An anti-ionizing radiation high-thermal-conductivity phase change microcapsule, a preparation method and application thereof

Abstract

The application provides an anti-ionizing radiation high-thermal-conductivity phase change microcapsule and a preparation method and application thereof, the phase change microcapsule comprises a shell layer and a phase change core material, the shell layer is composed of barium carbonate and hydrophobic modified graphene, and the core material is composed of n-octadecane and n-eicosane. The phase change microcapsule has the anti-ionizing radiation performance, the shell layer has high thermal conductivity, is sensitive to environmental temperature change, can be applied to an anti-ionizing radiation and temperature control wall body in specific places such as a medical C-T room wall body, and can well meet the requirements of multifunctional engineering applicability.

Description

Technical Field

[0001] This application belongs to the field of microcapsule preparation technology, and more specifically, relates to a phase change microcapsule with high thermal conductivity and resistance to ionizing radiation, its preparation method and application. Background Technology

[0002] In daily life, radiology based on gamma rays and X-rays has become an indispensable part of the human health system, primarily used for diagnosis and treatment in medical services. Both gamma rays and X-rays are powerful photon streams harmful to the human body. Therefore, for safety reasons, equipment is usually housed in specialized rooms. Technically, when photons collide with atoms of higher atomic numbers, the energy of the rays can be attenuated through the photoelectric effect and the Compton effect, providing new technological solutions in terms of building materials and safety.

[0003] Phase change materials (PCMs) are heat-absorbing and heat-storing materials that maintain a stable ambient temperature by gaining or losing water or undergoing phase changes. Microencapsulation technology can encapsulate PCMs within a solid and dense shell, further solving the leakage problem during heat storage and making PCMs more practical for engineering applications. Thermal conductivity is a crucial factor in evaluating microcapsule performance. Conventional PCM microcapsules often use polymers with poor thermal conductivity as the shell material, resulting in poor sensitivity to changes in ambient temperature and an inability to respond promptly to temperature variations. Therefore, improving the thermal conductivity efficiency of PCM microcapsules is a pressing issue that needs to be addressed.

[0004] To better realize the engineering applicability of phase change microcapsules, it is of great significance to develop phase change microcapsules with multifunctional rather than single thermal storage functions. Summary of the Invention

[0005] The purpose of this application is to provide a phase change microcapsule with high thermal conductivity and resistance to ionizing radiation, its preparation method and application, so as to solve the technical problem that the phase change microcapsule with single heat storage function in the prior art cannot well meet the requirements of multifunctional engineering applicability.

[0006] To achieve the above objectives, a first aspect of this application provides a phase change microcapsule with high thermal conductivity and resistance to ionizing radiation, comprising a shell and a phase change core material, wherein the shell is composed of barium carbonate and hydrophobically modified graphene, and the core material is composed of n-octadecane and n-eicosane.

[0007] Furthermore, the hydrophobically modified graphene accounts for 2 wt% to 6 wt% of the weight of the shell layer.

[0008] Furthermore, the core material is composed of n-octadecane and n-eicosane in a weight ratio of 1:1 to 1:3.

[0009] A second aspect of this application provides a method for preparing ionizing radiation-resistant, high thermal conductivity phase change microcapsules, comprising the following steps:

[0010] The surfactant is dissolved in deionized water to obtain a surfactant solution;

[0011] n-Octadecane and n-eicosane are uniformly mixed to form a phase change core material;

[0012] Under stirring conditions of 60–65°C, the phase change core material and hydrophobically modified graphene are added to the surfactant solution to obtain a first emulsion.

[0013] Barium salt powder is dissolved in deionized water to obtain a barium salt solution;

[0014] Dissolve the carbonate powder in deionized water to obtain a carbonate solution;

[0015] Under stirring conditions of 60–65°C and 350–400 r / min, the barium salt solution was added to the first emulsion to obtain the second emulsion.

[0016] The temperature of the second emulsion was maintained at 60-65°C, the stirring speed was reduced to 250-300 r / min, and a carbonate solution was added to obtain the third emulsion.

[0017] The temperature of the third emulsion was maintained at 60-65°C, and the stirring speed was reduced to 150-200 r / min to obtain a microcapsule suspension.

[0018] The microcapsule suspension was filtered, washed, and the filter residue was dried to obtain high thermal conductivity phase change microcapsules resistant to ionizing radiation.

[0019] Furthermore, the surfactant includes one or more of polyvinyl alcohol, Span 80, and sodium dodecylbenzene sulfonate.

[0020] Furthermore, the concentration of the surfactant in the surfactant solution is 0.1 g / L to 0.2 g / L.

[0021] Furthermore, the barium salt is barium chloride.

[0022] Furthermore, the carbonate is sodium carbonate.

[0023] Furthermore, the hydrophobically modified graphene is prepared by the following method: under the catalysis of aluminum chloride, stearic acid undergoes lipophilic modification with graphene, followed by drying without washing to obtain modified graphene.

[0024] A third aspect of this application provides the application of high thermal conductivity phase change microcapsules resistant to ionizing radiation in ionizing radiation-resistant and temperature-controlled walls.

[0025] Compared with the prior art, this application has the following technical effects:

[0026] This application discloses a phase change microcapsule with high thermal conductivity and resistance to ionizing radiation. Hydrophobically modified graphene is added to the barium carbonate shell. Due to the high thermal conductivity of graphene, the shell material's sensitivity to environmental temperature changes is enhanced, and its temperature stability is improved. Furthermore, the barium element in the shell has a high atomic number; when photons collide with atoms of higher atomic numbers, the energy of the radiation is attenuated through the photoelectric effect and Compton effect, thus providing resistance to ionizing radiation. Therefore, the phase change microcapsule simultaneously possesses the multifunctional properties of resistance to ionizing radiation and high thermal conductivity. In addition, the dense shell material minimizes the risk of leakage of the phase change core material.

[0027] The present application discloses a high thermal conductivity phase change microcapsule resistant to ionizing radiation, which uses a mixture of n-octadecane and n-eicosane as the phase change core material. It has a wide phase change temperature range. When the ambient temperature rises or falls to the phase change point of the phase change core material, the phase change core material undergoes a phase change, absorbing or releasing heat from the surrounding environment to reduce the rate of temperature change.

[0028] The method for preparing the anti-ionizing radiation high thermal conductivity phase change microcapsule of this application is simple, low-cost, and suitable for large-scale production. The prepared phase change microcapsule has anti-ionizing radiation properties and high thermal conductivity of the shell, and is sensitive to changes in ambient temperature.

[0029] The high thermal conductivity phase change microcapsule with anti-ionizing radiation proposed in this application can be applied to anti-ionizing radiation and temperature-controlled walls in specific locations such as medical CT room walls, which can well meet the requirements of multi-functional engineering applicability. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A schematic diagram of the structure of a high thermal conductivity phase change microcapsule resistant to ionizing radiation provided in an embodiment of this application; wherein, 1 is the shell layer and 2 is the phase change core material;

[0032] Figure 2 A schematic diagram of the experimental principle for determining the linear attenuation coefficient;

[0033] Figure 3 The graph shows the change in thermal conductivity of the multifunctional phase change microcapsules with high thermal conductivity and resistance to ionizing radiation, in Example 1 of this application, with different amounts of hydrophobically modified graphene added to the shell layer.

[0034] Figure 4 This is a scan image of the anti-ionizing radiation, high thermal conductivity, multifunctional phase change microcapsule prepared in Example 1 of this application under industrial CT.

[0035] Figure 5 This is a scanning electron microscope image of the ionizing radiation-resistant, high thermal conductivity, multifunctional phase change microcapsule prepared in Example 1 of this application;

[0036] Figure 6 Compressive strength of concrete after 7 days of curing with different dosages of multifunctional phase change microcapsules with high thermal conductivity and anti-ionizing radiation (Example 1);

[0037] Figure 7 Linear attenuation coefficient diagram of concrete with different dosages of high thermal conductivity multifunctional phase change microcapsules for resisting ionizing radiation (Example 1) under different incident photon intensities. Detailed Implementation

[0038] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0039] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0040] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0041] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0042] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0043] Please refer to Figure 1 This application provides an embodiment of a phase change microcapsule with high thermal conductivity and resistance to ionizing radiation. The microcapsule has a spherical, slug-like appearance. It consists of a phase change core material with temperature control and a shell layer surrounding the core material, which provides resistance to ionizing radiation and enhanced thermal conductivity. The shell layer is composed of barium carbonate and hydrophobically modified graphene, while the core material is composed of n-octadecane and n-eicosane.

[0044] The phase change core material can be composed of n-octadecane and n-eicosane in a weight ratio of 1:1 to 1:3, so that the phase change core material has a wider temperature change range and can better meet the application requirements of temperature control scenarios.

[0045] Hydrophobically modified graphene accounts for 2wt% to 6wt% of the shell weight, which enables the shell to maintain high density and high strength while having good thermal conductivity.

[0046] The phase change microcapsules of this application possess a core-shell structure. The internal phase change core material, protected by the shell, is not in direct contact with the surrounding environment, thus ensuring the heat storage density of the core material. The shell, made of barium carbonate and hydrophobically modified graphene, exhibits resistance to ionizing radiation and enhanced thermal conductivity. Barium, with its high atomic number, provides excellent resistance to ionizing radiation when used as the shell material. The addition of hydrophobically modified graphene further improves the thermal conductivity of the microcapsules and enhances the core material's sensitivity to temperature changes in the surrounding environment. The shell, made of barium carbonate and hydrophobically modified graphene, possesses high mechanical strength, reducing not only the damage to the mechanical properties of concrete caused by external materials (such as phase change materials and aggregates) but also the damage to the basic properties of concrete specimens caused by the phase change core material during the phase change process.

[0047] This application also provides a method for preparing the above-mentioned anti-ionizing radiation high thermal conductivity phase change microcapsules, including the following steps:

[0048] (1) Mix n-octadecane and n-eicosane in a weight ratio of 1:1 to 1:3 until they stand without separating into layers to obtain a core material liquid;

[0049] (2) Dissolve the surfactant in deionized water to obtain a surfactant solution; the concentration of the surfactant in the surfactant solution is 0.1 g / L to 0.2 g / L; the surfactant includes one or more of polyvinyl alcohol, Span 80, and sodium dodecylbenzene sulfonate;

[0050] (3) Under the conditions of water bath temperature controlled at 60-65℃ and stirring speed of 350r / min-400r / min, phase change core material and hydrophobic modified graphene are added to surfactant solution and stirred for 1h to obtain the first emulsion.

[0051] (4) Dissolve the barium salt in deionized water to obtain a barium salt solution; the barium salt can be barium chloride powder, and the concentration of the barium salt solution can be 0.2 g / mL;

[0052] (5) Dissolve the carbonate in deionized water to obtain a carbonate solution; sodium carbonate powder can be used as the carbonate, and the concentration of the carbonate solution can be 0.1 g / mL;

[0053] (6) Under the conditions of water bath at 60-65℃ and stirring at 350-400r / min, the barium salt solution is slowly added dropwise to the first emulsion to obtain the second emulsion; the stirring speed is controlled at 350-400r / min in this step in order to better disperse the core material into small core material droplets and allow the barium salt to better contact the surface of the core material.

[0054] (7) Keep the temperature of the second emulsion constant at 60-65℃, reduce the stirring speed to 250-300 r / min, and slowly add carbonate solution to obtain the third emulsion;

[0055] (8) Keep the temperature of the third emulsion constant at 60-65℃ and reduce the stirring speed to 150-200 r / min to obtain a microcapsule suspension;

[0056] (9) Filter the microcapsule suspension, wash and dry the filter residue to obtain anti-ionizing radiation high thermal conductivity phase change microcapsules.

[0057] The hydrophobically modified graphene in step (3) above was prepared by the following method: under the catalysis of aluminum chloride, stearic acid reacted with the hydroxyl groups on the graphene surface to undergo esterification, completing the lipophilic modification. Finally, under drying conditions at 40°C, without washing, the hydrophobically modified graphene was obtained. Through the hydrophobic modification reaction, stearic acid was grafted onto the graphene surface, making the graphene hydrophobic, thereby more uniformly doping it into the barium carbonate shell, resulting in a denser shell and higher mechanical strength.

[0058] The method for preparing high thermal conductivity phase change microcapsules resistant to ionizing radiation provided in this application is low in cost, simple in process, and suitable for large-scale production.

[0059] In this application, high thermal conductivity phase change microcapsules resistant to ionizing radiation were added to concrete. Micro-CT was used to analyze the linear attenuation coefficient (μ) of the high thermal conductivity phase change microcapsules with different dosages at different X-ray energies, to evaluate the ionizing radiation resistance performance of the microcapsules. The experimental principle for determining the linear attenuation coefficient using Brown's law is as follows: Figure 2 As shown:

[0060] I = l0·e -μx ;

[0061] I is the intensity of the photon after interaction with the absorber, in MeV; I0 is the initial photon intensity, in MeV; x is the thickness of the absorber, in cm. -1 μ is the linear attenuation coefficient, cm -1 .

[0062] The following examples illustrate an anti-ionizing radiation high thermal conductivity phase change microcapsule, its preparation method, and its application.

[0063] Example 1

[0064] (1) Dissolve 0.2 g of stearic acid in a mixture of 100 mL of deionized water and 20 mL of ethanol. Then, add 4 g of ultrafine graphene and 0.22 g of aluminum chloride as catalysts to the mixture and stir in a water bath at 65 °C for 1.5 h. Finally, without washing, hydrophobically modified graphene is obtained under drying conditions at 40 °C.

[0065] (2) Mix n-octadecane and n-eicosane in a weight ratio of 1:1 until the mixture is completely miscible and does not separate into layers when left to stand, thus obtaining a core material liquid.

[0066] Dissolve 10g of barium chloride powder in 50mL of deionized water and stir until completely dissolved to prepare a 0.2g / mL barium chloride solution.

[0067] Dissolve 1g of polyvinyl alcohol powder in 100mL of deionized water (water bath temperature is 90℃) to obtain a surfactant solution. Pour the surfactant solution into a three-necked flask and place the three-necked flask in a 65℃ water bath for 1h.

[0068] (3) Take 5g of core material liquid and add it to the above surfactant solution. Heat and stir in a water bath (water bath temperature 65℃, stirring rate 400r / min) to obtain the first emulsion. Add barium chloride solution and hydrophobic modified graphene powder to the first emulsion according to the dosage of hydrophobic modified graphene in the shell layer of 0, 2wt%, 4wt%, 6wt%, and 8wt%, respectively. The barium chloride solution is added slowly (30-40 drops / min) while heating and stirring in a water bath (water bath temperature 65℃, stirring rate 300r / min, reaction time 2h) to obtain the second emulsion.

[0069] (4) Keep the water bath temperature of the second emulsion unchanged, reduce the stirring rate to 300 r / min, and slowly add 0.1 g / mL sodium carbonate solution (30-40 drops / min) to the second emulsion to form the third emulsion.

[0070] (5) The water bath temperature was kept at 65℃, the stirring rate was reduced to 200r / min, and the microcapsule suspension was obtained after stirring for 0.5h.

[0071] (6) Filter the microcapsule suspension, wash the filter residue with deionized water and dry it in a constant temperature drying oven at 40℃ for 1 day to obtain anti-ionizing radiation high thermal conductivity phase change microcapsules.

[0072] Example 2

[0073] (1) Dissolve 0.2 g of stearic acid in a mixture of 100 mL of deionized water and 20 mL of ethanol. Then, add 4 g of ultrafine graphene and 0.22 g of aluminum chloride as catalysts to the mixture and stir in a water bath at 65 °C for 1.5 h. Finally, without washing, hydrophobically modified graphene is obtained under drying conditions at 40 °C.

[0074] (2) Mix n-octadecane and n-eicosane at a weight ratio of 1:2 until the mixture is completely miscible and does not separate into layers when left to stand, thus obtaining the core material liquid.

[0075] Dissolve 10g of barium chloride powder in 50mL of deionized water and stir until completely dissolved to prepare a barium chloride solution.

[0076] Dissolve 1g of polyvinyl alcohol powder in 100mL of deionized water (water bath temperature is 90℃) to obtain a surfactant solution. Pour the surfactant solution into a three-necked flask and place the three-necked flask in a 60℃ water bath for 1 hour.

[0077] (3) Take 5g of core material liquid and add it to the above surfactant solution. Heat and stir in a water bath (water bath temperature 60℃, stirring rate 400r / min) to obtain the first emulsion. Add barium chloride solution and hydrophobic modified graphene powder to the first emulsion according to the dosage of hydrophobic modified graphene in the shell layer of 0, 2wt%, 4wt%, 6wt%, and 8wt%, respectively. The barium chloride solution is added slowly (30-40 drops / min) while heating and stirring in a water bath (water bath temperature 60℃, stirring rate 400r / min, reaction time 2h) to obtain the second emulsion.

[0078] (4) Keep the water bath temperature of the second emulsion unchanged, reduce the stirring rate to 300 r / min, and slowly add 0.1 g / mL sodium carbonate solution (30-40 drops / min) to the second emulsion to form the third emulsion.

[0079] (5) The water bath temperature was kept at 60℃, the stirring rate was reduced to 200r / min, and the microcapsule suspension was obtained after stirring for 0.5h.

[0080] (6) Filter the microcapsule suspension, wash the filter residue with deionized water and dry it in a constant temperature drying oven at 40℃ for 1 day to obtain anti-ionizing radiation high thermal conductivity phase change microcapsules.

[0081] Example 3

[0082] (1) Dissolve 0.2 g of stearic acid in a mixture of 100 mL of deionized water and 20 mL of ethanol. Then, add 4 g of ultrafine graphene and 0.22 g of aluminum chloride as catalysts to the mixture and stir in a water bath at 65 °C for 1.5 h. Finally, without washing, hydrophobically modified graphene is obtained under drying conditions at 40 °C.

[0083] (2) Mix n-octadecane and n-eicosane in a weight ratio of 1:3 until the mixture is completely miscible and does not separate into layers when left to stand, thus obtaining a core material liquid.

[0084] Dissolve 10g of barium chloride powder in 50mL of deionized water and stir until completely dissolved to prepare a barium chloride solution.

[0085] Dissolve 1g of polyvinyl alcohol powder in 100mL of deionized water (water bath temperature is 90℃) to obtain a surfactant solution. Pour the surfactant solution into a three-necked flask and place the three-necked flask in a 60℃ water bath for 1 hour.

[0086] (3) Take 5g of core material liquid and add it to the above surfactant solution. Heat and stir in a water bath (water bath temperature 60℃, stirring rate 350r / min) to obtain the first emulsion. Add barium chloride solution and hydrophobic modified graphene powder to the first emulsion according to the dosage of hydrophobic modified graphene in the shell layer of 0, 2wt%, 4wt%, 6wt%, and 8wt%, respectively. The barium chloride solution is added slowly (30-40 drops / min) while heating and stirring in a water bath (water bath temperature 60℃, stirring rate 350r / min, reaction time 2h) to obtain the second emulsion.

[0087] (4) Keep the water bath temperature of the second emulsion unchanged, reduce the stirring rate to 250 r / min, and slowly add 0.1 g / mL sodium carbonate solution (30-40 drops / min) to the second emulsion to form the third emulsion.

[0088] (5) The water bath temperature was kept at 60℃, the stirring rate was reduced to 150r / min, and the microcapsule suspension was obtained after stirring for 0.5h.

[0089] (6) Filter the microcapsule suspension, wash the filter residue with deionized water and dry it in a constant temperature drying oven at 40℃ for 1 day to obtain anti-ionizing radiation high thermal conductivity phase change microcapsules.

[0090] The compatibility of the ultrafine graphene and hydrophobically modified graphene in Example 1 of this application with mixed alkanes was tested: 1g of unmodified (ultrafine graphene) and hydrophobically modified graphene were mixed with 5g of a mixed alkane consisting of n-octadecane and n-eicosane, respectively, and observed. After observation, 20g of barium carbonate was added, and the mixture was thoroughly mixed in a 1cm×1cm cubic mold to prepare a barium carbonate solid sample for thermal conductivity testing. The results are shown in Table 1. The experimental results show that the compatibility of hydrophobically modified graphene with mixed alkanes is significantly better than that of unmodified graphene. Due to the increased graphene content in the microcapsules, the increase in the thermal conductivity of the microcapsules is more significant. Therefore, hydrophobically modified graphene is more conducive to increasing the thermal conductivity of the microcapsules, thereby improving the sensitivity of the microcapsules to temperature changes.

[0091] Table 1. Compatibility of graphene with mixed alkanes before and after modification, and changes in the thermal conductivity of the microcapsules.

[0092] Unmodified graphene Hydrophobic modified graphene The existence of graphene Less, and it settles in the lower half. Numerous and evenly distributed Thermal conductivity of the test block (W / mK) 0.242 0.375

[0093] Table 2. DSC data for octadecane, eicosane, octadecane and eicosane, and microcapsules.

[0094]

[0095]

[0096] Table 2 shows the DSC data for octadecane, eicosane, a mixed phase change core material (octadecane:eicosane = 1:1), and the multifunctional phase change microcapsules prepared in Example 1. Since the mixed phase change core material is a binary phase change core material composed of octadecane and eicosane, two exothermic and endothermic peaks appeared on the DSC curves during crystallization and melting. Compared with the phase change temperatures of octadecane (31.16℃) and eicosane (40.12℃), the phase change temperature of the mixed phase change core material is somewhat lower. This phenomenon is caused by the fact that all molecules in the pure phase change core material are similar in size and arranged regularly, while the size differences and more disordered arrangement of molecules in the mixed phase change core material lead to a decrease in intermolecular interaction forces. On the DSC curves of the phase change microcapsules, the microencapsulation of BaCO3 and the good thermal conductivity of BaCO3 and hydrophobically modified graphene increase the heat transfer area and efficiency of the phase change microcapsules, thereby improving the temperature sensitivity of the phase change microcapsules. Therefore, during the same heating and cooling process, the phase change microcapsules undergo a phase change before being mixed with the phase change core material. The phase change temperatures of the phase change microcapsules are 5.54℃ and 32.60℃, respectively, which fall within the comfortable temperature range for winter and summer.

[0097] Figure 3 The graph shows the change in thermal conductivity of the multifunctional phase change microcapsules with high thermal conductivity and resistance to ionizing radiation prepared in Example 1 by adding different amounts of modified graphene to the shell layer. The experimental results show that, due to the high thermal conductivity of hydrophobically modified graphene, the thermal conductivity of the multifunctional phase change microcapsules with high thermal conductivity and resistance to ionizing radiation prepared in Example 1 is enhanced with the increase of the modified graphene doping amount.

[0098] Figure 4 This is a scanning electron microscope (SEM) image of the ionizing radiation-resistant, high thermal conductivity, multifunctional phase change microcapsules prepared in Example 1. The particle size of the multifunctional phase change microcapsules ranges from 20 to 300 μm. Figure 4 It can be seen that the anti-ionizing radiation, high thermal conductivity, multifunctional phase change microcapsules prepared in Example 1 have good sphericity.

[0099] Figure 5 The image shown is an industrial CT scan of the multifunctional phase change microcapsules with high thermal conductivity and ionizing radiation resistance prepared in Example 1. Figure 5 As can be seen, the microcapsules have good sphericity, a stable core wall structure, and a relatively dense shell, making them less prone to leakage.

[0100] The modified graphene-modified, radiation-resistant, high-thermal-conductivity, multifunctional phase change microcapsules with 8 wt% added, prepared in Example 1, were incorporated into standard mix concrete at dosages of 0 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt%, and 10 wt% to prepare concrete specimens. Figure 6The image shows the compressive strength of the concrete specimens after 7 days of curing. The results indicate that the appropriate addition of the anti-ionizing radiation, high thermal conductivity, multifunctional phase change microcapsules prepared in Example 1 can increase the compressive strength of the concrete specimens.

[0101] Figure 7 for Figure 6 The linear attenuation coefficient (μ) of the concrete sample under different X-ray incident photon intensities. Figure 7 It can be seen that the shielding effect against ionizing radiation becomes more pronounced with the increase of the content of high thermal conductivity, multifunctional phase change microcapsules that resist ionizing radiation. At lower photon energies, the incorporation of multifunctional phase change microcapsules significantly increases the μ value of concrete. However, this trend gradually weakens with increasing incident photon energy. Compared with reference concrete, at 0.05 MeV energy, the μ value of concrete with 10% multifunctional phase change microcapsules increased by 42.3%, while at 0.15 MeV energy, the μ value of concrete with 10% multifunctional phase change microcapsules increased by only 23.4%. The interaction between the photoelectric effect and the Compton effect mainly leads to the attenuation of photon energy. When photons enter the cement paste with energies of 0.01–0.1 MeV, the photoelectric effect plays a dominant role. The attenuation principle is that when photons collide with atoms, the photon energy is completely converted into ionization energy leaving the atomic nucleus and kinetic energy of electrons. The strong binding force of high atomic number atomic nuclei to electrons increases the cross-sectional probability (the probability of an incident photon interacting with a target atom per unit area) that satisfies the photoelectric effect condition. The addition of multifunctional phase-change microcapsules with high thermal conductivity and resistance to ionizing radiation increases the concentration of barium ions (high atomic number element) in cement slurry, thereby improving the slurry's shielding ability at low photon energies. However, as photon energy increases, the binding energy of the atomic nucleus to the electron becomes less important. More photons only transfer a portion of their kinetic energy to the electron and continue emitting themselves at even lower energies.

[0102] Introducing the high thermal conductivity, multifunctional phase change microcapsules with anti-ionizing radiation prepared in the embodiments of this application into the interior of concrete can effectively regulate the rate of indoor temperature change by utilizing the heat absorption or release characteristics of the phase change process of the microcapsules, thus playing a role in heat preservation and control, saving energy and protecting the environment. Simultaneously, when applied to interior walls of medical diagnostic facilities, it can enhance the wall's anti-ionizing radiation performance while providing heat preservation and control, ensuring personal and property safety.

[0103] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. Anti-ionizing radiation high thermal conductivity phase change microcapsules, characterized in that, The shell layer is composed of barium carbonate and hydrophobic modified graphene, and the core material is composed of n-octadecane and n-eicosane. The hydrophobic modified graphene accounts for 2wt%-6wt% of the weight of the shell layer. The hydrophobic modified graphene is prepared by lipophilic modification of stearic acid and graphene under the catalysis of aluminum chloride, and then dried without washing to obtain modified graphene. The preparation method of the anti-ionizing radiation high-thermal-conductivity phase change microcapsule comprises the following steps: Dissolve the surfactant into deionized water to obtain a surfactant solution; Mix n-octadecane and n-eicosane uniformly as a phase change core material; Under the stirring condition at 60-65℃, add the phase change core material and hydrophobic modified graphene into the surfactant solution to obtain a first emulsion; Dissolve barium salt powder into deionized water to obtain a barium salt solution; Dissolve carbonate powder into deionized water to obtain a carbonate solution; Under the stirring condition at 60-65℃ and 350r / min-400r / min, add the barium salt solution into the first emulsion to obtain a second emulsion; Keep the temperature of the second emulsion at 60-65℃, reduce the stirring speed to 250r / min-300r / min, and add the carbonate solution to obtain a third emulsion; Keep the temperature of the third emulsion at 60-65℃, reduce the stirring speed to 150r / min-200r / min to obtain a microcapsule suspension. Filter the microcapsule suspension, wash and dry the filter residue to obtain the anti-ionizing radiation high-thermal-conductivity phase change microcapsule.

2. The anti-ionizing radiation high thermal conductivity phase change microcapsule of claim 1, wherein, The core material is composed of n-octadecane and n-eicosane with a weight ratio of 1:1-1:

3.

3. The anti-ionizing radiation high thermal conductivity phase change microcapsule of claim 1, wherein, The surfactant includes one or more of polyvinyl alcohol, Span 80 and sodium dodecyl benzene sulfonate.

4. The anti-ionizing radiation high thermal conductivity phase change microcapsule of claim 3, wherein, The concentration of the surfactant in the surfactant solution is 0.1g / L-0.2g / L.

5. The anti-ionizing radiation high thermal conductivity phase change microcapsule of claim 1, wherein, The barium salt is barium chloride.

6. The anti-ionizing radiation high thermal conductivity phase change microcapsule of claim 1, wherein, The carbonate is sodium carbonate.

7. The anti-ionizing radiation high-thermal-conductivity phase change microcapsule according to any one of claims 1-6 is applied to anti-ionizing radiation and temperature control wall.

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