Phenolic resin-based carbon aerogel and preparation method thereof

Abstract

The invention belongs to the technical field of carbon aerogel, and particularly relates to phenolic resin-based carbon aerogel and a preparation method thereof.The preparation method comprises the following steps that 1, phenolic resin is prepared, specifically, a phenolic compound and an aldehyde compound are added into a reaction kettle for a reaction, a catalyst is added for continuous stirring, the heating temperature and stirring time of the reaction kettle are controlled, and phenolic resin is prepared; phenolic resin is obtained; 2, phenolic resin treatment: taking out the prepared phenolic resin, adding an organic solvent, and stirring to prepare a phenolic resin solution; step 3, gel preparation: putting the mixed solution into a reaction kettle, adding an organic solvent, continuously heating, then stopping heating, and cooling a high-pressure kettle to obtain organic aerogel; step 4, gel treatment: activating the organic carbon material to form a carbon aerogel precursor, and activating and cleaning the surface by adopting a normal pressure plasma technology; the organic aerogel is added into a cracking furnace, protective gas is added, the cracking furnace is heated, heat preservation is conducted, cooling is conducted, and the carbon aerogel is obtained.The newly-prepared phenolic resin is adopted, it is avoided that the quality of the phenolic resin is affected by long-time storage, the organic matter is added, and the carbon aerogel is prepared by carbonizing the organic matter after activating treatment; therefore, the forming quality of the carbon aerogel is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon aerogels, and in particular relates to a phenolic resin-based carbon aerogel and a preparation method thereof. Background Art

[0002] Carbon aerogel has unique properties, such as continuous porosity, low density, high specific surface area, high thermal insulation and sound insulation, high electrical conductivity, ultra-high temperature thermal stability in non-oxidizing atmosphere, etc. It has great potential as adsorbent, chromatographic coating agent, gas diffusion electrode, capacitor deionization, molecular sieve, thermal protection system insulation material, supercapacitor or rechargeable battery electrode, fuel cell advanced catalyst carrier, inertial confinement nuclear fusion target material, etc. Resorcinol-formaldehyde aerogel (RF) is the most studied organic aerogel and the most commonly used precursor for preparing carbon aerogel.

[0003] Carbon aerogel is mainly produced by carbonizing organic precursor aerogel with a porous hierarchical structure. Micropores are generated during the carbonization process, thereby producing a high specific surface area. Organic precursors include glucose, fructose, bacterial cellulose, phenolic resin, etc.

[0004] At present, when preparing carbon aerogel, prepared phenolic resin is usually used as raw material. After the phenolic resin is stored for a long time, dust will adhere to the surface, which will reduce the quality of the phenolic resin itself. When organic solvents are added, there are more impurities in the mixed liquid, which affects the molding quality of the carbon aerogel. Summary of the invention

[0005] In order to solve the problems in the prior art, the present invention provides a phenolic resin-based carbon aerogel and a preparation method thereof, which adopts newly prepared phenolic resin to avoid affecting the quality of the phenolic resin by long-term storage, and adds organic matter, and carbonizes the organic matter after activation treatment to obtain carbon aerogel, so as to ensure the molding quality of the carbon aerogel.

[0006] The present invention solves the technical problem by adopting the following technical solutions:

[0007] The present invention aims to provide a method for preparing phenolic resin-based carbon aerogel, comprising the following steps:

[0008] Step 1, preparing phenolic resin: adding phenolic compound and aldehyde compound into a reaction kettle for reaction, adding catalyst for continuous stirring, heating for reaction, and obtaining phenolic resin;

[0009] Step 2, phenolic resin treatment: taking out the prepared phenolic resin, adding an organic solvent and stirring to obtain a phenolic resin solution;

[0010] Step 3, gel preparation: placing a phenolic resin solution in a reaction kettle, adding an organic solvent and continuously heating, then stopping the heating and cooling the autoclave to obtain an organic aerogel;

[0011] Step 4: Gel treatment: Activate the organic carbon material to form a carbon aerogel precursor, and use normal pressure plasma technology to activate and clean the surface;

[0012] Step 5: Gel carbonization: Add the organic aerogel into the cracking furnace, add protective gas, heat the cracking furnace and keep it warm, and cool it to obtain carbon aerogel.

[0013] The present invention first prepares phenolic resin by using phenolic compounds and aldehyde compounds, and after treating the phenolic resin, adds an organic solvent to prepare organic aerogel, performs activation treatment on organic carbon material to form a carbon aerogel precursor, and then adds the organic aerogel into a cracking furnace for carbonization to obtain carbon aerogel. The newly prepared phenolic resin is used to avoid affecting the quality of the phenolic resin by long-term storage, and organic matter is added, and the organic matter is carbonized after activation to obtain carbon aerogel, thereby ensuring the molding quality of the carbon aerogel.

[0014] Furthermore, in step 1, 200 parts of phenolic compound, 70-100 parts of aldehyde compound and 2-9 parts of catalyst are used.

[0015] Furthermore, in step 1, the heating temperature of the reaction kettle is controlled to be 50-70° C., the heating time is 25-40 minutes, and the stirring time is 8-15 minutes.

[0016] The preparation method of phenolic resin uses liquefied gas as a catalyst. The raw materials and catalyst are mixed and placed in a reactor. Under heating and stirring conditions, the reaction is continued until the required viscosity is reached, and then cooled to form. Compared with other methods, it is more efficient, has the least pollution, and has a higher purity of phenolic resin.

[0017] Furthermore, in step 2, the organic solvent is methanol or isopropanol. By adding the organic solvent, the phenolic resin contains carbon groups, and the carbon groups are provided by the organic solvent.

[0018] Furthermore, in step three, the mixed solution is placed in a reactor through a container, and the ratio of the amount of organic solvent added to the volume of the reactor is 1.5:7.

[0019] Furthermore, in step three, the heating temperature is 120-220° C., and the heating time is 2-7 hours.

[0020] After the organic phenolic resin solution is heated, it is uniformly mixed with stirring, so that the organic phenolic resin solution is continuously gelled. After natural cooling, the inside of the colloid shrinks to form pores, thereby forming an organic aerogel.

[0021] Furthermore, in step 4, the surface of the gel is ultrasonically cleaned, dried naturally after cleaning, and activated after drying.

[0022] Atmospheric pressure plasma technology is used to increase surface energy, which is convenient for subsequent carbonization treatment. Atmospheric pressure plasma technology has the advantages of simple process, convenient operation, fast processing speed, good treatment effect, low environmental pollution, and energy saving, which can effectively improve surface adhesion and product quality.

[0023] Furthermore, in step five, the protective gas is nitrogen or argon.

[0024] Furthermore, in step five, the gel is dried under normal pressure to obtain an aerogel, and the aerogel is added to a pyrolysis furnace to obtain a phenolic resin-based carbon aerogel.

[0025] A cracking furnace is a device used to crack hydrocarbons. By continuously heating, the organic matter in the organic aerogel is carbonized to eventually form a carbon aerogel.

[0026] A phenolic resin-based carbon aerogel is prepared by adopting the preparation method of the phenolic resin-based carbon aerogel.

[0027] Compared with the prior art, the beneficial technical effects of the present invention are:

[0028] The present invention first prepares phenolic resin by using phenolic compounds and aldehyde compounds, and after treating the phenolic resin, adds an organic solvent to prepare organic aerogel, performs activation treatment on organic carbon material to form a carbon aerogel precursor, and then adds the organic aerogel into a cracking furnace for carbonization to obtain carbon aerogel. The newly prepared phenolic resin is used to avoid affecting the quality of the phenolic resin by long-term storage, and organic matter is added, and the organic matter is carbonized after activation to obtain carbon aerogel, thereby ensuring the molding quality of the carbon aerogel.

[0029] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above contents of the present invention and its objectives, features and advantages more obvious and easy to understand, the specific implementation methods of the present invention are listed below. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary illustrations and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0031] In addition, unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0032] Example 1

[0033] A method for preparing a phenolic resin-based carbon aerogel comprises the following steps:

[0034] Step 1, preparing phenolic resin: 200 parts of phenolic compounds and 70 parts of aldehyde compounds are added to a reactor for reaction, 2 parts of catalyst are added for continuous stirring, the heating temperature of the reactor is controlled to be 50° C., the heating time is 25 minutes, and the stirring time is 8 minutes to obtain phenolic resin;

[0035] Step 2, phenolic resin treatment: taking out the prepared phenolic resin, adding an organic solvent, methanol, and stirring to obtain a phenolic resin solution;

[0036] Step 3, gel preparation: placing the phenolic resin solution in a reactor through a container, adding an organic solvent and continuously heating, the ratio of the amount of organic solvent added to the volume of the reactor is 1.5:7; the heating temperature is 120° C., the heating time is 2 hours, then the heating is stopped, and the autoclave is cooled to obtain an organic aerogel;

[0037] Step 4, gel treatment: ultrasonically clean the gel surface, dry it naturally after cleaning, activate the organic carbon material after drying to form a carbon aerogel precursor, and use normal pressure plasma technology to activate and clean the surface;

[0038] Step 5, gel carbonization: The gel is dried under normal pressure, and the dried organic aerogel is added to a cracking furnace, and protective gas nitrogen is added. The cracking furnace is heated and kept warm, and carbon aerogel is obtained after cooling.

[0039] The carbon aerogel prepared in this embodiment has a specific surface area of ​​1150 m 2 / g, density is 0.28g / cm 3 The pore size of the micropores is 2.3nm, the pore size of the mesopores is 15nm, and the pore size of the macropores is 70nm.

[0040] Example 2

[0041] A method for preparing a phenolic resin-based carbon aerogel comprises the following steps:

[0042] Step 1, preparing phenolic resin: 200 parts of phenolic compounds and 100 parts of aldehyde compounds are added to a reactor for reaction, 9 parts of a catalyst are added for continuous stirring, the heating temperature of the reactor is controlled to be 70° C., the heating time is 40 minutes, and the stirring time is 15 minutes to obtain a phenolic resin;

[0043] Step 2, phenolic resin treatment: taking out the prepared phenolic resin, adding isopropanol as an organic solvent and stirring to obtain a phenolic resin solution;

[0044] Step 3, gel preparation: placing the phenolic resin solution in a reactor through a container, adding an organic solvent and continuously heating, the ratio of the amount of organic solvent added to the volume of the reactor is 1.5:7, the heating temperature is 220°C, the heating time is 7 hours, and then the heating is stopped, the autoclave is cooled, and the organic aerogel is obtained;

[0045] Step 4, gel treatment: ultrasonically clean the gel surface, dry it naturally after cleaning, activate the organic carbon material after drying to form a carbon aerogel precursor, and use normal pressure plasma technology to activate and clean the surface;

[0046] Step 5, gel carbonization: The gel is dried under normal pressure, and the dried organic aerogel is added to a cracking furnace, and protective gas argon is added, and the cracking furnace is heated and kept warm, and carbon aerogel is obtained after cooling.

[0047] The surface area of ​​the prepared carbon aerogel is 1280 m 2 / g, density is 0.24g / cm 3 The pore size of the micropores is 2.6nm, the pore size of the mesopores is 17nm, and the pore size of the macropores is 78nm.

[0048] Example 3

[0049] A method for preparing a phenolic resin-based carbon aerogel comprises the following steps:

[0050] Step 1, preparing phenolic resin: 200 parts of phenolic compounds and 85 parts of aldehyde compounds are added to a reactor for reaction, 5 parts of a catalyst are added for continuous stirring, the heating temperature of the reactor is controlled to be 60° C., the heating time is 30 minutes, and the stirring time is 11 minutes to obtain a phenolic resin;

[0051] Step 2, phenolic resin treatment: taking out the prepared phenolic resin, adding an organic solvent, methanol, and stirring to obtain a phenolic resin solution;

[0052] Step 3, gel preparation: placing the phenolic resin solution in a reactor through a container, adding an organic solvent and continuously heating, the ratio of the amount of organic solvent added to the volume of the reactor is 1.5:7; the heating temperature is 170° C., the heating time is 5 hours, then the heating is stopped, the autoclave is cooled, and the organic aerogel is obtained;

[0053] Step 4, gel treatment: ultrasonically clean the gel surface, dry it naturally after cleaning, activate the organic carbon material after drying to form a carbon aerogel precursor, and use normal pressure plasma technology to activate and clean the surface;

[0054] Step 5, gel carbonization: The gel is dried under normal pressure, and the dried organic aerogel is added to a cracking furnace, and protective gas nitrogen is added. The cracking furnace is heated and kept warm, and carbon aerogel is obtained after cooling.

[0055] The surface area of ​​the prepared carbon aerogel is 1410 m 2 / g, density is 0.21g / cm 3 The pore size of the micropores is 2.9nm, the pore size of the mesopores is 19nm, and the pore size of the macropores is 91nm.

[0056] Comparative Example 1

[0057] A method for preparing a phenolic resin-based carbon aerogel comprises the following steps:

[0058] Step 1: Phenolic resin treatment: taking phenolic resin, adding organic solvent methanol and stirring to obtain a phenolic resin solution;

[0059] Step 2, gel preparation: placing the phenolic resin solution in a reactor through a container, adding an organic solvent and continuously heating, the ratio of the amount of organic solvent added to the volume of the reactor is 1.5:7; the heating temperature is 120° C., the heating time is 2 hours, then the heating is stopped, and the autoclave is cooled to obtain an organic aerogel;

[0060] Step 3, gel carbonization: The gel is dried under normal pressure, and the dried organic aerogel is added to a cracking furnace, and protective gas nitrogen is added. The cracking furnace is heated and kept warm, and carbon aerogel is obtained after cooling.

[0061] The specific surface area of ​​the carbon aerogel prepared in Comparative Example 1 is 560 m 2 / g, density is 0.39g / cm 3 The pore size of the micropores is 1.3nm, the pore size of the mesopores is 7nm, and the pore size of the macropores is 40nm.

[0062] Comparative Example 2

[0063] This embodiment includes the following steps:

[0064] (1) Preparation of phenolic resin solution: 100 g of phenolic resin (purchased from Beijing Glass Steel Institute Composite Materials Co., Ltd., the phenolic resin is an ethanol solution, the original resin concentration is 68 wt%) is mixed with 100 g of methanol to make the concentration of phenolic resin in the solution 34 wt%, and stirred to form a transparent red solution;

[0065] (2) High temperature and high pressure gelation and aging: Pour the phenolic resin solution into a glass beaker, place the beaker into an autoclave, add methanol equivalent to 15% of the volume of the autoclave (in this embodiment, the volume of the autoclave is 10 L, and the volume of the added methanol is 1.5 L), and the mouth of the beaker is higher than the methanol liquid level in the autoclave to isolate the phenolic resin solution and methanol; fill with nitrogen to a pressure of 2 MPa to prevent the organic solvent from volatilizing, heat the autoclave at a heating rate of 1°C / min, heat to a holding temperature of 150°C, and keep it warm for 5 hours;

[0066] (3) Supercritical drying: Continue to heat the autoclave at a heating rate of 2°C / min to a drying temperature of 255°C, so that the organic solvent reaches a supercritical state. After a holding time of 2 hours, the supercritical organic solvent is released while maintaining the temperature. Then, stop heating, allow the autoclave to cool overnight, and discharge the material to obtain an organic aerogel.

[0067] (4) Cracking and carbonization: The organic aerogel is added into a cracking furnace with a flowing nitrogen atmosphere as the protective gas. The cracking furnace is heated at a heating rate of 2°C / min. After heating to the cracking temperature of 1000°C, the temperature is kept for 1 hour, and then the power is turned off, cooled, and discharged to obtain carbon aerogel.

[0068] The specific surface area of ​​the carbon aerogel obtained in Comparative Example 2 is 471.2 m 2 / g, average pore size 40nm, average particle size 24nm.

[0069] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0070] The embodiments of the present invention are described above, but the present invention is not limited to the above-mentioned specific implementation modes. The above-mentioned specific implementation modes are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all within the protection of the present invention.

Claims

1. A method for preparing phenolic resin-based carbon aerogel, characterized in that: The following steps are involved: Step 1, preparing phenolic resin: adding phenolic compound and aldehyde compound into a reaction kettle for reaction, adding catalyst for continuous stirring, heating for reaction, and obtaining phenolic resin; Step 2, phenolic resin treatment: taking out the prepared phenolic resin, adding an organic solvent and stirring to obtain a phenolic resin solution; Step 3, gel preparation: placing a phenolic resin solution in a reaction kettle, adding an organic solvent and continuously heating, then stopping the heating, and cooling to obtain an organic aerogel; Step 4: Gel treatment: Activate the organic carbon material to form a carbon aerogel precursor, and use normal pressure plasma technology to activate and clean the surface; Step 5: Gel carbonization: Add the organic aerogel into the cracking furnace, add protective gas, heat the cracking furnace and keep it warm, and cool it to obtain carbon aerogel.

2. The method for preparing a phenolic resin-based carbon aerogel according to claim 1, characterized in that: In step 1, 200 parts of phenolic compound, 70-100 parts of aldehyde compound and 2-9 parts of catalyst are used.

3. The method for preparing a phenolic resin-based carbon aerogel according to claim 2, characterized in that: In step 1, the heating temperature of the reaction kettle is controlled to be 50-70° C., the heating time is 25-40 minutes, and the stirring time is 8-15 minutes.

4. The method for preparing a phenolic resin-based carbon aerogel according to claim 1, characterized in that: In step 2, the organic solvent is methanol or isopropanol.

5. The method for preparing a phenolic resin-based carbon aerogel according to claim 1, characterized in that: In step 3, the ratio of the amount of organic solvent added to the volume of the reactor is 1.5:

7.

6. A method for preparing a phenolic resin-based carbon aerogel according to claim 5, characterized in that: In step 3, the heating temperature is 120-220° C. and the heating time is 2-7 hours.

7. The method for preparing a phenolic resin-based carbon aerogel according to claim 1, characterized in that: In step 4, the surface of the gel is ultrasonically cleaned, dried naturally after cleaning, and activated after drying.

8. The method for preparing a phenolic resin-based carbon aerogel according to claim 1, characterized in that: In step 5, the protective gas is nitrogen or argon.

9. A phenolic resin-based carbon aerogel, characterized in that: The carbon aerogel is prepared by the method for preparing a phenolic resin-based carbon aerogel according to any one of claims 1 to 8.