A composite cigarette paper, its preparation method and application

Abstract

This invention provides a composite cigarette paper, its preparation method, and its application. The preparation method includes the following steps: (1) mixing ferric oleate, oleic acid, and a solvent, heating and reacting the mixture, and then preparing the resulting solid into a Fe3O4 colloidal nanocrystal dispersion; (2) wetting the substrate with an inducing agent solution and then adding the dispersion to the substrate surface; (3) heat-treating the substrate, coating it with a methyl methacrylate solution, and then etching it to obtain a mesoporous carbon film; (4) calcining the mesoporous carbon film and then coating it onto the surface of the cigarette paper to obtain the composite cigarette paper. This invention utilizes the self-assembly of colloidal nanocrystals to construct a mesoporous graphene framework material. This material has good chemical stability and high thermal conductivity, which can not only improve the structural stability of the cigarette paper, but also reduce the draw resistance of the cigarette during inhalation, increase oxygen to ensure complete combustion of the tobacco, reduce the amount of tar produced, and improve the combustibility of the cigarette.

Description

Technical Field

[0001] This invention belongs to the field of cigarette combustion technology, and relates to a composite cigarette paper, its preparation method, and its application. Background Technology

[0002] Currently, there are two main conventional methods to improve the combustion performance of cigarettes. The first is to improve the combustion performance of tobacco by adding a liquid containing a combustion improver to the tobacco leaves. The second is to improve the combustion performance of cigarettes by using highly permeable cigarette paper.

[0003] As a type of specialty paper, the flammability of cigarette paper is a very important indicator. Poor flammability of cigarette paper will increase the number of puffs required to smoke a cigarette, increase the amount of tar released, and often cause the cigarette to go out when it is still burning.

[0004] CN115214216A discloses a multi-layer composite cigarette paper structure and manufacturing method with good ash-coating performance, including an inner layer of cigarette paper disposed on the outside of tobacco and an outer layer of cigarette paper disposed on the outside of the inner layer of cigarette paper. An ash-coating layer is disposed between the inner layer of cigarette paper and the outer layer of cigarette paper. A functional groove is provided on the side of the inner layer of cigarette paper away from the tobacco, and a friction surface is provided on the side of the ash-coating layer close to the inner layer of cigarette paper.

[0005] CN114622435A discloses a cigarette paper, the raw material composition of which, by weight, includes: 20-45 parts of modified low-polymerization degree cotton linter dissolving pulp, 25-40 parts of calcium carbonate, 0.5-1.5 parts of starch, and 1-5 parts of flame retardant.

[0006] Although the cigarette paper disclosed in the above scheme can improve the combustibility of cigarette paper, its specific structure and the selection of additives reduce the structural stability of the cigarette paper. Furthermore, the additives reduce the thermal conductivity of the cigarette paper during combustion, thereby reducing the user experience. Summary of the Invention

[0007] The purpose of this invention is to provide a composite cigarette paper, its preparation method, and its application. This invention utilizes the self-assembly of colloidal nanocrystals to construct a continuous and uniform mesoporous graphene framework material. The mesoporous graphene framework film material has good chemical stability and high thermal conductivity, which can not only improve the structural stability of the cigarette paper, but also reduce the draw resistance of the cigarette during inhalation, increase oxygen to ensure complete combustion of tobacco, reduce the amount of tar produced, and improve the combustibility of the cigarette.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing composite cigarette paper, the method comprising the following steps:

[0010] (1) Mix ferric oleate, oleic acid and the first solvent, heat and react, then separate the solid and liquid, and mix the obtained solid with the second solvent to obtain Fe3O4 colloidal nanocrystal dispersion;

[0011] (2) After wetting the substrate with an inducing agent solution, Fe3O4 colloidal nanocrystal dispersion is added to the substrate surface to obtain a substrate loaded with Fe3O4 nanocrystal superlattice two-dimensional thin film;

[0012] (3) After heat treatment of the substrate loaded with Fe3O4 nanocrystal superlattice two-dimensional thin film, methyl methacrylate solution is coated on one side of the two-dimensional thin film loaded with Fe3O4 nanocrystal superlattice, and then etched to obtain mesoporous carbon thin film.

[0013] (4) The mesoporous carbon film is calcined to obtain a mesoporous graphene framework film, and the mesoporous graphene framework film is then coated onto the surface of cigarette paper to obtain the composite cigarette paper.

[0014] This invention uses monodisperse colloidal Fe3O4 nanocrystals as templates. The uniform surface of the nanoparticles is coated with a layer of organic ligands (oleic acid). Under the induction of an inducing agent, the organic ligands self-assemble on the substrate through intermolecular forces, assembling into a superlattice thin film structure in a face-centered cubic close-packed arrangement. The organic ligands are then carbonized by heat treatment, and the nanoparticles and substrate are etched to obtain a highly ordered mesoporous carbon framework thin film material. Further high-temperature treatment of the mesoporous carbon framework material ultimately synthesizes a centimeter-sized, self-supporting mesoporous graphene framework thin film. The pore structure of this mesoporous graphene framework thin film material is highly ordered and continuous. When applied to the surface of cigarette paper, it not only improves the structural stability of the cigarette paper, but the unique structure of the mesoporous graphene framework thin film material also enhances the combustion performance, additive absorption, and air permeability of the cigarette paper.

[0015] Preferably, in step (1), the first solvent comprises octadecene.

[0016] Preferably, the molar ratio of ferric oleate to oleic acid in step (1) is 1:(0.6~0.9), for example: 1:0.6, 1:0.65, 1:0.7, 1:0.8 or 1:0.9, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] Preferably, a vacuum treatment is performed before the heating reaction in step (1).

[0018] Preferably, the heating reaction temperature in step (1) is 300~350℃, for example: 300℃, 310℃, 320℃, 330℃ or 350℃, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0019] Preferably, the heating reaction time in step (1) is 20 to 40 minutes, for example: 20 minutes, 25 minutes, 30 minutes, 35 minutes or 40 minutes, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0020] Preferably, centrifugal washing is performed before solid-liquid separation in step (1).

[0021] Preferably, the detergent used in the centrifugal washing process includes any one or a combination of at least two of hexane, ethanol, or isopropanol. Typical but non-limiting combinations include combinations of hexane and ethanol, hexane and ethanol, or ethanol and isopropanol.

[0022] Preferably, in step (1), the second solvent comprises n-hexane and / or chloroform.

[0023] Preferably, the concentration of the Fe3O4 colloidal nanocrystal dispersion in step (1) is 20~100g / L, for example: 20g / L, 40g / L, 60g / L, 80g / L or 100g / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] Preferably, the induction solution in step (2) comprises a diethylene glycol solution.

[0025] Preferably, the substrate in step (2) comprises aluminum foil.

[0026] Preferably, the addition method in step (2) includes drip addition.

[0027] Preferably, the inducing agent is extracted after the addition in step (2).

[0028] Preferably, the heat treatment temperature in step (3) is 400~550℃, for example: 400℃, 420℃, 450℃, 500℃ or 550℃, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0029] Preferably, the heat treatment time in step (3) is 1 to 3 hours, for example: 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] Preferably, the solvent of the methyl methacrylate solution in step (3) includes toluene.

[0031] Preferably, the mass concentration of the methyl methacrylate solution in step (3) is 1~3%, for example: 1%, 1.5%, 2%, 2.5% or 3%, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0032] Preferably, after coating in step (3), the coating is subjected to a room temperature standing treatment and a heated standing treatment.

[0033] Preferably, the temperature for the room temperature settling treatment is 20~30℃, for example: 20℃, 22℃, 25℃, 28℃ or 30℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] Preferably, the time for the room temperature standing treatment is 20 to 40 minutes, for example: 20 minutes, 25 minutes, 30 minutes, 35 minutes or 40 minutes, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the temperature of the heating and settling treatment is 100~150℃, for example: 100℃, 110℃, 120℃, 140℃ or 150℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the heating and settling time is 5 to 15 minutes, for example: 5 minutes, 8 minutes, 10 minutes, 12 minutes or 15 minutes, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] Preferably, the etchant used in step (3) includes hydrochloric acid.

[0038] Preferably, the calcination temperature in step (4) is 900~1200℃, for example: 900℃, 950℃, 1000℃, 1100℃ or 1200℃, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0039] Preferably, the calcination time in step (4) is 1 to 3 hours, for example: 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Preferably, before coating in step (4), the mesoporous graphene skeleton film is mixed with a reinforcing agent, a combustion aid, microcrystalline cellulose, and water.

[0041] Preferably, the reinforcing agent comprises chitosan.

[0042] Preferably, the combustion aid includes sodium citrate.

[0043] Preferably, the microcrystalline cellulose includes hydroxyethyl cellulose.

[0044] Preferably, the mass ratio of the mesoporous graphene framework film to the reinforcing agent, combustion aid, and microcrystalline cellulose is (40~60):(5~10):(0.5~2):(5~10), for example: 40:5:0.5:5, 45:8:1:6, 50:8:0.6:5, 55:10:2:5, or 60:10:2:10, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0045] Preferably, the coating is followed by drying and pressing.

[0046] In a second aspect, the present invention provides a composite cigarette paper, which is prepared by the method described in the first aspect.

[0047] Thirdly, the present invention provides a combustible cigarette comprising the composite cigarette paper as described in the second aspect.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The present invention utilizes the self-assembly of colloidal nanocrystals to construct a continuous and uniform mesoporous graphene framework material. The mesoporous graphene framework film material has good chemical stability and high thermal conductivity, which can not only improve the structural stability of cigarette paper, but also reduce the draw resistance of cigarettes during smoking, increase oxygen so that the tobacco can burn completely, reduce the amount of tar produced, and improve the combustibility of cigarettes.

[0050] (2) The smoldering rate of cigarettes made using the composite cigarette paper described in this invention can reach within 64s / 150mm, which greatly improves the combustibility of cigarettes. Detailed Implementation

[0051] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0052] Example 1

[0053] This embodiment provides a composite cigarette paper, which is prepared by the following method:

[0054] (1) Using octadecene (ODE, CAS No. 112-88-9) as solvent, ferric oleate and oleic acid were added in a molar ratio of 4:3. The mixture was vacuumed at 120°C to remove the low-boiling solvent. Then it was heated to 320°C and held for 30 min. After cooling, 5 mL of n-hexane, 5 mL of ethanol, and 20 mL of isopropanol were added to every 20 mL of mother liquor. The mixture was centrifuged at 4000 rpm for 3 min. The resulting precipitate was dissolved in 20 mL of n-hexane, 5 mL of ethanol, and 20 mL of isopropanol were added. The mixture was centrifuged at 4000 rpm for 3 min. This step was repeated twice. The resulting nanocrystals were dispersed in n-hexane to obtain Fe3O4 colloidal nanocrystal dispersion.

[0055] (2) Place appropriately sized aluminum foil (1.5×1.5cm) into the polytetrafluoroethylene tank. 2 Add diethylene glycol solution to completely wet the aluminum foil, add 1.0 mL of Fe3O4 colloidal nanocrystal dispersion with a concentration of 40 g / L, and allow n-hexane to evaporate completely at 25 °C. Remove the diethylene glycol to obtain a Fe3O4 nanocrystal superlattice two-dimensional thin film assembled on the aluminum foil.

[0056] (3) The assembled Fe3O4 nanocrystalline superlattice film was transferred to a tube furnace and heated to 500°C at a heating rate of 2°C / min under an argon atmosphere and held for 2 hours to carbonize the oleic acid ligands on the surface of the Fe3O4 nanoparticles. Amorphous carbon was then coated on the surface of the Fe3O4 nanoparticles. After cooling to 25°C, the film was removed and the obtained nanocrystalline superlattice film was black. A layer of toluene solution of methyl methacrylate with a weight ratio of 2% was spin-coated on the surface of the film. The film was placed at 25°C for 30 minutes and then at 120°C for 10 minutes. The film was then repeatedly transferred to a dilute hydrochloric acid solution to completely etch the Fe3O4 nanoparticles and aluminum foil. The film surface was washed repeatedly with distilled water to remove a small amount of FeCl3 and AlCl3 impurities. This mesoporous carbon skeleton film can be directly transferred from the aqueous phase to any substrate and then dried in a vacuum drying oven.

[0057] (4) The mesoporous carbon film is transferred to a graphite boat and kept at 1000°C for 2 hours under an argon atmosphere to transform the ordered mesoporous carbon skeleton film into a highly graphitized mesoporous graphene skeleton film. The mesoporous graphene skeleton film, chitosan, sodium citrate and hydroxyethyl cellulose are mixed with water in a mass ratio of 50:8:1:6 and coated on the surface of cigarette paper. The composite cigarette paper is obtained by drying and pressing.

[0058] Example 2

[0059] This embodiment provides a composite cigarette paper, which is prepared by the following method:

[0060] (1) Using octadecene (ODE) as solvent, ferric oleate and oleic acid were added in a molar ratio of 4:2.4. The mixture was vacuumed at 120°C to remove the low-boiling-point solvent. Then it was heated to 300°C and held for 40 min. After cooling, 5 mL of n-hexane, 5 mL of ethanol, and 20 mL of isopropanol were added to every 20 mL of mother liquor. The mixture was centrifuged at 4000 rpm for 3 min. The resulting precipitate was dissolved in 20 mL of n-hexane, 5 mL of ethanol, and 20 mL of isopropanol were added. The mixture was centrifuged at 4000 rpm for 3 min. This step was repeated twice. The resulting nanocrystals were dispersed in n-hexane to obtain Fe3O4 colloidal nanocrystal dispersion.

[0061] (2) Place appropriately sized aluminum foil (1.5×1.5cm) into the polytetrafluoroethylene tank. 2 Add diethylene glycol solution to completely wet the aluminum foil, add 1.0 mL of Fe3O4 colloidal nanocrystal dispersion with a concentration of 20 g / L, and allow n-hexane to evaporate completely at 25 °C. Remove the diethylene glycol to obtain a Fe3O4 nanocrystal superlattice two-dimensional thin film assembled on the aluminum foil.

[0062] (3) The assembled Fe3O4 nanocrystalline superlattice film was transferred to a tube furnace and heated to 400°C at a heating rate of 2°C / min under an argon atmosphere and held for 3 hours to carbonize the oleic acid ligands on the surface of the Fe3O4 nanoparticles. Amorphous carbon was then coated on the surface of the Fe3O4 nanoparticles. After cooling to 25°C, the film was removed and the obtained nanocrystalline superlattice film was black. A layer of toluene solution of methyl methacrylate with a weight ratio of 1% was spin-coated on the surface of the film. The film was placed at 25°C for 30 minutes and then at 120°C for 10 minutes. The film was then repeatedly transferred to a dilute hydrochloric acid solution to completely etch the Fe3O4 nanoparticles and aluminum foil at the same time. The film surface was washed repeatedly with distilled water to remove a small amount of FeCl3 and AlCl3 impurities. This mesoporous carbon framework film can be directly transferred from the aqueous phase to any substrate and then dried in a vacuum drying oven.

[0063] (4) The mesoporous carbon film is transferred to a graphite boat and kept at 900°C for 3 hours under an argon atmosphere, so that the ordered mesoporous carbon skeleton film is transformed into a highly graphitized mesoporous graphene skeleton film. The mesoporous graphene skeleton film, chitosan, sodium citrate and hydroxyethyl cellulose are mixed with water in a mass ratio of 40:5:0.5:5 and coated on the surface of cigarette paper. The composite cigarette paper is obtained by drying and pressing.

[0064] Example 3

[0065] This embodiment provides a composite cigarette paper, which is prepared by the following method:

[0066] (1) Using octadecene (ODE) as solvent, ferric oleate and oleic acid were added in a molar ratio of 4:3.6. The mixture was vacuumed at 120ºC to remove low-boiling-point solvents. Then it was heated to 350℃ and held for 20 min. After cooling, 5 mL of n-hexane, 5 mL of ethanol, and 20 mL of isopropanol were added to every 20 mL of mother liquor. The mixture was centrifuged at 4000 rpm for 3 min. The resulting precipitate was dissolved in 20 mL of n-hexane, 5 mL of ethanol, and 20 mL of isopropanol were added. The mixture was centrifuged at 4000 rpm for 3 min. This step was repeated twice. The resulting nanocrystals were dispersed in n-hexane to obtain Fe3O4 colloidal nanocrystal dispersion.

[0067] (2) Place appropriately sized aluminum foil (1.5×1.5cm) into the polytetrafluoroethylene tank. 2 Add diethylene glycol solution to completely wet the aluminum foil, add 1.0 mL of Fe3O4 colloidal nanocrystal dispersion with a concentration of 100 g / L, and allow the n-hexane to evaporate completely at 25 °C. Remove the diethylene glycol to obtain a Fe3O4 nanocrystal superlattice two-dimensional thin film assembled on the aluminum foil.

[0068] (3) The assembled Fe3O4 nanocrystalline superlattice film was transferred to a tube furnace and heated to 550°C at a heating rate of 2°C / min under an argon atmosphere and held for 1 hour to carbonize the oleic acid ligands on the surface of the Fe3O4 nanoparticles. Amorphous carbon was then coated on the surface of the Fe3O4 nanoparticles. After cooling to room temperature, the obtained nanocrystalline superlattice film was black. A layer of toluene solution of methyl methacrylate with a weight ratio of 3% was spin-coated on the film surface. The film was placed at 25°C for 30 minutes and then at 150°C for 5 minutes. The film was then repeatedly transferred to a dilute hydrochloric acid solution to completely etch the Fe3O4 nanoparticles and aluminum foil at the same time. The film surface was washed repeatedly with distilled water to remove a small amount of FeCl3 and AlCl3 impurities. This mesoporous carbon framework film can be directly transferred from the aqueous phase to any substrate and then dried in a vacuum drying oven.

[0069] (4) The mesoporous carbon film is transferred to a graphite boat and kept at 1200°C for 1 hour under an argon atmosphere, so that the ordered mesoporous carbon skeleton film is transformed into a highly graphitized mesoporous graphene skeleton film. The mesoporous graphene skeleton film, chitosan, sodium citrate and hydroxyethyl cellulose are mixed with water in a mass ratio of 60:10:2:10 and coated on the surface of cigarette paper. The composite cigarette paper is obtained by drying and pressing.

[0070] Example 4

[0071] The only difference between this embodiment and embodiment 1 is that the heating temperature in step (1) is 250°C, while the other conditions and parameters are exactly the same as in embodiment 1.

[0072] Example 5

[0073] The only difference between this embodiment and embodiment 1 is that the heating temperature in step (1) is 400°C, while the other conditions and parameters are exactly the same as in embodiment 1.

[0074] Example 6

[0075] The only difference between this embodiment and embodiment 1 is that the temperature of the heat treatment in step (3) is 350°C, while the other conditions and parameters are exactly the same as in embodiment 1.

[0076] Example 7

[0077] The only difference between this embodiment and embodiment 1 is that the temperature of the heat treatment in step (3) is 600°C, while the other conditions and parameters are exactly the same as in embodiment 1.

[0078] Comparative Example 1

[0079] The only difference between this comparative example and Example 1 is that no inducing agent solution is added in step (2), while the other conditions and parameters are exactly the same as in Example 1.

[0080] Comparative Example 2

[0081] The only difference between this comparative example and Example 1 is that the methyl methacrylate solution is not coated; all other conditions and parameters are exactly the same as in Example 1.

[0082] Comparative Example 3

[0083] The only difference between this comparative example and Example 1 is that the calcination treatment in step (4) is not performed, and the mesoporous carbon film is used directly. The other conditions and parameters are exactly the same as those in Example 1.

[0084] Performance testing:

[0085] The cigarette paper prepared in the examples and comparative examples was used to make cigarettes and combustion tests were conducted. The tobacco used and the environmental conditions were the same. The test results are shown in Table 1.

[0086]

[0087] As can be seen from Table 1, as demonstrated in Examples 1-3, the smoldering rate of cigarettes made using the composite cigarette paper described in this invention can reach less than 64s / 150mm, which significantly improves the combustibility of cigarettes.

[0088] Comparing Examples 1 and 4-5, it can be seen that the heating temperature in step (1) of the preparation process of the composite cigarette paper of the present invention will affect its performance. Controlling the heating temperature at 300~350℃ can yield Fe3O4 colloidal nanocrystals with better results. If the heating temperature is too low, the oleic acid iron conversion is incomplete and the content of Fe3O4 colloidal nanocrystals is low. If the heating temperature is too high, the iron oxide colloid will partially decompose and the decomposed part cannot generate nanocrystals.

[0089] Comparing Examples 1 and 6-7, it can be seen that the temperature of heat treatment in step (3) of the preparation process of the composite cigarette paper of the present invention will affect its performance. By controlling the temperature of heat treatment in step (3) at 400~550℃, Fe3O4 colloidal nanocrystals with better effect can be obtained. If the heat treatment temperature is too low, the ligands on the surface of iron oxide cannot be completely converted into carbon, resulting in less carbon material generated. If the heat treatment temperature is too high, the aluminum in the matrix will partially melt and enter the carbon material and be encapsulated. The subsequent etching process is incomplete, resulting in aluminum impurities in the material, which reduces its effect.

[0090] By comparing Example 1 and Comparative Example 1, it can be seen that by adding an inducing agent, the organic ligands on the surface of iron oxide (Fe3O4) self-assemble on aluminum foil or other substrates under the action of the inducing agent, and assemble into a superlattice thin film structure in a face-centered cubic close-packed arrangement.

[0091] As can be seen from the comparison between Example 1 and Comparative Example 2, methyl methacrylate solution can avoid the damage of nanocrystalline superlattice films during the process and ensure their morphology.

[0092] As can be seen from the comparison between Example 1 and Comparative Example 2, calcination treatment can directly graphitize the mesoporous carbon framework film at high temperature, resulting in a highly ordered mesoporous graphene framework film, which further improves the performance of the material.

[0093] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing composite cigarette paper, characterized in that, The preparation method includes the following steps: (1) After mixing ferric oleate, oleic acid and the first solvent, heating, centrifuging and washing are performed to separate the solid and liquid. The obtained solid is mixed with the second solvent to obtain Fe3O4 colloidal nanocrystal dispersion. (2) After wetting the substrate with an inducing agent solution, Fe3O4 colloidal nanocrystal dispersion is added to the substrate surface to obtain a substrate loaded with Fe3O4 nanocrystal superlattice two-dimensional thin film; (3) After heat treatment of the substrate loaded with Fe3O4 nanocrystal superlattice two-dimensional thin film, a methyl methacrylate solution with a mass concentration of 1~3% is coated on one side of the two-dimensional thin film loaded with Fe3O4 nanocrystal superlattice. The substrate is subjected to room temperature static treatment and heated static treatment, and then etched to obtain a mesoporous carbon thin film. (4) The mesoporous carbon film is calcined to obtain a mesoporous graphene framework film. The mesoporous graphene framework film is mixed with the reinforcing agent chitosan, the combustion aid sodium citrate, hydroxyethyl cellulose and water and coated on the surface of cigarette paper. The mixture is then dried and pressed to obtain the composite cigarette paper. The molar ratio of ferric oleate to oleic acid in step (1) is 1:(0.6~0.9); The detergent used in the centrifugal washing process includes any one or a combination of at least two of hexane, ethanol, or isopropanol. The concentration of the Fe3O4 colloidal nanocrystal dispersion in step (1) is 20~100g / L; The room temperature settling treatment is at a temperature of 20~30℃ for 20~40 min, and the heated settling treatment is at a temperature of 100~150℃ for 5~15 min.

2. The preparation method according to claim 1, characterized in that, Step (1) The first solvent includes octadecene.

3. The preparation method according to claim 1, characterized in that, Before the heating reaction described in step (1), a vacuum process is performed.

4. The preparation method according to claim 1, characterized in that, The heating reaction in step (1) is carried out at a temperature of 300~350℃.

5. The preparation method according to claim 1, characterized in that, The heating reaction time in step (1) is 20~40 min.

6. The preparation method according to claim 1, characterized in that, Step (1) The second solvent includes n-hexane and / or chloroform.

7. The preparation method according to claim 1, characterized in that, The inducing agent solution in step (2) includes a diethylene glycol solution.

8. The preparation method according to claim 1, characterized in that, The substrate in step (2) includes aluminum foil.

9. The preparation method according to claim 1, characterized in that, The method of addition in step (2) includes dripping.

10. The preparation method according to claim 1, characterized in that, After the addition in step (2), the inducing agent is extracted.

11. The preparation method according to claim 1, characterized in that, The heat treatment temperature in step (3) is 400~550℃.

12. The preparation method according to claim 1, characterized in that, The heat treatment time in step (3) is 1 to 3 hours.

13. The preparation method according to claim 1, characterized in that, The solvent for the methyl methacrylate solution in step (3) includes toluene.

14. The preparation method according to claim 1, characterized in that, The etching agent in step (3) includes hydrochloric acid.

15. The preparation method according to claim 1, characterized in that, The calcination temperature in step (4) is 900~1200℃.

16. The preparation method according to claim 1, characterized in that, The calcination process in step (4) takes 1 to 3 hours.

17. The preparation method according to claim 1, characterized in that, The mass ratio of the mesoporous graphene framework film to the reinforcing agent, combustion aid and hydroxyethyl cellulose is (40~60):(5~10):(0.5~2):(5~10).

18. A composite cigarette paper, characterized in that, The composite cigarette paper is prepared by the method described in any one of claims 1-17.

19. A type of combustible cigarette, characterized in that, The burning cigarette comprises the composite cigarette paper as described in claim 18.

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