A method for manufacturing nano SWCNT / PA@SiO2 phase change nanocapsules

Abstract

The application provides a manufacturing method of a nano SWCNT / PA@SiO2 phase change nanocapsule. The method comprises the following steps: uniformly treating, by using an ultrasonic cell disruptor, tetraethyl orthosilicate and carbon nanotubes through ultrasonic mixing to obtain a dispersion liquid A; uniformly treating, by using the ultrasonic cell disruptor, behenyl alcohol and the dispersion liquid A through ultrasonic mixing to obtain an oil phase B in which a shell material prepolymer, a core material phase change material and the carbon nanotubes are mixed; uniformly mixing deionized water, anhydrous ethanol and a surfactant to obtain an aqueous phase C; adding the oil phase B into the aqueous phase C to obtain an O / W emulsion; transferring the O / W emulsion into a three-necked flask, adding ammonia water into the three-necked flask, stirring the solution in the three-necked flask, and obtaining a WCNT / PA@SiO2 phase change nanocapsule emulsion. After filtration, washing and drying, the SWCNT / PA@SiO2 phase change nanocapsule is obtained. The application provides an inorganic shell nanometer phase change capsule with a carbon nanotube core material modification. Since the size is nanometer, the enthalpy value can be improved through the effect of intermolecular nanometer limitation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of phase change materials, and particularly relates to a manufacturing method of a nano SWCNT / PA@SiO2 phase change nano capsule. BACKGROUND

[0002] Phase change materials are a new type of energy storage materials, which allow a large amount of latent heat to be stored in the phase change process. Due to the characteristics of phase change materials, phase change materials are widely used in various fields, such as textiles, solar energy and thermal management, etc. Among various phase change materials, solid-liquid phase change materials are widely studied due to their high latent heat. However, the phase change materials will flow and cause leakage, pollution, etc. during the phase change process, which limits the application of phase change materials.

[0003] The microcapsule technology is used to encapsulate the solid-liquid phase change materials in the shell to obtain a microcapsule type composite phase change material, which not only can completely avoid the occurrence of liquid leakage, but also makes the application of solid-liquid phase change materials more flexible. Phase change capsules are divided into large capsules, microcapsules and nanocapsules due to different sizes, and smaller capsules have larger specific surface area, which can improve heat transfer. In order to make phase change capsules applied in various fields, the modification of phase change capsules is also various, and the modification way is to add thermal conductive fillers such as nanoparticles, carbon nanotubes and graphene in the shell material or core material. The modification of phase change capsules can further improve the stability and thermal conductivity of phase change microcapsules.

[0004] At present, the prior art provides a microcapsule phase change material (MPCM) with carbon nanotube reinforced filler core modification and binary core. The MPCM has improved thermal conductivity and adjustable working temperature range, which is suitable for various thermal energy storage applications.

[0005] The disadvantages of the above-mentioned microcapsule phase change material (MPCM) include that the MPCM uses an organic shell as a shell material, and most of the organic shells are not heat-resistant and non-flame-retardant; the improvement in thermal performance is not high, and it is difficult to be applied in the field of thermal management and thermal interface. The phase change capsule MPCM is in micrometer level, and is not heat-resistant and poor in thermal conductivity, and the manufacturing method needs to modify the carbon nanotube in advance, which is complex in process and changes the structure of the carbon nanotube to some extent. The enthalpy value of the capsule decreases to some extent due to the addition of the thermal conductive material.

[0006] The prior art also provides a carbon nanotube (CNT) loaded paraffin phase change material, a phase change microcapsule material in a poly (melamine-formaldehyde) shell. Disadvantages of the phase change microcapsule material include: the method uses an organic shell as a shell material, the prepared capsule is at a micron level, the added inorganic nanoparticles are difficult to play a nano confinement role, the simple addition of inorganic nanoparticles reduces the phase change enthalpy value, and excellent heat-resistant high-thermal-conductivity materials and enthalpy value performance cannot be obtained. The manufacturing method introduces other solvent processes, which are complex, and the organic shell has low thermal conductivity, and cannot balance the enthalpy value and thermal conductivity performance. SUMMARY

[0007] Embodiments of the present application provide a manufacturing method of a nano SWCNT / PA@SiO2 phase change nanocapsule to effectively prepare nano phase change capsules with inorganic shell materials at a nanometer level.

[0008] To achieve the above-mentioned purpose, the present application adopts the following technical solutions.

[0009] A manufacturing method of a nano SWCNT / PA@SiO2 phase change nanocapsule, comprising:

[0010] Selecting tetraethyl orthosilicate as a shell material prepolymer, and weighing the tetraethyl orthosilicate and the ground carbon nanotubes according to a mass ratio of 1: (0.01-0), using an ultrasonic cell disruptor to uniformly treat the tetraethyl orthosilicate and the ground carbon nanotubes at a first set temperature for a certain time, and obtaining a dispersion liquid A formed by the combination of the carbon nanotubes and the tetraethyl orthosilicate;

[0011] Selecting n-dodecane as a core material phase change material, weighing the n-dodecane according to a mass ratio of 2:3 of the tetraethyl orthosilicate to the n-dodecane, using an ultrasonic cell disruptor to uniformly treat the n-dodecane and the dispersion liquid A at a second set temperature for a certain time, and obtaining an oil phase B mixed with the shell material prepolymer, the core material phase change material and the carbon nanotubes;

[0012] Weighing deionized water, anhydrous ethanol and a surfactant, and mixing the deionized water, the anhydrous ethanol and the surfactant at a second set temperature to obtain a water phase C, wherein a mass ratio of the deionized water, the anhydrous ethanol and the n-dodecane is 14:7:3;

[0013] Adding the oil phase B to the water phase C at the second set temperature to obtain an O / W emulsion;

[0014] Put the O / W emulsion into a three-necked flask, add ammonia water with a volume ratio of 1:54 with deionized water in the three-necked flask, stir the solution in the three-necked flask at a second set temperature, so that the tetraethyl orthosilicate in the solution reacts to generate silicon dioxide after hydrolysis under alkaline conditions, the silicon dioxide coats the n-dodecane and the carbon nanotubes remaining in the oil phase to form an inorganic silicon dioxide shell material, and the SWCNT / PA@SiO2 phase change nanocapsule emulsion is obtained.

[0015] After the SWCNT / PA@SiO2 phase change nanocapsule emulsion is sequentially filtered, washed and dried, the SWCNT / PA@SiO2 phase change nanocapsule is obtained.

[0016] Preferably, the process of producing the milled carbon nanotubes in the method comprises:

[0017] Marble balls and carbon nanotubes are weighed according to a ball-to-material ratio of 10:1, mixed and then put into a ball mill, milled in the ball mill for 10 h, and the milled carbon nanotubes with shortened length are obtained.

[0018] Preferably, the first set temperature is 80℃ and the second set temperature is 60℃.

[0019] Preferably, the concentration of the surfactant and the deionized water is 0.013 g / mL.

[0020] Preferably, the surfactant is hexadecyl trimethyl ammonium bromide.

[0021] Preferably, the three-necked flask is preheated in an oil bath for 10 min at 60℃, and the rotation speed of the three-necked flask during stirring is 350 rpm.

[0022] Preferably, the washing is carried out with petroleum ether, deionized water and ethanol in turn for 3-4 times, and the drying is carried out using a culture dish at room temperature for 24 h.

[0023] As can be seen from the technical solutions provided by the above embodiments of the present application, the present application provides an inorganic shell nanometer phase change capsule with carbon nanotube core material modification, which not only makes up for the problem that the organic shell is not heat-resistant and is difficult to synergize with modified inorganic nanoparticles, but also has the ability to improve the enthalpy value through intermolecular nanometer confinement, so that the thermal conductivity is enhanced while the enthalpy value is also improved, and the overall thermal performance is excellent. It can be applied in the fields of heat storage, thermal management, thermal interface, etc.

[0024] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0026] Figure 1 A process flow chart of a manufacturing method of a nano SWCNT / PA@SiO2 (carbon nanotube loaded paraffin silica coated) phase change nanocapsule is provided for the embodiments of the present application.

[0027] Figure 2 The complete (a) SEM of the SWCNT / PA@SiO2 phase change nanocapsule synthesized in Example 4, and the (b, c) SEM of the observation of the inside of the capsule after crushing Example 3, and the (d) TEM electron microscope spectrum can see that the complete phase change nanocapsule is synthesized, and the core material contains carbon nanotubes, and the (e) nanoparticle size instrument measured particle size of Example 3 can be seen. All capsules are in nanometer level.

[0028] Figure 3 The infrared test spectrum of all examples can be seen. The characteristic peaks corresponding to -CH and C-H can be seen in the spectrum of C22 and the capsule. The characteristic peak of Si-O-Si can be seen in the capsule sample, which shows that there is no chemical interaction between the components, and also shows that the n-dodecane is wrapped by SiO2, and the phase change nanocapsule is successfully synthesized.

[0029] Figure 4 The (a) DSC test graph and the (b) thermal conductivity test graph of all examples can be seen. The enthalpy value and the thermal conductivity are improved to a certain extent compared with the phase change nanocapsule without carbon nanotubes in Example 2.

[0030] Figure 5 The (a) infrared imaging graph and the (b) temperature change graph of all examples can be seen. Heat is transferred from the bottom to the top. In the early stage of temperature rise, the sample with higher enthalpy value can absorb more heat, so the temperature rises more slowly. The temperature of Example 3 rises most slowly, which matches its enthalpy value performance. When the overall temperature exceeds about 45℃, the sample with higher thermal conductivity can conduct heat faster, so the temperature rises faster. Figure 5 The thermal conductivity performance is matched as shown in Example 4.

[0031] Figure 6 The particle size statistical graph obtained by the nanoparticle size instrument of all examples. DETAILED DESCRIPTION

[0032] Embodiments of the present application are described in detail below with reference to several examples illustrated in the attached drawings, wherein like or similar elements are denoted by the same or similar reference numerals throughout the drawings. The embodiments described below are exemplary only, and are not to be construed as limiting the present application.

[0033] Those skilled in the art can understand that the singular forms "a," "an," and "the" used herein include plural referents unless the context clearly dictates otherwise. It should also be further understood that the term "comprising" as used in the specification, including the claims, means that there are no restrictions on the presence of other features, integers, steps, operations, elements, components, and / or groups thereof, unless the context clearly dictates otherwise. It should be understood that when we say an element is "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements can also be present. In addition, "connected" or "coupled" as used herein can include wireless connection or coupling. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have meanings consistent with those in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless otherwise defined.

[0035] In order to facilitate the understanding of the embodiments of the present application, the following will be further explained in conjunction with the drawings by way of several specific examples, and each example does not constitute a limitation on the embodiments of the present application.

[0036] Example 1

[0037] The processing flow of the manufacturing method of the nanometer SWCNT / PA@SiO2 (carbon nanotube loaded paraffin silica coated) phase change nanocapsule provided by the embodiments of the present application is shown in Figure 1 as follows:

[0038] Step S1: According to the ratio of 10:1, agate balls and carbon nanotubes are weighed, wherein the agate balls are used as grinding medium. After mixing the agate balls and carbon nanotubes, they are put into a ball mill, and ground in the ball mill for 10h to obtain carbon nanotubes with shortened length after grinding. The amount of carbon nanotubes added is determined according to the size of the ball mill capacity. The larger the ball-to-material ratio, the better the grinding effect, and the shorter the length of the carbon nanotubes.

[0039] Step S2, tetraethyl orthosilicate is selected as the shell material prepolymer, and the mass ratio of tetraethyl orthosilicate and the ground carbon nanotubes is 1: (0.01-0). After mixing, the mixture is placed in an ultrasonic cell disruptor, and the ultrasonic cell disruptor is used to uniformly treat the tetraethyl orthosilicate and the ground carbon nanotubes at 80℃ for a certain period of time to obtain a stable dispersion liquid A formed by the combination of carbon nanotubes and tetraethyl orthosilicate, so that the carbon nanotubes are introduced into the oil phase by the tetraethyl orthosilicate. The above-mentioned certain period of time can be several hours, so that the carbon nanotubes and the tetraethyl orthosilicate are fully combined and stabilized.

[0040] Step S3, n-docosane (i.e. paraffin) is selected as the core material phase change material. The mass ratio of tetraethyl orthosilicate to n-docosane is 2:3, and n-docosane is mixed with dispersion liquid A and then placed in an ultrasonic cell disruptor. The n-docosane and the dispersion liquid A are uniformly treated by ultrasonic mixing at 60℃ for a certain period of time to obtain an oil phase B mixed with the shell material prepolymer, the core material phase change material and the carbon nanotubes. Through this step, the modified substance carbon nanotubes are closely combined with the oil phase, which is an important step for the successful synthesis of the inorganic shell-core material modified capsules.

[0041] Step S4, the mass ratio of deionized water, anhydrous ethanol and n-docosane used is 14:7:3, and the concentration of the surfactant and deionized water is 0.013g / mL. The deionized water, anhydrous ethanol and surfactant are mixed uniformly at 60℃ to obtain an aqueous phase C. In this invention, the concentration of the surfactant is about 0.01-0.015g / ml. Different capsule preparation methods and different types of surfactants have different concentrations. The more the surfactant, the smaller the capsule particle size. However, if there is too much or too little, a stable emulsion cannot be formed.

[0042] The above-mentioned surfactant can be hexadecyl trimethyl ammonium bromide.

[0043] Step S5, the oil phase B is added to the aqueous phase C at 60℃ to obtain an O / W emulsion.

[0044] Since tetraethyl orthosilicate is more soluble in ethanol, the tetraethyl orthosilicate molecules slowly hydrolyze and move to the water phase during the process, while the carbon nanotubes and paraffin are left in the oil phase. The homogenization speed of the oil phase B in the aqueous phase C of the method of the present invention is usually 10000rpm.

[0045] Step S6, the homogeneous O / W emulsion is transferred to a three-necked flask, ammonia is added as a catalyst, the three-necked flask is added with ammonia in a volume ratio of 1:54 with deionized water, and the solution in the three-necked flask is stirred at 350 rpm at 60°C to make the solution fully react. The above three-necked flask needs to be preheated in an oil bath at 60°C for 10 min to ensure that the emulsion is not damaged. After the addition of ammonia, the tetraethyl orthosilicate reacts to form silicon dioxide under alkaline conditions, and the silicon dioxide coats the n-docosane and the carbon nanotubes remaining in the oil phase to form an inorganic silicon dioxide shell material, thereby obtaining the SWCNT / PA@SiO2 phase change nanocapsule emulsion. The shell material of the SWCNT / PA@SiO2 phase change nanocapsule emulsion is silicon dioxide, that is, the SWCNT / PA@SiO2 phase change nanocapsule emulsion has an inorganic shell.

[0046] The carbon nanotubes are inserted in the core material phase change material and in contact with the silicon dioxide shell material to form a heat transfer path inside the capsule to enhance heat conduction. At the same time, due to the addition of carbon nanotubes, the structure restricts the movement of phase change material molecules, so that the binding energy of the core material phase change material is increased, the crystallinity is enhanced, and the enthalpy of the whole capsule is increased.

[0047] Step S7, the SWCNT / PA@SiO2 phase change nanocapsule emulsion is filtered, washed and dried in sequence to obtain the SWCNT / PA@SiO2 phase change nanocapsule.

[0048] The above washing is 3-4 times of washing with petroleum ether, deionized water and ethanol in turn. The above drying is drying for 24 h at room temperature using a culture dish.

[0049] The above added carbon nanotubes have hydrophilic groups on the surface and can act as particles in a "Pickering emulsion" to achieve emulsification assistance, thereby reducing the particle size of the capsule together with the surfactant; when the carbon nanotubes are too much, they have the characteristics of aggregation, thereby promoting the aggregation of the phase change material together with the carbon nanotubes to form larger emulsion droplets, resulting in larger capsule size. Therefore, by increasing or decreasing the amount of carbon nanotubes, the size of the SWCNT / PA@SiO2 phase change nanocapsule can be controlled.

[0050] Of course, the homogenization speed and the amount of surfactant are also the main factors that make the capsule size reach the nanometer level. When the homogenization speed reaches a certain degree, sufficient shear force can result in smaller emulsion droplets in the form of phase change capsule re-emulsion; the concentration of the surfactant also affects the emulsion particle size. Proper surfactant concentration can ensure that the emulsification process is sufficient and stable, thereby helping to form smaller emulsion particle size.

[0051] The method of the present application controls the size of the SWCNT / PA@SiO2 phase change nanocapsule by comprehensively controlling the amount of carbon nanotubes, the homogenization speed of the oil phase B in the water phase C and the amount of surfactant, so that the size of the prepared SWCNT / PA@SiO2 phase change nanocapsule can reach the nanometer level. For example, by controlling the content of carbon nanotubes, when the ratio of carbon nanotube content to tetraethyl orthosilicate is (0.005-0):1, nanometer-level phase change capsules can be obtained.

[0052] Different phase change capsule samples are prepared according to different contents of carbon nanotubes, and the particle size and performance of the obtained modified capsules are different (particle size graph is added), the particle size is from nanometer to micrometer, and the thermal conductivity and enthalpy value are different, but the overall performance is improved.

[0053] When used in building materials, large particle size phase change capsules can provide more stable and durable temperature control effect, and are suitable for large area temperature regulation. Small particle size phase change capsules are suitable for integration into clothing to provide local heat management and comfort, such as sportswear, thermal clothing, etc. The sample with the best thermal conductivity and enthalpy value is suitable for application in the field of heat dissipation.

[0054] Example two:

[0055] Step 1, according to the mass ratio of tetraethyl orthosilicate to n-dodecane 2:3, n-dodecane is weighed, n-dodecane is mixed with dispersion liquid A, and an ultrasonic cell disruptor is also used to mix uniformly at 60°C, to obtain an oil phase B mixed with shell material pre-polymer, core material phase change material and carbon nanotubes;

[0056] Step 2, deionized water and anhydrous ethanol are weighed, and the mass ratio of the used n-dodecane is 14:7:3, and the concentration of the surfactant and deionized water is 0.013g / mL, and the deionized water, anhydrous ethanol and surfactant are mixed uniformly at 60°C to obtain a water phase C;

[0057] Step 3, at 60°C, the oil phase B is added to the water phase C to obtain an O / W emulsion;

[0058] Step 4, after the O / W emulsion obtained by homogenization is transferred to a three-necked flask, ammonia water with a volume ratio of 1:54 to deionized water is added as a catalyst, and it is fully reacted at 60°C with a stirring speed of 350 rpm to obtain a PA@SiO2 phase change nanocapsule emulsion;

[0059] Step 5, after the PA@SiO2 phase change nanocapsule emulsion is sequentially filtered, washed and dried, PA@SiO2 phase change nanocapsules are obtained as a comparative sample.

[0060] Example three:

[0061] Step 1, take agate balls and carbon nanotubes according to the ratio of 10:1, ball mill in the ball mill for 10h, obtain the length of the grinding carbon nanotubes;

[0062] Step 2, according to the mass ratio of 1:0.0025, take tetraethyl orthosilicate and ground carbon nanotubes, use ultrasonic cell crusher to mix uniformly at 80℃ to obtain carbon nanotube and prepolymer dispersion A;

[0063] Step 3, according to the mass ratio of 2:3 of tetraethyl orthosilicate and n-dodecane, mix n-dodecane with dispersion A, also use ultrasonic cell crusher to mix uniformly at 60℃, obtain oil phase B of shell material prepolymer, core material phase change material and carbon nanotubes;

[0064] Step 4, take deionized water and anhydrous ethanol with the mass ratio of 14:7:3 of the used n-dodecane, also take the concentration of surfactant and deionized water as 0.013g / mL, mix deionized water, anhydrous ethanol and surfactant uniformly at 60℃ to obtain water phase C;

[0065] Step 5, at 60℃, add oil phase B to water phase C to obtain O / W emulsion;

[0066] Step 6, after transferring the O / W emulsion obtained by homogenization to a three-necked flask, add ammonia water with a volume ratio of 1:54 of deionized water as catalyst, stir at 60℃ with a speed of 350rpm to make it fully react, obtain SWCNT / PA@SiO2 phase change nanocapsule emulsion;

[0067] Step 7, after filtering, washing and drying SWCNT / PA@SiO2 phase change nanocapsule emulsion in turn, obtain SWCNT / PA@SiO2 phase change nanocapsule.

[0068] Example four:

[0069] Step 1, take agate balls and carbon nanotubes according to the ratio of 10:1, ball mill in the ball mill for 10h, obtain the length of the grinding carbon nanotubes;

[0070] Step 2, according to the mass ratio of 1:0.005, take tetraethyl orthosilicate and ground carbon nanotubes, use ultrasonic cell crusher to mix uniformly at 80℃ to obtain carbon nanotube and prepolymer dispersion A;

[0071] Step 3, according to the mass ratio of tetraethyl orthosilicate to n-dodecane 2:3, n-dodecane is mixed with dispersion liquid A, and is also uniformly mixed at 60°C using an ultrasonic cell disruptor to obtain oil phase B mixed with shell material prepolymers, core phase change materials and carbon nanotubes;

[0072] Step 4, according to the mass ratio of deionized water and anhydrous ethanol to n-dodecane used 14:7:3, and also according to the concentration of surfactant to deionized water 0.013 g / mL, deionized water, anhydrous ethanol and surfactant are uniformly mixed at 60°C to obtain water phase C;

[0073] Step 5, at 60°C, oil phase B is added to water phase C to obtain O / W emulsion;

[0074] Step 6, after the O / W emulsion obtained by homogenization is transferred to a three-necked flask, ammonia water with a volume ratio of 1:54 to deionized water is added as a catalyst, and is fully reacted at 60°C with stirring at a speed of 350 rpm to obtain SWCNT / PA@SiO2 phase change nanocapsule emulsion;

[0075] Step 7, after the SWCNT / PA@SiO2 phase change nanocapsule emulsion is sequentially filtered, washed and dried, SWCNT / PA@SiO2 phase change nanocapsules are obtained.

[0076] Figure 2 Figures (a) SEM of the complete SWCNT / PA@SiO2 phase change nanocapsules synthesized in Example Four, and (b, c) SEM of the capsules after being crushed to observe the inside of the capsules, (d) TEM electron spectrogram can see that complete phase change nanocapsules are synthesized, and the core material contains carbon nanotubes, and Figure (e) is the particle size of Example Four measured by a nanoparticle size analyzer, which can be seen that all the capsules are in the nanometer level.

[0077] Example Five:

[0078] Step 1, according to the ratio of 10:1 of ball to material, agate balls and carbon nanotubes are weighed and mixed in a ball mill for 10h to obtain carbon nanotubes with shortened length after grinding;

[0079] Step 2, according to the mass ratio of 1:0.0075 of tetraethyl orthosilicate and ground carbon nanotubes, dispersion liquid A of carbon nanotubes and prepolymers is obtained by uniformly mixing at 80°C using an ultrasonic cell disruptor;

[0080] Step 3, according to the mass ratio of tetraethyl orthosilicate to n-dodecane 2:3, n-dodecane is mixed with dispersion liquid A, and is also uniformly mixed at 60°C using an ultrasonic cell disruptor to obtain oil phase B mixed with shell material prepolymers, core phase change materials and carbon nanotubes;

[0081] Step 4, take deionized water and anhydrous ethanol with the mass ratio of n-dodecane used as 14:7:3, and also take the concentration of surfactant and deionized water as 0.013 g / mL, mix deionized water, anhydrous ethanol and surfactant uniformly at 60°C to obtain water phase C;

[0082] Step 5, at 60°C, add oil phase B to water phase C to obtain O / W emulsion by homogenization;

[0083] Step 6, after transferring the O / W emulsion obtained by homogenization to a three-necked flask, add ammonia water with a volume ratio of 1:54 to deionized water as a catalyst, and stir at 350 rpm at 60°C to make it fully react to obtain SWCNT / PA@SiO2 phase change nanocapsule emulsion;

[0084] Step 7, after filtering, washing and drying the SWCNT / PA@SiO2 phase change nanocapsule emulsion in sequence, obtain SWCNT / PA@SiO2 phase change nanocapsule.

[0085] Example Six:

[0086] Step 1, take agate balls and carbon nanotubes according to the ratio of ball to material of 10:1, ball mill in a ball mill for 10h to obtain carbon nanotubes with shortened length after grinding;

[0087] Step 2, take tetraethyl orthosilicate and ground carbon nanotubes according to the mass ratio of 1:0.01, and use an ultrasonic cell disruptor to mix uniformly at 80°C to obtain dispersion liquid A of carbon nanotubes and prepolymers;

[0088] Step 3, take n-dodecane according to the mass ratio of tetraethyl orthosilicate to n-dodecane of 2:3, mix it with dispersion liquid A, and also use an ultrasonic cell disruptor to mix uniformly at 60°C to obtain oil phase B of mixed shell material prepolymers, core material phase change material and carbon nanotubes;

[0089] Step 4, take deionized water and anhydrous ethanol with the mass ratio of n-dodecane used as 14:7:3, and also take the concentration of surfactant and deionized water as 0.013 g / mL, mix deionized water, anhydrous ethanol and surfactant uniformly at 60°C to obtain water phase C;

[0090] Step 5, at 60°C, add oil phase B to water phase C to obtain O / W emulsion by homogenization;

[0091] Step 6, after transferring the O / W emulsion obtained by homogenization to a three-necked flask, add ammonia water with a volume ratio of 1:54 to deionized water as a catalyst, and stir at 350 rpm at 60°C to make it fully react to obtain SWCNT / PA@SiO2 phase change nanocapsule emulsion;

[0092] Step 7, after the SWCNT / PA@SiO2 phase change nanocapsule emulsion is filtered, washed and dried in sequence, SWCNT / PA@SiO2 phase change nanocapsules are obtained.

[0093] Those skilled in the art should understand that the values of the ball material ratio and the mass ratio described above are only examples, and other existing or future values of the ball material ratio and the mass ratio, such as those applicable to the embodiments of the present application, should also be included in the protection scope of the present application and are hereby incorporated by reference.

[0094] Figure 3 For the infrared test spectrum of the SWCNT / PA@SiO2 phase change nanocapsules of all the embodiments, it can be seen that in the spectrum of C22 and the capsules, characteristic peaks corresponding to -CH and C-H can be seen, and in the capsule sample, characteristic peaks of Si-O-Si can be seen, indicating that no chemical interaction occurs between the components, and also indicating that the docosane is wrapped by SiO2, and the phase change nanocapsules are successfully synthesized.

[0095] Figure 4 For the (a) DSC test graph and (b) thermal conductivity test graph of all the embodiments, it can be seen that the enthalpy value and the thermal conductivity are improved to a certain extent compared with the phase change nanocapsules without carbon nanotubes in Example Two.

[0096] Figure 5 For the (a) infrared imaging graph and (b) temperature change graph of all the embodiments, heat is transferred from the bottom to the top. In the early stage of temperature rise, the sample with a higher enthalpy value can absorb more heat, and thus the temperature rises more slowly. The temperature of Example Four rises most slowly, which matches its enthalpy value performance. When the overall temperature exceeds about 45℃, the sample with a higher thermal conductivity can conduct heat faster, and thus the temperature rises faster, as shown in Figure 5 .

[0097] Figure 6 For the particle size statistical graph obtained by the nanometer particle size analyzer of all the embodiments, the particle size obtained by adding different amounts of carbon nanotubes is different. With the increase of the amount of carbon nanotubes, the particle size first decreases and then increases (the reason is shown in the specific embodiment), and nanometer to micrometer level phase change capsules can be obtained in sequence.

[0098] In summary, the SWCNT / PA@SiO2 phase change nanocapsules prepared in the embodiments of the present application have a synergistic effect between the silica shell material and the modified carbon nanotubes in the core material, which improves the thermal conductivity and heat transfer performance of the material, and can be well applied in the fields of thermal interface and thermal management which require heat storage and heat transfer.

[0099] The core material modified capsule in the application is nanometer level, and there is no core material modified phase change capsule of nanometer level and no core material modified capsule with inorganic shell material at present. The application overcomes the difficulty of modification and structure making of materials with small size, and combines the method of incorporating carbon nanotubes into the manufacturing method of the capsule. The compatibility of inorganic nanomodified materials and oil phase is improved by ultrasonic modification of carbon nanotubes and shell material prepolymers, without introducing other modification reagents and solvents, greatly simplifying the manufacturing method.

[0100] In the application, the carbon nanotubes are inserted in the core material phase change material and contact with the shell material, forming a heat transfer path in the capsule to enhance heat conduction. At the same time, due to the addition of carbon nanotubes, the structure restricts the activity of phase change material molecules, making the binding energy larger and the crystallinity enhanced, so that the overall enthalpy of the capsule is increased. The pain point that the addition of inorganic materials in the current technology reduces the enthalpy is solved, and both excellent thermal conductivity and good enthalpy are obtained.

[0101] Those skilled in the art can understand that the drawings are only schematic of an embodiment, and the modules or flows in the drawings are not necessarily required for implementing the application.

[0102] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other. Each embodiment mainly describes the difference from other embodiments. Especially, the device or system embodiment is basically similar to the method embodiment, so the description is relatively simple, and the related parts can be referred to the part of the method embodiment. The above described device and system embodiment is only schematic, and the units described as separate components can be or can not be physically separated, and the components displayed as units can be or can not be physical units, that is, they can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiment according to the actual needs. Those skilled in the art can understand and implement without creative labor.

[0103] The above is only the preferred embodiment of the application, but the protection scope of the application is not limited to this. Any changes or replacements within the technical range disclosed by the application can be easily thought by those skilled in the art, which should be covered in the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A method for manufacturing nano-SWCNT / PA@SiO2 phase change nanocapsules, characterized in that: include: Selecting tetraethyl orthosilicate as the shell material prepolymer, tetraethyl orthosilicate and ground carbon nanotubes were weighed in a mass ratio of 1:(0.0025-0.01). Using an ultrasonic cell disruptor, the tetraethyl orthosilicate and ground carbon nanotubes were ultrasonically mixed for a certain period of time at a first set temperature to obtain a dispersion A formed by the combination of carbon nanotubes and tetraethyl orthosilicate. Selecting n-docosane as the core phase change material, n-docosane is weighed according to a mass ratio of ethyl orthosilicate to n-docosane of 2:3, and the n-docosane and the dispersion A are ultrasonically mixed for a certain period of time at a second set temperature in an ultrasonic cell disruptor to obtain an oil phase B mixed with a shell prepolymer, a core phase change material, and carbon nanotubes; Weighing deionized water, anhydrous ethanol, and a surfactant, wherein the mass ratio of the deionized water, anhydrous ethanol, and n-docosane is 14:7:3, and uniformly mixing the deionized water, anhydrous ethanol, and the surfactant at a second set temperature to obtain an aqueous phase C; adding the oil phase B to the water phase C and homogenizing at a second set temperature to obtain an O / W emulsion; The O / W emulsion is placed in a three-necked flask, and ammonia water is added to the three-necked flask at a volume ratio of 1:54 to deionized water. The solution in the three-necked flask is stirred at a second set temperature to hydrolyze the ethyl orthosilicate in the solution under alkaline conditions and then react to form silica. The silica coats the n-docosane and the carbon nanotubes remaining in the oil phase to form an inorganic silica shell material, thereby obtaining a SWCNT / PA@SiO2 phase change nanocapsule emulsion; The SWCNT / PA@SiO2 phase change nanocapsule emulsion is filtered, washed, and dried in sequence to obtain SWCNT / PA@SiO2 phase change nanocapsules; The first set temperature is 80°C, and the second set temperature is 60°C; The surfactant is cetyltrimethylammonium bromide, and the concentration of the surfactant and the deionized water is 0.013 g / mL.

2. The method according to claim 1, characterized in that The process of producing the ground carbon nanotubes in the method includes: Agate balls and carbon nanotubes were weighed in a ball-to-material ratio of 10:1, the agate balls and carbon nanotubes were mixed and placed in a ball mill, and ground in the ball mill for 10 hours to obtain carbon nanotubes that were cut short after grinding.

3. The method according to claim 1, characterized in that The three-necked flask was preheated in an oil bath at 60° C. for 10 min, and the rotation speed of the three-necked flask during stirring was 350 rpm.

4. The method according to claim 1, wherein The washing step was performed by alternately washing with petroleum ether, deionized water, and ethanol for 3-4 times, and the drying step was performed by drying the mixture at room temperature for 24 hours using a culture dish.

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