High-thermal-conductivity glass fiber reinforced phase change laminated board and preparation method thereof

Abstract

The application provides a high-thermal-conductivity glass fiber reinforced phase change laminated board and a preparation method thereof, and comprises the following steps: S1, mixing expanded graphite and molten n-octadecane, then performing vacuum impregnation treatment, and then adding molten n-alkane to obtain a second composite phase change material; S2, using a silane coupling agent to modify a single side of a glass fiber cloth, and coating the second composite phase change material on the modified side of the single-side modified glass fiber cloth to form a temperature control coating; S3, mixing modified nano-silicon dioxide, polyurethane acrylic resin and a silane coupling agent, and then coating the mixture on the unmodified side of the single-side modified glass fiber cloth to obtain double-side modified glass fiber cloth; and S4, symmetrically stacking two layers of the double-side modified glass fiber cloth, and then performing hot pressing to obtain the high-thermal-conductivity glass fiber reinforced phase change laminated board. Through the synergistic reinforcing effect of the expanded graphite and the glass fiber and the design of the barrier coating, the problems of phase change material liquid leakage and low thermal conductivity are effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology, specifically relating to a high thermal conductivity glass fiber reinforced phase change laminate and its preparation method. Background Technology

[0002] With the rapid development of high-performance electronic devices such as 5G communication, artificial intelligence, consumer electronics, and new energy vehicles, the integration of electronic devices continues to increase. Consequently, thermal management has become a key factor restricting the stable operation and reliable performance of these devices. As an emerging and efficient heat dissipation solution, thermally conductive phase change materials (PCMs) have become a research hotspot in the fields of energy science and materials science in recent years. PCMs are materials that absorb and release latent heat through reversible phase transitions within a limited temperature range. Among them, organic PCMs are widely used due to their high latent heat and wide phase transition temperature range. Alkanes, fatty acids, and polyols are the three major organic-based PCMs used for medium- and low-temperature thermal energy storage. However, in practical applications, organic-based PCMs have revealed many scientific problems that urgently need to be solved, namely, low thermal conductivity and easy leakage in the molten state.

[0003] To address the aforementioned issues, the thermal conductivity of PCM can be improved through composite modification and other methods based on existing materials, thereby mitigating material leakage. However, currently developed novel phase change materials still face significant technical bottlenecks in simultaneously resolving the liquid-phase leakage phenomenon of organic phase change materials and improving their relatively low thermal conductivity. Summary of the Invention

[0004] The purpose of this invention is to provide a high thermal conductivity glass fiber reinforced phase change laminate and its preparation method, which solves the problems of liquid phase leakage and low thermal conductivity of phase change materials, and gives them excellent mechanical properties.

[0005] S1. Expanded graphite and molten n-octadecane are mixed evenly to obtain a first mixture; the first mixture is subjected to vacuum impregnation treatment to obtain a first composite phase change material; molten n-alkane is added to the first composite phase change material to obtain a second composite phase change material.

[0006] S2 uses a silane coupling agent to modify one side of the glass fiber cloth to obtain a one-sided modified glass fiber cloth; and then coats the second composite phase change material onto the modified surface of the one-sided modified glass fiber cloth by a roller coating process to form a temperature control coating.

[0007] S3 mixes modified nano-silica, polyurethane acrylic resin and silane coupling agent evenly to obtain a second mixture. The second mixture is then coated onto the unmodified side of the single-sided modified glass fiber cloth by a scraping process to form a barrier coating, thus obtaining a double-sided modified glass fiber cloth.

[0008] S4 involves symmetrically stacking two layers of double-sided modified glass fiber cloth with the barrier coating facing outwards and the temperature control coating facing inwards, followed by hot pressing to form a primary laminate. Then, epoxy resin is used to coat and seal the sides of the primary laminate to obtain a high thermal conductivity glass fiber reinforced phase change laminate.

[0009] Specifically, the vacuum impregnation treatment in step S1 involves impregnating the first mixture under vacuum conditions at 40-60°C for 12-15 hours; the mass ratio of the expanded graphite, n-octadecane, and n-alkanes is 1:(5-10):(0.1-0.5).

[0010] Specifically, the expanded graphite in step S1 is obtained by graphite undergoing high-temperature expansion treatment; the high-temperature expansion treatment temperature is 900-1000℃, and the treatment time is 10-60s.

[0011] Specifically, the silane coupling agent mentioned in steps S2 and S3 is any one of KH570, KH550, KH792 and KH571.

[0012] Specifically, step S2 further includes:

[0013] S21 uses hydrochloric acid to adjust the pH of the ethanol aqueous solution to 3, then adds silane coupling agent to it, and stirs continuously at room temperature for 0.5-1h to obtain the coupling agent solution;

[0014] S22. The glass fiber cloth is immersed in the coupling agent solution on one side for 0.5-1h, and then the glass fiber is taken out and dried in a vacuum oven at 120℃ for 2-4h to obtain the single-sided modified glass fiber cloth.

[0015] S23 The second composite phase change material is coated onto the modified surface of the single-sided modified glass fiber cloth by roller coating process, and cooled at room temperature for 10-30 minutes to form a temperature-controlled coating.

[0016] Specifically, in step S3, the mass ratio of modified nano-silica, silane coupling agent, and polyurethane acrylic resin is 1:1:50; the preparation method of the second mixture includes: mixing the modified nano-silica, silane coupling agent, and polyurethane acrylic resin and then mechanically stirring at a speed of 800 r / min for 20 min to obtain the second mixture.

[0017] Specifically, the preparation method of the modified nano-silica in step S3 includes: mixing modified trititanate isopropyl ester and nano-silica, and stirring at 50-70℃ and a speed of 600-800 r / min for 4 hours to obtain modified nano-silica; the mass ratio of the modified trititanate isopropyl ester to nano-silica is 1:10.

[0018] Specifically, the preparation method of the modified trititanate isopropyl ester in step S3 includes: adding anhydrous ethanol to trititanate isopropyl ester in increments of 10 mL every 30 min, stirring at 90°C and a speed of 1000 r / min for 90 min to prepare the modified trititanate isopropyl ester.

[0019] Specifically, in step S4, the hot-pressing composite pressure is 0.3-0.5 MPa, the time is 60 s, and the temperature is 80-90 ℃; the epoxy resin is bisphenol A type.

[0020] The second objective of this invention is to provide a high thermal conductivity glass fiber reinforced phase change laminate prepared by the preparation method described above.

[0021] Compared with the prior art, the beneficial effects of the present invention include:

[0022] (1) This invention uses expanded graphite and n-octadecane to form a temperature-controlled coating, creating a highly efficient thermally conductive network within the phase change material, enabling faster heat conduction within the phase change material and thus improving the overall thermal conductivity of the phase change laminate. A dense barrier coating formed by modified silica nanoparticles and polyurethane acrylic resin, with glass fiber cloth as the skeleton support, is used to prepare a high thermal conductivity glass fiber reinforced phase change laminate via hot pressing. This laminate has advantages such as high thermal conductivity, high leakage resistance, excellent mechanical properties, good thermal stability, and good weather resistance.

[0023] (2) Expanded graphite has a large specific surface area and good adsorption performance. When blended with molten n-octadecane and n-alkanes, it can effectively adsorb n-octadecane organic phase change materials. When the phase change material changes from solid to liquid, expanded graphite can restrict its flow and prevent liquid phase leakage.

[0024] (3) After modifying the glass fiber cloth on one side with silane coupling agent, the composite phase change material and barrier material are coated on the two surfaces respectively, which enhances the bonding force between the temperature control coating, the barrier coating and the glass fiber cloth, so that the phase change material forms a stable coating on the surface of the glass fiber cloth, further reducing the risk of liquid phase leakage; In addition, the glass fiber cloth has high strength and certain thermal conductivity. As a reinforcing material, it not only makes the phase change laminate have better mechanical stability and durability, but also can quickly transfer the heat in the phase change material, further improving the thermal conductivity of the phase change laminate.

[0025] (4) The present invention blends modified silica nanoparticles with polyurethane acrylic resin to form a dense barrier coating, which can effectively block the direct contact between the phase change material and the external environment. Even when the phase change material is in a molten state, it can prevent leakage and further reduce the leakage rate of the composite phase change material. In addition, the barrier coating improves the weather resistance of the phase change laminate, enabling it to maintain good performance under different environmental conditions, extending the service life of the phase change laminate, and improving the thermal stability and functional durability of the composite material. Attached Figure Description

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Figure 1 This is a schematic diagram of the structure of the phase change laminate prepared in Example 1 of the present invention;

[0028] Figure 2 This is a schematic diagram of the process flow for preparing the first composite phase change material in Example 1 of the present invention;

[0029] Figure 3 The DSC curve of the temperature-controlled coating prepared in Example 1 of the present invention after 50 cooling-heating cycle experiments;

[0030] Figure 4 This is a histogram comparing the thermal conductivity of the phase change laminates prepared in Examples 1-3 of the present invention.

[0031] Figure 5 The above is a histogram comparing the leakage rates of the phase change thermally conductive laminates prepared in Examples 1-3 of this invention after 100 heating / cooling cycles. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below in conjunction with the content of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing specific embodiments only and is not intended to limit the present invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. It should be understood that, unless otherwise specified, all the raw materials used in the present invention are commercially available.

[0033] Example 1

[0034] Figure 1 This is a schematic diagram of the structure of the phase change laminate prepared in Example 1 of the present invention; as shown. Figure 1 As shown, the laminate includes two fiberglass cloth layers, a temperature control coating fixed between the two fiberglass cloth layers, and a barrier coating on the outermost layer of the two fiberglass cloth layers. Figure 2 This is a schematic diagram of the process flow for preparing the first composite phase change material in Example 1 of the present invention; the specific preparation method is as follows:

[0035] S1. Place a beaker containing 10g of n-octadecane in a constant temperature water bath at 40℃ until it is completely melted to obtain molten n-octadecane; mix 1g of expanded graphite with 10g of molten n-octadecane and place the mixture in a constant temperature water bath at 40℃ and stir for 2h to obtain a first mixture a; vacuum impregnate the first mixture a at 40℃ for 12h to obtain a first composite phase change material; add 0.5g of molten n-alkane to the first composite phase change material to obtain a second composite phase change material a;

[0036] S2 uses hydrochloric acid solution to adjust the pH of 95% ethanol aqueous solution to 3, adds (2wt%) KH570, and stirs continuously at room temperature for 30 min to obtain coupling agent solution a; immerses one side of glass fiber cloth (size 15cm×15cm, thickness 0.5mm) in the coupling agent solution, and after immersion for 0.5h, remove glass fiber cloth a and place it in a vacuum oven at 120℃ to dry for 2h to obtain single-sided modified glass fiber cloth a; and coat the second composite phase change material a on the modified surface of the single-sided modified glass fiber cloth by roller coating process, cool at room temperature for 10 min to cure the second composite phase change material a, forming a temperature-controlled coating a;

[0037] S3 first added anhydrous ethanol in increments of 10 mL every 30 min to trititanate isopropyl ester, and stirred at 1000 r / min for 90 min at 90 °C to synthesize modified trititanate isopropyl ester; 0.4 g of modified trititanate isopropyl ester and 4 g of nano-silica particles were mixed and stirred at 600 r / min for 4 h at 50 °C to obtain modified silica nanoparticles.

[0038] This invention involves initiating a transesterification reaction of isopropyl tritiate with anhydrous ethanol. The ethoxy groups in the ethanol substitute for the isopropoxy groups in the isopropyl tritiate, thereby adjusting the reactivity and steric hindrance of the titanate precursor. The surface of nano-silica is rich in silanol groups, and the modified titanate molecules retain active alkoxy groups. Under heating conditions, these alkoxy groups undergo a condensation reaction with the silanol groups on the silica surface, forming stable covalent bonds and providing a strong chemical connection between the inorganic particles and the organic modified layer. Modification of nano-silica significantly improves the dispersion stability of silica nanoparticles in the organic phase and significantly enhances the interfacial interaction with organic matrices such as polymers.

[0039] Then, 0.2g of modified nano-silica, 0.2g of silane coupling agent and 10g of polyurethane acrylic resin are mixed and mechanically stirred in a beaker at 800r / min for 20min to obtain a second mixture a. The second mixture a is coated onto the unmodified surface of the single-sided modified glass fiber cloth a by a scraping process to form a barrier coating a, thus obtaining a double-sided modified glass fiber cloth a.

[0040] S4 After symmetrically stacking two layers of double-sided modified glass fiber cloth a with the barrier coating facing outward and the temperature control coating facing inward, hot-pressing composite is performed at 80°C with a pressure of 0.5MPa for 60s to form a primary laminate a; then, the sides of the primary laminate a are coated and sealed with bisphenol A type epoxy resin to obtain a high thermal conductivity glass fiber reinforced phase change laminate a.

[0041] from Figure 1The partial structural diagram of the temperature-controlled coating shows that n-octadecane is uniformly distributed within the expanded graphite framework, while n-alkanes are distributed on the surface of the expanded graphite framework. Together, they form a temperature-controlled coating with high thermal conductivity and structural stability. Expanded graphite has a large specific surface area and good adsorption properties. After blending with molten n-octadecane and n-alkanes, it can effectively adsorb n-octadecane organic phase change materials. When the phase change material changes from a solid to a liquid state, expanded graphite can restrict its flow and prevent liquid phase leakage. In addition, the composite of expanded graphite and n-octadecane forms a highly efficient thermally conductive network within the phase change material, allowing heat to be conducted more quickly within the phase change material, thereby improving the thermal conductivity of the entire phase change laminate. N-alkanes have a certain latent heat of phase change, and their addition can increase the total latent heat of the phase change material. The formed temperature-controlled coating can absorb or release more heat during the phase change process, thereby increasing the energy storage density of the entire system and enabling it to store energy more effectively in the energy storage field.

[0042] Example 2

[0043] S1. Place a beaker containing 5g of n-octadecane in a 40°C constant temperature water bath until it is completely melted to obtain molten n-octadecane; mix 1g of expanded graphite with 5g of molten n-octadecane and place the mixture in a 40°C constant temperature water bath and stir for 2h to obtain a first mixture b; vacuum impregnate the first mixture b at 60°C for 15h to obtain a first composite phase change material; add 0.1g of molten n-alkane to the first composite phase change material to obtain a second composite phase change material b;

[0044] S2 uses hydrochloric acid solution to adjust the pH of 95% ethanol aqueous solution to 3, adds (2wt%) KH550, and stirs continuously at room temperature for 1 hour to obtain coupling agent solution b; immerses one side of glass fiber cloth (size 15cm×15cm, thickness 0.5mm) in the coupling agent solution for 1 hour, then removes glass fiber cloth b and places it in a vacuum oven at 120℃ to dry for 4 hours to obtain single-sided modified glass fiber cloth b; and coats the second composite phase change material b onto the modified surface of the single-sided modified glass fiber cloth using a roller coating process, cools at room temperature for 30 minutes to cure the second composite phase change material b, forming a temperature-controlled coating b;

[0045] S3 firstly, anhydrous ethanol was added to tritiate isopropyl acetate in increments of 10 mL every 30 min, and the mixture was stirred at 1000 r / min for 90 min at 90 °C to synthesize modified tritiate isopropyl acetate. 0.4 g of modified tritiate isopropyl acetate and 4 g of nano-silica particles were mixed and stirred at 800 r / min for 4 h at 70 °C to obtain modified silica nanoparticles. Then, 0.2 g of modified nano-silica, 0.2 g of silane coupling agent, and 10 g of polyurethane acrylic resin were mixed and mechanically stirred in a beaker at 800 r / min for 20 min to obtain a second mixture b. This second mixture b was then coated onto the unmodified surface of a single-sided modified glass fiber cloth b using a blade coating process to form a barrier coating b, resulting in a double-sided modified glass fiber cloth b.

[0046] S4 After symmetrically stacking two layers of double-sided modified glass fiber cloth b with the barrier coating facing outward and the temperature control coating facing inward, hot-pressing composite is performed at 90°C with a pressure of 0.3MPa for 80s to form a primary laminate b; then, the sides of the primary laminate b are coated and sealed with bisphenol A type epoxy resin to obtain a high thermal conductivity glass fiber reinforced phase change laminate b.

[0047] Example 3

[0048] S1. Place 8g of n-octadecane in a beaker at 40℃ in a constant temperature water bath until it is completely melted to obtain molten n-octadecane; mix 1g of expanded graphite with 5g of molten n-octadecane and place the mixture in a constant temperature water bath at 40℃ and stir for 2h to obtain a first mixture c; vacuum impregnate the first mixture c at 50℃ for 14h to obtain a first composite phase change material; add 0.3g of molten n-alkane to the first composite phase change material to obtain a second composite phase change material c;

[0049] S2 uses hydrochloric acid solution to adjust the pH of 95% ethanol aqueous solution to 3, adds (2wt%) KH792, and stirs continuously at room temperature for 50 min to obtain coupling agent solution c; immerses one side of glass fiber cloth (size 15cm×15cm, thickness 0.5mm) in the coupling agent solution for 50 min, then removes glass fiber cloth c and places it in a vacuum oven at 120℃ to dry for 3 h to obtain single-sided modified glass fiber cloth c; and coats the second composite phase change material c onto the modified surface of the single-sided modified glass fiber cloth using a roller coating process, cools at room temperature for 20 min to cure the second composite phase change material c, forming a temperature-controlled coating c;

[0050] S3 firstly, anhydrous ethanol was added to tritiate isopropyl acetate in increments of 10 mL every 30 min, and the mixture was stirred at 1000 r / min for 90 min at 90 °C to synthesize modified tritiate isopropyl acetate. 0.4 g of modified tritiate isopropyl acetate and 4 g of nano-silica particles were mixed and stirred at 700 r / min for 4 h at 60 °C to obtain modified silica nanoparticles. Then, 0.2 g of modified nano-silica, 0.2 g of silane coupling agent, and 10 g of polyurethane acrylic resin were mixed and mechanically stirred in a beaker at 800 r / min for 20 min to obtain a second mixture c. This second mixture c was then coated onto the unmodified surface of a single-sided modified glass fiber cloth c using a blade coating process to form a barrier coating c, resulting in a double-sided modified glass fiber cloth c.

[0051] S4 After symmetrically stacking two layers of double-sided modified glass fiber cloth c with the barrier coating facing outward and the temperature control coating facing inward, hot-pressing composite is performed at 85°C with a pressure of 0.4MPa for 70s to form a primary laminate c; then, the sides of the primary laminate c are coated and sealed with bisphenol A type epoxy resin to obtain a high thermal conductivity glass fiber reinforced phase change laminate c.

[0052] Example 4

[0053] S1. Place 8g of n-octadecane in a beaker at 40°C in a constant temperature water bath until it is completely melted to obtain molten n-octadecane; mix 1g of expanded graphite with 5g of molten n-octadecane and place the mixture in a constant temperature water bath at 40°C for 2 hours to obtain a first mixture d; vacuum impregnate the first mixture d at 40°C for 13 hours to obtain a first composite phase change material d; add 0.4g of molten n-alkane to the first composite phase change material to obtain a second composite phase change material d;

[0054] S2 uses hydrochloric acid solution to adjust the pH of 95% ethanol aqueous solution to 3, adds (2wt%) KH571, and stirs continuously at room temperature for 30 min to obtain coupling agent solution d; immerses one side of glass fiber cloth (size 15cm×15cm, thickness 0.5mm) in coupling agent solution d for 40 min, then removes glass fiber cloth d and places it in a vacuum oven at 120℃ to dry for 4 h to obtain single-sided modified glass fiber cloth d; and coats the second composite phase change material d onto the modified surface of the single-sided modified glass fiber cloth d using a roller coating process, cools at room temperature for 10 min to cure the second composite phase change material d, forming a temperature-controlled coating d;

[0055] S3 firstly, anhydrous ethanol was added to tritiate isopropyl acetate in increments of 10 mL every 30 min, and the mixture was stirred at 1000 r / min for 90 min at 90 °C to synthesize modified tritiate isopropyl acetate. 0.4 g of modified tritiate isopropyl acetate and 4 g of nano-silica particles were mixed and stirred at 700 r / min for 4 h at 60 °C to obtain modified silica nanoparticles. Then, 0.2 g of modified nano-silica, 0.2 g of silane coupling agent, and 10 g of polyurethane acrylic resin were mixed and mechanically stirred in a beaker at 800 r / min for 20 min to obtain a second mixture d. This second mixture d was then coated onto the unmodified surface of a single-sided modified glass fiber cloth d using a blade coating process to form a barrier coating d, resulting in a double-sided modified glass fiber cloth d.

[0056] S4 After symmetrically stacking two layers of double-sided modified glass fiber cloth d with the barrier coating facing outward and the temperature control coating facing inward, hot-pressing composite is performed at 80°C with a pressure of 0.5MPa for 60s to form a primary laminate d; then, the sides of the primary laminate d are coated and sealed with bisphenol A type epoxy resin to obtain a high thermal conductivity glass fiber reinforced phase change laminate d.

[0057] Comparative Example 1

[0058] The preparation method is the same as in Example 1, except that the phase change laminate does not contain a barrier coating.

[0059] Comparative Example 2

[0060] The preparation method is the same as in Example 1, except that the phase change coating in the phase change laminate does not contain expanded graphite.

[0061] Performance testing

[0062] To demonstrate the role of the prepared high thermal conductivity glass fiber reinforced phase change laminate in temperature control, temperature control tests were conducted. The phase change laminate prepared in Example 1 was subjected to DSC testing. Figure 3 The DSC curve of the temperature-controlled coating prepared in Example 1 of this invention after 50 cooling-heating cycles is shown. Its endothermic peak temperature is 28.5℃, and its endothermic enthalpy is 172 J / g; its exothermic peak temperature is 26.6℃, and its exothermic enthalpy is 168 J / g. It can be seen that the thermal conductivity of the temperature-controlled coating in this phase change laminate is significantly improved, and it possesses a high latent heat of phase change.

[0063] To demonstrate the thermal conductivity of the prepared high thermal conductivity glass fiber reinforced phase change laminate, a transient planar heat source thermal conductivity meter was used for testing. Thermal conductivity testing: The phase change laminates prepared in Examples 1-3 and Comparative Example 2 were cut into circular pieces with a diameter of 3 cm and tested according to the method in ASTM D5470-2006.

[0064] Figure 4 This is a histogram comparing the thermal conductivity of the phase change laminates prepared in Examples 1-3 of this invention. Figure 4 As shown, the thermal conductivity of the phase change laminates prepared in Examples 1-3 were 4.92 W / (m·K), 4.76 W / (m·K), and 4.25 W / (m·K), respectively. Compared with the 2.17 W / (m·K) of the phase change laminate prepared in Comparative Example 2, the thermal conductivity was increased by up to 55.8%. Examples 1-3 and Comparative Example 2 demonstrate that the phase change laminate with expanded graphite has higher thermal conductivity, indicating that expanded graphite and molten n-octadecane synergistically enhance thermal conductivity.

[0065] To demonstrate the leak-proof effect of the prepared high thermal conductivity glass fiber reinforced phase change laminate, a leak-proof test was conducted. Leakage test: The phase change laminates prepared in Examples 1-3 and Comparative Example 1 were placed in a high and low temperature cycling environment. After 100 cycles, a leak test was conducted, and the morphological changes of each phase change laminate were observed, and the leakage rate was calculated based on the mass change. Figure 5 This is a histogram comparing the leakage rates of the phase change thermally conductive laminates prepared in Examples 1-3 of this invention after 100 heating / cooling cycles. The phase change laminate prepared in Comparative Example 1 showed partial liquid leakage on its surface after heating, while the phase change laminates prepared in Examples 1-3 showed no liquid leakage. Figure 5 As shown, the leakage rates of the phase change laminates prepared in Examples 1-3 were 2.74%, 8.49%, and 2.91%, respectively. This indicates that compared to the 16.2% leakage rate of the phase change laminate prepared in Comparative Example 1, the leakage rate of the phase change laminate containing the barrier coating can be reduced by up to 78%. Examples 1-3 and Comparative Example 1 demonstrate that blending modified silica nanoparticles with polyurethane acrylic resin to form a dense barrier coating can effectively prevent direct contact between the phase change material and the external environment, further reducing the leakage rate of the composite phase change material even in the molten state.

[0066] To demonstrate the mechanical properties of the prepared high thermal conductivity glass fiber reinforced phase change laminate, mechanical property tests were conducted. The mechanical properties were tested according to GB / T1040.1-2006 and GB / T9639.1-2008. The tensile strengths of the phase change laminates prepared in Examples 1-3 and Comparative Examples 1-2 were 160 MPa, 280 MPa, 260 MPa, 120 MPa, and 90 MPa, respectively. It is evident that the unilateral modification of the glass fiber cloth using a silane coupling agent enhanced the bonding force between the temperature control coating, the barrier coating, and the glass fiber cloth. As a reinforcing material, the glass fiber cloth enabled the phase change laminates prepared in Examples 1-3 to possess better mechanical stability and durability.

[0067] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a high thermal conductivity glass fiber reinforced phase change laminate, characterized in that, Includes the following steps: S1. Expanded graphite and molten n-octadecane are mixed evenly to obtain a first mixture; the first mixture is subjected to vacuum impregnation treatment to obtain a first composite phase change material; molten n-alkane is added to the first composite phase change material to obtain a second composite phase change material. S2 uses a silane coupling agent to modify one side of the glass fiber cloth to obtain a one-sided modified glass fiber cloth; and then coats the second composite phase change material onto the modified surface of the one-sided modified glass fiber cloth by a roller coating process to form a temperature control coating. S3 mixes modified nano-silica, polyurethane acrylic resin and silane coupling agent evenly to obtain a second mixture. The second mixture is then coated onto the unmodified side of the single-sided modified glass fiber cloth by a scraping process to form a barrier coating, thus obtaining a double-sided modified glass fiber cloth. S4 involves symmetrically stacking two layers of double-sided modified glass fiber cloth with the barrier coating facing outwards and the temperature control coating facing inwards, followed by hot pressing to form a primary laminate. Then, epoxy resin is used to coat and seal the sides of the primary laminate to obtain a high thermal conductivity glass fiber reinforced phase change laminate. The vacuum impregnation treatment in step S1 involves impregnating the first mixture under vacuum conditions at 40-60°C for 12-15 hours; the mass ratio of the expanded graphite, n-octadecane, and n-alkanes is 1:(5-10):(0.1-0.5). The mass ratio of modified nano-silica, silane coupling agent and polyurethane acrylic resin in step S3 is 1:1:50; the preparation method of the second mixture includes: mixing modified nano-silica, silane coupling agent and polyurethane acrylic resin and then mechanically stirring at a speed of 800 r / min for 20-30 min to obtain the second mixture; The preparation method of the modified nano silica in step S3 includes: mixing modified trititanate isopropyl ester and nano silica, and stirring at 50-70℃ and 600-800 r / min for 4-6 h to obtain modified nano silica; the mass ratio of the modified trititanate isopropyl ester to nano silica is 1:

10.

2. The preparation method according to claim 1, characterized in that, The expanded graphite mentioned in step S1 is obtained by graphite through high-temperature expansion treatment; the high-temperature expansion treatment temperature is 900-1000℃ and the treatment time is 10-60 s.

3. The preparation method according to claim 1, characterized in that, The silane coupling agent mentioned in steps S2 and S3 is any one of KH570, KH550, KH792 and KH571.

4. The preparation method according to claim 1, characterized in that, Step S2 further includes: S21 uses hydrochloric acid to adjust the pH of the ethanol aqueous solution to 3, then adds silane coupling agent to it, and stirs continuously at room temperature for 0.5-1h to obtain the coupling agent solution; S22. The glass fiber cloth is immersed in the coupling agent solution on one side for 0.5-1h, and then the glass fiber is taken out and dried in a vacuum oven at 120°C for 2-4h to obtain the single-sided modified glass fiber cloth. S23 The second composite phase change material is coated onto the modified surface of the single-sided modified glass fiber cloth by roller coating process, and cooled at room temperature for 10-30 minutes to form a temperature-controlled coating.

5. The preparation method according to claim 1, characterized in that, The method for preparing modified trititanate isopropyl ester in step S3 includes: adding anhydrous ethanol to trititanate isopropyl ester in increments of 10 mL every 30 min, stirring at 90°C and a speed of 1000 r / min for 90 min to obtain modified trititanate isopropyl ester.

6. The preparation method according to claim 1, characterized in that, In step S4, the hot-pressing composite pressure is 0.3-0.5 MPa, the time is 60-80 s, and the temperature is 80-90 ℃; the epoxy resin is bisphenol A type.

7. A high thermal conductivity glass fiber reinforced phase change laminate prepared by the preparation method according to any one of claims 1 to 6.

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