A highly elastic silicone aerogel and a method for preparing the same

Abstract

The application discloses a kind of high elasticity organosilicon aerogel and preparation method thereof, belong to porous material technical field;Including the following steps: S1, aldehyde group carboxymethyl cellulose is added in morpholine ethanesulfonic acid buffer solution stirring dissolution, add morpholinium, stirring reaction, add 3-amino phenylboronic acid, continue stirring reaction, washing dialysis, freeze drying, and obtain modified carboxymethyl cellulose;S2, organosilicon precursor is added in deionized water stirring uniform, add modified carboxymethyl cellulose, modified inorganic filler continues stirring reaction, add acid and adjust pH and carry out hydrolysis reaction, and obtain sol;S3, to sol is added in alkali and adjust pH, stirring uniform, after standing, and obtain gel;S4, the gel is freeze-dried, and obtain high elasticity organosilicon aerogel;The preparation method process is simple, cost is relatively low, suitable for large-scale production, and the obtained organosilicon aerogel is excellent and mechanical property and low thermal conductivity, and has good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of porous materials, and particularly relates to a high-elasticity organosilicon aerogel and a preparation method thereof. BACKGROUND

[0002] The aerogel material is a kind of porous material with a three-dimensional space network structure, has extremely low density, large specific surface area, high porosity, extremely low thermal conductivity and other characteristics, and exhibits excellent performance in heat insulation, adsorption, catalysis and electrochemistry, and is widely applied to the fields of adsorption, catalysis, heat insulation, medical treatment, aerospace and the like. However, the unique structure not only endows the aerogel with excellent performance, but also brings problems of low strength, great brittleness and poor flexibility in mechanical properties, so that the aerogel faces difficulties in processing and treatment, and the application range of the aerogel is greatly limited. In addition, the aerogel generally has the problem of "powder and slag falling off" in the process of transportation, construction and use. The powder falling off not only brings inconvenience to work and threatens the health of workers, but also reduces the performance of the aerogel, and greatly limits the application range of the aerogel.

[0003] In order to improve the mechanical properties of the aerogel, domestic and foreign researchers mainly prepare aerogels with excellent performance through the ways of adding various materials as reinforcing components or directly enhancing the three-dimensional network skeleton. The skeleton strength of the aerogel can be improved by doping glass fibers, carbon fibers and ceramic fibers and the like, but the aerogel prepared by this method cannot form effective covalent bonds between the organosilane and the reinforcing material, so the strength and elasticity of the material cannot be fundamentally improved. In the patent application file with the publication number CN1749214A, different silicon sources are mixed to prepare a silica sol, and then reinforcing components such as high-silicon fiber, quartz fiber, carbon fiber and glass fiber are filled into the system through a soaking process, and an adiabatic composite aerogel material is obtained after supercritical drying. Although the density and thermal conductivity of the silica aerogel are reduced, and the mechanical properties of the material are improved, a large amount of organic solvent and porogen is needed in the preparation process, which causes serious environmental pollution. Moreover, the pore structure needs to be maintained through a supercritical drying process or vacuum drying, which has problems of high energy consumption and long time consumption. These problems seriously restrict the large-scale production of the aerogel material.

[0004] Therefore, it is of great significance to develop an aerogel with high strength, excellent mechanical properties, high elasticity, excellent stability and the like, and capable of meeting the needs of various fields in the market. SUMMARY

[0005] The application aims to provide a high-elasticity organosilicon aerogel and a preparation method thereof, so as to solve the problem of poor elasticity of the aerogel in the prior art.

[0006] The object of the present application can be achieved by the following technical solutions.

[0007] The present application provides a preparation method of high-elasticity silicone aerogel, comprising the following steps:

[0008] S1, add aldehyde carboxymethyl cellulose into morpholine ethanesulfonic acid buffer solution, stir and dissolve, add morpholine acid salt, stir and react, add 3-aminobenzene boronic acid, continue to stir and react for 22-24h, wash, dialysis, freeze-drying, to obtain modified carboxymethyl cellulose;

[0009] S2, add silicone precursor into deionized water, stir and mix, add modified carboxymethyl cellulose and modified inorganic filler, continue to stir and react, add acid to adjust pH to 4.5-5, to carry out hydrolysis reaction, to obtain sol;

[0010] S3, add alkali to the sol to adjust pH to 10-11, stir and mix, stand to obtain gel;

[0011] S4, freeze-drying the gel to obtain high-elasticity silicone aerogel.

[0012] As a further scheme of the present application, the amount ratio of aldehyde carboxymethyl cellulose, morpholine ethanesulfonic acid buffer solution, morpholine acid salt and 3-aminobenzene boronic acid in S1 is 1.0-1.3g:200mL:1.40-1.45g:0.053-0.55g.

[0013] As a further scheme of the present application, the amount ratio of silicone precursor, deionized water, modified carboxymethyl cellulose and modified inorganic filler in S2 is 60-80 parts:100-120 parts:15-25 parts:5-10 parts.

[0014] As a further scheme of the present application, the aldehyde carboxymethyl cellulose is prepared by the following steps:

[0015] Add carboxymethyl cellulose into deionized water, stir and dissolve, add sodium periodate, adjust pH to 2.8-3.0, stir and react in dark for 3.5-4h, precipitate with anhydrous ethanol, wash, freeze-drying, to obtain aldehyde carboxymethyl cellulose; wherein the amount ratio of carboxymethyl cellulose, deionized water and sodium periodate is 1.0g:200mL:1.0-1.1g.

[0016] As a further scheme of the present application, the modified inorganic filler is prepared by the following steps:

[0017] The inorganic filler is added into a Tris-HCl buffer solution, ultrasonic dispersion is carried out for 4-5 h, dopamine hydrochloride is added, the pH value is adjusted to 8-8.5, and stirring reaction is carried out for 8-10 h, centrifugal washing is carried out, and drying is carried out to obtain the modified inorganic filler. Dopamine can self-polymerize to form polydopamine on the surface of the inorganic filler, the polydopamine contains a large number of active functional groups such as hydroxyl groups and amino groups, can be coated on the surface of the inorganic filler to improve the interaction between the inorganic filler and the matrix, and is beneficial to improving the dispersion performance of the inorganic filler, so that the utilization rate of the inorganic filler is greatly improved. The inorganic filler modified by dopamine hydrochloride is combined into a hydrogel network, and the mechanical strength of the aerogel is further enhanced.

[0018] As a further scheme of the present application, the amount ratio of the inorganic filler, the Tris-HCl buffer solution and dopamine hydrochloride is 0.25-0.40 g: 200 mL: 0.40-0.42 g.

[0019] As a further scheme of the present application, the inorganic filler is at least one of nano graphene oxide, nano hexagonal boron nitride and nano molybdenum disulfide. The addition of the nano sheet layer structure inorganic material can provide high specific surface area and high porosity, and can effectively avoid the self-stacking problem, and greatly improve the surface utilization rate.

[0020] As a further scheme of the present application, the organic silicon precursor is one or a mixture of two of methyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane and vinylmethyldimethoxysilane.

[0021] As a further scheme of the present application, the acid in S2 is one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid and oxalic acid; and the base in S3 is one of sodium hydroxide and ammonia.

[0022] The second aspect of the present application provides the high-elasticity organic silicon aerogel obtained by the preparation method in the first aspect.

[0023] The present application has the following beneficial effects:

[0024] The present application uses an organic silicon precursor as a matrix, adds modified carboxymethyl cellulose and modified inorganic filler to react, and obtains the organic silicon aerogel with high strength, high toughness, high elasticity, good stability and excellent heat insulation performance after freeze-drying.

[0025] The modified carboxymethyl cellulose used in the present application is prepared by grafting reaction of aldehyde-based carboxymethyl cellulose and 3-aminobenzoic acid, which improves the shortcomings of high moisture absorption and low mechanical strength of carboxymethyl cellulose, and also endows the aerogel with certain antioxidant performance and antibacterial ability. Further, the hydroxyl groups on the molecular chain after hydrolysis of organosilane and the hydroxyl groups on the modified inorganic filler can modify the benzene boronic acid groups on the modified carboxymethyl cellulose to form benzene boronic acid ester bonds, and the Schiff base generated by the modified carboxymethyl cellulose itself, the obtained aerogel contains two kinds of dynamic covalent cross-linking, thereby constructing an aerogel with a multi-crosslinking network structure, more active groups have undergone chemical reaction, making the aerogel crosslinking network more compact and firm, and further improving the mechanical properties and mechanical strength of the aerogel, and reducing the powder dropping phenomenon of the aerogel material. In addition, the Schiff base and benzene boronic acid ester bond are both dynamic chemical bonds, the introduction of dynamic bonds into the organic silicon spatial network structure endows the aerogel with self-healing performance. The modified inorganic filler is used as a reinforcing agent to further improve the mechanical properties of the aerogel.

[0026] The preparation method of the high-elasticity organic silicon aerogel provided by the present application has the advantages of simple process, easily available raw materials, low cost and suitability for large-scale production. The obtained organic silicon aerogel has the advantages of high strength, excellent mechanical properties and elastic properties, low thermal conductivity coefficient and good application prospect, and can be widely applied in many fields such as flexible electronics, sensors and energy storage. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] Embodiment 1

[0029] The present embodiment provides a preparation method of high-elasticity organic silicon aerogel, and the preparation steps are as follows:

[0030] S1, 1.0g of carboxymethyl cellulose is added to 200mL of deionized water, stirred and dissolved, 1.0g of sodium periodate is added, the pH value is adjusted to 2.8, and the reaction is stirred in the dark for 3.5h, then precipitated with anhydrous ethanol, washed, and freeze-dried to obtain aldehyde-based carboxymethyl cellulose; then 1.0g of aldehyde-based carboxymethyl cellulose is added to 200mL of morpholine ethanesulfonic acid buffer solution (100mM, pH=5.5), stirred and dissolved, 1.40g of morpholine acid salt is added, stirred for 0.5h, 0.053g of 3-aminobenzoic acid is added, and the stirring reaction is continued for 24h, then washed, dialyzed, and freeze-dried to obtain modified carboxymethyl cellulose;

[0031] S2. Weigh out 60 parts by weight of methyltrimethoxysilane and add it to 100 parts of deionized water. Stir well, add 15 parts of modified carboxymethyl cellulose and 5 parts of modified inorganic filler and continue stirring to react. Add hydrochloric acid to adjust the pH to 4.5 and carry out hydrolysis reaction to obtain sol.

[0032] S3. Add sodium hydroxide to the sol to adjust the pH to 10, stir evenly, and let stand to obtain a gel;

[0033] S4. Freeze-dry the gel to obtain a highly elastic organosilicon aerogel.

[0034] The preparation steps of the modified inorganic filler are as follows:

[0035] 0.25 g of nano-graphene oxide was added to 200 mL of Tris-HCl buffer solution (1 mol / L, pH = 7.4), ultrasonically dispersed for 4 h, 0.40 g of dopamine hydrochloride was added, the pH was adjusted to 8, the reaction was stirred for 10 h, centrifuged and washed 3 times, and dried to obtain modified nano-graphene oxide.

[0036] The highly elastic organosilicon aerogel was prepared by the above steps.

[0037] Example 2

[0038] The only difference compared to Example 1 is:

[0039] S1. Add 1.0 g of carboxymethyl cellulose to 200 mL of deionized water, stir to dissolve, add 1.0 g of sodium periodate, adjust the pH to 3.0, stir and react in the dark for 3.5-4 h, precipitate with anhydrous ethanol, wash, and freeze dry to obtain aldehyde-modified carboxymethyl cellulose; then add 1.15 g of aldehyde-modified carboxymethyl cellulose to 200 mL of morpholine ethanesulfonic acid buffer solution (100 mM, pH = 5.5), stir to dissolve, add 1.42 g of morpholine salt, stir and react for 0.5 h, add 0.053 g of 3-aminophenylboronic acid, continue stirring and react for 24 h, wash, dialyze, and freeze dry to obtain modified carboxymethyl cellulose.

[0040] Example 3

[0041] The only difference compared to Example 1 is:

[0042] S1, 1.0 g of carboxymethyl cellulose was added into 200 mL of deionized water, stirred and dissolved, 1.0 g of sodium periodate was added, the pH value was adjusted to 2.8, and the reaction was stirred in the dark for 3.5 h. Anhydrous ethanol was used for precipitation, washing, and freeze-drying to obtain aldehyde-modified carboxymethyl cellulose. Then, 1.3 g of aldehyde-modified carboxymethyl cellulose was added into 200 mL of morpholine ethanesulfonic acid buffer solution (100 mM, pH = 5.5), stirred and dissolved, 1.45 g of morpholine acid salt was added, and the reaction was stirred for 0.5 h. Then, 0.55 g of 3-aminobenzenboronic acid was added, and the reaction was continuously stirred for 24 h. Washing, dialysis, and freeze-drying were performed to obtain modified carboxymethyl cellulose.

[0043] Example 4

[0044] Compared with Example 1, the only difference is that:

[0045] The preparation steps of the modified inorganic filler are as follows:

[0046] 0.30 g of nano-hexagonal boron nitride was added into 200 mL of Tris-HCl buffer solution (1 mol / L, pH = 7.4), ultrasonic dispersion was performed for 4 h, 0.40 g of dopamine hydrochloride was added, the pH value was adjusted to 8, and the reaction was stirred for 10 h. Centrifugal washing was performed for 3 times, and drying was performed to obtain the modified inorganic filler.

[0047] Example 5

[0048] Compared with Example 1, the only difference is that:

[0049] The preparation steps of the modified inorganic filler are as follows:

[0050] 0.40 g of nano-molybdenum disulfide was added into 200 mL of Tris-HCl buffer solution (1 mol / L, pH = 7.4), ultrasonic dispersion was performed for 4 h, 0.42 g of dopamine hydrochloride was added, the pH value was adjusted to 8, and the reaction was stirred for 10 h. Centrifugal washing was performed for 3 times, and drying was performed to obtain the modified inorganic filler.

[0051] Example 6

[0052] Compared with Example 1, the only difference is that:

[0053] In S2, 15 parts of the modified carboxymethyl cellulose were replaced by 25 parts of the modified carboxymethyl cellulose.

[0054] Example 7

[0055] Compared with Example 1, the only difference is that:

[0056] In S2, 5 parts of the modified inorganic filler were replaced by 10 parts of the modified inorganic filler.

[0057] Example 8

[0058] The difference compared with Example 1 is only that:

[0059] S2, by weight parts, 60 parts of vinyl trimethoxysilane is added to 110 parts of deionized water, stirred uniformly, 18 parts of modified carboxymethyl cellulose, 6 parts of modified inorganic filler are added to continue stirring reaction, hydrochloric acid is added to adjust pH to 4.5, hydrolysis reaction is carried out, and a sol is obtained.

[0060] Example 9

[0061] The difference compared with Example 1 is only that:

[0062] S2, by weight parts, 70 parts of vinyl trimethoxysilane is added to 110 parts of deionized water, stirred uniformly, 20 parts of modified carboxymethyl cellulose, 8 parts of modified inorganic filler are added to continue stirring reaction, hydrochloric acid is added to adjust pH to 5, hydrolysis reaction is carried out, and a sol is obtained.

[0063] Example 10

[0064] The difference compared with Example 1 is only that:

[0065] S2, by weight parts, 80 parts of vinyl trimethoxysilane is added to 120 parts of deionized water, stirred uniformly, 23 parts of modified carboxymethyl cellulose, 8 parts of modified inorganic filler are added to continue stirring reaction, hydrochloric acid is added to adjust pH to 5, hydrolysis reaction is carried out, and a sol is obtained.

[0066] Example 11

[0067] The difference compared with Example 1 is only that:

[0068] S3, sodium hydroxide is added to the sol to adjust pH to 11, stirred uniformly, and a gel is obtained after standing.

[0069] Comparative Example 1

[0070] The present comparative example provides a preparation method of a high-elasticity silicone aerogel, and the preparation steps are as follows:

[0071] S1, by weight parts, 60 parts of methyl trimethoxysilane is added to 100 parts of deionized water, stirred uniformly, hydrochloric acid is added to adjust pH to 4.5, and hydrolysis reaction is carried out, and a sol is obtained;

[0072] S2, sodium hydroxide is added to the sol to adjust pH to 10, stirred uniformly, and a gel is obtained after standing.

[0073] S3, the gel is freeze-dried to obtain a silicone aerogel.

[0074] The high-elasticity silicone aerogel is prepared by the above steps.

[0075] Comparative Example 2

[0076] The present comparative example provides a preparation method of a high-elasticity silicone aerogel, and the preparation steps are as follows:

[0077] S1, weighing, 60 parts of methyltrimethoxysilane were added into 100 parts of deionized water, stirred uniformly, 5 parts of modified inorganic filler was added for continuous stirring reaction, hydrochloric acid was added to adjust the pH to 4.5, and hydrolysis reaction was carried out to obtain a sol;

[0078] S2, sodium hydroxide was added to the sol to adjust the pH to 10, stirred uniformly, and a gel was obtained after standing;

[0079] S3, the gel was freeze-dried to obtain a silicone aerogel.

[0080] The preparation steps of the modified inorganic filler are as follows:

[0081] 0.25 g of nano-oxidized graphene was added into 200 mL of Tris-HCl buffer solution (1 mol / L, pH=7.4), ultrasonic dispersion was carried out for 4 h, 0.40 g of dopamine hydrochloride was added, the pH value was adjusted to 8, and stirring reaction was carried out for 10 h, centrifugal washing was carried out for 3 times, and drying was carried out to obtain modified nano-oxidized graphene.

[0082] The high-elasticity silicone aerogel is prepared by the above steps.

[0083] Comparative Example 3

[0084] The present comparative example provides a preparation method of a high-elasticity silicone aerogel, and the preparation steps are as follows:

[0085] S1, 1.0 g of carboxymethyl cellulose was added into 200 mL of deionized water, stirred and dissolved, 1.0 g of sodium periodate was added, the pH value was adjusted to 2.8, and stirring reaction was carried out for 3.5 h in the dark, and then aldehyde-modified carboxymethyl cellulose was obtained by using anhydrous ethanol for precipitation, washing, and freeze-drying; then 1.0 g of aldehyde-modified carboxymethyl cellulose was added into 200 mL of morpholine ethanesulfonic acid buffer solution (100 mM, pH=5.5), stirred and dissolved, 1.40 g of morpholine acid salt was added for stirring reaction for 0.5 h, 0.053 g of 3-aminobenzoic acid was added, and stirring reaction was continuously carried out for 24 h, and then modified carboxymethyl cellulose was obtained by washing, dialysis, and freeze-drying;

[0086] S2, weighing, 60 parts of methyltrimethoxysilane was added into 100 parts of deionized water, stirred uniformly, 15 parts of modified carboxymethyl cellulose was added for continuous stirring reaction, hydrochloric acid was added to adjust the pH to 4.5, and hydrolysis reaction was carried out to obtain a sol;

[0087] S3, adding sodium hydroxide to the sol to adjust pH to 10, stirring uniformly, and obtaining a gel after standing;

[0088] S4, freeze-drying the gel to obtain a silicone aerogel.

[0089] The high-elasticity silicone aerogel is prepared by the above steps.

[0090] Comparative Example 4

[0091] Compared with Example 1, the only difference is that:

[0092] S1, adding 1.5 g of carboxymethyl cellulose to 200 mL of deionized water, stirring to dissolve, adding 1.0 g of sodium periodate, adjusting the pH to 2.8, stirring to react in the dark for 3.5 h, precipitating, washing, and freeze-drying with anhydrous ethanol to obtain aldehyde-modified carboxymethyl cellulose; then adding 1.0 g of the aldehyde-modified carboxymethyl cellulose to 200 mL of a morpholine ethanesulfonic acid buffer solution (100 mM, pH = 5.5), stirring to dissolve, adding 1.40 g of morpholine acid salt, stirring to react for 0.5 h, adding 0.053 g of 3-aminobenzenboronic acid, continuing to stir to react for 24 h, washing, dialysis, and freeze-drying to obtain modified carboxymethyl cellulose.

[0093] Comparative Example 5

[0094] Compared with Example 1, the only difference is that:

[0095] S1, adding 1.0 g of carboxymethyl cellulose to 200 mL of deionized water, stirring to dissolve, adding 1.0 g of sodium periodate, adjusting the pH to 2.8, stirring to react in the dark for 3.5 h, precipitating, washing, and freeze-drying with anhydrous ethanol to obtain aldehyde-modified carboxymethyl cellulose; then adding 0.75 g of the aldehyde-modified carboxymethyl cellulose to 200 mL of a morpholine ethanesulfonic acid buffer solution (100 mM, pH = 5.5), stirring to dissolve, adding 1.40 g of morpholine acid salt, stirring to react for 0.5 h, adding 0.053 g of 3-aminobenzenboronic acid, continuing to stir to react for 24 h, washing, dialysis, and freeze-drying to obtain modified carboxymethyl cellulose.

[0096] Comparative Example 6

[0097] Compared with Example 1, the only difference is that:

[0098] S1, 1.0 g carboxymethyl cellulose was added into 200 mL deionized water, stirred and dissolved, 1.0 g sodium periodate was added, the pH value was adjusted to 2.8, and the reaction was stirred in the dark for 3.5 h. Anhydrous ethanol was used for precipitation, washing, and freeze-drying to obtain aldehyde carboxymethyl cellulose. Then 1.65 g of aldehyde carboxymethyl cellulose was added into 200 mL of morpholine ethanesulfonic acid buffer solution (100 mM, pH = 5.5), stirred and dissolved, 1.40 g of morpholine acid salt was added, and the reaction was stirred for 0.5 h. 0.053 g of 3-aminobenzenboronic acid was added, and the reaction was continuously stirred for 24 h. Washing, dialysis, and freeze-drying were performed to obtain modified carboxymethyl cellulose.

[0099] Comparative Example 7

[0100] Compared with Example 1, the only difference is that:

[0101] The preparation steps of the modified inorganic filler are as follows:

[0102] 0.15 g of nano-oxidized graphene was added into 200 mL of Tris-HCl buffer solution (1 mol / L, pH = 7.4), ultrasonic dispersion was performed for 4 h, 0.40 g of dopamine hydrochloride was added, the pH value was adjusted to 8, and the reaction was stirred for 10 h. Centrifugal washing was performed for 3 times, and drying was performed to obtain modified nano-oxidized graphene.

[0103] Comparative Example 8

[0104] Compared with Example 1, the only difference is that:

[0105] The preparation steps of the modified inorganic filler are as follows:

[0106] 0.50 g of nano-oxidized graphene was added into 200 mL of Tris-HCl buffer solution (1 mol / L, pH = 7.4), ultrasonic dispersion was performed for 4 h, 0.40 g of dopamine hydrochloride was added, the pH value was adjusted to 8, and the reaction was stirred for 10 h. Centrifugal washing was performed for 3 times, and drying was performed to obtain modified nano-oxidized graphene.

[0107] Comparative Example 9

[0108] Compared with Example 1, the only difference is that:

[0109] In S2, 15 parts of modified carboxymethyl cellulose were replaced by 8 parts of modified carboxymethyl cellulose.

[0110] Comparative Example 10

[0111] Compared with Example 1, the only difference is that:

[0112] In S2, 15 parts of modified carboxymethyl cellulose were replaced by 33 parts of modified carboxymethyl cellulose.

[0113] Comparative Example 11

[0114] The difference compared with Example 1 is only that:

[0115] In S2, 5 parts of modified inorganic filler is replaced by 3 parts of modified inorganic filler.

[0116] Comparative Example 12

[0117] The difference compared with Example 1 is only that:

[0118] In S2, 5 parts of modified inorganic filler is replaced by 12 parts of modified inorganic filler.

[0119] Comparative Example 13

[0120] The difference compared with Example 1 is only that:

[0121] S2, according to the weight parts, 45 parts of methyltrimethoxysilane is added into 100 parts of deionized water, stirred uniformly, 15 parts of modified carboxymethyl cellulose, 5 parts of modified inorganic filler is added to continue stirring reaction, hydrochloric acid is added to adjust pH to 4.5, hydrolysis reaction is carried out, and sol is obtained.

[0122] Comparative Example 14

[0123] The difference compared with Example 1 is only that:

[0124] S2, according to the weight parts, 60 parts of methyltrimethoxysilane is added into 130 parts of deionized water, stirred uniformly, 10 parts of modified carboxymethyl cellulose, 5 parts of modified inorganic filler is added to continue stirring reaction, hydrochloric acid is added to adjust pH to 4.5, hydrolysis reaction is carried out, and sol is obtained.

[0125] Comparative Example 15

[0126] The difference compared with Example 1 is only that:

[0127] S2, according to the weight parts, 70 parts of methyltrimethoxysilane is added into 100 parts of deionized water, stirred uniformly, 10 parts of modified carboxymethyl cellulose, 13 parts of modified inorganic filler is added to continue stirring reaction, hydrochloric acid is added to adjust pH to 4.5, hydrolysis reaction is carried out, and sol is obtained.

[0128] Comparative Example 16

[0129] The difference compared with Example 1 is only that:

[0130] S2, according to the weight parts, 60 parts of methyltrimethoxysilane is added into 100 parts of deionized water, stirred uniformly, 15 parts of modified carboxymethyl cellulose, 5 parts of modified inorganic filler is added to continue stirring reaction, hydrochloric acid is added to adjust pH to 3.5, hydrolysis reaction is carried out, and sol is obtained.

[0131] Comparative Example 17

[0132] S3, sodium hydroxide was added to the sol to adjust the pH to 12, stirred uniformly, and a gel was obtained after standing.

[0133] The high-elasticity silicone aerogels obtained in Examples 1-11 and Comparative Examples 1-17 were subjected to the following performance tests:

[0134] (1) Thermal conductivity test: tested according to GB / T 10294-2008.

[0135] (2) Compression resilience test: tested according to GB / T 34336-2017.

[0136] (3) Mass loss rate test: tested according to GB / T 34336-2017.

[0137] (4) Deformation test: the deformation sample size was 330 mm long, 122 mm wide and 3 mm high, and a mechanical property testing machine was used to press to 0.25 MPa (loading rate 2 mm / min, pre-load force 3 N). After the test was completed, the deformation value corresponding to the stress of 0.25 MPa was obtained.

[0138] (5) Antibacterial performance test: 1x106CFU / mL of E. coli and S. aureus were inoculated onto the surface of the silicone aerogel, incubated at 37°C and constant humidity for 24 h, the bacteria on the surface of the sample were eluted, ultrasonically collected, and the resulting bacterial solution was diluted with PBS solution to an appropriate multiple, and then spread on LB solid medium and incubated at 37°C and constant humidity for 18 h. Finally, the sample was photographed and analyzed using software to calculate the antibacterial rate, and the formula was: antibacterial rate (%) = (C-T) / C x 100%, C was the average number of colonies of the PI aerogel sample, and T was the average number of colonies of each test group.

[0139] The test results are shown in Table 1:

[0140] Table 1

[0141]

[0142]

[0143] As can be seen from Examples 1-11, after the silicone precursor, modified inorganic filler and modified carboxymethyl cellulose are mixed, the prepared silicone aerogel has excellent resilience and mechanical properties, and a low thermal conductivity, the lowest being 0.0142 W / (m·K), excellent thermal insulation performance; at the same time, the mass loss rate is low, reducing the "powder and residue" situation, and having excellent antibacterial performance, the antibacterial rate against S. aureus being as high as 83.45%, which can further expand the application scenarios of the silicone aerogel.

[0144] It can be seen from Comparative Examples 1-3 that, in Comparative Example 1, no modified carboxymethyl cellulose and no modified inorganic filler are added, in Comparative Example 2, no carboxymethyl cellulose is added, and in Comparative Example 3, no modified inorganic filler is added, and the thermal conductivity, mass loss rate of Comparative Examples 1-3 are all higher than those of Examples 1-11, and the compression resilience, deformation value and antibacterial rate are all lower than those of Examples 1-11. It can be seen that, under the synergistic effect of the modified carboxymethyl and the modified inorganic filler, the prepared silicone aerogel has excellent mechanical properties, resilience, thermal insulation performance and excellent antibacterial performance.

[0145] It can be seen from Comparative Examples 4-17 that, the preparation methods of the silicone aerogels in Comparative Examples 4-17 are all different from the preparation method provided in the present application, and the mechanical properties, resilience, thermal insulation performance and antibacterial performance of the obtained aerogels are all poorer than those of Examples 1-11. It can be seen that, in the process of preparing the silicone aerogel, the use, ratio and preparation process of the raw materials will all affect the comprehensive performance of the obtained aerogel.

[0146] It can be seen from the above that, the high-elasticity silicone aerogel prepared in the present application has excellent mechanical properties and elastic properties, and low elastic properties, and has good antibacterial properties, and the obtained silicone aerogel has good application prospects and can be widely applied in flexible electronics, sensors, energy storage fields and many other fields.

[0147] It should be noted that, in this document, relationship terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device.

[0148] Although the embodiments of the present application have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-elasticity silicone aerogel, characterized by, Comprising the following steps: S1, carboxymethyl cellulose is added to deionized water, stirred and dissolved, sodium periodate is added, the pH is adjusted to 2.8-3.0, and the reaction is stirred in the dark for 3.5-4h, precipitated with anhydrous ethanol, washed, and freeze-dried to obtain aldehyde carboxymethyl cellulose; wherein the amount ratio of carboxymethyl cellulose, deionized water and sodium periodate is 1.0g:200mL:1.0-1.1g; The aldehyde carboxymethyl cellulose is added to a morpholine ethanesulfonic acid buffer solution, stirred and dissolved, morpholine acid salt is added, stirred and reacted, 3-aminobenzenboronic acid is added, and the stirring is continued for 22-24h, washed, dialyzed, and freeze-dried to obtain modified carboxymethyl cellulose, wherein the amount ratio of aldehyde carboxymethyl cellulose, morpholine ethanesulfonic acid buffer solution, morpholine acid salt and 3-aminobenzenboronic acid is 1.0-1.3g:200mL:1.40-1.45g:0.053-0.55g; S2, the organic silicon precursor is added to deionized water, stirred and mixed, the modified carboxymethyl cellulose and the modified inorganic filler are added and the stirring is continued, an acid is added to adjust the pH to 4.5-5, and a hydrolysis reaction is carried out to obtain a sol; S3, a base is added to the sol to adjust the pH to 10-11, the stirring is continued until uniform, and the gel is obtained after standing; S4, the gel is freeze-dried to obtain a high-elasticity organic silicon aerogel; In S2, the modified inorganic filler is prepared by the following steps: The inorganic filler is added to a Tris-HCl buffer solution, ultrasonically dispersed for 4-5h, dopamine hydrochloride is added to adjust the pH to 8-8.5, and the stirring is continued for 8-10h, centrifuged, washed, and dried to obtain the modified inorganic filler; The amount ratio of the inorganic filler, the Tris-HCl buffer solution and the dopamine hydrochloride is 0.25-0.40g:200mL:0.40-0.42g.

2. The method for preparing a highly elastic organosilicon aerogel according to claim 1, characterized in that, The amount ratio by weight of the organic silicon precursor, deionized water, modified carboxymethyl cellulose and modified inorganic filler in S2 is 60-80 parts:100-120 parts:15-25 parts:5-10 parts.

3. The method for preparing a highly elastic organosilicon aerogel according to claim 1, characterized in that, The inorganic filler is at least one of nano graphene oxide, nano hexagonal boron nitride and nano molybdenum disulfide.

4. The method for preparing a highly elastic organosilicon aerogel according to claim 1, characterized in that, The organic silicon precursor is one or a mixture of two of methyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane and vinylmethyldimethoxysilane.

5. The method for preparing a highly elastic organosilicon aerogel according to claim 1, characterized in that, The acid in S2 is one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid and oxalic acid; and the base in S3 is one of sodium hydroxide and ammonia.

6. A high-elasticity silicone aerogel characterized by, Prepared by the preparation method of any one of claims 1-5.

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