Method for preparing silica aerogel material

[0044] Example 1

[0045] The molar ratio of raw materials is TEOS: EtOH: MTMS: H 2 O=1:10:0.3:8, add 5.5ml of TEOS and 14.4ml of absolute ethanol into the container to start stirring, then add 1.4ml of MTMS modifier, continue to stir, slowly add 4.5ml of Distilled water, after another 10 minutes, add hydrochloric acid alcohol solution evenly after stirring, adjust the pH value to make the pH value of the solution 1.5~2.0; after continuous stirring for 8 hours, slowly add a certain amount of ammonia water alcohol solution to make the final pH value of the system 7.5~ 8.0. After 10min, stop stirring and add SiO 2 Pour the sol into the mold and let it stand for about 1 hour until the sample gels. After the gel is formed, soak the wet gel in the ethanol solution and leave it for aging. The aging temperature is 55℃ and the aging time is 5h; after aging, the gel is immersed in the secondary mixing modification solution, and the components of the secondary modification solution The volume ratio is: TMCS: EtOH: n-hexane = 1: 1: 8; modified for 1 to 2 days under sealed conditions. After modification, take out the gel, soak it with n-hexane to remove the modified solution remaining on the surface of the sample, and soak it in n-hexane, put it in a sealed container, and then put it into a smart device with a controllable heating rate Dry in a temperature-controlled drying oven, and finally obtain SiO 2 Aerogel.

[0046] The drying process is as follows: the gel sample is kept at 55°C for 3 hours, then heated to 80°C at a rate of 1°C/min, held for 4 hours, then heated to 130°C at a rate of 1°C/min, and held for 3 hours, and finally at 1 The temperature is increased to 150°C at a rate of ℃/min, kept for 2h, and then cooled to room temperature with the drying box, and finally transparent SiO is obtained 2 Aerogel.

[0047] Figure 1~5 Respectively, the relevant characterization results of the example samples, and other performance parameters are shown in Table 1.

[0048] Table 1 Example 1 Transparent SiO 2 Main performance parameters of aerogel

[0049]

[0050] Example 2

[0051] The molar ratio of raw materials is TEOS: EtOH: MTES: H 2 O=1:10:0.4:6, add 5.5ml of TEOS and 14.4ml of absolute ethanol into the container to start stirring, then add 2ml of MTES modifier, continue to stir, slowly add 2.7ml of distilled water after 15min After stirring, add the hydrochloric acid alcohol solution dropwise to adjust the pH value to about 2.0; after continuous stirring for 8-10 hours, slowly add a certain amount of ammonia water alcohol solution to make the final pH value of the system about 8.0. Stop stirring after a few minutes, and add SiO 2 Pour the sol into the mold and let it stand for about 1 hour until the sample gels. The wet gel is soaked in ethanol solution for aging, the aging temperature is 50℃, and the aging time is 6h; after aging, the gel is immersed in the secondary mixing modification solution. The components of the secondary modification solution are TMCS: Anhydrous ethanol: n-hexane = 2:3:15; modified for 1 to 2 days under sealed conditions. After modification, take out the gel, immerse it in n-hexane and soak it in n-hexane, put it in a sealed container and then put it in a smart temperature-controlled drying oven with a controllable heating rate to dry, and finally obtain SiO 2 Aerogel.

[0052] The drying process is the same as in Example 1.

[0053] Example 3

[0054] The molar ratio of raw materials is TEOS: EtOH: MTMS: H 2 O=1:10:0.3:10, add 5.5ml of TEOS and 14.4ml of absolute ethanol to the container to start stirring, then add 1.1ml of MTMS modifier, continue to stir, slowly add 3.6ml of Distilled water, after another 15 minutes, evenly add the hydrochloric acid dilute alcohol solution, adjust the pH value of the solution at 1.5 ~ 2.0; control the stirring speed at 300 ~ 400 rpm/min, and continuously stir for 8 hours, then slowly add a certain amount of ammonia water dilute alcohol solution to make The final pH value of the system is between 7.5 and 8.0. After 10 minutes, the stirring is stopped and the SiO 2 Pour the sol into the mold and let it stand for about 1 hour until the sample gels. After the gel is formed, add a small amount of ethanol to the mold to soak the gel in ethanol for aging, and age at 60°C for about 6 hours; then use the prepared secondary modification solution for sealing modification. The proportion of the modification solution is The volume ratio is: TMCS: absolute ethanol: n-hexane=1:1:8; after modification for about 2 days, the sample is taken out and soaked in n-hexane, and then soaked in n-hexane solution for drying.

[0055] The drying process is the same as in Example 1.