CN113072916A - Modified graphene-based heat conduction enhanced ionic liquid composite phase change heat storage material and preparation method thereof - Google Patents
Modified graphene-based heat conduction enhanced ionic liquid composite phase change heat storage material and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a modified graphene-based heat conduction enhanced ionic liquid composite phase-change heat storage material and a preparation method thereof. And further, mixing the modified graphene and the imidazole ionic liquid phase-change material matrix, and controlling conditions such as rotary evaporation and drying to obtain a mixture of different modified graphene loading amounts and the ionic liquid matrix phase-change material. The material has the characteristics of large phase change latent heat and good thermal stability, and meanwhile, the thermal conductivity is increased by 4.4-127.9% compared with that of the ionic liquid without the modified graphene, so that the thermal energy storage and conduction characteristics of the material are obviously improved.
Description
Technical Field
The invention relates to the field of composite materials, in particular to a modified graphene-based heat conduction enhanced ionic liquid composite phase-change heat storage material and a preparation method thereof.
Background
The solid-liquid Phase change heat storage technology is realized by absorbing a large amount of heat through solid-liquid Phase change of Phase Change Materials (PCMs) when the ambient temperature reaches the melting point, and the solid-liquid Phase change heat storage technology is rapidly developed into a potential heat storage technology due to the advantages of large Phase change latent heat, small volume, simple structure, easily available materials, small pollution and the like. The solid-liquid phase change material mainly comprises paraffin, hydrated salt, alloy and the like, but the paraffin has the defects of inflammability and poor heat conductivity, the hydrated salt has the defects of supercooling, phase separation and the like, and the alloy is suitable for high-temperature heat storage due to high melting point.
Ionic Liquids (ILs) are room-temperature molten salts which are composed of organic cations and organic or inorganic anions and have a melting point below 100 ℃, and have the advantages of good physical and chemical stability, wide liquid path, no vapor pressure, non-flammability, simple preparation, no toxicity, no corrosiveness, high latent heat of phase change and excellent physicochemical property adjustability. By changing the types and combination modes of the anions and the cations, the ionic liquid with different densities, phase change enthalpies and melting points can be synthesized, has strong designability, and is suitable for the requirements of different scenes on the phase change material.
Chinese patent (application number: 201510861168.6) discloses a preparation method of an ionic liquid-water system phase-change energy storage material, which comprises the steps of directly melting and uniformly mixing an ionic liquid and water, and then adding a nucleating agent, wherein the mass percent of the water is less than 20%, and the mass percent of the nucleating agent is less than 5%.
Chinese patent (application number: 201310229487.6) discloses a preparation method of a cross-season phase change heat storage material by adopting an ionic liquid material, wherein the method selects alkyl imidazole bromide ionic liquid as the cross-season heat storage material, places the ionic liquid into a container to absorb industrial waste heat, and then releases phase change latent heat through crystallization of a nucleating agent so as to realize recycling of the waste heat. However, the phase-change material has the defects of low thermal conductivity, complex separation of nucleating agents and the like.
Chinese patent (application number: 201610188010.1) discloses a preparation method of an ionic liquid composite phase-change material for an air energy water heater. The method comprises the steps of firstly preparing 1-methylimidazole dihydrogen phosphate and propylamine formate ionic liquid, then adding a surfactant and loading the ionic liquid on the surface of the expanded graphite. The composite phase change material has high latent heat and good cycle performance, but no report of heat conductivity of related materials exists.
Chinese patent (application No. 201410283646.5) discloses a preparation method of functional group modified ionic liquid with electronegative atoms. In the method, functional groups comprise oxygen-containing groups such as carboxyl, hydroxyl, ester groups, aldehyde groups and ether groups, and the obtained ionic liquid has high thermal stability (decomposition temperature is higher than 200 ℃), high specific heat capacity (> 2J/g.K), but low latent heat of phase change (32.14-121.76J/g).
Because the intrinsic thermal conductivity of the ionic liquid is generally low, the ionic liquid needs to be uniformly filled with the heat-conducting filler in the ionic liquid matrix so as to improve the heat-conducting property of the material. The commonly used high-thermal-conductivity filler is mainly carbon materials, metal particles, metal oxides and the like, but the granular thermal-conductivity filler is difficult to form a thermal-conductivity channel in a matrix and has a certain thermal-conductivity enhancing effect only when the filling amount is large, and the high-thermal-conductivity carbon materials such as graphite, carbon nano tubes and the like have a large amount of phonon scattering on the contact surface of the filler and the matrix due to poor compatibility between a sheet layer and the matrix, so that the heat-conductivity improving efficiency of the composite material is not ideal.
Graphene is a two-dimensional layered carbon material composed of sp2 hybridized carbon atoms, has high intrinsic thermal conductivity, high thermal stability and good electrical and mechanical properties, and is widely applied to the fields of materials, chemical engineering, power electronics and the like. The two-dimensional structure of the graphene is beneficial to rapid transmission of electrons and phonons, and is an ideal heat-conducting filler, but the intermolecular action of the graphene is strong, the graphene is easy to gather and is not easy to disperse in an ionic liquid matrix, and meanwhile, phonon scattering can also occur between the graphene and a phase-change material matrix, so that a continuous effective heat-conducting path is difficult to form in the ionic liquid, the heat-conducting enhancement effect of the graphene is influenced, and the application of the graphene in the ionic liquid phase-change material is restricted.
Disclosure of Invention
In order to solve the above problems, the present invention provides a heat-conducting enhanced ionic liquid composite phase-change material and a preparation method thereof.
In order to achieve the purpose, the invention adopts the technical scheme that:
mixing an alkyl imidazole bromide ionic liquid solution and graphene which is covalently functionalized and modified by an alkyl imidazole ionic liquid containing terminal amino groups, uniformly dispersing, and then performing rotary evaporation and drying to obtain the modified graphene-based heat conduction enhanced ionic liquid composite phase-change heat storage material.
The further improvement of the invention is that the preparation method of the alkyl imidazole bromide ionic liquid comprises the following steps: firstly, adding 1-methylimidazole and bromo-n-hexadecane into a container, then adding a solvent, reacting for 12-48 h at 80-90 ℃ after purging with inert gas, and purifying to obtain the alkylimidazole bromide ionic liquid.
The further improvement of the invention is that the molar ratio of the 1-methylimidazole to the bromo-n-hexadecane is 1: 1.0-1: 1.2; the volume ratio of the solvent to the 1-methylimidazole is 1: 1-1: 10;
the solvent is one or more of ethanol, acetonitrile, ethyl acetate, toluene and benzene; ethanol is preferred.
The inert gas is nitrogen or argon;
the stirring speed during the reaction is 300-500 rpm;
the specific process of purification is as follows: and (3) performing rotary evaporation on the product after reaction for 12-48 h to remove the solvent to obtain a crude product, adding the crude product into one or more of ethyl acetate, acetone, toluene and tetrahydrofuran for recrystallization, filtering and drying to obtain the alkyl imidazole bromide ionic liquid.
The invention further improves the preparation method of the alkyl imidazole ionic liquid containing terminal amino groups, which comprises the following steps: adding 1-methylimidazole and amino-halogenated alkane into a container, adding a solvent, purging with inert gas, carrying out quaternization reaction at 70-100 ℃ for 12-48 h, and purifying to obtain the alkyl imidazole ionic liquid containing terminal amino groups.
The further improvement of the invention is that the molar ratio of the 1-methylimidazole to the amino halogenated alkane is 1: 1.0-1: 1.2, the carbon number of the alkane of the amino halogenated alkane is 2-3, the halogen atom is one or more of chlorine, bromine and iodine, and 3-bromopropylamine hydrobromide is preferred;
the solvent is one or more of ethanol, acetonitrile, ethyl acetate, toluene and benzene, preferably ethanol; the volume ratio of the solvent to the 1-methylimidazole is 1: 1-10;
the inert gas is nitrogen or argon;
preferably, the quaternization reaction temperature is 80-90 ℃, and the reaction time is 24-48 h.
The invention further improves the purification process as follows: performing rotary evaporation on a product after reaction for 12-48 h to obtain a crude product, dissolving the crude product in ethanol, adding alkali, stirring and reacting for 1-12 h, wherein the alkali is one or two of sodium hydroxide and potassium hydroxide, filtering to obtain a filtrate, and performing rotary evaporation on the filtrate to obtain a crude product of the alkylimidazolium ionic liquid containing terminal amino; dissolving a crude product of the alkyl imidazole ionic liquid containing the terminal amino group by using an ethanol-tetrahydrofuran mixed solvent, wherein the volume ratio of ethanol to tetrahydrofuran is 1: 0.5-4.0, filtering, carrying out rotary evaporation on the filtrate, recrystallizing the product in one or more of ethyl acetate, tetrahydrofuran and acetonitrile to obtain a white solid, and drying at 20-40 ℃ for 24-48 h to obtain the alkyl imidazole ionic liquid containing the terminal amino group.
The invention has the further improvement that the alkyl imidazole ionic liquid containing terminal amino is one or more of 1-aminopropyl-3-methylimidazole bromine salt, 1-aminoethyl-3-methylimidazole bromine salt, 1-aminopropyl-3-methylimidazole tetrafluoroborate, 1-aminoethyl-3-methylimidazole tetrafluoroborate, 1-aminopropyl-3-methylimidazole nitrate and 1-aminoethyl-3-methylimidazole nitrate. 1-aminopropyl-3-methylimidazolium bromide is preferred.
The further improvement of the invention is that the graphene which is covalently functionalized and modified by the alkyl imidazole ionic liquid containing the terminal amino is prepared by the following steps: dissolving graphene oxide in water, and uniformly dispersing to obtain a graphene oxide aqueous solution; wherein the concentration of the graphene oxide is 0.1-3 mg/mL, preferably 1 mg/mL; adding an alkyl imidazole ionic liquid containing terminal amino into a graphene oxide solution, wherein the mass ratio of graphene oxide to the alkyl imidazole ionic liquid containing terminal amino is 1: 1-10, and reacting at 70-90 ℃ for 12-48 h to obtain modified graphene oxide; dissolving modified graphene oxide in water, adding hydrazine hydrate after ultrasonic dispersion, and reacting for 24-48 h at 80-90 ℃ to obtain graphene covalently functionalized and modified by an alkyl imidazole ionic liquid containing terminal amino groups;
the further improvement of the invention is that the mass ratio of the alkyl imidazole bromide ionic liquid to the graphene which is covalently functionalized and modified by the alkyl imidazole ionic liquid containing terminal amino groups is (70-99): (1-30);
the size of graphene covalently functionalized and modified by an alkyl imidazole ionic liquid containing terminal amino groups is 1-20 microns;
the solvent is one or more of ethanol, ethyl acetate, acetonitrile, DMSO and water, preferably ethanol;
the dispersion mode is ultrasonic or stirring, and ultrasonic is preferred;
the temperature of rotary evaporation is 30-80 ℃, preferably 40 ℃, and the drying temperature is 20-40 ℃, preferably 40 ℃.
A heat conduction enhanced ionic liquid composite phase change heat storage material based on modified graphene has the phase change heat of 133.3-164.5J/g, the decomposition temperature of 255-265 ℃, and the heat diffusion coefficient of 0.134-0.250 mm2And the thermal conductivity coefficient is 0.236-0.515W/(m.K), and the thermal conductivity coefficient is improved by 4.4-127.9%.
Compared with the prior art, the invention has the following beneficial effects:
(1) the whole phase-change material synthesis and purification method is simple, high in yield and high in purity. The base material has high latent heat of phase change (165.3J/g) and good thermal stability; meanwhile, the material has moderate phase-change temperature, no vapor pressure, nonflammability, wide raw material sources, no toxicity or corrosion, and is beneficial to popularization and application of large-scale heat storage.
(2) The terminal amino group-containing ionic liquid covalently modified graphene effectively utilizes the steric effect of ionic liquid cations, increases the interlayer spacing of graphene sheets, and can effectively avoid the aggregation of graphene fillers so as to improve the dispersion uniformity of the graphene fillers in the composite material; the pi-pi interaction exists between the modified graphene and the ionic liquid phase-change material matrix, so that the interface compatibility of the graphene heat-conducting filler and the ionic liquid phase-change material matrix is enhanced, and phonon scattering at the interface is reduced, so that the interface thermal resistance is reduced, and the heat conductivity coefficient of the material is improved.
(3) The composite phase-change material has high phase-change latent heat of the ionic liquid, and the thermal conductivity is improved by adding the graphene; the ionic liquid/graphene composite material is prepared by a solution mixing method, the material dispersibility is good, the process is simple, and the method is suitable for large-scale production.
Drawings
The invention is described in further detail below with reference to the following drawings and detailed description.
FIG. 1 is a nuclear magnetic spectrum of a phase change material matrix in an embodiment of the present invention1H-NMR)；
FIG. 2 is an infrared spectrum (FTIR) of a phase change material matrix in an embodiment of the present invention;
FIG. 3 is a nuclear magnetic spectrum of graphene oxide modifier in an embodiment of the present invention: (1H-NMR)；
Fig. 4 is an infrared spectrum (FTIR) of modified graphene in an embodiment of the present invention;
fig. 5 is an XRD diffractogram of modified graphene in an example of the present invention;
FIG. 6 is an enlarged view taken at the circle in FIG. 5;
fig. 7 is an SEM image of modified graphene in example 1 of the present invention; wherein, the medium magnification factor in (a) is 3000 times, and the medium magnification factor in (b) is 77700 times;
FIG. 8 is an SEM photograph of a composite material in example 1 of the present invention;
FIG. 9 is a graph of the thermal weight loss of the composite phase change material of examples 1-5 of the present invention; wherein a is example 1, b is example 2, c is example 3, d is example 4, and e is example 5;
FIG. 10 is a DSC curve of the composite phase change material of examples 1-5 of the present invention; wherein a is example 1, b is example 2, c is example 3, d is example 4, and e is example 5;
FIG. 11 is a graph showing the thermal conductivity of the composite phase change material according to examples 1 to 5 of the present invention;
FIG. 12 shows the thermal diffusivity of the composite phase change material in examples 1-5 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
A preparation method of a modified graphene-based heat conduction enhanced ionic liquid composite phase-change heat storage material comprises the following steps: the composite material is prepared by taking methylimidazole bromide ionic liquid with large phase change latent heat and good thermal stability as a matrix, taking graphene which is subjected to covalent functionalization modification on the ionic liquid containing terminal amino groups as a heat conduction reinforcing material, and further compounding the matrix and the graphene through the processes of ultrasonic dispersion, rotary evaporation, drying and the like. According to the invention, the enhancement of the heat conductivity of the phase-change material is realized by adding modified graphene into an ionic liquid matrix, and the modified graphene is prepared by performing functional modification on conventional graphene oxide through the covalent functionalization of amino-terminated ionic liquid and then reducing the graphene oxide through hydrazine hydrate.
The preparation process of the amino-terminated ionic liquid for modified graphene comprises the following steps:
adding 1-methylimidazole and amino-halogenated alkane into a container, adding a solvent, purging with inert gas, carrying out quaternization reaction at 70-100 ℃ for 12-48 hours to obtain a crude product, adding strong base to remove protection on amino in the crude product, wherein the base can be KOH or NaOH, and stirring for reaction for 1-12 hours; then purifying the solvent, and drying in vacuum to obtain the alkyl imidazole ionic liquid containing terminal amino. Wherein the molar ratio of the 1-methylimidazole to the amino halogenated alkane is 1: 1.0-1.2;
the carbon number of the alkane of the amino halogenated alkane is 2-3, the halogen atom is one or more of chlorine, bromine and iodine, and 3-bromopropylamine hydrobromide is preferred;
the solvent can be one or more of ethanol, acetonitrile, ethyl acetate, toluene and benzene, preferably ethanol;
the volume ratio of the solvent to the 1-methylimidazole is 1: 1-10;
purging with inert gas to remove air and moisture in the reaction device, wherein the inert gas can be nitrogen or argon;
the quaternization reaction temperature is 70-100 ℃, preferably 80-90 ℃, the water bath heating reflux reaction is carried out for 12-48 hours, preferably 24-48 hours, the stirring speed is 300-500 rpm, the reflux condenser pipe can be a snake-shaped condenser pipe or a spherical condenser pipe, and the temperature of the condensate water is 0-10 ℃;
the product purification solvent is an ethanol-tetrahydrofuran mixed solvent, wherein the volume ratio of the ethanol-tetrahydrofuran mixed solvent is 1: 0.5-4, preferably 1: 4;
the vacuum drying temperature of the product is 20-40 ℃, and the drying time is 24-48 h;
the preparation method of the graphene which is modified by covalent functionalization of the ionic liquid containing the terminal amino comprises the following steps:
adding an alkyl imidazole ionic liquid containing terminal amino into a graphene oxide solution, and reacting at 70-90 ℃ for 12-48 h to obtain modified graphene oxide; dissolving modified graphene oxide in water, adding hydrazine hydrate after ultrasonic dispersion, wherein the reaction temperature is 70-90 ℃, and the reaction time is 12-48 h; preferably, the reaction is carried out for 24-48 h at 80-90 ℃ to obtain the graphene covalently functionalized and modified by the alkyl imidazole ionic liquid containing terminal amino;
wherein, the alkyl imidazole ionic liquid containing terminal amino can be: 1-aminopropyl-3-methylimidazole bromine salt, 1-aminoethyl-3-methylimidazole bromine salt, 1-aminopropyl-3-methylimidazole tetrafluoroborate, 1-aminoethyl-3-methylimidazole tetrafluoroborate, 1-aminopropyl-3-methylimidazole nitrate, 1-aminoethyl-3-methylimidazole nitrate and the like, and preferably 1-aminopropyl-3-methylimidazole bromine salt.
The concentration of the graphene oxide solution is 0.1-3 mg/mL, preferably 1 mg/mL;
in the preparation process of the modified graphene oxide, the modified graphene oxide is prepared from the following components in parts by mass: the ratio of the alkyl imidazole ionic liquid containing terminal amino groups is 1: 1-10;
based on the mass of the modified graphene oxide, the amount of hydrazine hydrate used for reduction is 50-200 mu L/100mg of the modified graphene oxide.
The preparation method of the ionic liquid composite phase-change material comprises the following steps:
adding an alkyl imidazole bromide ionic liquid solution into a solvent, then adding graphene which is covalently functionalized and modified by an alkyl imidazole ionic liquid containing terminal amino groups, uniformly dispersing, removing the solvent, and performing vacuum drying to obtain the modified graphene-based heat conduction enhanced ionic liquid composite phase change heat storage material.
According to the mass fraction, the alkyl imidazole bromide ionic liquid in the composite phase-change material is as follows: the graphene covalently functionalized and modified by the alkyl imidazole ionic liquid containing terminal amino groups (namely modified graphene) is (70-99): (1-30);
the size of the modified graphene is 1-20 mu m;
the solvent can be one or more of ethanol, ethyl acetate, acetonitrile, DMSO and water, preferably ethanol;
the dispersion mode can be ultrasonic or stirring, and ultrasonic is preferred;
removing the solvent by rotary evaporation at a temperature of 30-80 ℃, preferably 40 ℃;
the vacuum drying temperature is 20-40 ℃, and preferably 40 ℃.
The phase-change heat storage material has the phase-change heat of 133.3-164.5J/g, the decomposition temperature of 255-265 ℃, and the heat diffusion coefficient of 0.134-0.250 mm2And/s, the heat conductivity coefficient is 0.236-0.515W/(m.K), and the heat conductivity coefficient is improved by 4.4-127.9%.
Before each example, a phase-change material matrix 1-hexadecyl-3-methylimidazolium bromide ionic liquid is prepared:
1-methylimidazole (0.1mol) and bromohexadecane (0.1mol) were added to a three-necked flask, 50mL of anhydrous ethanol was added to the three-necked flask, and the apparatus was purged with nitrogen to remove air and moisture. Heating and refluxing in 90 ℃ water bath for 24 hours, stirring at 500rpm, and cooling with 5 ℃ of condensed water. After the reaction is finished, the product is subjected to rotary evaporation to remove the solvent, the crude product is added into 100mL ethyl acetate and washed for 3 times, and after the last washingFiltering, and drying at 40 ℃ for 24h to obtain the 1-hexadecyl-3-methylimidazolium bromide ionic liquid phase-change material. By nuclear magnetic characterization of1H-NMR) confirmed the structure of the synthesized ionic liquid, as shown in figure 1,1H NMR(600MHz，DMSO-d6) δ 9.17(s, 1H), 7.79(s, 1H), 7.72(s, 1H), 4.16(t, J ═ 7.2Hz, 2H), 3.86(s, 3H), 1.77(t, J ═ 7.4Hz, 2H), 1.30-1.25 (m, 2H), 1.25(s, 4H), 1.24(s, 20H), 0.86(t, J ═ 6.9Hz, 3H). The functional group and structure of the ionic liquid were further confirmed by Fourier Transform Infrared (FTIR) technique (FIG. 2), wherein the wave number was 2914cm-1And 2850cm-1The peak and the strong peak correspond to the stretching vibration infrared characteristic absorption peak of methylene (-CH2-) group in the side chain n-hexadecyl of the ionic liquid, and the wave number is 1573cm-1The peak is a stretching vibration absorption peak of C ═ N bond on imidazole heterocycle, and the wave number is 1175cm-1The peak at (B) corresponds to the stretching vibration of the C-N bond, and appears at 1473cm-1The peak at (A) corresponds to the bending vibration absorption peak of-CH 2-.
Example 1
1. 1-methylimidazole (0.1mol) and 3-bromopropylamine hydrobromide (0.1mol) were each charged into a three-necked flask, and 50mL of ethanol was added. The apparatus was purged with nitrogen to remove air and moisture. Heating and refluxing in 90 ℃ water bath for 24 hours, stirring at 400rpm and condensing water at 5 ℃. After the reaction is finished, carrying out rotary evaporation on the reaction liquid to obtain a crude product, dissolving the crude product in ethanol again, adding KOH (0.1mol) to carry out deprotection on amino, stirring for reaction for 12h, filtering, and carrying out rotary evaporation on the filtrate to obtain a crude product of the alkylimidazole ionic liquid containing terminal amino. Dissolving the crude product with ethanol-tetrahydrofuran (volume ratio 1: 4) mixed solvent, filtering, removing the mixed solvent by rotary evaporation of the filtrate, recrystallizing the product in ethyl acetate to obtain white solid, and drying at 40 ℃ for 24h to obtain the 3-aminopropyl-1-methylimidazolium bromide ionic liquid. By nuclear magnetic characterization of1H-NMR) confirmed the structure of the synthesized ionic liquid, as shown in figure 3,1H NMR(600MHz，DMSO-d6)δ9.20(s，1H)，7.82(s，1H)，7.75(s，1H)，4.31(t，J＝6.9Hz，2H)，3.87(s，3H)，2.91-2.79(m，2H)，2.10(p，J＝7.1Hz，3H)。
2. graphene oxide (0.1g) was dissolved in water and dispersed by ultrasound to give a homogeneous graphene oxide aqueous solution (1 mg/mL). Adding 3-aminopropyl-1-methylimidazolium bromide ionic liquid (0.5g) into a graphene oxide solution, reacting at 90 ℃ for 24 hours, and filtering, washing and drying to obtain ionic liquid modified graphene oxide; dissolving the prepared ionic liquid modified graphene oxide in water, performing ultrasonic dispersion, and adding a certain amount of hydrazine hydrate, wherein the using amount of the hydrazine hydrate is 100 mu L/100mg of the modified graphene oxide. And reacting for 24 hours at 90 ℃, and filtering, washing and drying the product to obtain the reduced ionic liquid modified graphene. FIG. 4 is an infrared spectrum (FTIR) of modified graphene, with a wave number of 1553cm-1The peak is attributed to the stretching vibration absorption peak of C ═ N bond on imidazole heterocycle in the terminal amino group-containing ionic liquid, and the wave number is 1155cm-1The peak at (B) corresponds to the stretching vibration of the C-N bond in the ionic liquid and appears at 1204cm-1The peak corresponds to the C-OH stretching vibration absorption peak in the chemically reduced graphene, and belongs to 1738cm of the oxidized graphene-1、1035cm-1The infrared absorption peak of (2) disappears. The results show that the ionic liquid modified graphene is successfully prepared. Fig. 5 and 6 are XRD diffractograms of the modified graphene, in which a peak at 2 θ ═ 18 ° corresponds to an XRD diffraction peak of the ionic liquid modified graphene. FIG. 7 is an SEM image of modified graphene, which shows that the size of the modified graphene is 1-20 μm.
3. Dissolving 99mg of 1-hexadecyl-3-methylimidazolium bromide ionic liquid phase-change material in 1mL of ethanol, adding 1mg of modified graphene, performing ultrasonic treatment for 1h to uniformly disperse the graphene in an ionic liquid matrix, performing rotary evaporation on the mixture at 40 ℃ to remove the solvent, and performing vacuum drying at 40 ℃ to obtain the ionic liquid composite phase-change heat storage material (namely: IL/FG-1%), wherein the material naming method is as follows: IL refers to an Ionic Liquid phase change material substrate (Ionic Liquid), FG refers to Functionalized modified Graphene (Functionalized Graphene), and 1% refers to the addition amount of 1 wt% of the modified Graphene.
Fig. 8 is a scanning electron micrograph of the composite material, and it can be seen that the ionic liquid is uniformly adsorbed on the modified graphene. FIG. 9a shows a composite material according to the present embodimentThe thermal weight loss curve of the composite material has the decomposition temperature of 260 ℃ and good thermal stability. As shown in figure 10a, the enthalpy value of the composite phase change material is 164.50J/g, and the composite phase change material has high latent heat of phase change. As shown in FIGS. 11 and 12, the thermal diffusivity of the composite material is 0.134mm2And the thermal conductivity coefficient is 0.236W/(m.K), which is improved by 4.4% compared with the ionic liquid phase-change material without the thermal conductive filler.
Example 2
1. 1-methylimidazole (0.5mol) and 3-bromopropylamine hydrobromide (0.5mol) were added to a three-necked flask, and 250mL of ethanol was added thereto. The apparatus was purged with nitrogen to remove air and moisture. Heating and refluxing in 90 ℃ water bath for 48 hours, stirring at 500rpm and condensing at 5 ℃. After the reaction is finished, carrying out rotary evaporation on the reaction liquid to obtain a crude product, dissolving the crude product in ethanol again, adding KOH (0.55mol) to carry out deprotection on amino, stirring for reaction for 12h, filtering, and carrying out rotary evaporation on the filtrate to obtain a crude product of the alkylimidazole ionic liquid containing terminal amino. Dissolving the crude product with ethanol-tetrahydrofuran (3: 2) mixed solvent, filtering, removing the mixed solvent by rotary evaporation of the filtrate, recrystallizing the product in ethyl acetate to obtain white solid, and drying at 40 ℃ for 24h to obtain the 3-aminopropyl-1-methylimidazolium bromide ionic liquid.
2. Graphene oxide (0.1g) was dissolved in water and dispersed by ultrasound to give a homogeneous graphene oxide aqueous solution (1 mg/mL). Adding 3-aminopropyl-1-methylimidazolium bromide (0.5g) into a graphene oxide solution, reacting at 90 ℃ for 24 hours, and filtering, washing and drying to obtain ionic liquid modified graphene oxide; dissolving the prepared ionic liquid modified graphene oxide in water, performing ultrasonic dispersion, and adding a certain amount of hydrazine hydrate, wherein the using amount of the hydrazine hydrate is 100 mu L/100mg of the modified graphene oxide. And reacting for 24 hours at 90 ℃, and filtering, washing and drying the product to obtain the ionic liquid modified graphene.
3. Dissolving 96mg of 1-hexadecyl-3-methylimidazolium bromide ionic liquid phase-change material in 1mL of ethanol, adding 4mg of modified graphene, performing ultrasonic treatment for 1h to uniformly disperse the graphene in an ionic liquid matrix, performing rotary evaporation on the mixture at 40 ℃ to remove the solvent, and performing vacuum drying at 40 ℃ to obtain the ionic liquid composite phase-change heat storage material (IL/FG-4%).
Fig. 9b is a graph of the thermal weight loss of the composite material of this example, which has a decomposition temperature of 255 c and good thermal stability. As shown in FIG. 10b, the enthalpy of the composite phase change material is 159.5J/g, and the composite phase change material has high latent heat of phase change. As shown in FIGS. 11 and 12, the thermal diffusivity of the composite material is 0.170mm2And the thermal conductivity coefficient is 0.303W/(m.K), and is improved by 34.1% compared with the ionic liquid phase-change material without the thermal conductive filler.
Example 3
1. 1-methylimidazole (0.5mol) and 3-bromopropylamine hydrobromide (0.55mol) were added to a three-necked flask, and 250mL of ethanol was added thereto. The apparatus was purged with nitrogen to remove air and moisture. Heating and refluxing in 90 ℃ water bath for 24 hours, stirring at 400rpm and condensing water at 5 ℃. After the reaction is finished, carrying out rotary evaporation on the reaction liquid to obtain a crude product, dissolving the crude product in ethanol again, adding KOH (0.6mol) to carry out deprotection on amino, stirring for reaction for 12h, filtering, and carrying out rotary evaporation on the filtrate to obtain a crude product of the alkylimidazole ionic liquid containing terminal amino. Dissolving the crude product with ethanol-tetrahydrofuran (1: 4) mixed solvent, filtering, removing the mixed solvent by rotary evaporation of the filtrate, recrystallizing the product in ethyl acetate to obtain white solid, and drying at 40 ℃ for 24h to obtain the 3-aminopropyl-1-methylimidazolium bromide ionic liquid.
2. Graphene oxide (0.5g) was dissolved in water and dispersed by ultrasound to give a homogeneous graphene oxide aqueous solution (1 mg/mL). Adding 3-aminopropyl-1-methylimidazolium bromide (2g) into a graphene oxide solution, reacting at 90 ℃ for 24 hours, and filtering, washing and drying to obtain ionic liquid modified graphene oxide; dissolving the prepared ionic liquid modified graphene oxide in water, performing ultrasonic dispersion, and adding a certain amount of hydrazine hydrate, wherein the using amount of the hydrazine hydrate is 200 mu L/100mg of the modified graphene oxide. And reacting for 24 hours at 90 ℃, and filtering, washing and drying the product to obtain the ionic liquid modified graphene.
3. Dissolving 93mg of 1-hexadecyl-3-methylimidazolium bromide ionic liquid phase-change material in 1mL of ethanol, adding 7mg of modified graphene, performing ultrasonic treatment for 1h to uniformly disperse the graphene in an ionic liquid matrix, performing rotary evaporation on the mixture at 40 ℃ to remove the solvent, and performing vacuum drying at 40 ℃ to obtain the ionic liquid composite phase-change heat storage material (IL/FG-7%).
Fig. 9c is a graph of the thermal weight loss of the composite material of this example, which has a decomposition temperature of 265 deg.c and good thermal stability. As shown in FIG. 10c, the enthalpy of the composite phase change material is 154.0J/g, and the composite phase change material has high latent heat of phase change. As shown in FIGS. 11 and 12, the thermal diffusivity of the composite material is 0.182mm2And the thermal conductivity coefficient is 0.350W/(m.K), and is improved by 54.9 percent compared with the ionic liquid phase-change material without the thermal conductive filler.
Example 4
1. 1-methylimidazole (0.1mol) and 3-bromopropylamine hydrobromide (0.1mol) were each charged into a three-necked flask, and 50mL of ethanol was added. The apparatus was purged with nitrogen to remove air and moisture. Heating and refluxing in 90 ℃ water bath for 24 hours, stirring at 400rpm and condensing water at 5 ℃. After the reaction is finished, carrying out rotary evaporation on the reaction liquid to obtain a crude product, dissolving the crude product in ethanol again, adding KOH (0.1mol) to carry out deprotection on amino, stirring for reaction for 12h, filtering, and carrying out rotary evaporation on the filtrate to obtain a crude product of the alkylimidazole ionic liquid containing terminal amino. Dissolving the crude product with ethanol-tetrahydrofuran (1: 4) mixed solvent, filtering, removing the mixed solvent by rotary evaporation of the filtrate, recrystallizing the product in ethyl acetate to obtain white solid, and drying at 40 ℃ for 24h to obtain the 3-aminopropyl-1-methylimidazolium bromide ionic liquid.
2. Graphene oxide (0.1g) was dissolved in water and dispersed by ultrasound to give a homogeneous graphene oxide aqueous solution (1 mg/mL). Adding the 3-aminopropyl-1-methylimidazolium bromide (0.5g) prepared in the step 2 into a graphene oxide solution, reacting for 24 hours at 90 ℃, and filtering, washing and drying to obtain ionic liquid modified graphene oxide; dissolving the prepared ionic liquid modified graphene oxide in water, performing ultrasonic dispersion, and adding a certain amount of hydrazine hydrate, wherein the using amount of the hydrazine hydrate is 100 mu L/100mg of the modified graphene oxide. And reacting for 24 hours at 90 ℃, and filtering, washing and drying the product to obtain the ionic liquid modified graphene.
3. And (2) dissolving 90mg of the 1-hexadecyl-3-methylimidazolium bromide ionic liquid phase-change material prepared in the step (1) in 1mL of ethanol, adding 10mg of modified graphene, performing ultrasonic treatment for 1h to uniformly disperse the graphene in an ionic liquid matrix, performing rotary evaporation on the mixture at 40 ℃ to remove the solvent, and performing vacuum drying at 40 ℃ to obtain the ionic liquid composite phase-change heat storage material (IL/FG-10%).
Fig. 9d is a graph of the thermal weight loss of the composite material of this example, which has a decomposition temperature of 263 c and good thermal stability. As shown in FIG. 10d, the enthalpy of the composite phase change material is 148.5J/g, and the composite phase change material has high latent heat of phase change. As shown in FIGS. 11 and 12, the thermal diffusivity of the composite material is 0.196mm2And the thermal conductivity coefficient is 0.412W/(m.K), which is improved by 82.3% compared with the ionic liquid phase-change material without the thermal conductive filler.
Example 5
1. 1-methylimidazole (0.1mol) and 3-bromopropylamine hydrobromide (0.1mol) were each charged into a three-necked flask, and 50mL of ethanol was added. The apparatus was purged with nitrogen to remove air and moisture. Heating and refluxing in 90 ℃ water bath for 24 hours, stirring at 400rpm and condensing water at 5 ℃. After the reaction is finished, carrying out rotary evaporation on the reaction liquid to obtain a crude product, dissolving the crude product in ethanol again, adding KOH (0.1mol) to carry out deprotection on amino, stirring for reaction for 12h, filtering, and carrying out rotary evaporation on the filtrate to obtain a crude product of the alkylimidazole ionic liquid containing terminal amino. Dissolving the crude product with ethanol-tetrahydrofuran (1: 4) mixed solvent, filtering, removing the mixed solvent by rotary evaporation of the filtrate, recrystallizing the product in ethyl acetate to obtain white solid, and drying at 30 ℃ for 24h to obtain the 3-aminopropyl-1-methylimidazolium bromide ionic liquid.
2. Graphene oxide (0.5g) was dissolved in water and dispersed by ultrasound to give a homogeneous graphene oxide aqueous solution (1 mg/mL). Adding 3-aminopropyl-1-methylimidazolium bromide (3g) into a graphene oxide solution, reacting at 90 ℃ for 24 hours, and filtering, washing and drying to obtain ionic liquid modified graphene oxide; dissolving the prepared ionic liquid modified graphene oxide in water, performing ultrasonic dispersion, and adding a certain amount of hydrazine hydrate, wherein the using amount of the hydrazine hydrate is 200 mu L/100mg of the modified graphene oxide. And reacting for 24 hours at 90 ℃, and filtering, washing and drying the product to obtain the ionic liquid modified graphene.
3. Dissolving 85mg of 1-hexadecyl-3-methylimidazolium bromide ionic liquid phase-change material in 1mL of ethanol, adding 15mg of modified graphene, performing ultrasonic treatment for 1h to uniformly disperse the graphene in an ionic liquid matrix, performing rotary evaporation on the mixture at 40 ℃ to remove the solvent, and performing vacuum drying at 40 ℃ to obtain the ionic liquid composite phase-change heat storage material (IL/FG-15%).
Fig. 9e is a graph of the thermal weight loss of the composite material of this example, which has a decomposition temperature of 261 ℃ and good thermal stability. As shown in FIG. 10e, the enthalpy of the composite phase change material is 133.3J/g. As shown in FIGS. 11 and 12, the thermal diffusivity of the composite material is 0.250mm2And the thermal conductivity coefficient is 0.515W/(m.K), and the thermal conductivity coefficient is improved by 127.9 percent compared with that of the ionic liquid phase-change material without the thermal conductive filler. Compared with a pure ionic liquid phase-change material, the phase-change latent heat of the composite material is reduced, but the heat conduction capability of the composite material is doubled, so that the composite material is beneficial to the rapid transfer and storage of heat in the composite material.
Example 6
1. 1-methylimidazole (0.1mol) and bromohexadecane (0.12mol) were added to a three-necked flask, 50mL of anhydrous acetonitrile was added to the three-necked flask, and the apparatus was purged with argon to remove air and moisture. Heating in 70 deg.C water bath, refluxing and reacting for 48h with stirring speed of 300rpm, wherein the reflux condenser tube is a serpentine condenser tube, and the temperature of condensed water is 0 deg.C. After the reaction is finished, the product is subjected to rotary evaporation to remove the solvent, then is added into 100mL ethyl acetate, is washed for 3 times, is filtered after the last washing, and is dried for 24 hours at the temperature of 40 ℃ to obtain the alkyl imidazole bromide ionic liquid.
2. 1-methylimidazole (0.1mol) and amino haloalkane (0.11mol) were added to a three-necked flask, and 50mL of acetonitrile was added. The apparatus was purged with argon to remove air and moisture. Heating and refluxing in 70 ℃ water bath for 48 hours, stirring speed is 400rpm, and the temperature of condensed water is 5 ℃. After the reaction is finished, performing rotary evaporation to obtain a crude product, dissolving the crude product in ethanol, adding KOH, stirring for reaction for 12 hours, filtering to obtain a filtrate, and performing rotary evaporation on the filtrate to obtain a crude product of the alkyl imidazole ionic liquid containing terminal amino; dissolving a crude product of the alkyl imidazole ionic liquid containing the terminal amino group by using an ethanol-tetrahydrofuran mixed solvent, wherein the volume ratio of ethanol to tetrahydrofuran is 1: 4.0, filtering, carrying out rotary evaporation on the filtrate, recrystallizing the product in a mixture of ethyl acetate and tetrahydrofuran to obtain a white solid, and drying at 40 ℃ for 24h to obtain the alkyl imidazole ionic liquid containing the terminal amino group. Wherein, the carbon atom number of the alkyl of the amino halogenated alkyl is 2, and the halogen atom is bromine;
3. adding an alkyl imidazole ionic liquid containing terminal amino into a graphene oxide solution, and reacting at 70 ℃ for 48 hours to obtain modified graphene oxide; dissolving modified graphene oxide in water, adding hydrazine hydrate after ultrasonic dispersion, and reacting for 48 hours at 80 ℃ to obtain graphene covalently functionalized and modified by alkyl imidazole ionic liquid containing terminal amino; wherein the concentration of the graphene oxide solution is 0.1 mg/mL; the mass ratio of the graphene oxide to the alkyl imidazole ionic liquid containing the terminal amino is 1: 1. The amount of the reduced hydrazine hydrate is 150 mu L/100mg of the modified graphene oxide;
4. adding alkyl imidazole bromide ionic liquid into a mixture of acetonitrile and DMSO, adding graphene which is covalently functionalized and modified by alkyl imidazole ionic liquid containing terminal amino groups, mixing according to a mass ratio of 70: 30, uniformly stirring, performing rotary evaporation at 60 ℃, and drying at 30 ℃ to obtain the heat conduction enhancement type ionic liquid composite phase change heat storage material based on the modified graphene.
Example 7
1. 1-methylimidazole (0.1mol) and bromohexadecane (0.11mol) were each charged into a three-necked flask, 50mL of ethyl acetate was added to the three-necked flask, and the apparatus was purged with nitrogen to remove air and moisture. Heating in 80 deg.C water bath, reflux reacting for 40h with stirring speed of 400rpm, reflux condensing tube is snake-shaped condensing tube, and condensing water temperature is 10 deg.C. After the reaction is finished, the product is subjected to rotary evaporation to remove the solvent, then is added into 100mL of a mixture of toluene and tetrahydrofuran, is washed for 3 times, is filtered after the last washing, and is dried for 24 hours at the temperature of 40 ℃ to obtain the alkyl imidazole bromide ionic liquid.
2. 1-methylimidazole (0.1mol) and amino-haloalkane (0.12mol) were added to a three-necked flask, and 50mL of ethyl acetate was added thereto. The apparatus was purged with argon to remove air and moisture. Heating and refluxing in 100 ℃ water bath for 12 hours, stirring at 400rpm and condensing water at 5 ℃. After the reaction is finished, performing rotary evaporation to obtain a crude product, dissolving the crude product in ethanol, adding NaOH, stirring for reaction for 1h, filtering to obtain a filtrate, and performing rotary evaporation on the filtrate to obtain a crude product of the alkylimidazolium ionic liquid containing terminal amino; dissolving a crude product of the alkyl imidazole ionic liquid containing the terminal amino group by using an ethanol-tetrahydrofuran mixed solvent, wherein the volume ratio of ethanol to tetrahydrofuran is 1: 2, filtering, carrying out rotary evaporation on the filtrate, recrystallizing the product in acetonitrile to obtain a white solid, and drying at 30 ℃ for 30h to obtain the alkyl imidazole ionic liquid containing the terminal amino group. Wherein, the carbon atom number of the alkyl of the amino halogenated alkyl is 3, and the halogen atom is chlorine;
3. adding an alkyl imidazole ionic liquid containing terminal amino into a graphene oxide solution, and reacting at 90 ℃ for 12h to obtain modified graphene oxide; dissolving modified graphene oxide in water, adding hydrazine hydrate after ultrasonic dispersion, and reacting at 90 ℃ for 24 hours to obtain graphene covalently functionalized and modified by alkyl imidazole ionic liquid containing terminal amino groups; dissolving graphene oxide in water, and uniformly dispersing to obtain a graphene oxide aqueous solution; wherein the concentration of the graphene oxide is 3.0 mg/mL; the mass ratio of the graphene oxide to the alkyl imidazole ionic liquid containing the terminal amino is 1: 10. The amount of the reduced hydrazine hydrate is 200 mu L/100mg of the modified graphene oxide;
4. adding an alkyl imidazole bromide ionic liquid solution into acetonitrile, adding graphene which is covalently functionalized and modified by an alkyl imidazole ionic liquid containing terminal amino groups, mixing according to the mass ratio of 80: 20, uniformly stirring, performing rotary evaporation at 80 ℃, and drying at 40 ℃ to obtain the heat conduction enhanced ionic liquid composite phase-change heat storage material based on the modified graphene.
Example 8
1. 1-methylimidazole (0.1mol) and bromohexadecane (0.1mol) were each charged into a three-necked flask, 50mL of toluene was added to the three-necked flask, and the apparatus was purged with nitrogen to remove air and moisture. Heating in 90 deg.C water bath, reflux reacting for 30h with stirring speed of 300rpm, reflux condensing tube being spherical condensing tube, and condensing water temperature being 5 deg.C. After the reaction is finished, the product is subjected to rotary evaporation to remove the solvent, then is added into 100mL of toluene, is washed for 3 times, is filtered after the last washing, and is dried for 24 hours at the temperature of 40 ℃ to obtain the alkyl imidazole bromide ionic liquid.
2. 1-methylimidazole (0.1mol) and amino haloalkane (0.1mol) were added to a three-necked flask, and 50mL of acetonitrile was added. The apparatus was purged with argon to remove air and moisture. Heating and refluxing in 80 ℃ water bath for 35 hours, stirring at 400rpm and condensing water at 5 ℃. After the reaction is finished, performing rotary evaporation to obtain a crude product, dissolving the crude product in ethanol, adding KOH, performing stirring reaction for 6 hours, filtering to obtain a filtrate, and performing rotary evaporation on the filtrate to obtain a crude product of the alkyl imidazole ionic liquid containing terminal amino; dissolving a crude product of the alkyl imidazole ionic liquid containing the terminal amino group by using an ethanol-tetrahydrofuran mixed solvent, wherein the volume ratio of ethanol to tetrahydrofuran is 1: 1, filtering, carrying out rotary evaporation on the filtrate, recrystallizing the product in tetrahydrofuran to obtain a white solid, and drying at 30 ℃ for 40h to obtain the alkyl imidazole ionic liquid containing the terminal amino group. Wherein, the carbon atom number of the alkyl of the amino halogenated alkyl is 2, and the halogen atom is chlorine and bromine;
3. adding an alkyl imidazole ionic liquid containing terminal amino into a graphene oxide solution, and reacting at 80 ℃ for 30h to obtain modified graphene oxide; dissolving modified graphene oxide in water, adding hydrazine hydrate after ultrasonic dispersion, and reacting for 80 hours at 85 ℃ to obtain graphene covalently functionalized and modified by alkyl imidazole ionic liquid containing terminal amino; dissolving graphene oxide in water, and uniformly dispersing to obtain a graphene oxide aqueous solution; wherein the concentration of the graphene oxide is 0.8 mg/mL; the mass ratio of the graphene oxide to the alkyl imidazole ionic liquid containing the terminal amino is 1: 5. The amount of the reduced hydrazine hydrate is 50 mu L/100mg of the modified graphene oxide;
4. adding an alkyl imidazole bromide ionic liquid solution into ethyl acetate, then adding graphene which is covalently functionalized and modified by an alkyl imidazole ionic liquid containing terminal amino groups, mixing according to the mass ratio of 99: 1, performing ultrasonic treatment to uniformly disperse the graphene, performing rotary evaporation at 30 ℃, and drying at 20 ℃ to obtain the heat conduction enhanced ionic liquid composite phase change heat storage material based on the modified graphene.
Example 9
1. 1-methylimidazole (0.1mol) and bromohexadecane (0.1mol) were each charged into a three-necked flask, 50mL of benzene was charged into the three-necked flask, and the apparatus was purged with nitrogen to remove air and moisture. Heating in 100 ℃ water bath, refluxing and reacting for 12h, wherein the stirring speed is 400rpm, the reflux condenser pipe is a snake-shaped condenser pipe, and the temperature of the condensed water is 7 ℃. After the reaction is finished, the product is subjected to rotary evaporation to remove the solvent, then added into 100mL of acetone, washed for 3 times, filtered after the last washing, and dried for 24 hours at 40 ℃ to obtain the 1-hexadecyl-3-methylimidazolium bromide ionic liquid phase-change material.
2. 1-methylimidazole (0.1mol) and amino haloalkane (0.12mol) were added to a three-necked flask, and 50mL of acetonitrile was added. The apparatus was purged with argon to remove air and moisture. Heating and refluxing in 90 ℃ water bath for 24 hours, stirring at 400rpm and condensing water at 5 ℃. After the reaction is finished, performing rotary evaporation to obtain a crude product, dissolving the crude product in ethanol, adding alkali, stirring for reaction for 8 hours, filtering to obtain a filtrate, and performing rotary evaporation on the filtrate to obtain a crude product of the alkylimidazolium ionic liquid containing terminal amino; dissolving a crude product of the alkyl imidazole ionic liquid containing the terminal amino group by using an ethanol-tetrahydrofuran mixed solvent, wherein the volume ratio of ethanol to tetrahydrofuran is 1: 3, filtering, carrying out rotary evaporation on the filtrate, recrystallizing the product in ethyl acetate to obtain a white solid, and drying at 20 ℃ for 48h to obtain the alkyl imidazole ionic liquid containing the terminal amino group. Wherein, the carbon atom number of the alkyl of the amino halogenated alkyl is 3, and the halogen atom is bromine;
3. adding an alkyl imidazole ionic liquid containing terminal amino into a graphene oxide solution, and reacting at 75 ℃ for 40h to obtain modified graphene oxide; dissolving modified graphene oxide in water, adding hydrazine hydrate after ultrasonic dispersion, and reacting at 88 ℃ for 28 hours to obtain graphene which is 1-20 mu m in size and is covalently functionalized and modified by alkyl imidazole ionic liquid containing terminal amino; dissolving graphene oxide in water, and uniformly dispersing to obtain a graphene oxide aqueous solution; wherein the concentration of the graphene oxide is 2 mg/mL; the mass ratio of the graphene oxide to the alkyl imidazole ionic liquid containing the terminal amino is 1: 7. The amount of the reduced hydrazine hydrate is 200 mu L/100mg of the modified graphene oxide;
4. adding an alkyl imidazole bromide ionic liquid solution into ethanol, then adding graphene which is covalently functionalized and modified by an alkyl imidazole ionic liquid containing terminal amino groups, mixing according to the mass ratio of 70: 30, performing ultrasonic treatment to uniformly disperse the graphene, performing rotary evaporation at 60 ℃, and drying at 25 ℃ to obtain the heat conduction enhanced ionic liquid composite phase change heat storage material based on the modified graphene.
According to the invention, the amino-terminated ionic liquid is prepared through quaternization, the amino group of the ionic liquid is utilized to carry out covalent functionalization modification on graphene oxide, and the modified graphene oxide reacts with hydrazine hydrate to reduce the graphene oxide, so that the dispersibility and the interface compatibility of the graphene filler in the ionic liquid phase-change material matrix are improved, and the heat conduction characteristic of the composite material is improved. And further ultrasonically mixing the modified graphene and the imidazole ionic liquid phase-change material matrix according to a certain proportion, and controlling conditions such as rotary evaporation and drying to obtain a mixture of different modified graphene loading amounts and the ionic liquid matrix phase-change material. The material has the characteristics of large phase change latent heat and good thermal stability, and meanwhile, the thermal conductivity is increased by 4.4-127.9% compared with that of the ionic liquid without the modified graphene, so that the thermal energy storage and conduction characteristics of the material are obviously improved.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. The preparation method of the heat conduction enhancement type ionic liquid composite phase-change heat storage material based on the modified graphene is characterized in that an alkyl imidazole bromide ionic liquid solution and the graphene which is covalently functionalized and modified by an alkyl imidazole ionic liquid containing terminal amino groups are mixed, uniformly dispersed, and then subjected to rotary evaporation and drying to obtain the heat conduction enhancement type ionic liquid composite phase-change heat storage material based on the modified graphene.
2. The preparation method of the heat conduction enhanced ionic liquid composite phase change heat storage material based on the modified graphene as claimed in claim 1, wherein the preparation method of the alkyl imidazole bromide ionic liquid is as follows: firstly, adding 1-methylimidazole and bromo-n-hexadecane into a container, then adding a solvent, reacting for 12-48 h at 70-100 ℃ after purging with inert gas, and purifying to obtain the alkylimidazole bromine salt ionic liquid.
3. The preparation method of the heat conduction enhanced ionic liquid composite phase change heat storage material based on the modified graphene as claimed in claim 2, wherein the molar ratio of 1-methylimidazole to bromo-n-hexadecane is 1: 1.0-1: 1.2; the volume ratio of the solvent to the 1-methylimidazole is 1: 1-1: 10;
the solvent is one or more of ethanol, acetonitrile, ethyl acetate, toluene and benzene;
the inert gas is nitrogen or argon;
the stirring speed during the reaction is 300-500 rpm;
the specific process of purification is as follows: and (3) performing rotary evaporation on the product after reaction for 12-48 h to remove the solvent to obtain a crude product, adding the crude product into one or more of ethyl acetate, acetone, toluene and tetrahydrofuran for recrystallization, filtering and drying to obtain the alkyl imidazole bromide ionic liquid.
4. The preparation method of the modified graphene-based heat conduction enhanced ionic liquid composite phase-change heat storage material is characterized in that the preparation method of the amino-terminated alkyl imidazole ionic liquid comprises the following steps: adding 1-methylimidazole and amino-halogenated alkane into a container, adding a solvent, purging with inert gas, carrying out quaternization reaction at 70-100 ℃ for 12-48 h, and purifying to obtain the alkyl imidazole ionic liquid containing terminal amino groups.
5. The preparation method of the heat conduction enhanced ionic liquid composite phase change heat storage material based on the modified graphene as claimed in claim 4, wherein the molar ratio of the 1-methylimidazole to the amino halogenated alkane is 1: 1.0-1: 1.2, the number of carbon atoms of the alkyl of the amino halogenated alkane is 2-3, and the halogen atom is one or more of chlorine, bromine and iodine;
the solvent is one or more of ethanol, acetonitrile, ethyl acetate, toluene and benzene; the volume ratio of the solvent to the 1-methylimidazole is 1: 1-1: 10;
the inert gas is nitrogen or argon.
6. The preparation method of the heat conduction enhanced ionic liquid composite phase change heat storage material based on the modified graphene as claimed in claim 4, wherein the specific purification process comprises the following steps: performing rotary evaporation on the product after 12-48 h of reaction to obtain a crude product, dissolving the crude product in ethanol, adding alkali, stirring to react for 1-12 h, filtering to obtain a filtrate, and performing rotary evaporation on the filtrate to obtain a crude product of the alkylimidazole ionic liquid containing terminal amino; dissolving a crude product of the alkyl imidazole ionic liquid containing the terminal amino group by using an ethanol-tetrahydrofuran mixed solvent, wherein the volume ratio of ethanol to tetrahydrofuran is 1: 0.5-4.0, filtering, carrying out rotary evaporation on the filtrate, recrystallizing the product in one or more of ethyl acetate, tetrahydrofuran and acetonitrile to obtain a white solid, and drying at 20-40 ℃ for 24-48 h to obtain the alkyl imidazole ionic liquid containing the terminal amino group.
7. The preparation method of the heat conduction enhancement type ionic liquid composite phase change heat storage material based on the modified graphene as claimed in claim 4, wherein the alkyl imidazole ionic liquid containing terminal amino groups is one or more of 1-aminopropyl-3-methylimidazole bromide, 1-aminoethyl-3-methylimidazole bromide, 1-aminopropyl-3-methylimidazole tetrafluoroborate, 1-aminoethyl-3-methylimidazole tetrafluoroborate, 1-aminopropyl-3-methylimidazole nitrate and 1-aminoethyl-3-methylimidazole nitrate.
8. The preparation method of the heat conduction enhanced ionic liquid composite phase change heat storage material based on the modified graphene as claimed in claim 1, wherein the modified graphene is prepared by performing covalent functionalization on alkyl imidazole ionic liquid containing terminal amino groups through the following processes: dissolving graphene oxide in water, uniformly dispersing to obtain a graphene oxide aqueous solution, adding an alkylimidazole ionic liquid containing terminal amino groups into the graphene oxide solution, and reacting at 70-90 ℃ for 12-48 hours to obtain modified graphene oxide; dissolving modified graphene oxide in water, adding hydrazine hydrate after ultrasonic dispersion, and reacting for 24-48 h at 80-90 ℃ to obtain graphene covalently functionalized and modified by an alkyl imidazole ionic liquid containing terminal amino groups; wherein the concentration of the graphene oxide aqueous solution is 0.1-3.0 mg/mL; the mass ratio of the graphene oxide to the alkyl imidazole ionic liquid containing the terminal amino is 1: 1-10.
9. The preparation method of the heat conduction enhanced ionic liquid composite phase change heat storage material based on the modified graphene as claimed in claim 1, wherein the mass ratio of the alkyl imidazole bromide ionic liquid to the graphene covalently functionalized and modified by the alkyl imidazole ionic liquid containing terminal amino groups is (70-99): (1-30);
the size of graphene covalently functionalized and modified by an alkyl imidazole ionic liquid containing terminal amino groups is 1-20 microns;
the solvent is one or more of ethanol, ethyl acetate, acetonitrile, DMSO and water;
the dispersion mode is ultrasonic or stirring;
the rotary evaporation temperature is 30-80 ℃, and the drying temperature is 20-40 ℃.
10. A method according to any one of claims 1 to 9The modified graphene-based heat conduction enhanced ionic liquid composite phase change heat storage material is characterized in that the phase change heat of the phase change heat storage material is 133.3-164.5J/g, the decomposition temperature is 255-265 ℃, and the thermal diffusion coefficient is 0.134-0.250 mm2And/s, the heat conductivity coefficient is 0.236-0.515W/(m.K), and the heat conductivity coefficient is improved by 4.4-127.9%.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113637275A (en) * | 2021-08-28 | 2021-11-12 | 安徽大学 | Charged polythiophene modified graphene heat-conducting filler and heat-conducting composite material based on same |
| CN116113217A (en) * | 2023-02-18 | 2023-05-12 | 广东工业大学 | Flexible heat-conducting ionic liquid phase-change gel material and preparation method and application thereof |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101805592A (en) * | 2010-04-20 | 2010-08-18 | 北京化工大学 | Ionic liquid base composite phase-change heat accumulation material and preparation method thereof |
| CN101985354A (en) * | 2010-09-21 | 2011-03-16 | 中国科学院长春应用化学研究所 | Method for preparing ionic liquid functionalized graphene material |
| CN102142294A (en) * | 2010-01-29 | 2011-08-03 | 海洋王照明科技股份有限公司 | Graphene-ionic liquid composite material and preparation method thereof |
| CN102732230A (en) * | 2012-06-29 | 2012-10-17 | 华南理工大学 | Preparation method for ionic liquid nanometer fluid for high temperature heat utilization in solar energy |
| US20130165353A1 (en) * | 2011-12-21 | 2013-06-27 | Baker Hughes Incorporated | Stable suspensions of carbon nanoparticles for nano-enhanced pdc, lbl coatings, and coolants |
| CN103275675A (en) * | 2013-06-08 | 2013-09-04 | 山西潞安矿业(集团)有限责任公司 | Application of ionic liquid material serving as cross-seasonal phase change heat storage material |
| CN105860403A (en) * | 2016-06-01 | 2016-08-17 | 辽宁大学 | Graphene nano composite material with dual intelligent responsivities |
| CN105949129A (en) * | 2016-06-06 | 2016-09-21 | 辽宁大学 | Imidazolium bromide ionic liquid containing amine groups and preparation method and application of ionic liquid |
| CN106045913A (en) * | 2016-06-06 | 2016-10-26 | 辽宁大学 | Imidazolium perrhenate ionic liquid with amino groups as well as preparation method and application of imidazolium perrhenate ionic liquid |
| CN106928907A (en) * | 2017-02-23 | 2017-07-07 | 华南理工大学 | A kind of nano-fluid black liquor of high-temperature stable and preparation method and application |
| CN107189493A (en) * | 2017-04-10 | 2017-09-22 | 桂林理工大学 | A kind of preparation method of ion liquid modified graphene |
| CN108360079A (en) * | 2018-02-07 | 2018-08-03 | 华南理工大学 | A kind of phase-changing and temperature-regulating fiber and preparation method thereof containing ionic liquid |
-
2021
- 2021-03-05 CN CN202110245637.7A patent/CN113072916A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102142294A (en) * | 2010-01-29 | 2011-08-03 | 海洋王照明科技股份有限公司 | Graphene-ionic liquid composite material and preparation method thereof |
| CN101805592A (en) * | 2010-04-20 | 2010-08-18 | 北京化工大学 | Ionic liquid base composite phase-change heat accumulation material and preparation method thereof |
| CN101985354A (en) * | 2010-09-21 | 2011-03-16 | 中国科学院长春应用化学研究所 | Method for preparing ionic liquid functionalized graphene material |
| US20130165353A1 (en) * | 2011-12-21 | 2013-06-27 | Baker Hughes Incorporated | Stable suspensions of carbon nanoparticles for nano-enhanced pdc, lbl coatings, and coolants |
| CN102732230A (en) * | 2012-06-29 | 2012-10-17 | 华南理工大学 | Preparation method for ionic liquid nanometer fluid for high temperature heat utilization in solar energy |
| CN103275675A (en) * | 2013-06-08 | 2013-09-04 | 山西潞安矿业(集团)有限责任公司 | Application of ionic liquid material serving as cross-seasonal phase change heat storage material |
| CN105860403A (en) * | 2016-06-01 | 2016-08-17 | 辽宁大学 | Graphene nano composite material with dual intelligent responsivities |
| CN105949129A (en) * | 2016-06-06 | 2016-09-21 | 辽宁大学 | Imidazolium bromide ionic liquid containing amine groups and preparation method and application of ionic liquid |
| CN106045913A (en) * | 2016-06-06 | 2016-10-26 | 辽宁大学 | Imidazolium perrhenate ionic liquid with amino groups as well as preparation method and application of imidazolium perrhenate ionic liquid |
| CN106928907A (en) * | 2017-02-23 | 2017-07-07 | 华南理工大学 | A kind of nano-fluid black liquor of high-temperature stable and preparation method and application |
| CN107189493A (en) * | 2017-04-10 | 2017-09-22 | 桂林理工大学 | A kind of preparation method of ion liquid modified graphene |
| CN108360079A (en) * | 2018-02-07 | 2018-08-03 | 华南理工大学 | A kind of phase-changing and temperature-regulating fiber and preparation method thereof containing ionic liquid |
Non-Patent Citations (3)
| Title |
|---|
| CHENGBAO LIU ET AL.: "An ionic liquid-graphene oxide hybrid nanomaterial: synthesis and anticorrosive applications", 《NANOSCALE》 * |
| HUAFENG YANG ET AL.: "Covalent functionalization of polydisperse chemically-converted grapheme sheets with amine-terminated ionic liquid", 《CHEM. COMMUN.》 * |
| 郭建强等: "氧化石墨烯的化学还原方法与机理研究进展", 《材料工程》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113637275A (en) * | 2021-08-28 | 2021-11-12 | 安徽大学 | Charged polythiophene modified graphene heat-conducting filler and heat-conducting composite material based on same |
| CN116113217A (en) * | 2023-02-18 | 2023-05-12 | 广东工业大学 | Flexible heat-conducting ionic liquid phase-change gel material and preparation method and application thereof |
| CN116113217B (en) * | 2023-02-18 | 2023-08-22 | 广东工业大学 | Flexible heat-conducting ionic liquid phase-change gel material and preparation method and application thereof |
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