Silica airgel based on linear organosilicon oligomer, preparation method and application
A silicon oxide aerogel and organosiloxane technology, which is applied in chemical instruments and methods, inorganic chemistry, silicon compounds, etc., can solve the problems of difficult industrialized production, long preparation cycle, and increased preparation process, and achieve easy Clear, shorten the preparation cycle, the effect of simple process
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[0045] The preparation of hydrophilic silica airgel still relies on supercritical drying, that is, the hydrophilic silica aerogel can be prepared by supercritical drying of unhydrophobized silica wet gel. Silica aerogels that are both hydrophilic and lipophilic (i.e., amphiphilic silica airgel) are prepared by atmospheric drying method. While reducing the preparation cost, its application range can also be extended from heat insulation to biomedicine and cosmetics. It has important scientific and practical application value.
[0046] One aspect of the embodiments of the present invention provides a method for preparing a linear silicone oligomer-based silica airgel, including three key steps:
[0047] (1) Synthesis of sol precursor; (2) Synthesis and aging of gel; (3) Drying of gel.
[0048] Specifically, the preparation method of the silica airgel based on the linear organosilicon oligomer comprises:
[0049] (1) uniformly mixing organosiloxane, acidic aqueous solution and ...
Embodiment 1
[0089] (1) Synthesis of sol precursor: get 1mol of methyl orthosilicate, 1.8mol of hydrochloric acid aqueous solution (hydrochloric acid content is 10 -4 mol) and 1 mol of ethanol, after mixing the three evenly, stirring at 80°C for 12 hours to obtain a linear organosilicon polymer precursor with 5-10 silicon atoms. For the mass spectrum of this precursor see figure 1 , for a schematic diagram of the molecular structure see figure 2 . Here it is necessary to explain why the molar ratio of methyl orthosilicate to water is 1:1.8. If the molar ratio of the two is 1: (2.2), the hydrolyzate has too many functional groups and is prone to cross-linking, and it is impossible to form a linear short chain of silicon polymerization.
[0090] (2) Synthesis and aging of the gel: take 10 parts of the sol precursor obtained above, and then take 30 parts of ethanol, mix the two fully, add 5 parts of sodium hydroxide, stir at room temperature for 20 minutes, and let stand A gel formed with...
Embodiment 2
[0094] (1) Synthesis of sol precursor: get 1mol of tetraethyl orthosilicate, 2.2mol of hydrochloric acid aqueous solution (hydrochloric acid content is 10 -6 mol) and 10 mol of methanol, after mixing the three evenly, stirring at 150° C. for 5 hours to obtain a linear organosilicon polymer precursor with 5-10 silicon atoms. The schematic diagram of the molecular structure of the precursor can be found in figure 2 . Here we need to explain why the molar ratio of tetraethyl orthosilicate to water is 1:2.2. If the molar ratio of the two is 1:(2.2), the hydrolyzate has too many functional groups and is prone to cross-linking, and it is impossible to form a linear short chain of silicon polymerization.
[0095](2) Synthesis and aging of the gel: Take 10 parts of the sol precursor obtained above, and then take 1 part of methanol, mix the two fully, add 0.1 part of urea, stir at room temperature for 30 minutes, and let stand for 5 minutes Gel formed within hours. The gel was then...
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