Alcohol reversible thermochromic flexible shaped composite phase change heat storage material and preparation method thereof

Abstract

The invention relates to the technical field of phase change heat storage material preparation and heat energy storage, in particular to an alcohol reversible thermochromic flexible shaped composite phase change heat storage material and a preparation method thereof. According to the composite phase change material, the combination of the 2-phenylamino-3-methyl-6-diethylfluorane, the 2, 2-bis (4-hydroxybenzene) propane and the fatty alcohol phase change material is used for playing a thermochromic role; and a thermoplastic elastomer hydrogenated styrene-butadiene block copolymer (SEBS) is used for playing a role in shaping and packaging. The novel phase change heat storage material which is good in packaging effect, high in phase change enthalpy value and high in heat stability and integrates the functions of thermochromism, phase change heat storage, flexible shaping and the like is prepared by selecting raw materials with low cost and using a simple and rapid mechanical melt blending preparation method. In addition, the alcohol reversible thermochromic flexible shaped composite phase change heat storage material also has the advantage that the color change temperature is flexible and adjustable at 24-70 DEG C, and the application range of the phase change heat storage material is further expanded. The method has great application potential in the fields of temperature warning, battery heat management, solar heat utilization and the like.

Description

Technical Field

[0001] The invention belongs to the field of reversible thermochromic composite phase-change heat storage materials, and in particular relates to an alcohol reversible thermochromic flexible shaped composite phase-change heat storage material and a preparation method thereof. Technical Background

[0002] At present, the widely used green and clean energy such as solar energy and wind energy are highly volatile due to the influence of the changing seasons and weather changes. Developing efficient thermal energy storage technology is an important means to solve the above problems and expand the scope of solar energy application.

[0003] Phase change materials, which use the latent heat generated or released during phase change to store thermal energy, are considered to be an ideal candidate material because of their advantages such as large heat capacity, low price and strong stability. Among them, reversible thermochromic composite phase change materials with phase change materials as cosolvents can store and release heat while changing color. This new type of intelligent functional material is widely used in the fields of building energy conservation, textile industry, color-changing inks, solar energy and battery thermal management. However, when the cosolvent in the thermochromic composite phase change material undergoes phase change, solid-liquid transition will occur, causing leakage. At present, microencapsulation technology is mostly used to encapsulate reversible thermochromic materials. However, microencapsulated thermochromic materials have problems such as complicated preparation process, high production cost, mostly solidified tiny particles, and insignificant thermochromic effect.

[0004] Thermoplastic elastomer hydrogenated styrene-butadiene block copolymer (SEBS) has similar chemical properties to fatty alcohol phase change materials, has good compatibility, and can be effectively shaped and encapsulated by them. SEBS also has good thermal stability and can still maintain the shape stability and mechanical properties of the composite material at high temperatures. This makes SEBS and fatty alcohol phase change materials an excellent combination for preparing composite materials with flexible and shaped functions. At present, the preparation of a flexible and shaped composite phase change heat storage material that combines color change and energy storage is a major challenge to be faced in the future. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned technologies, the purpose of the present invention is to provide an alcohol-based reversible thermochromic flexible shaped composite phase-change heat storage material. The composite phase-change heat storage material has low raw material cost and simple preparation process, and successfully integrates the functions of thermochromic, phase change heat storage, thermoflexibility and shaped packaging.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is: The invention discloses an alcohol-based reversible thermochromic flexible shape-fixing composite phase-change heat storage material, which is composed of: 0.32% to 2.4% of 2-phenylamino-3-methyl-6-diethylfluoran, 0.66% to 9.12% of 2,2-bis(4-hydroxyphenyl)propane, 51.4% to 78.7% of a cosolvent and 20% to 40% of a hydrogenated styrene-butadiene block copolymer.

[0007] Furthermore, 2-phenylamino-3-methyl-6-diethylfluoran (ODB-1), 2,2-bis(4-hydroxyphenyl)propane (BPA) and a solvent (fatty alcohol phase change material) play a role in thermochromism. Hydrogenated styrene-butadiene block copolymer (SEBS) plays a role in network skeleton support in the composite material.

[0008] Further, 2-phenylamino-3-methyl-6-diethylfluoran (C 31 H 28 N 2 O 3 , CAS: 29512-49-0); 2,2-bis(4-hydroxyphenyl)propane (C 15 H 16 O 2 , CAS: 80-05-7); hydrogenated styrene-butadiene block copolymer was produced by Kraton Performance Polymers, USA.

[0009] Furthermore, the co-solvent is a fatty alcohol phase change material with a phase change temperature of 24 to 70°C.

[0010] Furthermore, the fatty alcohol phase change material is n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecyl alcohol, n-eicosanol, and n-docosahexadecyl alcohol.

[0011] Furthermore, the preparation method of the alcohol reversible thermochromic flexible shape-fixed composite phase change heat storage material comprises the following experimental steps:

[0012] (1) heating and melting the co-solvent in an oil bath heating device, starting mechanical stirring after the co-solvent is completely melted, then adding 2-phenylamino-3-methyl-6-diethylfluoran, continuing stirring for 5 to 10 minutes, then adding 2,2-bis(4-hydroxyphenyl)propane, and mechanically stirring and melting and blending for 60 to 80 minutes to obtain a clear thermochromic composite phase change material solution;

[0013] (2) Adding the dried hydrogenated styrene-butadiene block copolymer to the thermochromic composite phase change material solution obtained in step (1), mechanically stirring and melt blending for 80 to 100 minutes, and after the mixed solution becomes transparent and clear, casting and cooling by means of a mold to finally obtain an alcohol-based reversible thermochromic flexible shaped composite phase change heat storage material.

[0014] Furthermore, in step (1), the oil bath temperature is 10-20° C. higher than the phase transition temperature of the co-solvent, and the mechanical stirring speed is 300-500 rpm.

[0015] Furthermore, in step (2), during the mechanical stirring and melting, the oil bath temperature is 150-180°C.

[0016] Furthermore, in step (2), when the melting is mechanically stirred, the stirring speed is 600 to 800 rpm.

[0017] Furthermore, in step (2), during cooling, the mixture is placed in a room temperature environment and cooled naturally.

[0018] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0019] (1) The present invention uses low-cost, easily available raw materials and a simple and easy preparation method to successfully combine a reversible thermochromic composite phase change material with a copolymer to prepare an alcohol-based reversible thermochromic flexible shape-fixing composite phase change heat storage material. Its uniqueness lies in that under temperature stimulation, phase change heat absorption and release and reversible color change are carried out simultaneously. A new phase change heat storage material with good encapsulation effect, high phase change enthalpy value and strong thermal stability is provided, which integrates thermochromic, phase change heat storage and flexible shape-fixing functions.

[0020] (2) The present invention selects fatty alcohol phase change materials as cosolvents to provide a necessary reaction environment for the electron exchange between the color former 2-phenylamino-3-methyl-6-diethylfluoran and the developer 2,2-bis(4-hydroxyphenyl)propane. The hydrogenated styrene-butadiene block copolymer has good compatibility with the fatty alcohol phase change materials, and can make the thermochromic part evenly dispersed therein, so as to achieve the effect of no leakage above the phase change temperature and flexible bending and deformation.

[0021] (3) The present invention selects non-toxic 2-phenylamino-3-methyl-6-diethylfluoran as a colorant, which can produce a significant color change when combined with 2,2-bis(4-hydroxyphenyl)propane, specifically: during the heating process, it appears black when it is below the phase transition temperature. A color gradient from black to colorless occurs near the phase transition temperature. When the temperature is higher than the phase transition temperature, it is colorless and transparent; during the cooling process, it first appears colorless and transparent and then slowly changes to color. When it is below the phase transition temperature, it appears black again. And multiple heating and cooling will not change this thermochromic process.

[0022] (4) Fatty alcohol phase change materials have excellent thermal properties and high phase change enthalpy values; they have a wide range of phase change temperatures and are suitable for a variety of application scenarios; they have good chemical compatibility and can be combined with a variety of matrix materials. Thermoplastic elastomer SEBS is non-toxic and environmentally friendly and has good weather resistance, heat resistance, and chemical resistance, and can provide effective protection for the thermochromic part.

[0023] (5) The present invention adopts a mechanical melt blending method to prepare alcohol reversible thermochromic flexible shape-fixed composite phase change heat storage material, which has a simple preparation method, mild conditions and low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Thermochromic properties of the alcohol reversible thermochromic flexible shaped composite phase change heat storage material obtained in Example 1;

[0025] Figure 2 This is the thermal weight loss curve of the alcohol reversible thermochromic flexible shape-fixed composite phase change heat storage material obtained in Example 2;

[0026] Figure 3 The DSC curves of the alcohol reversible thermochromic flexible shape-fixed composite phase-change heat storage materials obtained in Examples 1 to 3; DETAILED DESCRIPTION

[0027] Example 1

[0028] The invention discloses an alcohol-based reversible thermochromic flexible shaped composite phase-change heat storage material, which is composed of the following raw materials: 0.03 g of 2-phenylamino-3-methyl-6-diethylfluoran, 0.09 g of 2,2-bis(4-hydroxyphenyl)propane, 3.6 g of n-docosanol and 1.59 g of hydrogenated styrene-butadiene block copolymer.

[0029] The alcohol-based reversible thermochromic flexible shaped composite phase change heat storage material comprises the following preparation process:

[0030] (1) heating n-dodecyl alcohol in an oil bath heating device at 90° C. to melt, and after it is completely melted, mechanically stirring at a speed of 500 rpm for 10 minutes, then adding 2-phenylamino-3-methyl-6-diethylfluoran, continuing to stir for 5 minutes, and then adding 2,2-bis(4-hydroxyphenyl)propane, mechanically stirring and melting and blending for 70 minutes to obtain a clear thermochromic composite phase change material solution;

[0031] (2) Add the dried hydrogenated styrene-butadiene block copolymer to the thermochromic composite phase change material solution obtained in step (1), and melt blend them at 150° C. and 800 rpm with mechanical stirring for 80 min. After the mixed solution becomes transparent and clear, cast it into a mold and cool it to obtain an alcohol-based reversible thermochromic flexible shaped composite phase change heat storage material.

[0032] The alcohol reversible thermochromic flexible shaped composite phase change heat storage material was cast into a 8mm×2mm circular sample, one side of which was heated on a heating table, and the surface temperature of the sample was tested using a Tix1060 infrared thermal imager produced by Fluke Corporation of the United States. The images obtained at different temperatures are shown in Figure 2. Figure 1 shown.

[0033] observe Figure 1 It can be seen that as the temperature rises, the color of the composite phase change thermal storage material gradually changes from black to white; when the temperature rises to 75°C, it becomes colorless and transparent, the color no longer changes, and the fonts such as "HEBUT" can be clearly seen. No obvious leakage of the phase change material was observed during this process, indicating that the shaped packaging effect is good.

[0034] Example 2

[0035] The invention discloses an alcohol-based reversible thermochromic flexible shape-fixing composite phase-change heat storage material, which is composed of the following raw materials: 0.02 g of 2-phenylamino-3-methyl-6-diethylfluoran, 0.06 g of 2,2-bis(4-hydroxyphenyl)propane, 3.6 g of n-docosanol and 1.58 g of hydrogenated styrene-butadiene block copolymer.

[0036] The alcohol-based reversible thermochromic flexible shaped composite phase change heat storage material comprises the following preparation process:

[0037] (1) heating n-dodecyl alcohol in an oil bath heating device at 90° C. to melt, and after it is completely melted, mechanically stirring at 300 rpm for 10 minutes, then adding 2-phenylamino-3-methyl-6-diethylfluoran, continuing to stir for 5 minutes, and then adding 2,2-bis(4-hydroxyphenyl)propane, mechanically stirring and melting and blending for 60 minutes to obtain a clear thermochromic composite phase change material solution;

[0038] (2) Add the dried hydrogenated styrene-butadiene block copolymer to the thermochromic composite phase change material solution obtained in step (1), and melt blend them at 150° C. and 800 rpm with mechanical stirring for 80 min. After the mixed solution becomes transparent and clear, cast it into a mold and cool it to obtain an alcohol-based reversible thermochromic flexible shaped composite phase change heat storage material.

[0039] The STA449F5 synchronous thermal analyzer produced by NETZSCH in Germany was used. 2 The prepared alcohol reversible thermochromic flexible shape-fixed composite phase change heat storage material was heated from room temperature to 600°C at a rate of 10°C / min in an atmosphere, and the thermal stability test results were as follows: Figure 2 shown.

[0040] observe Figure 2 From the thermogravimetric curve, we can see that the thermogravimetric loss between 200 and 420 °C is mainly attributed to the thermal decomposition of n-docosanol, while the mass loss between 420 and 500 °C is mainly caused by the decomposition of SEBS. In general, the sample has good thermal stability.

[0041] Example 3

[0042] The invention discloses an alcohol-based reversible thermochromic flexible shaped composite phase-change heat storage material, which is composed of the following raw materials: 0.03 g of 2-phenylamino-3-methyl-6-diethylfluoran, 0.09 g of 2,2-bis(4-hydroxyphenyl)propane, 3.6 g of n-docosanol and 2.4 g of hydrogenated styrene-butadiene block copolymer.

[0043] The alcohol-based reversible thermochromic flexible shaped composite phase-change heat storage material comprises the following preparation process:

[0044] (1) heating n-dodecyl alcohol in an oil bath heating device at 90° C. to melt, and after it is completely melted, mechanically stirring at a speed of 500 rpm for 10 minutes, then adding 2-phenylamino-3-methyl-6-diethylfluoran, continuing to stir for 5 minutes, and then adding 2,2-bis(4-hydroxyphenyl)propane, mechanically stirring and melting and blending for 70 minutes to obtain a clear thermochromic composite phase change material solution;

[0045] (2) Add the dried hydrogenated styrene-butadiene block copolymer to the thermochromic composite phase change material solution obtained in step (1), and melt blend under mechanical stirring at 150° C. and 800 rpm for 100 min. After the mixed solution becomes transparent and clear, it is cast by a mold and cooled to obtain an alcohol-based reversible thermochromic flexible shaped composite phase change heat storage material.

[0046] The DSC214 differential scanning calorimeter produced by NETZSCH in Germany was used to 2 The phase change performance of the alcohol reversible thermochromic flexible shape-fixing composite phase change heat storage materials prepared in Examples 1 to 3 was tested in the temperature range of 0 to 100°C at a heating and cooling rate of 5°C / min in an atmosphere. The DSC curves and thermophysical property results obtained were as follows: Figure 3 Shown and listed in Table 1.

[0047] Table 1 Thermophysical properties of alcohol reversible thermochromic flexible shape-fixed composite phase change thermal storage materials

[0048] Example PCM ratio SEBS Ratio <![CDATA[T m1 ]]> <![CDATA[T m2 ]]> <![CDATA[ΔH m ]]> Example 1 67.7wt.% 30wt.% 58.7℃ 68.8℃ 172.5J / g Example 2 68.5wt.% 30wt.% 60.2℃ 69.6℃ 173.7J / g Example 3 58.1wt.% 40wt.% 62.3℃ 70.4℃ 142.9J / g

[0049] As can be seen from Table 1, the phase change enthalpy value of the alcohol reversible thermochromic flexible set composite phase change heat storage material prepared by the present invention is determined by the amount of fatty alcohol phase change material loaded in the set system. The higher the mass fraction of the fatty alcohol phase change material, the higher the phase change enthalpy value. Even if the mass fraction of the hydrogenated styrene-butadiene block copolymer without heat storage capacity is 40wt.%, the phase change enthalpy value of the composite phase change heat storage material is still as high as 142.9J / g.

[0050] Although the specific implementation of the present invention is described in detail in conjunction with the drawings, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. An alcohol reversible thermochromic flexible shaped composite phase change heat storage material and a preparation method thereof, characterized in that: The invention comprises the following raw materials in percentage by weight: 0.32% to 2.4% of 2-phenylamino-3-methyl-6-diethylfluoran, 0.66% to 9.12% of 2,2-bis(4-hydroxyphenyl)propane, 51.4% to 78.8% of a cosolvent and 20% to 40% of a hydrogenated styrene-butadiene block copolymer. The cosolvent is a fatty alcohol phase change material with a phase change temperature of 24 to 70°C; The fatty alcohol phase change material is n-dodecyl alcohol, n-tetradecyl alcohol, n-hexadecanol, n-octadecyl alcohol, n-eicosanol, and n-behenyl alcohol.

2. The alcohol reversible thermochromic flexible shaped composite phase change heat storage material according to claim 1, characterized in that: The setting system is a thermoplastic elastomer hydrogenated styrene-butadiene block copolymer (SEBS).

3. The method for preparing any alcohol reversible thermochromic flexible shape-fixed composite phase change heat storage material according to claim 1, characterized in that: The following steps are involved: (1) heating and melting the co-solvent in an oil bath heating device, starting mechanical stirring after the co-solvent is completely melted, then adding 2-phenylamino-3-methyl-6-diethylfluoran, continuing stirring for 5 to 10 minutes, and then adding 2,2-bis(4-hydroxyphenyl)propane, mechanically stirring and melting and blending for 60 to 80 minutes to obtain a clear thermochromic composite phase change material solution; (2) Adding the dried hydrogenated styrene-butadiene block copolymer to the thermochromic composite phase change material solution obtained in step (1), mechanically stirring and melt blending for 80 to 100 minutes, and after the mixed solution becomes transparent and clear, casting and cooling with the help of a mold to finally obtain an alcohol-based reversible thermochromic flexible shaped composite phase change heat storage material.

4. The method for preparing the alcohol reversible thermochromic flexible shape-fixed composite phase change heat storage material as claimed in claim 3, characterized in that: In step (1), the oil bath temperature is 10-20° C. higher than the phase transition temperature of the co-solvent, and the mechanical stirring speed is 300-500 rpm.

5. The method for preparing the alcohol reversible thermochromic flexible shape-fixed composite phase change heat storage material as claimed in claim 3, characterized in that: In step (2), during the mechanical stirring and melting, the oil bath temperature is 150-180°C.

6. The method for preparing the alcohol reversible thermochromic flexible shape-fixed composite phase-change heat storage material as claimed in claim 3, characterized in that: In step (2), when the melting is mechanically stirred, the stirring speed is 600 to 800 rpm.

7. The method for preparing the alcohol reversible thermochromic flexible shape-fixed composite phase-change heat storage material as claimed in claim 3, characterized in that: In step (2), during cooling, the mixture is placed in a room temperature environment and cooled naturally.

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