The process of aerogels composite materials and nanometer micro-hole insulation materials
Date of release:2018-10-22 Author: Click:
Aerogels are generally too brittle to be used on their own, and most of the aerogel products sold on the market are composite products of aerogels and reinforced fibers. The way of recombination is also roughly divided into two types, one is called in situ recombination or one recombination, the other is called two recombination.
The so-called primary recombination is in the sol-gel stage of the aerogel preparation process. The silica sol directly infiltrates and strengthens the fiber, and jointly experiences gel aging, modification and drying until the end of production. Compared to the aerogel composites obtained by this method, the aerogel is continuous phase and the fiber is dispersed phase. The obtained aerogel products can usually obtain low thermal conductivity and have good consistency in product quality, which is also the mainstream composite method for domestic and foreign aerogel enterprises at present.
Secondary recombination is the preparation of the aerogels powder first, and then the aerogels powder is managed to be combined with the fiber. This method is not continuous phase to obtain product aerogel and fiber, and it is difficult to evenly disperse aerogel. (a domestic project introduced a national technology, the introduction said that China is now basically a secondary compound, their advantage is a compound, really good sense of humor.)
However, it is not that the secondary compound method is completely useless. The nanometer microporous products we are going to talk about follow this method. In terms of product performance, it should be said that it is very successful.
In the family of nano-pore adiabatic materials, besides aerogels, there is another branch of nano-pore adiabatic materials, whose excellent insulation performance at high temperature is even better than that of current aerogels.
Nano porous thermal insulation material and the aerogel material main difference is that in the process of aerogel using sol-gel technique to obtain the overall continuous nanopore structure, image, like a tiny honeycomb holes size, nanometer porous thermal insulation material preparation process typically by dispersed nanoparticles of different components in mixing process and enhance fiber evenly dispersed, add a certain amount of binder, then through forming technology, nano holes are formed by nanoparticles accumulation structure; In the form of products, the aerogel is mainly felt and plate at present, and the nanometer micropore is mainly plate and shaped part. On the application of temperature, aerogel generally applied to under 650 ℃, nano porous thermal insulation material commonly used in the above 700 ℃, 1200 ℃ below. The two are complementary in terms of temperature of use and product form.
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