基于发泡和固化法的硅酸盐无机外墙保温材料制备与性能研究

发布时间：2018-08-09 11:05

【摘要】：近年来由于缺乏相关消防安全法规,大量可燃的有机保温材料被用于建筑外墙,造成了火灾事故频发。现阶段我国建筑外墙保温技术最突出的问题就是节能和防火之间的矛盾,有机保温材料虽然隔热性能好、质轻和价格便宜,但是可燃烧,一旦被点燃会释放大量的热量、烟气和毒性气体,并且会在建筑外立面上迅速蔓延,造成严重的后果,而无机保温材料防火性能优异,但是导热系数较大,而且易吸水,节能效率不高。本文从先防火再节能方面考虑,提出研发一种低导热系数、低成本、憎水和环境友好的无机外墙保温材料。本文采用理论分析与实验制备相结合的方法,利用发泡和固化法制备出导热系数较低,强度合适且具有憎水性的硅酸盐无机多孔保温材料,完成的主要研究工作如下：首先,研究了多孔保温材料内部的传热机理,发展了新型有效介质理论来描述多孔保温材料的内部传热。利用传热分析推导出理论的数学表达式并且验证了该理论的有效性,而且根据理论模型提出高孔隙率(或低容重)、低导热系数固相骨架与合理的孔隙结构这三种途径可以使多孔材料具有低导热系数,为研发工作提供了理论依据。然后,以工业莫来石粉为骨料和玉米淀粉为胶凝材料利用发泡和淀粉固化的方法制备了高孔隙率的莫来石基多孔保温材料,孔隙率最高的样品导热系数可以达到0.1W/mK左右,为研发工作奠定了实验基础。接着,针对发泡和淀粉固化法的缺点,以工业莫来石粉为骨料,用更经济更环保的水泥代替淀粉作为胶凝材料,利用发泡和水泥固化法制备了莫来石基多孔保温材料,降低了成本和减少了排放,优化了制备方法。最后,选择成本更低和更轻质的工业废料粉煤灰作为骨料,利用发泡和水泥固化法制备粉煤灰基多孔保温材料,并且采用发泡液先独立发泡再与浆料混合的方法代替之前的浆料直接发泡,制备出导热系数更低的样品。此外本文还使用水溶性防水剂对样品进行渗透性防水处理,经过防水处理后样品具有憎水性。
[Abstract]:In recent years, due to the lack of relevant fire safety regulations, a large number of combustible organic insulation materials have been used in building exterior walls, resulting in frequent fire accidents. At the present stage, the most prominent problem of external wall insulation technology in our country is the contradiction between energy saving and fire prevention. Although organic insulation materials have good thermal insulation, light weight and low price, they can burn, once ignited, they will release a large amount of heat. The smoke and toxic gas will spread rapidly on the exterior of the building, causing serious consequences. The inorganic insulation material has excellent fire resistance, but its thermal conductivity is high, and it is easy to absorb water, and the efficiency of energy saving is not high. In this paper, a kind of inorganic exterior wall insulation material with low thermal conductivity, low cost, hydrophobicity and environmental friendliness is proposed from the point of view of fire prevention and energy saving. In this paper, silicate inorganic porous thermal insulation materials with low thermal conductivity, suitable strength and hydrophobicity were prepared by using foaming and curing methods, by combining theoretical analysis with experimental preparation. The main work is as follows: firstly, the heat transfer mechanism of porous thermal insulation material is studied, and a new effective medium theory is developed to describe the internal heat transfer of porous thermal insulation material. The mathematical expression of the theory is derived by heat transfer analysis and the validity of the theory is verified. According to the theoretical model, three approaches, high porosity (or low bulk density), low thermal conductivity solid skeleton and reasonable pore structure, can make porous materials have low thermal conductivity, which provides a theoretical basis for research and development. Then, the mullite porous insulation material with high porosity was prepared by using industrial mullite powder as aggregate and corn starch as cementitious material. The thermal conductivity of the sample with the highest porosity could reach about 0.1W/mK. For the research and development work laid the experimental foundation. Then, in view of the shortcomings of foaming and starch curing methods, mullite based porous insulation materials were prepared by using industrial mullite powder as aggregate, using more economical and environmental friendly cement instead of starch as cementitious material, and using foaming and cement curing methods. The cost and emission are reduced, and the preparation method is optimized. Finally, the industrial waste fly ash with lower cost and lighter weight is selected as aggregate, and the porous thermal insulation material based on fly ash is prepared by foaming and cement curing method. The foaming fluid was used to foaming independently and then mixed with the slurry instead of the former directly foaming to prepare the sample with lower thermal conductivity. In addition, the water-soluble waterproof agent was used to treat the sample with permeable waterproofing, and the sample was hydrophobic after waterproofing.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU551.3

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