Method for preparing nano-porous materials with high mechanical property by organic modification

Abstract

The invention provides a method for preparing nano-porous materials with high mechanical property by organic modification, comprising steps as follows: (1) taking alkyl-containing organosilane as a precursor and adding organic high polymer materials into silicon dioxide sol for compounding; (2) carrying out standing and aging on wet gel for 1-7 days, with aging temperature of 25-65 DEG C; (3) cleaning the wet gel structure with solvent and soaking and modifying the wet gel structure with surface modifiers, and then drying the wet gel structure; (4) carrying out heat treatment on the dried nano-porous materials under the temperature of 200-500 DEG C. By the method, the alkyl is successfully linked on a main chain of the silicon dioxide under the condition of hydrolysis and the final xerogel products are ensured to have better mechanical property and hydrophobicity through mutual repulsion effect among alkyl; meanwhile, the organic high polymer materials are added in the process of hydrolysis for compounding to form a high interpenetrating cross-linked network, thus not only improving the flexibility and mechanical strength of the main chain of the silicon dioxide, but also adjusting aperture distribution and finally preparing the light nano-porous materials with large specific surface.

Description

technical field [0001] The invention belongs to the field of inorganic nanoporous materials, and in particular relates to a method for preparing nanoporous materials by compounding organic polymer materials. Background technique [0002] Silicon dioxide (SiO 2 ) Airgel is a lightweight nanoporous material with a spatial network structure composed of colloidal particles or polymer molecules cross-linked with each other, because of its nanoporous structure (1-100nm), low density (1-500kg / m 3 ), low thermal conductivity (0.003~0.025w / m.k), high porosity (80%~99.8%), high specific surface area (200~1000m 2 / g), low sound propagation velocity (~100m / s) and other characteristics, it has become the lightest solid material known so far, and it is also the material with the best thermal insulation performance so far. Therefore, it has broad and huge application prospects in the fields of optics, heat insulation, acoustics, catalyst carrier, microelectronics, chemical industry, ae...

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Problems solved by technology

DigambarY.Nadargi et al. (DigambarY.Nadargi, SanjayS.Latthe, HiroshiHirashima, A.VenkateswaraRao.Microporous and Mesoporous Materials117 (2009) 617-626) use methyltriethoxysilane (MTES) as the silane prepolymer, using acid-base Airgel with significantly improved flexibility and mechanical strength obtained by two-step method and supercritical drying, with a Young's modulus of 15.03*10 4 ~3.95*10 4 N / m 2 , Poisson's ratio 0.14, but the cost of supercritical drying in this method is expensive and the process is more complicated

[0004] While the above methods improve the mechanical strength of the material, they also bring a series of problems, such as the poor flexibility of the material, the increase of thermal conductivity, the insignificant improvement of the mechanical strength of the material, and the high preparation cost.

In practical applications, materials with certain strength and flexibility, light weight, low thermal conductivity, and large porosity are required in many places, such as core materials for vacuum insulation panels, flexible insulation layers, etc., so developing a low-cost, high-efficiency The preparation method of nanoporous materials with mechanical properties, ultra-low density and low thermal conductivity is very necessary

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