MXene modified bamboo-based composite phase change energy storage material and preparation method thereof

Abstract

The invention discloses an MXene modified bamboo-based composite phase change energy storage material, which is characterized in that a Xene modified bamboo parenchyma cell-based packaging framework is used as a packaging matrix, and a phase change material is packaged in the packaging matrix. The preparation method comprises the following steps: (1) preparing the multi-cell-cavity bamboo parenchyma cells; (2) preparing a delignification bamboo parenchyma cell framework; (3) preparing an MXene modified bamboo parenchyma cell-based packaging framework; and (4) preparing the MXene modified bamboo-based composite phase change energy storage material. Compared with the prior art, the composite phase-change material has the following outstanding effects: the polyethylene glycol encapsulation rate of the composite phase-change material is as high as 80%, and the composite phase-change material has good heat storage capacity; the MXene modified bamboo parenchyma cytoskeleton MDBP can improve the flame retardant property of the composite material and reduce the heat release rate, and meanwhile, the carbon residue is increased to 6.1-15.1 w% from 4.28%; the composite phase change material shows good light absorption and heat conversion performance, and the peak temperature reached under the same light source irradiation time is far beyond that of a bamboo-based composite phase change material without MXene modification; the composite phase change material has thermal stability, flame retardance and photothermal conversion performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass-based composite phase change materials, and specifically relates to a MXene-modified bamboo-based composite phase change energy storage material and a preparation method thereof. Background Art

[0002] The effective recovery and storage of thermal energy has become a key link in improving energy utilization efficiency. According to statistics from the International Energy Agency, nearly 50% of the world's energy consumption is used for heating purposes, of which more than 60% is lost in the form of waste heat. Therefore, the development of efficient and sustainable thermal energy storage and management systems is of great strategic significance. In these systems, phase change materials (PCMs) have become the core research materials in the field of thermal energy management because they can reversibly store and release a large amount of latent heat during the phase change process. Polyethylene glycol (PEG), as a typical organic phase change material, has the advantages of high phase change enthalpy, simple preparation, and non-toxicity. However, it has inherent defects such as easy leakage during solid-liquid phase change and low thermal conductivity, which seriously restricts its practical application.

[0003] To address the problem of PEG's easy leakage, current research focuses on using porous substrates to encapsulate PEG in a fixed shape. In recent years, the preparation of porous biomaterials using biomass as raw materials has become a research hotspot in the field of energy storage and functional materials. These biomass materials can be converted into porous materials through physical, chemical, or biological treatments, which can then be used to adsorb phase change materials and construct shape-stable bio-based composite phase change energy storage materials. The thin-walled cell structure in bamboo is often burned or converted into bamboo charcoal as a processing residue due to its loose and porous structure and low mechanical strength. However, the unique structure of bamboo parenchyma cells with thin cell walls and large cell cavities not only provides abundant storage space but also opens up the possibility of efficient encapsulation of phase change materials. It is worth noting that organic phase change materials have poor absorption capacity for the solar spectrum, and the application of composite materials simply combining bamboo parenchyma cells with PEG in the field of photothermal conversion is limited. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies of the above existing technologies and provide a MXene-modified bamboo-based composite phase change energy storage material. The bamboo parenchyma cells of delignified bamboo processing waste modified with functional two-dimensional material MXene are used as a supporting skeleton and encapsulated with polyethylene glycol as a phase change material. The encapsulation rate is as high as 80%, and the material has good heat storage capacity.

[0005] Another object of the present invention is to provide a method for preparing a MXene-modified bamboo-based composite phase change energy storage material.

[0006] In order to achieve the above-mentioned purpose of the present invention, the technical solution adopted by the present invention is: a MXene-modified bamboo-based composite phase change energy storage material, using a Xene-modified bamboo parenchyma cell-based packaging frame as a packaging matrix, and encapsulating a phase change material in the packaging matrix.

[0007] The phase change material is polyethylene glycol, preferably polyethylene glycol 2000.

[0008] A method for preparing a MXene-modified bamboo-based composite phase change energy storage material comprises the following steps:

[0009] (1) Preparation of BP from multicellular bamboo parenchyma cells;

[0010] (2) Preparation of delignified bamboo parenchyma cell framework DBP, delignification treatment of multicellular bamboo parenchyma cell material BP to obtain delignified multicellular bamboo parenchyma cell material DBP with greater pore openness;

[0011] (3) Preparation of MXene-modified bamboo parenchyma cell-based encapsulation framework: Dropping MXene two-dimensional material aqueous dispersion onto the DBP surface, and immersing it in a vacuum drying oven to prepare MXene-modified bamboo parenchyma cell-based encapsulation framework MDBP;

[0012] (4) Preparation of MXene-modified bamboo-based composite phase change energy storage material MDBPP: The phase change material is encapsulated into the MXene-modified bamboo parenchyma cell-based framework MDBP by vacuum impregnation to prepare the MXene-modified bamboo-based composite phase change energy storage material MDBPP.

[0013] The preparation method of the multicellular bamboo parenchyma cell BP comprises the following steps:

[0014] (1) Cutting natural bamboo pieces into small pieces with a cutting machine and then crushing them in a grinder to make bamboo powder;

[0015] (2) Pour bamboo powder into deionized water and let it stand;

[0016] (3) Remove the bamboo parenchyma cells floating on the surface of deionized water;

[0017] (4) Spread the bamboo parenchyma cells into a thin layer and dry them.

[0018] The method for preparing delignified bamboo parenchyma cell DBP comprises the following steps:

[0019] (1) preparing a mixed solution of sodium chlorite and glacial acetic acid: first preparing a sodium hypochlorite aqueous solution with a concentration of 1 w%, and then adding glacial acetic acid dropwise to the sodium hypochlorite aqueous solution until the pH value of the mixed solution reaches 4.6;

[0020] (2) Pour the multicellular bamboo parenchyma cell BP into the mixed solution and boil until the sample turns pure white;

[0021] (3) The cooked multicellular bamboo parenchyma cells BP were placed in deionized water for ultrasonic washing;

[0022] (4) Freeze drying.

[0023] The preparation method of the MXene-modified bamboo parenchyma cell-based encapsulation framework comprises the following steps:

[0024] (1) Preparing MXene aqueous dispersion;

[0025] (2) Drop the MXene aqueous dispersion into the delignified bamboo parenchyma cell framework DBP and immerse it in a vacuum drying oven;

[0026] The proportion of the MXene in the delignified bamboo parenchyma cell framework DBP is 0.5-8w%.

[0027] The method for preparing the MXene aqueous dispersion comprises the following steps according to the following proportions:

[0028] (1) Dissolve 3.1128 g of lithium fluoride powder in a mixed solution consisting of 30 ml of concentrated hydrochloric acid and 10 ml of deionized water;

[0029] (2) 2 g of titanium aluminum carbon powder (MAX phase) was slowly added to the mixed solution in small amounts and multiple times, and the mixture was reacted in a 38°C water bath for 48 h;

[0030] (3) After the reaction, centrifugation was performed using 1 mol / L HCl solution, 1 mol / L LiCl solution, and deionized water, respectively. Each solution was washed three times. Subsequently, deionized water was used for repeated centrifugation until the pH value reached 6. All centrifugation steps were performed at 8000 rpm and 15°C.

[0031] (4) The washed precipitate was evenly dispersed in 150 ml of deionized water and subjected to ultrasonic treatment at 20 °C for 1 h at an ultrasonic frequency of 80 kHz. After ultrasonication, the mixture was centrifuged at 3500 rpm / min for 1 h. The upper layer was the aqueous dispersion of MXene nanosheets.

[0032] (5) The obtained MXene aqueous dispersion was freeze-dried at -40 °C and 10 kPa pressure for 72 h to obtain MXene powder.

[0033] The preparation method of the MXene-modified bamboo-based composite phase change energy storage material MDBPP comprises the following steps:

[0034] (1) dissolving the phase change material solid flakes in deionized water and sonicating them until they are completely dissolved to prepare a phase change material dispersion;

[0035] (2) Dropping the phase change material dispersion into the MXene-modified bamboo parenchyma cell framework MDBP;

[0036] (3) Vacuum impregnation.

[0037] It also includes the shaping of MXene-modified bamboo-based composite phase change energy storage materials, including the following steps:

[0038] (1) Mixing epoxy resin, curing agent, and diluent in proportion, stirring evenly with a stirrer to prepare an auxiliary setting adhesive;

[0039] (2) The adhesive and the MXene-modified bamboo-based composite phase change energy storage material MDBPP were stirred and mixed evenly, poured into a square mold with a size of 2 cm × 2 cm × 0.5 cm, and naturally cooled to form.

[0040] The epoxy resin can be the readily soluble diepoxy resin EPON produced by Dow Chemical Company. TM Resin862.

[0041] The curing agent can be EPIKURE produced by Hanson Chemical Company of the United States TM Curing Agent 3282.

[0042] The diluent may be butyl glycidyl ether.

[0043] Compared with the existing technology, the beneficial effects of the present invention are: the polyethylene glycol encapsulation rate of the composite phase change material is as high as 80%, and it has good heat storage capacity; the MXene-modified bamboo thin-walled cell skeleton MDBP can improve the flame retardant properties of the composite material, reduce the heat release rate, and at the same time increase the residual carbon from 4.28% to 6.1-15.1w%; the composite phase change material exhibits good light absorption and thermal conversion properties, and the peak temperature reached under the same light source irradiation time far exceeds that of the bamboo-based composite phase change material without MXene modification; the composite phase change material has thermal stability, flame retardant properties and light-to-heat conversion properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 SEM image of the MXene-modified bamboo parenchyma cell framework before encapsulation of phase change materials;

[0045] Figure 2 This is the SEM image of the MXene-modified bamboo-based composite phase change energy storage material after encapsulating the phase change material;

[0046] Figure 3 is the infrared spectrum of M1DBPP;

[0047] Figure 4 is the thermogravimetric curve of M1DBPP;

[0048] Figure 5 is the MCC curve of M1DBPP;

[0049] Figure 6 is the DSC curve of M1DBPP;

[0050] Figure 7 is the light-to-heat conversion curve of M1DBPP;

[0051] Figure 8 is the thermogravimetric curve of M2DBPP;

[0052] Figure 9 is the MCC curve of M2DBPP;

[0053] Figure 10 is the DSC curve of M2DBPP;

[0054] Figure 11 is the light-to-heat conversion curve of M2DBPP;

[0055] Figure 12 is the thermogravimetric curve of M3DBPP;

[0056] Figure 13 is the MCC curve of M3DBPP;

[0057] Figure 14 is the DSC curve of M3DBPP;

[0058] Figure 15 is the light-to-heat conversion curve of M3DBPP;

[0059] Figure 16 is the thermogravimetric curve of M4DBPP;

[0060] Figure 17 is the MCC curve of M4DBPP;

[0061] Figure 18 is the DSC curve of M4DBPP;

[0062] Figure 19 This is the photothermal conversion curve of M4DBPP. DETAILED DESCRIPTION

[0063] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The following embodiments are further explanations of the present invention, but the scope of protection of the present invention is not limited to the contents described above.

[0064] Example 1

[0065] A method for preparing a MXene-modified bamboo-based composite phase change energy storage material comprises the following steps:

[0066] (1) Preparation of multicellular bamboo parenchyma cell BP, the steps are as follows:

[0067] (1) Natural bamboo strips were cut into small bamboo pieces of 4 cm × 4 cm × 0.5 cm using a cutting machine, and then the small bamboo pieces were crushed into powder using a crusher, and then sieved through 60 mesh to make bamboo powder;

[0068] (2) Bamboo powder was placed in deionized water, stirred at a speed of 60 rpm, and then allowed to stand to separate bamboo fibers from bamboo parenchyma cells by physical sedimentation;

[0069] (3) Remove the bamboo parenchyma cells floating on the upper layer of deionized water, and repeat the physical sedimentation separation operation in step (2) three times;

[0070] (4) Spread the bamboo parenchyma cells into a thin layer and place them in an oven to dry at 80°C.

[0071] (2) Preparation of delignified bamboo parenchyma cell framework DBP, according to the following proportions, the steps are as follows:

[0072] (1) preparing a mixed solution of sodium hypochlorite (NaClO2) and glacial acetic acid (CH3COOH): first preparing a sodium hypochlorite aqueous solution with a concentration of 1 w%, and then adding glacial acetic acid dropwise to the sodium hypochlorite aqueous solution until the pH value of the mixed solution reaches 4.6;

[0073] (2) soaking the multicellular bamboo parenchyma cells BP in a mixed solution, wherein the ratio of the multicellular bamboo parenchyma cells BP to the mixed solution is 1:3, heating the mixture in an oil bath at 120° C., and performing a soaking and boiling treatment for 24 hours under stirring at 120 rpm until the multicellular bamboo parenchyma cells BP are completely bleached into pure white;

[0074] (3) The cooked multicellular bamboo parenchyma cells BP were taken out and placed in deionized water, and ultrasonic washing was repeated three times at an ultrasonic frequency of 80 kHz and a volume ratio of multicellular bamboo parenchyma cells BP to deionized water of 1:3;

[0075] (4) The obtained white sample was freeze-dried at -40°C and 10 kPa pressure for 48 h to obtain delignified bamboo parenchyma cell framework DBP. Figure 1 As shown, its microstructure is porous hollow cells.

[0076] (III) Preparation of MXene-modified bamboo parenchyma cell-based encapsulation framework M1DBP, according to the following proportions, the steps are as follows: weigh 0.01579 g of MXene powder and dissolve it in 5 ml of deionized water to prepare a MXene aqueous dispersion; drop the MXene aqueous dispersion into 0.3 g of delignified bamboo parenchyma cell framework DBP, place it in a vacuum drying oven, and immerse it at 60°C and 0.1 MPa pressure for 8 h to prepare a MXene-modified bamboo parenchyma cell-based encapsulation framework M1DBP;

[0077] (IV) Preparation of MXene-modified bamboo-based composite phase change energy storage material M1DBPP, according to the following proportions, the steps are as follows:

[0078] (1) Weigh 1.26 g of polyethylene glycol 2000 (PEG2000) solid flakes and dissolve them in 10 ml of deionized water to prepare a PEG dispersion.

[0079] (2) Dropping the PEG dispersion into the MXene-modified bamboo parenchyma cell framework M1DBP;

[0080] (3) Place it in a vacuum drying oven and immerse it at 60°C and 0.1 MPa pressure for 10 hours. After taking it out, cool it to below 25°C to obtain a 1% MXene-modified bamboo-based composite phase change energy storage material M1DBPP.

[0081] The samples were tested and the results were as follows Figure 2 As shown. Figure 1 and Figure 2 By comparison, it can be seen that the interior of the cell cavity of the bamboo parenchyma cells has been filled with PEG2000, proving that the phase change material has been successfully encapsulated.

[0082] (V) Preparation of MXene-modified bamboo-based composite phase change energy storage material M1DBPP, the steps are as follows:

[0083] (1) Prepare an auxiliary setting adhesive by mixing 2.5 g of epoxy resin, 2.5 g of curing agent, and 1 g of diluent with a stirring paddle at 250 rpm for 15 min;

[0084] (2) The adhesive was mixed into M1DBPP and stirred evenly, then poured into a square mold and allowed to stand for 48 hours to obtain a square block composite phase change material M1DBPP with a size of 2 cm × 2 cm × 0.5 cm.

[0085] Example 2

[0086] A method for preparing a MXene-modified bamboo-based composite phase change energy storage material comprises the following steps:

[0087] (1) Preparation of multicellular bamboo parenchyma cell BP, the steps are as follows:

[0088] (1) Natural bamboo strips were cut into small bamboo pieces of 4 cm × 4 cm × 0.5 cm using a cutting machine, and then the small bamboo pieces were crushed into powder using a crusher, and then sieved through 60 mesh to make bamboo powder;

[0089] (2) Bamboo powder was placed in deionized water, stirred at a speed of 60 rpm, and then allowed to stand to separate bamboo fibers from bamboo parenchyma cells by physical sedimentation;

[0090] (3) Remove the bamboo parenchyma cells floating on the upper layer of deionized water, and repeat the physical sedimentation separation operation in step (2) three times;

[0091] (4) Spread the bamboo parenchyma cells into a thin layer and place them in an oven to dry at 80°C.

[0092] (2) Preparation of delignified bamboo parenchyma cell framework DBP, according to the following proportions, the steps are as follows:

[0093] (1) preparing a mixed solution of sodium hypochlorite (NaClO2) and glacial acetic acid (CH3COOH): first preparing a sodium hypochlorite aqueous solution with a concentration of 1 w%, and then adding glacial acetic acid dropwise to the sodium hypochlorite aqueous solution until the pH value of the mixed solution reaches 4.6;

[0094] (2) soaking the multicellular bamboo parenchyma cells BP in a mixed solution, wherein the ratio of the multicellular bamboo parenchyma cells BP to the mixed solution is 1:3, heating the mixture in an oil bath at 120° C., and performing a soaking and boiling treatment for 24 hours under stirring at 120 rpm until the multicellular bamboo parenchyma cells BP are completely bleached into pure white;

[0095] (3) The cooked multicellular bamboo parenchyma cells BP were taken out and placed in deionized water, and ultrasonic washing was repeated three times at an ultrasonic frequency of 80 kHz and a volume ratio of multicellular bamboo parenchyma cells BP to deionized water of 1:3;

[0096] (4) The obtained white sample was freeze-dried at -40°C and 10 kPa pressure for 48 h to obtain delignified bamboo parenchyma cell framework DBP, whose microstructure is porous hollow cell cavity.

[0097] (III) Preparation of MXene-modified bamboo parenchyma cell-based encapsulation framework M2DBP, according to the following proportions, the steps are as follows: weigh 0.034 g of MXene powder and dissolve it in 5 ml of deionized water to prepare a MXene aqueous dispersion; drop the MXene aqueous dispersion into 0.3 g of delignified bamboo parenchyma cell framework DBP, place it in a vacuum drying oven, and immerse it at 60°C and 0.1 MPa pressure for 8 h to prepare a MXene-modified bamboo parenchyma cell-based encapsulation framework M2DBP;

[0098] (IV) Preparation of MXene-modified bamboo-based composite phase change energy storage material M2DBPP, according to the following proportions, the steps are as follows:

[0099] (1) Weigh 1.34 g of polyethylene glycol 2000 (PEG2000) solid flakes and dissolve them in 10 ml of deionized water to prepare a PEG dispersion.

[0100] (2) Dropping PEG dispersion into the MXene-modified bamboo parenchyma cell framework M2DBP;

[0101] (3) Place it in a vacuum drying oven and immerse it at 60°C and 0.1 MPa pressure for 10 hours. After taking it out, cool it to below 25°C to obtain a 2% MXene-modified bamboo-based composite phase change energy storage material M2DBPP.

[0102] (V) Preparation of MXene-modified bamboo-based composite phase change energy storage material M2DBPP, the steps are as follows:

[0103] (1) Prepare an auxiliary setting adhesive by mixing 2.5 g of epoxy resin, 2.5 g of curing agent, and 1 g of diluent with a stirring paddle at 250 rpm for 15 min;

[0104] (2) The adhesive was mixed into M2DBPP and stirred evenly, then poured into a square mold and allowed to stand for 48 h to obtain a square block composite phase change material M2DBPP with a size of 2 cm × 2 cm × 0.5 cm.

[0105] Example 3

[0106] A method for preparing a MXene-modified bamboo-based composite phase change energy storage material comprises the following steps:

[0107] (1) Preparation of multicellular bamboo parenchyma cell BP, the steps are as follows:

[0108] (1) Natural bamboo strips were cut into small bamboo pieces of 4 cm × 4 cm × 0.5 cm using a cutting machine, and then the small bamboo pieces were crushed into powder using a crusher, and then sieved through 60 mesh to make bamboo powder;

[0109] (2) Bamboo powder was placed in deionized water, stirred at a speed of 60 rpm, and then allowed to stand to separate bamboo fibers from bamboo parenchyma cells by physical sedimentation;

[0110] (3) Remove the bamboo parenchyma cells floating on the upper layer of deionized water, and repeat the physical sedimentation separation operation in step (2) three times;

[0111] (4) Spread the bamboo parenchyma cells into a thin layer and place them in an oven to dry at 80°C.

[0112] (2) Preparation of delignified bamboo parenchyma cell framework DBP, according to the following proportions, the steps are as follows:

[0113] (1) preparing a mixed solution of sodium hypochlorite (NaClO2) and glacial acetic acid (CH3COOH): first preparing a sodium hypochlorite aqueous solution with a concentration of 1 w%, and then adding glacial acetic acid dropwise to the sodium hypochlorite aqueous solution until the pH value of the mixed solution reaches 4.6;

[0114] (2) soaking the multicellular bamboo parenchyma cells BP in a mixed solution, wherein the ratio of the multicellular bamboo parenchyma cells BP to the mixed solution is 1:3, heating the mixture in an oil bath at 120° C., and performing a soaking and boiling treatment for 24 hours under stirring at 120 rpm until the multicellular bamboo parenchyma cells BP are completely bleached into pure white;

[0115] (3) The cooked multicellular bamboo parenchyma cells BP were taken out and placed in deionized water, and ultrasonic washing was repeated three times at an ultrasonic frequency of 80 kHz and a volume ratio of multicellular bamboo parenchyma cells BP to deionized water of 1:3;

[0116] (4) The obtained white sample was freeze-dried at -40°C and 10 kPa pressure for 48 h to obtain delignified bamboo parenchyma cell framework DBP, whose microstructure is porous hollow cell cavity.

[0117] (III) Preparation of MXene-modified bamboo parenchyma cell-based encapsulation framework M3DBP, according to the following proportions, the steps are as follows: weigh 0.05294 g of MXene powder and dissolve it in 5 ml of deionized water to prepare a MXene aqueous dispersion; drop the MXene aqueous dispersion into 0.3 g of delignified bamboo parenchyma cell framework DBP, place it in a vacuum drying oven, and immerse it at 60°C and 0.1 MPa pressure for 8 h to prepare a MXene-modified bamboo parenchyma cell-based encapsulation framework M3DBP;

[0118] (IV) Preparation of MXene-modified bamboo-based composite phase change energy storage material M3DBPP, according to the following proportions, the steps are as follows:

[0119] (1) Weigh 1.41 g of polyethylene glycol 2000 (PEG2000) solid flakes and dissolve them in 10 ml of deionized water to prepare a PEG dispersion.

[0120] (2) Dropping the PEG dispersion into the MXene-modified bamboo parenchyma cell framework M3DBP;

[0121] (3) Place it in a vacuum drying oven and immerse it at 60°C and 0.1 MPa pressure for 10 hours. After taking it out, cool it to below 25°C to obtain a 3% MXene-modified bamboo-based composite phase change energy storage material M3DBPP.

[0122] (V) Preparation of MXene-modified bamboo-based composite phase change energy storage material M3DBPP, the steps are as follows:

[0123] (1) Prepare an auxiliary setting adhesive by mixing 2.5 g of epoxy resin, 2.5 g of curing agent, and 1 g of diluent with a stirring paddle at 250 rpm for 15 min;

[0124] (2) The adhesive was mixed into M3DBPP and stirred evenly, then poured into a square mold and allowed to stand for 48 h to obtain a square block composite phase change material M3DBPP with a size of 2 cm × 2 cm × 0.5 cm.

[0125] Example 4

[0126] A method for preparing a MXene-modified bamboo-based composite phase change energy storage material comprises the following steps:

[0127] (1) Preparation of multicellular bamboo parenchyma cell BP, the steps are as follows:

[0128] (1) Natural bamboo strips were cut into small bamboo pieces of 4 cm × 4 cm × 0.5 cm using a cutting machine, and then the small bamboo pieces were crushed into powder using a crusher, and then sieved through 60 mesh to make bamboo powder;

[0129] (2) Bamboo powder was placed in deionized water, stirred at a speed of 60 rpm, and then allowed to stand to separate bamboo fibers from bamboo parenchyma cells by physical sedimentation;

[0130] (3) Remove the bamboo parenchyma cells floating on the upper layer of deionized water, and repeat the physical sedimentation separation operation in step (2) three times;

[0131] (4) Spread the bamboo parenchyma cells into a thin layer and place them in an oven to dry at 80°C.

[0132] (2) Preparation of delignified bamboo parenchyma cell framework DBP, according to the following proportions, the steps are as follows:

[0133] (1) preparing a mixed solution of sodium hypochlorite (NaClO2) and glacial acetic acid (CH3COOH): first preparing a sodium hypochlorite aqueous solution with a concentration of 1 w%, and then adding glacial acetic acid dropwise to the sodium hypochlorite aqueous solution until the pH value of the mixed solution reaches 4.6;

[0134] (2) soaking the multicellular bamboo parenchyma cells BP in a mixed solution, wherein the ratio of the multicellular bamboo parenchyma cells BP to the mixed solution is 1:3, heating the mixture in an oil bath at 120° C., and performing a soaking and boiling treatment for 24 hours under stirring at 120 rpm until the multicellular bamboo parenchyma cells BP are completely bleached into pure white;

[0135] (3) The cooked multicellular bamboo parenchyma cells BP were taken out and placed in deionized water, and ultrasonic washing was repeated three times at an ultrasonic frequency of 80 kHz and a volume ratio of multicellular bamboo parenchyma cells BP to deionized water of 1:3;

[0136] (4) The obtained white sample was freeze-dried at -40°C and 10 kPa pressure for 48 h to obtain delignified bamboo parenchyma cell framework DBP, whose microstructure is porous hollow cell cavity.

[0137] (III) Preparation of MXene-modified bamboo parenchyma cell-based encapsulation framework M4DBP, according to the following proportions, the steps are as follows: weigh 0.0750 g of MXene powder and dissolve it in 5 ml of deionized water to prepare a MXene aqueous dispersion; drop the MXene aqueous dispersion into 0.3 g of delignified bamboo parenchyma cell framework DBP, place it in a vacuum drying oven, and immerse it at 60°C and 0.1 MPa pressure for 8 h to prepare a MXene-modified bamboo parenchyma cell-based encapsulation framework M4DBP;

[0138] (IV) Preparation of MXene-modified bamboo-based composite phase change energy storage material M4DBPP, according to the following proportions, the steps are as follows:

[0139] (1) Weigh 1.50 g of polyethylene glycol 2000 (PEG2000) solid flakes and dissolve them in 10 ml of deionized water to prepare a PEG dispersion.

[0140] (2) Dropping the PEG dispersion into the MXene-modified bamboo parenchyma cell framework M4DBP;

[0141] (3) Place it in a vacuum drying oven and immerse it at 60°C and 0.1 MPa pressure for 10 hours. After taking it out, cool it to below 25°C to obtain a 4% MXene-modified bamboo-based composite phase change energy storage material M4DBPP.

[0142] (V) Preparation of MXene-modified bamboo-based composite phase change energy storage material M4DBPP, the steps are as follows:

[0143] (1) Prepare an auxiliary setting adhesive by mixing 2.5 g of epoxy resin, 2.5 g of curing agent, and 1 g of diluent with a stirring paddle at 250 rpm for 15 min;

[0144] (2) The adhesive was mixed into M4DBPP and stirred evenly, then poured into a square mold and allowed to stand for 48 h to obtain a square block composite phase change material M4DBPP with a size of 2 cm × 2 cm × 0.5 cm.

[0145] Performance testing of MXene-modified bamboo-based composite phase change energy storage materials

[0146] Example 5

[0147] FTIR tests were performed on BP, DBP, PEG and M1DBPP, such as Figure 3 As shown, for natural bamboo powder without chemical treatment, at 1603cm -1 、1512cm -1 and 1465cm -1 The absorption peak at 1746cm represents the aromatic stretching vibration of lignin, but this peak is almost not observed in the delignified DBP, indicating that the lignin in BP is effectively removed after treatment. However, the hemicellulose-related peak in DBP (1746cm -1 and 1241cm -1 ) was retained, indicating that the treatment method selectively retained hemicellulose, further confirming that the bamboo-based skeleton still existed. After the introduction of the encapsulation framework, the spectrum of M1DBPP was almost consistent with that of PEG, and no obvious new absorption peaks were found, indicating that PEG was successfully adsorbed into the MXene-modified bamboo parenchyma cell cavity structure, and only physical interaction occurred between PEG and the supporting skeleton, and no new chemical interaction occurred. Take 10 mg of the 1 w% MXene-modified bamboo-based composite phase change energy storage material M1DBPP prepared in Example 1 and 10 mg of pure PEG2000 (control) for TGA testing, as shown Figure 4 As shown in Figure 2, pure PEG2000 is almost completely pyrolyzed, while the residual carbon content of the bamboo-based composite phase change energy storage material modified with 1w% MXene is 6.11wt%. Similarly, 5mg M1DBPP and 5mg pure PEG2000 (control) were taken for MCC test, as shown in Figure 2. Figure 5 As shown in the figure, the peak thermal rate of pure PEG2000 is 566.61W / g, and the total heat release is 27.32kJ / g, while the peak thermal rate of the bamboo-based composite phase change energy storage material modified with 1w% MXene is 491.48W / g, and the total heat release is 19.67kJ / g. It can be seen that the thermal stability and flame retardant properties of the composite phase change material are improved to a certain extent; through DSC test, such as Figure 6 As shown in the figure, during the heating and cooling process, M1DBPP has a melting peak and a crystallization peak, which are similar to the peak shape of pure PEG. No chemical reaction occurs between PEG2000 and M1DBP. Pure DBPP and M1DBPP were subjected to a xenon lamp irradiation simulation test. After 90 seconds of xenon lamp irradiation, the peak temperature of M1DBPP reached 76.8℃, which is significantly higher than that of pure DBPP. Figure 7 shown.

[0148] Example 6

[0149] Take 10mg 2% MXene modified bamboo-based composite phase change energy storage material M2DBPP and 10mg pure PEG2000 (control) for TGA test, as shown in Figure 2. Figure 8 As shown in Figure 2, pure PEG2000 is almost completely pyrolyzed, while the residual carbon content of the bamboo-based composite phase change energy storage material modified with 2% MXene is 7.93 wt%. Similarly, 5 mg of M2DBPP and 5 mg of pure PEG (control) were taken for MCC test. Figure 9 As shown in the figure, the peak thermal rate of pure PEG2000 is 566.61W / g, and the total heat release is 27.32kJ / g, while the peak thermal rate of the bamboo-based composite phase change energy storage material modified with 2% MXene is 392.24W / g, and the total heat release is 18.41kJ / g. It can be seen that the thermal stability and flame retardant properties of the composite phase change material are improved to a certain extent; through DSC test, such as Figure 10 As shown in the figure, during the heating and cooling process, M2DBPP has a melting peak and a crystallization peak, which are similar to the peak shape of pure PEG2000. No chemical reaction occurs between PEG2000 and M2DBP. Pure DBPP and M2DBPP were subjected to a xenon lamp irradiation simulation test. After 90 seconds of xenon lamp irradiation, the peak temperature of M1DBPP reached 77.9℃, which is significantly higher than that of pure DBPP. Figure 11 shown.

[0150] Example 7

[0151] Take 10mg 3% MXene modified bamboo-based composite phase change energy storage material M3DBPP and 10mg pure PEG2000 (control) for TGA test. Figure 12 As shown in Figure 2, pure PEG2000 is almost completely pyrolyzed, while the residual carbon content of the bamboo-based composite phase change energy storage material modified with 3% MXene is 8.89 wt%. Similarly, 5 mg of M3DBPP and 5 mg of pure PEG (control) were taken for MCC test. Figure 13 As shown in the figure, the peak thermal rate of pure PEG2000 is 566.61W / g, and the total heat release is 27.32kJ / g, while the peak thermal rate of the bamboo-based composite phase change energy storage material modified with 3% MXene is 228.05W / g, and the total heat release is 15.57kJ / g. It can be seen that the thermal stability and flame retardant properties of the composite phase change material are improved to a certain extent; through DSC test, such as Figure 14 As shown in the figure, during the heating and cooling process, M3DBPP has a melting peak and a crystallization peak, which are similar to the peak shape of pure PEG2000. No chemical reaction occurs between PEG2000 and M3DBP. Pure DBPP and M3DBPP were subjected to a xenon lamp irradiation simulation test. After 90 seconds of xenon lamp irradiation, the peak temperature of M1DBPP reached 82.5℃, which is significantly higher than that of pure DBPP. Figure 15 shown.

[0152] Example 8

[0153] Take 10mg 4% MXene modified bamboo-based composite phase change energy storage material M4DBPP and 10mg pure PEG2000 (control) for TGA test. Figure 16 As shown in Figure 2, pure PEG2000 is almost completely pyrolyzed, while the residual carbon content of the bamboo-based composite phase change energy storage material modified with 4% MXene is 15.06 wt%. Similarly, 5 mg of M4DBPP and 5 mg of pure PEG (control) were taken for MCC test. Figure 17 As shown in the figure, the peak thermal rate of pure PEG is 566.61W / g, and the total heat release is 27.32kJ / g, while the peak thermal rate of the bamboo-based composite phase change energy storage material modified with 4% MXene is 209.63W / g, and the total heat release is 14.98kJ / g. It can be seen that the thermal stability and flame retardant properties of the composite phase change material are improved to a certain extent; through DSC test, such as Figure 18 As shown in the figure, during the heating and cooling process, M4DBPP has a melting peak and a crystallization peak, which are similar to the peak shape of pure PEG2000. There is no chemical reaction between PEG2000 and M4DBP. Pure DBPP and M4DBPP were subjected to a xenon lamp irradiation simulation test. After 90 seconds of xenon lamp irradiation, the peak temperature of M1DBPP reached 95.2℃, which is significantly higher than that of pure DBPP. Figure 19 shown.

[0154] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A MXene-modified bamboo-based composite phase change energy storage material, characterized in that: A Xene-modified bamboo parenchyma cell-based packaging frame is used as a packaging matrix, and a phase change material is encapsulated in the packaging matrix.

2. The MXene-modified bamboo-based composite phase change energy storage material according to claim 1, characterized in that: The phase change material is polyethylene glycol.

3. The method for preparing a MXene-modified bamboo-based composite phase change energy storage material according to claim 1 or 2, characterized in that: The steps involved are as follows: (1) Preparation of multicellular bamboo parenchyma cells; (2) Preparation of delignified bamboo parenchyma cell framework; (3) Preparation of MXene-modified bamboo parenchyma cell-based encapsulation framework; (4) Preparation of MXene-modified bamboo-based composite phase change energy storage materials.

4. The method for preparing a MXene-modified bamboo-based composite phase change energy storage material according to claim 3, characterized in that: The preparation method of the multicellular bamboo parenchyma cells comprises the following steps: (1) Cutting natural bamboo pieces into small pieces with a cutting machine and then crushing them in a grinder to make bamboo powder; (2) Pour bamboo powder into deionized water and let it stand; (3) Remove the bamboo parenchyma cells floating on the surface of deionized water; (4) Spread the bamboo parenchyma cells into a thin layer and dry them.

5. The method for preparing a MXene-modified bamboo-based composite phase change energy storage material according to claim 3, characterized in that: The method for preparing delignified bamboo parenchyma cells comprises the following steps: (1) preparing a mixed solution of sodium chlorite and glacial acetic acid: first preparing a sodium hypochlorite aqueous solution with a concentration of 1 w%, and then adding glacial acetic acid dropwise to the sodium hypochlorite aqueous solution until the pH value of the mixed solution reaches 4.6; (2) Pour the multicellular bamboo parenchyma cells into the mixed solution and boil until the sample turns pure white; (3) taking out the cooked multicellular bamboo parenchyma cells and placing them in deionized water for ultrasonic washing; (4) Freeze drying.

6. The method for preparing a MXene-modified bamboo-based composite phase change energy storage material according to claim 3, characterized in that: The preparation method of the MXene-modified bamboo parenchyma cell-based encapsulation framework comprises the following steps: (1) Preparing MXene aqueous dispersion; (2) Dropping MXene aqueous dispersion into the delignified bamboo parenchyma cell framework and immersing it in a vacuum drying oven; The proportion of the MXene in the delignified bamboo parenchyma cell framework is 0.5-8w%.

7. The method for preparing a MXene-modified bamboo-based composite phase change energy storage material according to claim 3, characterized in that: The preparation method of the MXene-modified bamboo-based composite phase change energy storage material comprises the following steps: (1) dissolving a phase change material in deionized water to prepare a phase change material dispersion; (2) Dropping the phase change material dispersion into the MXene-modified bamboo parenchyma cell framework; (3) Vacuum impregnation.

8. The method for preparing a MXene-modified bamboo-based composite phase change energy storage material according to claim 3, characterized in that: The invention also includes shaping of a MXene-modified bamboo-based composite phase change energy storage material, which includes the following steps: 1) mixing and stirring an epoxy resin, a curing agent, and a diluent to prepare an adhesive for auxiliary shaping; (2) The adhesive and the MXene-modified bamboo-based composite phase change energy storage material were stirred and mixed evenly, poured into a square mold with a size of 2 cm × 2 cm × 0.5 cm, and naturally cooled to form.

9. The method for preparing a MXene-modified bamboo-based composite phase change energy storage material according to claim 8, characterized in that: The epoxy resin is the easily soluble diepoxy resin EPON produced by Dow Chemical Company TM Resin 862; the curing agent is EPIKURE produced by Hanson Chemical Company of the United States TM Curing Agent 3282; the diluent is butyl glycidyl ether.

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