Colorful flexible set phase change energy storage material and preparation method thereof

Abstract

The application discloses a kind of color flexible setting phase change energy storage materials and preparation method thereof, which belongs to the technical field of new materials.The material is obtained by reacting polyethylene glycol (PEG) with a compound containing a bifunctional group to obtain a bifunctional intermediate compound; dye molecules are mixed with small molecule chain extenders in a certain proportion to obtain a mixed chain extender, and the dye molecules are introduced into the polymer backbone by reacting the mixed chain extender with the bifunctional intermediate compound at a molar ratio of 1:1 to obtain a new phase change energy storage material. The dye is mainly responsible for giving the phase change material a bright color, and the small molecule chain extender is mainly responsible for adjusting the flexibility of the phase change material. The phase change temperature of the material can be adjusted, the shape is stable, the flexibility is strong, and the material can still give the material a bright color under the condition of low dye addition amount. The material can be used for the storage of thermal energy in special environments. The synthesis process of the material is simple, easy to use, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of color flexible fixed shape phase change energy storage material and its preparation method, it belongs to new material technical field. BACKGROUND

[0002] In recent years, energy shortage is a major dilemma faced by today's economic development, developing new energy storage technology, improving energy utilization is imminent, phase change energy storage material (PCM) by using physical phase transition, absorb or release a large amount of heat, so as to realize the storage and utilization of thermal energy, is one of the effective ways to improve the efficiency of thermal energy utilization, it has the advantages of large energy storage density, low price, wide temperature range, etc., can effectively solve the time and space mismatch problem of supply and demand of thermal energy.

[0003] But the traditional phase change material is rigid, poor toughness, brittle fracture under stress, so it is difficult to process, can not be easily installed in the device with space blocked, and it is difficult to achieve close to the device, resulting in increased thermal contact resistance, thermal management efficiency is reduced, so the preparation of flexible fixed shape phase change material has important application value.

[0004] But flexible phase change material also has certain problems, such as most flexible phase change material has intrinsic flexibility, easy to leak, color is single and not bright, has great limitation in practical application.

[0005] In order to give phase change material flexibility, relevant scientific researchers prepare flexible phase change material by physical embedding method or chemical bonding method. Su Xiaofeng et al. applied for a patent of flexible fixed shape composite phase change material, immersed the treated cellulose sponge into polyurethane solution, added a certain mass fraction of heat conducting filler, took out the cellulose sponge after impregnation, coagulated in the mixed solution, and then dried to obtain cellulose sponge / polyurethane composite material with flexibility and porous structure. The composite material has excellent mechanical properties, does not break when deformed below the melting point, and can restore to original shape after external force is removed, so that the material shows good flexibility, and can withstand any reversible deformation above the melting point, which can effectively reduce the thermal resistance between the material and thermal management equipment, improve the actual installation convenience, and expand its application in microelectronic device thermal energy storage field and management. [Su Xiaofeng, Wang Yazhen, Feng Xueling, et al. A kind of flexible fixed shape composite phase change material and its preparation method: CN110922944B[P]. 2019, 11, 05.] However, most of the flexible phase change materials have single color, not bright enough, and most of them are thermally flexible, which limits their further application.

[0006] By introducing polyethylene glycol and dye into the polymer skeleton, the obtained phase change material has excellent shape stability, better phase change performance, intrinsic flexibility and bright color. SUMMARY

[0007] In order to solve the problems in the prior art, the present application provides a new type of organic flexible fixed phase change energy storage material with easily adjustable phase change temperature and bright color. The material is obtained by introducing polyethylene glycol and dye into the polymer skeleton, and has adjustable phase change temperature, stable shape, good flexibility and bright color. The material can be used for the storage and release of heat energy in special environments. The synthesis process of the material is simple, and the material is convenient to use, so it has a wide application prospect.

[0008] A colored flexible fixed phase change energy storage material, which is composed of the following components in mass percentage:

[0009] The material is composed of 95-99wt% of organic polymer fixed phase change support material and 1-5wt% of mixed chain extender;

[0010] Preferably, the organic polymer fixed phase change support material is 97.8-98.3wt%; the mixed chain extender is 1.7-2.2%, and the mixed chain extender is obtained by mixing dye and small molecule chain extender, wherein the proportion of dye is 0.6-46wt%, and the proportion of small molecule chain extender is 54-99.4wt%.

[0011] The general structure of the organic polymer fixed phase change support material is as follows:

[0012]

[0013] Among them, the structure of the connecting group A is 、 or ;

[0014] D= , , , , or ;

[0015] V1 is Cl, F, NHCH3 or NHC4H9; V2 is H or CH3; m is an integer of 100-10000; n is an integer of 10-1000.

[0016] The dye molecule and the small molecule chain extender are both compounds containing double hydroxyl or double amino groups, which react with specific functional groups on the synthesized organic polymer fixed support material.

[0017] The color flexible fixed phase change energy storage material comprises an organic polymer fixed phase change support material and a mixed chain extender, wherein the organic polymer fixed phase change support material is a multi-block type polymer phase change material with polyether as a soft segment and an aromatic ring as a hard segment, and the mixed chain extender is obtained by mixing a small molecule chain extender and a dye according to a certain proportion.

[0018] Preferably, the dye has a similar reaction activity of a double hydroxyl or amino structure. The following is a detailed description of the preferred dye structure:

[0019] For anthraquinone dyes, the chemical structural formula is as follows:

[0020]

[0021] wherein R1 and R2 are the same structure and are selected from any one of OH, NH2, , , ,

[0022] The azo dye includes a heterocyclic azo dye and a non-heterocyclic azo dye; wherein the structure of the non-heterocyclic azo dye is as follows:

[0023]

[0024] wherein T1 is one of NO2 and SCO2H3, T2 and T3 are any one of H, Cl, Br, NO2 and CN, Y1 and Y2 are any one of H, CH3, OCH3, NHCOCH3, OCH3(OC2H5) and OC7H5(OCH3), and M1 and M2 are any one of CH2CH2OH and CH2OH;

[0025] The structure of the heterocyclic azo dye is as follows:

[0026]

[0027] wherein X is , , , , , , , , , , , , , , , ​Any one of the above, L1, L2 are H, CH3, OCH3, NHCOCH3, OCH3(OC2H5), OC7H5(OCH3) any one of, Q1, Q2 are CH2CH2OH, CH2OH any one of.

[0028] The chain extender is preferably one of N,N dihydroxyethyl aniline, triethylamine, glycerol, trimethylol ethane, 1,4-butanediol, trimethylol propane, dimethylene phenyl glycol, 1,4 cyclohexanediol.

[0029] The chain extender is preferably one of N,N dihydroxyethyl aniline, triethylamine, glycerol, trimethylol ethane, 1,4-butanediol, trimethylol propane, dimethylene phenyl glycol, 1,4 cyclohexanediol.

[0030] A preparation method of a color flexible fixed shape phase change energy storage material, comprising the following process steps: under stirring conditions, dissolving an organic polymer fixed shape phase change support material and a dye in a solvent according to a proportion, reacting at 80-120 DEG C for 4-12 h under N2 environment, evaporating the solvent, and vacuum drying to obtain the color flexible fixed shape phase change energy storage material.

[0031] In the above technical solution, the solvent is preferably one to three of tetrahydrofuran, dioxane, acetone, chloroform, dichloromethane, carbon tetrachloride, carbon disulfide, DMF, DMSO, benzene, toluene, xylene, polyethylene glycol dimethyl ether, chlorobenzene, cyclohexane or n-hexane.

[0032] A preparation method of a color flexible fixed shape phase change energy storage material, comprising the following steps:

[0033] (1) Polyethylene glycol with an average molecular weight of 2000-20000 is vacuum dried at 80 DEG C for 48 h.

[0034] (2) Polyethylene glycol and a double functional group containing aromatic ring compound are dissolved in a solvent according to a molar ratio of 1:2, and an appropriate amount of catalyst is added, the above raw materials are added to a three-necked flask under N2 environment, and stirring reaction is carried out at 40-60 DEG C for 4-10 h to obtain a solution of a double functional group containing intermediate compound.

[0035] The double functional group containing compound is a compound containing an epoxy, triazine or isocyanate structure; the mass ratio of the catalyst to the polyethylene glycol is 1:60-130; and the mass ratio of the solvent to the polyethylene glycol is 7-14:1.

[0036] The solvent is one to three of tetrahydrofuran, dioxane, acetone, chloroform, dichloromethane, carbon tetrachloride, carbon disulfide, DMF, DMSO, benzene, toluene, xylene, polyethylene glycol dimethyl ether, chlorobenzene, cyclohexane or n-hexane.

[0037] (3) according to the dye and the intermediate compound obtained in step (2) is 1:1 molar ratio of dye added to the three-mouth bottle, while the same amount of catalyst in step two, at 80~120 ℃ for 4~12 h, get organic polymer shape phase change support material.

[0038] The compound containing epoxy, triazine or isocyanate structure in the above step (2) is preferably a polyether compound containing isocyanate group, wherein the isocyanate functional group is connected to the polyether by an ester bond.

[0039] The compound containing epoxy, triazine or isocyanate structure in the above step (2) is preferably a polyether compound containing triazine group, wherein the triazine functional group is connected to the polyether by an ether bond.

[0040] The compound containing epoxy, triazine or isocyanate structure in the above step (2) is preferably a polyether compound containing epoxy group, wherein the epoxy functional group is connected to the polyether by an ether bond.

[0041] In the above step (2), the catalyst is preferably dibutyltin dilaurate.

[0042] The beneficial effects of the present application are: the material is reacted with a compound containing a bifunctional group by polyethylene glycol to obtain a bifunctional intermediate compound; the dye molecules are mixed with a small molecule chain extender in a certain proportion to obtain a mixed chain extender, and then reacted according to the molar ratio of 1:1 between the mixed chain extender and the bifunctional intermediate compound, and finally the solvent is evaporated by vacuum drying to obtain a new phase change energy storage material, wherein the organic polymer shape phase change support material accounts for 97.8~98.3wt%; the mixed chain extender accounts for 1.7~2.2wt%, and the dye accounts for 0.6~46wt% in the mixed chain extender, i.e. the dye accounts for 0.01~1wt% of the total weight of the material. The phase change temperature of the new color flexible phase change heat storage material can be adjusted, the shape is stable, the flexibility is good, and the bright color can still be displayed under the condition of less dye addition, which can be used for the storage and release of heat energy in special environment. The material synthesis process is simple, convenient to apply, and has broad application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 Digital photo of purple phase change material prepared in examples 1-6.

[0044] Figure 2 Infrared spectrum of purple phase change material prepared in example 1.

[0045] Figure 3 Infrared spectrum of blue phase change material prepared in example 7.

[0046] Figure 4 Infrared spectrum of orange phase change material prepared in Example 8.

[0047] Figure 5 K / S value test chart of purple phase change material prepared in Example 1.

[0048] Figure 6 K / S value test chart of blue phase change material prepared in Example 7.

[0049] Figure 7 K / S value test chart of orange phase change material prepared in Example 8.

[0050] Figure 8 XRD curve of PEG10000 in Example 1.

[0051] Figure 9 XRD curve of color phase change materials prepared in Examples 1, 7 and 8.

[0052] Figure 10 DSC performance test of color phase change materials prepared in Examples 1, 7 and 8.

[0053] Figure 11 Tensile performance test of color phase change materials prepared in Examples 1, 7 and 8.

[0054] Figure 12 Set property test of color phase change materials prepared in Examples 1, 7 and 8 after heating at 30 ℃, 60 ℃ and 80 ℃ for 15 mins.

[0055] Figure 13 TG and DTG curves of color phase change materials prepared in Examples 1, 7 and 8. DETAILED DESCRIPTION

[0056] The following non-limiting examples can make those skilled in the art more fully understand the present application, but do not limit the present application in any way.

[0057] In the following examples, the test methods are conventional methods unless otherwise specified; and the reagents and materials are commercially available unless otherwise specified.

[0058] (1) Polyethylene glycol with an average molecular weight of 2000-20000 is vacuum dried at 80 ℃ for 48 h.

[0059] (2) polyethylene glycol and a compound containing a bifunctional group are dissolved in a solvent at a molar ratio of 1:2, and a catalyst dibutyl tin dilaurate is added, the mass ratio of the catalyst to polyethylene glycol is 1:60-130, the mass ratio of the solvent to polyethylene glycol is 7-14:1, the above raw materials are added to a three-necked flask under N2 environment, and stirring reaction is carried out at 40-60 ℃ for 4-10 h to obtain a solution of an intermediate compound containing a bifunctional group. The intermediate compound containing a bifunctional group is an intermediate compound containing an epoxy group, an intermediate compound containing a triazine group and an intermediate compound containing an isocyanate group. The solvent is one to three of tetrahydrofuran, dioxane, petroleum ether, acetone, butanone, chloroform, dichloromethane, carbon tetrachloride, carbon disulfide, DMF, DMSO, benzene, toluene, xylene, nitrobenzene, chlorobenzene, cyclohexane or n-hexane.

[0060] (3) a dye is added to the three-necked flask at a molar ratio of 1:1 of the dye to the intermediate compound containing a bifunctional group, an equal amount of the catalyst in step (2) is added, and reaction is carried out at 80-120 ℃ for 4-12 h to obtain a solution of a color flexible set phase change material.

[0061] (4) the solvent is evaporated, and vacuum drying is carried out to obtain a color flexible set phase change energy storage material.

[0062]

[0063] In the above table, in the intermediate compound containing an epoxy group, PEG refers to polyethylene glycol, and the following number is the molecular weight thereof, and the epoxy functional group is connected to the polyether through an ether bond; in the intermediate compound containing a triazine group, PEG refers to polyethylene glycol, and the following number is the molecular weight thereof, and the triazine functional group is connected to the polyether through an ether bond; in the intermediate compound containing an isocyanate group, PEG refers to polyethylene glycol, and the following number is the molecular weight thereof, and the isocyanate functional group is connected to the polyether through an ester bond.

[0064] The above compounds 4#-15# are prepared according to the method in step (2): polyethylene glycol and a compound containing a bifunctional group (a compound containing an epoxy, triazine or isocyanate structure) are dissolved in a solvent at a molar ratio of 1:2, and a catalyst is added, the above raw materials are added to a three-necked flask with stirring under N2 environment, and reaction is carried out at 40 ℃ for 8 h to obtain a solution of an intermediate compound; wherein the catalyst is dibutyl tin dilaurate, and the mass ratio of the catalyst to polyethylene glycol is 1:100; the solvent is toluene, and the mass ratio of the solvent to polyethylene glycol is 10:1.

[0065] The compound containing a bifunctional group is a compound containing an epoxy, triazine or isocyanate structure, the compound containing a bifunctional group is ethylene oxide when 4# and 5# compounds are prepared, the compound containing a bifunctional group is , the compound containing bifunctional groups for preparing the 8# and 9# compounds is , the compound containing bifunctional groups for preparing the 10# compound is , the compound containing bifunctional groups for preparing the 11# compound is , the compound containing bifunctional groups for preparing the 12# compound is , the compound containing bifunctional groups for preparing the 13# compound is , the compound containing bifunctional groups for preparing the 14# compound is the compound containing bifunctional groups for preparing the 6# compound is , the compound containing bifunctional groups for preparing the 15# compound is .

[0066] Example 1

[0067] (1) The polyethylene glycol with an average molecular weight of 10000 was vacuum dried at 80 ℃ for 48 h.

[0068] (2) The polyethylene glycol and were dissolved in toluene at a molar ratio of 1:2, and dibutyltin dilaurate was added to toluene, the mass ratio of dibutyltin dilaurate to polyethylene glycol was 1:100; the mass ratio of toluene to polyethylene glycol was 10:1; the above raw materials were added to a three-necked flask with stirring in an N2 environment, and reacted at 40 ℃ for 8 h to obtain a toluene solution containing a bifunctional intermediate compound; the structure is as follows: .

[0069] (3) 2.6 mg of dye 1# was mixed with 89.1 mg of small molecule chain extender 16#, the dye accounted for 2.8 wt%, and the small molecule chain extender accounted for 97.2 wt%, and the obtained mixed chain extender and 5.17 g of intermediate compound 9# containing bifunctional groups (the molar ratio was about 1:1) were added to a three-necked flask for reaction, and the same amount of catalyst as in step (2) was added, and the reaction was carried out at 80 ℃ in an N2 environment for 10 h to obtain a color flexible shape memory phase change energy storage material solution.

[0070] (4) The solvent was evaporated and vacuum dried at 80 ℃ for 10-24 h to obtain a color flexible shape memory phase change energy storage material.

[0071] Example 2

[0072] The amount of dye added was adjusted to account for 1% of the total mass, and the corresponding color flexible shape memory phase change energy storage material was obtained, and other conditions were the same as in Example 1.

[0073] Example 3

[0074] Adjust the dye addition amount, so that it accounts for 2% of the total mass, to obtain the corresponding color flexible set phase change energy storage material, other conditions are consistent with example 1.

[0075] Example 4

[0076] Adjust the dye addition amount, so that it accounts for 3% of the total mass, to obtain the corresponding color flexible set phase change energy storage material, other conditions are consistent with example 1.

[0077] Example 5

[0078] Adjust the dye addition amount, so that it accounts for 0.01% of the total mass, to obtain the corresponding color flexible set phase change energy storage material, other conditions are consistent with example 1.

[0079] Example 6

[0080] Adjust the dye addition amount, so that it accounts for 0.1% of the total mass, to obtain the corresponding color flexible set phase change energy storage material, other conditions are consistent with example 1.

[0081] By performing a dye concentration gradient test to determine the appropriate amount of dye to add, the dye addition amount during the gradient test was 0.01% (Example 5), 0.05% (Example 1), 0.1% (Example 6), 1% (Example 2), 2% (Example 3), 3% (Example 4), and the final results are shown in Figure 1 : When the dye addition amount is higher than 1%, as the dye addition amount increases, the color of the obtained material will gradually deepen, gradually deviating from the original color of the dye. When the dye addition amount is 0.05%, the coloring is uniform, and the original color of the dye can be displayed, and the color is bright. Based on this concentration, purple, orange, and blue phase change materials were prepared.

[0082] Example 7

[0083] Use dye 2# instead of dye 1# to react, to obtain a blue flexible set phase change energy storage material, other conditions are consistent with the above example 1.

[0084] Example 8

[0085] Use dye 3# instead of dye 1# to react, to obtain an orange flexible set phase change energy storage material, other conditions are consistent with the above example 1.

[0086] Figures 2 to 4 The infrared spectra of the phase change materials in examples 1, 7 and 8 are shown respectively, it can be seen that: the infrared of the obtained color flexible set phase change energy storage material disappears compared with the infrared of the dye and the phase change component polyethylene glycol, and a carbonyl stretching vibration peak (1716 cm-1 ) and a stretching vibration peak (1532 cm -1 ), which proves the formation of amide bond, means that the dye is added to the polymer skeleton of the organic phase change support material by chemical bonding.

[0087] Figures 5 to 7 The K / S value test of the phase change material in Example 1, Example 7 and Example 8 is shown respectively, it can be seen that the prepared material has bright color, and the K / S value is 9.8, 8.9, 10.2 respectively, and the color is bright.

[0088] Figure 8 The XRD curve of PEG10000 in Example 1 is shown. Figure 9 The XRD curve of the color phase change material prepared in Example 1, 7 and 8 is shown; it can be seen from the XRD characterization of the material that the obtained color flexible shape phase change energy storage material has the same crystallization peak as the polyethylene glycol characteristic peak, and has crystallization characteristics.

[0089] Figure 10 The DSC performance test of the color phase change material prepared in Example 1, 7 and 8 is shown; it can be seen from the DSC curve of the color flexible shape phase change energy storage material that the phase change enthalpy value of the obtained phase change material is high, and the melting enthalpy value and the crystallization enthalpy value are both about 98 J / g, which proves that the material has good phase change heat storage characteristics.

[0090] Figure 11 The tensile property test of the color phase change material prepared in Example 1, 7 and 8 is shown; the tensile breaking strength is about 6.0 MPa, and the strain rate is about 550%, which proves that it has excellent flexibility.

[0091] Figure 12 The shape performance test of the color phase change material prepared in Example 1, 7 and 8 after heating at 30 °C, 60 °C and 80 °C for 15 mins is shown. It is shown in the figure that when the temperature is heated to 60 °C, the polyethylene glycol has begun to melt, and the obtained color flexible shape phase change energy storage material still remains solid state without flowing even when the temperature rises to 80 °C, which indicates that the material has excellent shape phase change characteristics.

[0092] Figure 13 The TG and DTG curves of the color phase change material prepared in Example 1, 7 and 8 are shown, it can be seen from the TG and DTG curves that the color flexible phase change material has two decomposition steps, the first step is at about 230 °C, which is the decomposition temperature of polyurethane, and the second step is above 400 °C, which is the decomposition temperature of polyether. Therefore, the prepared shape phase change material has good thermal stability, and the decomposition temperature is much higher than the phase change temperature, which can ensure that it does not decompose during work, and has wide application temperature range.

[0093] Examples 9-20

[0094] Using 4-8# and 10-15# compounds instead of 9# intermediate in example 1, react with dye 1#, get the corresponding color flexible set phase change energy storage materials, other conditions are consistent with example 1.

[0095] Examples 21-32

[0096] Using 4-8# and 10-15# compounds instead of 9# intermediate in example 7, react with dye 2#, get the corresponding color flexible set phase change energy storage materials, other conditions are consistent with example 7.

[0097] Examples 33-44

[0098] Using 4-8# and 10-15# compounds instead of 9# intermediate in example 8, react with dye 3#, get the corresponding color flexible set phase change energy storage materials, other conditions are consistent with example 8.

[0099] Examples 45-52

[0100] Small molecule chain extender: N, N dihydroxyethyl aniline, triethylamine, glycerol, trimethylol ethane, 1, 4-butanediol, trimethylol propane, dimethylene phenyl diol, 1, 4 cyclohexane glycol instead of 16# small molecule chain extender in example 1, react with dye 1#, get the corresponding color flexible set phase change energy storage materials, other conditions are consistent with example 1.

Claims

1. A colored flexible shaped phase change energy storage material, characterized in that: The colored flexible shaped phase change energy storage material is composed of 95-99% organic polymer shaped phase change support material and 1-5% mixed chain extender by weight; wherein the mixed chain extender is obtained by mixing small molecule chain extender and dye molecules, and the mass percentage of dye molecules in the mixed chain extender is 0.6-46 wt%. The small molecule chain extender is N,N-dihydroxyethylaniline, triethylamine, glycerol, trimethylolethane, 1,4-butanediol, trimethylolpropane, dimethylene phenyl glycol, or 1,4-cyclohexanediol. The general structural formula of the organic polymer-based shape-stabilized phase change support material is as follows: ； The structure of the connecting base A is as follows: , or ; D= , , , , or ; V1 is Cl, F, NHCH3 or NHC4H9; V2 is H or CH3; m is an integer from 100 to 10000; n is an integer from 10 to 1000.

2. The colored flexible shaped phase change energy storage material according to claim 1, characterized in that: The dye molecules include anthraquinone dyes or azo dyes; The general structural formula of the anthraquinone dyes is as follows: ； Among them, R1 and R2 have the same structure and are selected from OH, NH2, , , , Any one of them; The azo dyes include heterocyclic azo dyes and non-heterocyclic azo dyes; wherein the general structural formula of non-heterocyclic azo dyes is as follows: ； Wherein, T1 is one of NO2 and SCO2H3, T2 and T3 are any one of H, Cl, Br, NO2 and CN respectively, Y1 and Y2 are any one of H, CH3, OCH3, NHCOCH3, OCH3(OC2H5) and OC7H5(OCH3) respectively, and M1 and M2 are any one of CH2CH2OH and CH2OH respectively; The general structural formula of heterocyclic azo dyes is as follows: ； Where X can be any of the following structures: L1 and L2 are any one of H, CH3, OCH3, NHCOCH3, OCH3(OC2H5), and OC7H5(OCH3), respectively, and Q1 and Q2 are any one of CH2CH2OH and CH2OH, respectively.

3. The method for preparing the colored flexible shaped phase change energy storage material according to claim 1 or 2, characterized in that: Includes the following steps: (1) Vacuum dry polyethylene glycol with an average molecular weight of 2000~20000; (2) Polyethylene glycol and a compound containing a bifunctional group are dissolved in a solvent at a molar ratio of 1:2, and a catalyst is added. The mass ratio of the catalyst to polyethylene glycol is 1:60~130. The reaction is carried out in a N2 environment at 40~60 °C for 4~10 h with stirring to obtain a solution of an intermediate compound containing a bifunctional group. The compound containing a bifunctional group is a compound containing an epoxy, triazine or isocyanate structure. The mass ratio of the solvent to polyethylene glycol is 7~14:

1. (3) The dye and small molecule chain extender are physically mixed in proportion to obtain a mixed chain extender, wherein the dye accounts for 0.6~46wt%; the mixed chain extender is reacted with an intermediate compound containing a bifunctional group, and a catalyst of the same amount as in step (2) is added at the same time. The reaction is carried out in N2 environment at 80~120 ℃ for 4~12 h to obtain a colored flexible shaped phase change energy storage material solution. (4) Evaporate the solvent and vacuum dry to obtain the colored flexible shaped phase change energy storage material.

4. The method for preparing the colored flexible shaped phase change energy storage material according to claim 3, characterized in that: The structure of the intermediate compound containing bifunctional groups is as follows: 。 5. The method for preparing the colored flexible shaped phase change energy storage material according to claim 3, characterized in that: The molar ratio of the mixed chain extender to the intermediate compound containing a bifunctional group is 1:1, wherein the molar amount of the mixed chain extender is the molar amount of dihydroxy or diamino compounds.

6. The method for preparing the colored flexible shaped phase change energy storage material according to claim 3, characterized in that: The solvent is one to three of the following: tetrahydrofuran, dioxane, acetone, chloroform, dichloromethane, carbon tetrachloride, carbon disulfide, DMF, DMSO, benzene, toluene, xylene, polyethylene glycol dimethyl ether, chlorobenzene, cyclohexane, or n-hexane.

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