energy sources. The most efficient measure is external insulation technology in energy conservation in building and the critical part is development and utilization of insulation materials. The most commonly used organic insulation materials have some shortcomings of combustible and poor fire resistance. It is extremely urgent to research the new type external thermal insulation material with excellent incombustibility and thermal insulation performance.The diatomite/sodium silicate cementitious system is prepared by hydrothermal alkali soluble method. The preparation process of diatomite/sodium silicate cementitious system is confirmed by analysis of effect factors : ratio of liquid to solid is 2.0, ratio of alkali to diatomite is 0.2, reaction temperature is 95℃, reaction time is 40 min. Hydrogen peroxide and sodium fluosilicate are respectively chosen as the foaming agent and curing agent to be added in diatomite/sodium silicate cementitious system for preparing diatomite foaming material. And the suitable preparation process of foaming : viscosity is 60~65m Pa·s, the foaming agent content is 5wt%,the curing agent content is 4wt%, curing temperature is 60 ℃, curing time is 20 h. All the performance parameters of the obtained diatomite inorganic foaming material: compressive strength is 0.25 MPa, the compress distortion ratio is 0.40%, thermal conductivity is 0.0814W/m·K, volumetric water absorption is 27.8%, apparent density is0.355g/cm3, meet the standard of grade-A incombustible material. However, the problem of high brittleness and water absorption need to be solved.The weak base-weak acid-weak base method is chosen to prepare the urea-formaldehyde resin on the basis of classical theory. The compressive strength of obtained urea-formaldehyde resin is 5.2MPa, compress distortion ratio is 0.36%, water absorption is 18.2%. This obtained urea-formaldehyde resin has the problem of high brittleness and water absorption, it is necessary to modified it. Melamine and polyving akohol are chosen as modifying agent to decrease the brittleness and water absorption by chemical modification, and the appropriate melamine and polyving akohol content are 3wt% and 1.5wt% respectively. Compared to the unmodified resin, the water absorption of melamine-PVA modified resin reduced to 9.37%, compressive strength rose to 7.35 MPa, compress distortion ratio rose to 0.51%. The mechanism of melamine and polyving akohol decreasing the brittleness and water absorption is analyzed by FTIR and TG. The silicone rubber emulsion was used to further modified the melamine-PVA modified resin by physical blending. The appropriate vulcanized agent content in silicone rubber emulsion is 15wt%, the appropriate catalyst is 0.08wt%, vulcanizing time is 60 min. By researching the influence of different silicone rubber content on modified resin, the suitable silicone rubber content is 15wt%, the compress distortion ratio rose of eventual modified resin to 1.16%, the water absorption reduced to 2.4%.At last, composite foaming insulation material is prepared by blending the modified resin and diatomite foaming insulation material. By researching the influence of different modified resin content on composite foaming insulation material, the modified resin content is 25wt%. All the performance parameters of the obtained composite foaming insulation material: compressive strength is 0.7MPa, the compress distortion ratio is 0.78%, thermal conductivity is 0.0552W/m·K, volumetric water absorption is 5.3%, apparent density is 0.415g/cm3, meet the standard of grade-A incombustible material. |
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