Paraffin / graphene composite phase change energy storage material and preparation method thereof

Abstract

The application discloses a paraffin / graphene composite phase change energy storage material and a preparation method thereof. The method comprises the following steps: 1, mixing even carbon normal alkanes and substituted arylamide type beta nucleating agents according to weight parts, stirring and ultrasonic dispersion to obtain a paraffin phase change energy storage material; 2, mixing graphene nanoparticles and a paraffin modifier according to a mass ratio, sequentially stirring, centrifuging and drying to obtain high-thermal-conductivity graphene nanoparticles modified by the paraffin modifier; 3, mixing the paraffin phase change energy storage material, a phase-changeable energy storage polyethylene glycol diacrylate monomer and double pentaerythritol hexa-acrylate mixture, the high-thermal-conductivity graphene nanoparticles modified by the paraffin modifier and multi-layer assembled graphene foam according to weight parts, uniformly stirring and then obtaining a precursor; and 4, irradiating the precursor with ultraviolet light with a wavelength of 365 nm and a light intensity of 1-800 mW / cm 2 to obtain the paraffin / graphene composite phase change energy storage material, and the thermal conductivity and energy storage efficiency of the phase change energy storage material are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage materials, and specifically relates to a paraffin / graphene composite phase change energy storage material and a preparation method thereof. Background Art

[0002] Phase change energy storage technology, which stores a form of energy through physical or chemical changes, and releases and utilizes this energy in subsequent processes, is widely used in power supply, solar energy use, transportation, mobile electronics and other equipment. It can effectively improve energy utilization and thus save energy.

[0003] Phase-change energy storage materials, as a key component of phase-change energy storage technology, are not only energy-efficient and environmentally friendly, but also offer advantages such as high energy density, excellent energy-saving performance, constant operating temperature, ease of control, and virtually constant volume. They have become a key research topic in the current field of energy storage technology. Furthermore, their high phase-change enthalpy allows them to absorb or release large amounts of heat during the phase-change process.

[0004] Paraffin, as an organic phase-change energy storage material, exhibits excellent molding properties, lacks supercooling and phase separation, and exhibits relatively stable performance. Wang Ruoyu et al., using a melt-mixing method, developed a C14-C18 paraffin-based eutectic phase-change material with a low phase-change temperature and high latent heat. Its melting point and phase-change enthalpy are 1.0°C and 205 kJ / kg, respectively. Despite these advantages, paraffin's relatively low thermal conductivity (approximately 0.2 W / (m·K)) significantly hinders its application in phase-change energy storage.

[0005] Graphene foam with a spatial network structure can increase the contact area with the phase change energy storage material, which is beneficial to improving the thermal conductivity and mechanical properties of the phase change energy storage material. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a paraffin / graphene composite phase change energy storage material and a preparation method thereof, which improves the thermal conductivity and energy storage efficiency of the phase change energy storage material.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing a paraffin wax / graphene composite phase change energy storage material comprises the following steps:

[0009] Step 1: at 25-35° C., 91.5-99 parts by weight of an even-numbered normal alkane and 0.1-1 part by weight of a substituted aromatic amide type β-nucleating agent are mixed, stirred, and ultrasonically dispersed to obtain a paraffin phase change energy storage material;

[0010] Step 2: mixing graphene nanoparticles and paraffin modifiers at a mass ratio of 1:(3-6) at 25-40° C., stirring, centrifuging, and drying in sequence to obtain paraffin-modified graphene nanoparticles with high thermal conductivity;

[0011] The paraffin modifier is one of silane coupling agents KH570, KH550 or KH12;

[0012] Step 3, at 25° C., mixing 90-100 parts by weight of a paraffin phase change energy storage material, 10-30 parts of a mixture of a phase-changeable energy storage polyethylene glycol diacrylate monomer and dipentaerythritol hexaacrylate, 1-5 parts of high thermal conductivity graphene nanoparticles modified with a paraffin modifier, and 0.1-10 parts of multilayer assembled graphene foam, and stirring evenly to obtain a precursor;

[0013] Step 4: Use a wavelength of 365nm and a light intensity of 1-800mW / cm 2 The precursor is irradiated with ultraviolet light for 0.5-1.5 hours to obtain a paraffin / graphene composite phase change energy storage material.

[0014] Furthermore, the even-numbered carbon normal alkane in step 1 is one or more of n-dodecane, n-tetradecane, n-hexadecane, n-octadecane, n-tetracosane and n-octacosane.

[0015] Furthermore, the stirring in step 1 is carried out at a rotation speed of 100-700 r / min for 10-25 min.

[0016] Furthermore, the ultrasonic dispersion time in step 1 is 15-30 minutes.

[0017] Furthermore, the stirring in step 2 is carried out at a rotation speed of 500-3500 r / min for 10-20 min.

[0018] Furthermore, the centrifugation in step 2 is performed at a rotation speed of 9000-12000 r / min for 5-10 min.

[0019] Furthermore, the drying temperature in step 2 is 50-70°C.

[0020] Furthermore, the mixture of the phase-changeable energy storage polyethylene glycol diacrylate monomer and dipentaerythritol hexaacrylate in step 3 comprises 5-20 parts by weight of polyethylene glycol diacrylate I, 1-4 parts by weight of polyethylene glycol diacrylate II, 1-3 parts by weight of polyethylene glycol diacrylate III and 1-3 parts by weight of dipentaerythritol hexaacrylate;

[0021] The molecular weights of the polyethylene glycol segments of polyethylene glycol diacrylate I, polyethylene glycol diacrylate II and polyethylene glycol diacrylate III are 2300, 200 and 400 respectively.

[0022] Furthermore, the stirring in step 3 is carried out at a rotation speed of 300-1500 r / min for 20-30 min.

[0023] A paraffin / graphene composite phase change energy storage material.

[0024] Compared with the prior art, the present invention has the following technical effects:

[0025] As paraffin wax is a typical phase change energy storage material, it has the advantages of being chemically stable, non-corrosive, non-toxic, high latent heat of phase change, low price, and excellent compatibility with the encapsulating material graphene foam. The researchers first modified the graphene nanoparticles with a paraffin wax modifier to give them good dimensional stability, maintaining dimensional stability and non-deformation for a long time during application. This also further improved the phase change leakage problem. Adding a mixture of phase-changeable energy storage polyethylene glycol diacrylate monomers can improve the low filler content. Graphene foam has the characteristics of high thermal conductivity within a single layer plane and an extremely large aspect ratio (diameter / thickness ratio), which makes it easy to form chains or networks in the matrix, significantly enhancing the thermal conductivity of the matrix at low filler levels. Modifying the paraffin wax phase change energy storage material can significantly reduce the energy absorption and release time of the phase change energy storage material, thereby preparing a paraffin wax / graphene composite phase change energy storage material with high thermal conductivity, high energy storage efficiency, high mechanical properties, a wide phase change temperature range, a large phase change enthalpy, and a fast heat absorption / release rate. In addition, the preparation method of the present invention is simple, environmentally friendly and pollution-free, and has a high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 : Energy storage efficiency of the composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention;

[0027] Figure 2 : Thermal conductivity of the composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention;

[0028] Figure 3 : Phase change enthalpy values ​​of the composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention;

[0029] Figure 4 : DSC endothermic curves of the composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention;

[0030] Figure 5 : DSC exothermic curves of the composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention. DETAILED DESCRIPTION

[0031] The specific contents of the present invention are further explained in detail below with reference to the embodiments.

[0032] Example 1

[0033] Step 1: At 30° C., 1.5 parts of n-dodecane, 90 parts of n-tetradecane, and 0.1 parts of a substituted aromatic amide β-nucleating agent were mixed according to weight, stirred at a speed of 100 r / min for 10 minutes, and then ultrasonically dispersed for 15 minutes to obtain a paraffin phase change energy storage material;

[0034] Step 2: At 25° C., graphene nanoparticles and paraffin modifier KH570 were mixed in a mass ratio of 1:3, stirred at 500 rpm for 10 min, centrifuged at 9000 rpm for 5 min, and then dried at 50° C. to obtain paraffin-modified graphene nanoparticles with high thermal conductivity;

[0035] Step 3, at 25° C., 90 parts of paraffin phase change energy storage material, 5 parts of polyethylene glycol diacrylate I, 3 parts of polyethylene glycol diacrylate II, 3 parts of polyethylene glycol diacrylate III, 2.3 parts of dipentaerythritol hexaacrylate, 1 part of paraffin modifier-modified high thermal conductivity graphene nanoparticles, and 0.1 part of multilayer assembled graphene foam are mixed according to weight, and stirred evenly to obtain a precursor;

[0036] The molecular weights of the polyethylene glycol segments of polyethylene glycol diacrylate I, polyethylene glycol diacrylate II, and polyethylene glycol diacrylate III are 2300, 200, and 400, respectively;

[0037] Step 4: Use a wavelength of 365nm and a light intensity of 1-800mW / cm 2 The precursor was irradiated with ultraviolet light for 0.5 h to obtain a paraffin / graphene composite phase change energy storage material.

[0038] Example 2

[0039] Step 1: At 35° C., 90 parts of n-hexadecane, 3 parts of n-octadecane, and 0.2 parts of a substituted aromatic amide β-nucleating agent were mixed according to weight, stirred at a speed of 200 r / min for 12 minutes, and then ultrasonically dispersed for 17 minutes to obtain a paraffin phase change energy storage material;

[0040] Step 2: At 30° C., graphene nanoparticles and paraffin modifier KH550 were mixed in a mass ratio of 1:4, stirred at a speed of 1000 r / min for 12 minutes, centrifuged at a speed of 10000 r / min for 6 minutes, and then dried at 60° C. to obtain high thermal conductivity graphene nanoparticles modified with paraffin modifier;

[0041] Step 3, at 25° C., 93 parts of paraffin phase change energy storage material, 10 parts of polyethylene glycol diacrylate I, 1 part of polyethylene glycol diacrylate II, 3 parts of polyethylene glycol diacrylate III, 3 parts of dipentaerythritol hexaacrylate, 3 parts of paraffin modifier-modified high thermal conductivity graphene nanoparticles, and 5.1 parts of multilayer assembled graphene foam are mixed according to weight parts, and stirred evenly to obtain a precursor;

[0042] The molecular weights of the polyethylene glycol segments of polyethylene glycol diacrylate I, polyethylene glycol diacrylate II, and polyethylene glycol diacrylate III are 2300, 200, and 400, respectively;

[0043] Step 4: Use a wavelength of 365nm and a light intensity of 1-800mW / cm 2 The precursor was irradiated with ultraviolet light for 0.6 h to obtain a paraffin / graphene composite phase change energy storage material.

[0044] Example 3

[0045] Step 1: At 25° C., 4.4 parts of n-tetracosane, 90 parts of n-octacosane, and 0.4 parts of a substituted aromatic amide β-nucleating agent were mixed according to weight, stirred at a speed of 300 r / min for 15 minutes, and then ultrasonically dispersed for 19 minutes to obtain a paraffin phase change energy storage material;

[0046] Step 2: At 35° C., graphene nanoparticles and paraffin modifier KH12 were mixed in a mass ratio of 1:5, stirred at a speed of 1500 r / min for 14 minutes, centrifuged at a speed of 11000 r / min for 7 minutes, and then dried at 70° C. to obtain high thermal conductivity graphene nanoparticles modified with paraffin modifier;

[0047] Step 3, at 25° C., 95 parts of paraffin phase change energy storage material, 12.5 parts of polyethylene glycol diacrylate I, 2.5 parts of polyethylene glycol diacrylate II, 2.5 parts of polyethylene glycol diacrylate III, 2.5 parts of dipentaerythritol hexaacrylate, 2 parts of paraffin modifier-modified high thermal conductivity graphene nanoparticles, and 2 parts of multilayer assembled graphene foam are mixed according to weight parts, and stirred evenly to obtain a precursor;

[0048] The molecular weights of the polyethylene glycol segments of polyethylene glycol diacrylate I, polyethylene glycol diacrylate II, and polyethylene glycol diacrylate III are 2300, 200, and 400, respectively;

[0049] Step 4: Use a wavelength of 365nm and a light intensity of 1-800mW / cm 2 The precursor was irradiated with ultraviolet light for 0.7 h to obtain a paraffin / graphene composite phase change energy storage material.

[0050] Example 4

[0051] Step 1: At 30° C., 60 parts of n-dodecane, 36 parts of n-hexadecane, and 0.55 parts of a substituted aromatic amide β-nucleating agent were mixed according to weight, stirred at a speed of 400 r / min for 18 minutes, and then ultrasonically dispersed for 21 minutes to obtain a paraffin phase change energy storage material;

[0052] Step 2: At 40° C., graphene nanoparticles and paraffin modifier KH12 were mixed in a mass ratio of 1:4, stirred at a speed of 2000 r / min for 16 minutes, centrifuged at a speed of 12000 r / min for 8 minutes, and then dried at 55° C. to obtain high thermal conductivity graphene nanoparticles modified with the paraffin modifier;

[0053] Step 3, at 25° C., 98 parts of paraffin phase change energy storage material, 17 parts of polyethylene glycol diacrylate I, 2 parts of polyethylene glycol diacrylate II, 2 parts of polyethylene glycol diacrylate III, 2 parts of dipentaerythritol hexaacrylate, 4 parts of paraffin modifier-modified high thermal conductivity graphene nanoparticles, and 3.5 parts of multilayer assembled graphene foam are mixed according to weight parts, and stirred evenly to obtain a precursor;

[0054] The molecular weights of the polyethylene glycol segments of polyethylene glycol diacrylate I, polyethylene glycol diacrylate II, and polyethylene glycol diacrylate III are 2300, 200, and 400, respectively;

[0055] Step 4: Use a wavelength of 365nm and a light intensity of 1-800mW / cm 2 The precursor was irradiated with ultraviolet light for 0.8 h to obtain a paraffin / graphene composite phase change energy storage material.

[0056] Example 5

[0057] Step 1: At 25° C., 50 parts of n-tetradecane, 47 parts of n-tetracosane, and 0.8 parts of a substituted aromatic amide β-nucleating agent were mixed according to weight, stirred at a speed of 500 r / min for 20 minutes, and then ultrasonically dispersed for 24 minutes to obtain a paraffin phase change energy storage material;

[0058] Step 2: At 25° C., graphene nanoparticles and paraffin modifier KH550 were mixed in a mass ratio of 1:5, stirred at a speed of 2500 r / min for 18 minutes, centrifuged at a speed of 9500 r / min for 9 minutes, and then dried at 65° C. to obtain high thermal conductivity graphene nanoparticles modified with the paraffin modifier;

[0059] Step 3, at 25 ° C, 100 parts of paraffin phase change energy storage material, 19 parts of polyethylene glycol diacrylate I, 2.5 parts of polyethylene glycol diacrylate II, 2.5 parts of polyethylene glycol diacrylate III, 2 parts of dipentaerythritol hexaacrylate, 5 parts of paraffin modifier-modified high thermal conductivity graphene nanoparticles and 7 parts of multi-layer assembled graphene foam are mixed according to weight parts, and stirred evenly to obtain a precursor;

[0060] The molecular weights of the polyethylene glycol segments of polyethylene glycol diacrylate I, polyethylene glycol diacrylate II, and polyethylene glycol diacrylate III are 2300, 200, and 400, respectively;

[0061] Step 4: Use a wavelength of 365nm and a light intensity of 1-800mW / cm 2 The precursor was irradiated with ultraviolet light for 0.9 h to obtain a paraffin / graphene composite phase change energy storage material.

[0062] Example 6

[0063] Step 1: At 35° C., 46 parts of n-dodecane, 49 parts of n-octacosane, and 0.6 parts of a substituted aromatic amide β-nucleating agent were mixed according to weight, stirred at a speed of 600 r / min for 23 minutes, and then ultrasonically dispersed for 27 minutes to obtain a paraffin phase change energy storage material;

[0064] Step 2: At 30° C., graphene nanoparticles and paraffin modifier KH570 were mixed in a mass ratio of 1:6, stirred at a speed of 3000 r / min for 20 minutes, centrifuged at a speed of 10500 r / min for 10 minutes, and then dried at 50° C. to obtain high thermal conductivity graphene nanoparticles modified with paraffin modifier;

[0065] Step 3, at 25° C., 91 parts of paraffin phase change energy storage material, 7 parts of polyethylene glycol diacrylate I, 4 parts of polyethylene glycol diacrylate II, 3 parts of polyethylene glycol diacrylate III, 1.5 parts of dipentaerythritol hexaacrylate, 1 part of paraffin modifier-modified high thermal conductivity graphene nanoparticles, and 8.5 parts of multilayer assembled graphene foam are mixed according to weight parts, and stirred evenly to obtain a precursor;

[0066] The molecular weights of the polyethylene glycol segments of polyethylene glycol diacrylate I, polyethylene glycol diacrylate II, and polyethylene glycol diacrylate III are 2300, 200, and 400, respectively;

[0067] Step 4: Use a wavelength of 365nm and a light intensity of 1-800mW / cm 2 The precursor was irradiated with ultraviolet light for 1 hour to obtain a paraffin / graphene composite phase change energy storage material.

[0068] Example 7

[0069] Step 1: At 30° C., 5 parts of n-octadecane, 4 parts of n-tetracosane, 90 parts of n-octacosane, and 1 part of a substituted aromatic amide β-nucleating agent were mixed according to weight, stirred at a speed of 700 r / min for 25 minutes, and then ultrasonically dispersed for 30 minutes to obtain a paraffin phase change energy storage material;

[0070] Step 2: At 40° C., graphene nanoparticles and paraffin modifier KH550 were mixed in a mass ratio of 1:3, stirred at a speed of 3500 r / min for 15 minutes, centrifuged at a speed of 11500 r / min for 10 minutes, and then dried at 70° C. to obtain high thermal conductivity graphene nanoparticles modified with the paraffin modifier;

[0071] Step 3, at 25° C., 96 parts of paraffin phase change energy storage material, 20 parts of polyethylene glycol diacrylate I, 4 parts of polyethylene glycol diacrylate II, 3 parts of polyethylene glycol diacrylate III, 3 parts of dipentaerythritol hexaacrylate, 2 parts of paraffin modifier-modified high thermal conductivity graphene nanoparticles, and 10 parts of multilayer assembled graphene foam are mixed according to weight parts, and stirred evenly to obtain a precursor;

[0072] The molecular weights of the polyethylene glycol segments of polyethylene glycol diacrylate I, polyethylene glycol diacrylate II, and polyethylene glycol diacrylate III are 2300, 200, and 400, respectively;

[0073] Step 4: Use a wavelength of 365nm and a light intensity of 1-800mW / cm 2 The precursor was irradiated with ultraviolet light for 0.5 h to obtain a paraffin / graphene composite phase change energy storage material.

[0074] Depend on Figure 1 It can be seen that the energy storage efficiency of the paraffin wax / graphene composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention is above 92%, and has excellent energy storage effect.

[0075] Depend on Figure 2 It can be seen that the longitudinal and transverse thermal conductivities of the paraffin wax / graphene composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention are both above 350 W / m·K, and have good thermal conductivity.

[0076] Depend on Figure 3 It can be seen that the melting phase change enthalpy values ​​of the paraffin / graphene composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention are all above 153 kJ / kg, so they have excellent heat absorption capacity when melting; their solidification phase change enthalpy values ​​are all above 155 kJ / kg, so they have excellent heat release performance when solidifying.

[0077] Depend on Figure 4It can be seen that the initial melting temperature of the paraffin wax / graphene composite phase change energy storage material prepared in Example 1 of the present invention is -3.9°C, and the end point melting temperature is -2.1°C; the initial melting temperature of the paraffin wax / graphene composite phase change energy storage material prepared in Example 2 of the present invention is -4.8°C, and the end point melting temperature is -1.3°C; the initial melting temperature of the paraffin wax / graphene composite phase change energy storage material prepared in Example 3 of the present invention is -2.2°C, and the end point melting temperature is -1.1°C; the paraffin wax / graphene composite phase change energy storage material prepared in Example 4 of the present invention is -3.9°C, and the end point melting temperature is -2.1°C. The initial melting temperature of the material is -0.8°C, and the endpoint melting temperature is 1.4°C; the initial melting temperature of the paraffin / graphene composite phase change energy storage material prepared in Example 5 of the present invention is -3.3°C, and the endpoint melting temperature is -1.8°C; the initial melting temperature of the paraffin / graphene composite phase change energy storage material prepared in Example 6 of the present invention is -2.1°C, and the endpoint melting temperature is -0.3°C; the initial melting temperature of the paraffin / graphene composite phase change energy storage material prepared in Example 7 of the present invention is -1.3°C, and the endpoint melting temperature is 0.4°C.

[0078] Depend on Figure 5 It can be seen that the initial solidification temperature of the paraffin wax / graphene composite phase change energy storage material prepared in Example 1 of the present invention is -0.3°C, and the terminal solidification temperature is -2.2°C; the initial solidification temperature of the paraffin wax / graphene composite phase change energy storage material prepared in Example 2 of the present invention is 0.6°C, and the terminal solidification temperature is -3.3°C; the initial solidification temperature of the paraffin wax / graphene composite phase change energy storage material prepared in Example 3 of the present invention is -1.1°C, and the terminal solidification temperature is -2.3°C; the paraffin wax / graphene composite phase change energy storage material prepared in Example 4 of the present invention is 0.6°C, and the terminal solidification temperature is -3.3°C. The initial solidification temperature of the material is 1.3°C, and the terminal solidification temperature is -0.9°C; the initial solidification temperature of the paraffin / graphene composite phase change energy storage material prepared in Example 5 of the present invention is -1.2°C, and the terminal solidification temperature is -3.4°C; the initial solidification temperature of the paraffin / graphene composite phase change energy storage material prepared in Example 6 of the present invention is -0.2°C, and the terminal solidification temperature is -2.1°C; the initial solidification temperature of the paraffin / graphene composite phase change energy storage material prepared in Example 7 of the present invention is 0.7°C, and the terminal solidification temperature is -1.3°C.

[0079] The characteristics of the high thermal conductivity graphene nanoparticles modified with paraffin modifiers obtained in Examples 1 to 7 of the present invention are shown in Table 1, the characteristics of the multi-layer assembled graphene foams selected in Examples 1 to 7 are shown in Table 2, and the performance parameters of the paraffin / graphene composite phase change energy storage materials prepared in Examples 1 to 7 are shown in Table 3.

[0080] Table 1: Characteristics of high thermal conductivity graphene nanoparticles modified with paraffin modifiers of Examples 1 to 7

[0081] parameter Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Thickness (graphene layer) 2 3 4 5 6 7 8 Particle size (nm) 50 53 56 60 63 67 70 Thermal conductivity (W / m·K) 3000 3080 3160 3250 3330 3420 3500

[0082] Table 2: Characteristics of the multilayer assembled graphene foams selected in Examples 1 to 7

[0083]

[0084] Table 3: Performance parameters of paraffin wax / graphene composite phase change energy storage materials prepared in Examples 1 to 7

[0085] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Energy storage efficiency (%) 92.4 95.1 92.7 97.2 93.4 94.1 96.6 Longitudinal thermal conductivity (W / m·K) 375 396 413 498 391 384 453 Transverse thermal conductivity (W / m·K) 356 377 398 475 370 362 434 Initial melting temperature (℃) -3.92 -4.81 -2.24 0.85 -3.37 -2.16 -1.34 End point melting temperature (℃) -2.14 -1.33 -1.17 1.46 -1.86 -0.35 0.46 Initial solidification temperature (℃) -0.35 0.64 -1.16 1.37 -1.25 -0.26 0.75 End solidification temperature (℃) -2.21 -3.32 -2.35 -0.94 -3.46 -2.17 -1.36 Melting phase change enthalpy (kJ / kg) 153 162 157 169 155 164 159 Solidification phase change enthalpy (kJ / kg) 155 166 160 171 158 169 162 Heat release rate (W) 2314 2857 2586 3247 2475 3019 2663 Heat absorption rate (W) 2321 2864 2593 3251 2483 3106 2677

Claims

1. A method for preparing a paraffin wax / graphene composite phase change energy storage material, characterized in that: The steps include: Step 1: Mix 91.5-99 parts by weight of an even-numbered normal alkane and 0.1-1 part by weight of a substituted aromatic amide type β-nucleating agent at 25-35° C., stir, and ultrasonically disperse to obtain a paraffin phase change energy storage material; The even-numbered carbon normal alkane is one or more of n-dodecane, n-tetradecane, n-hexadecane, n-octadecane, n-tetracosane and n-octacosane; Step 2: mixing graphene nanoparticles and paraffin modifiers at a mass ratio of 1:(3-6) at 25-40° C., stirring, centrifuging, and drying in sequence to obtain paraffin-modified graphene nanoparticles with high thermal conductivity; The paraffin modifier is one of silane coupling agents KH570, KH550 or KH12; Step 3, at 25° C., mixing 90-100 parts by weight of a paraffin phase change energy storage material, 10-30 parts of a mixture of a phase-changeable energy storage polyethylene glycol diacrylate monomer and dipentaerythritol hexaacrylate, 1-5 parts of high thermal conductivity graphene nanoparticles modified with a paraffin modifier, and 0.1-10 parts of multilayer assembled graphene foam, and stirring evenly to obtain a precursor; Step 4: Use a wavelength of 365nm and a light intensity of 1-800mW / cm 2 The precursor is irradiated with ultraviolet light for 0.5-1.5 hours to obtain a paraffin / graphene composite phase change energy storage material.

2. The method for preparing the paraffin wax / graphene composite phase change energy storage material according to claim 1, characterized in that: The stirring in step 1 is carried out at a rotation speed of 100-700 r / min for 10-25 min.

3. The method for preparing the paraffin wax / graphene composite phase change energy storage material according to claim 1, characterized in that: The ultrasonic dispersion time in step 1 is 15-30 minutes.

4. The method for preparing the paraffin wax / graphene composite phase change energy storage material according to claim 1, characterized in that: The stirring in step 2 is carried out at a rotation speed of 500-3500 r / min for 10-20 min.

5. The method for preparing the paraffin wax / graphene composite phase change energy storage material according to claim 1, characterized in that: The centrifugation in step 2 is performed at a speed of 9000-12000 r / min for 5-10 min.

6. The method for preparing the paraffin wax / graphene composite phase change energy storage material according to claim 1, characterized in that: The drying temperature in step 2 is 50-70°C.

7. The method for preparing the paraffin wax / graphene composite phase change energy storage material according to claim 1, characterized in that: The mixture of the phase-changeable energy storage polyethylene glycol diacrylate monomer and dipentaerythritol hexaacrylate in step 3 comprises 5-20 parts by weight of polyethylene glycol diacrylate I, 1-4 parts by weight of polyethylene glycol diacrylate II, 1-3 parts by weight of polyethylene glycol diacrylate III and 1-3 parts by weight of dipentaerythritol hexaacrylate; The molecular weights of the polyethylene glycol segments of polyethylene glycol diacrylate I, polyethylene glycol diacrylate II and polyethylene glycol diacrylate III are 2300, 200 and 400 respectively.

8. The method for preparing the paraffin wax / graphene composite phase change energy storage material according to claim 1, characterized in that: The stirring in step 3 is carried out at a rotation speed of 300-1500 r / min for 20-30 min.

9. A paraffin wax / graphene composite phase change energy storage material prepared by the method according to any one of claims 1 to 8.

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