Reversible thermochromic energy storage floor and preparation method thereof

Abstract

The invention discloses a reversible thermochromic energy storage floor and a preparation method thereof, and belongs to the technical field of building material processing, and the preparation method comprises the following steps: step 1, preparing a reversible thermochromic dye: ultrasonically mixing fatty alcohol, alkane, a leuco agent and a color developing agent according to a certain mass ratio to obtain the reversible thermochromic dye; wherein the fatty alcohol and the alkane form a composite solvent; secondly, the oak wood is pretreated, specifically, the oak wood is sequentially placed in a sodium chlorite solution and an ethanol solution to be soaked, and the treated oak wood is obtained; and thirdly, the treated oak wood is sequentially placed in water and the reversible thermochromic dye to be subjected to vacuum pumping treatment, standing is conducted, the steps are repeated 2-5 times, and the reversible thermochromic energy storage floor is obtained. The floor prepared by the method has the characteristics of high latent heat value, proper color change temperature, excellent mechanical property and environmental friendliness.

Description

Technical Field

[0001] This invention belongs to the field of building materials processing technology, specifically relating to a reversible thermochromic energy storage floor and its preparation method. Background Technology

[0002] Wood, as a natural, renewable, and environmentally friendly biomass material, has wide applications in the construction and interior decoration fields. With the development of smart materials technology, combining wood with functional materials to develop new smart wood products has become a research trend in this field. Among them, reversible thermochromic materials possess dual functions of color change and energy storage, capable of reversibly altering their color according to changes in ambient temperature. Introducing them into a wood matrix can create smart color-changing wood, which not only enhances the visual appeal and interactivity of products but also opens up possibilities for their application in cutting-edge fields such as information encryption and intelligent temperature regulation. For example, combining transparent wood with reversible thermochromic dyes to create smart windows can adjust sunlight exposure according to temperature changes, thereby regulating indoor temperature; alternatively, reversible thermochromic dyes can be combined with films or paints and then coated or sprayed onto the wood surface, causing the wood color to change reversibly with temperature.

[0003] However, current research and practice on reversible thermochromic wood have significant limitations. First, most studies focus only on the reversible color change, resulting in materials with generally low latent heat values, mostly below 30 J / g, limiting their heat storage capacity. Second, existing technologies struggle to achieve uniform color development. Furthermore, regarding substrate selection, research often focuses on the high-value utilization of fast-growing timber, but the inherently poor mechanical properties of fast-growing timber limit its application in applications requiring high mechanical strength, such as flooring. While current technologies impart color-changing functionality to wood, they often neglect the protection and improvement of its overall performance, particularly its mechanical properties.

[0004] Therefore, it is of great significance to develop a reversible thermochromic energy storage floor that combines high latent heat value, suitable phase change temperature, excellent mechanical properties and good stability. Summary of the Invention

[0005] To address the shortcomings of existing reversible thermochromic wood, such as excessively high phase change temperature and poor latent heat capacity, this invention provides a reversible thermochromic energy storage floor and its preparation method. The floor prepared by this method has the characteristics of high latent heat value, suitable color change temperature, excellent mechanical properties, and environmental friendliness.

[0006] This invention is achieved through the following technical solution:

[0007] A method for preparing a reversible thermochromic energy storage floor specifically includes the following steps:

[0008] Step 1: Preparation of reversible thermochromic dyes:

[0009] A reversible thermochromic dye is obtained by ultrasonically mixing fatty alcohol, alkane, leuco agent and chromogenic agent in a certain mass ratio; wherein the fatty alcohol and alkane constitute a composite solvent.

[0010] Step 2: Pre-treatment of oak:

[0011] The oak wood was soaked in sodium chlorite solution and ethanol solution in turn to obtain the treated oak wood.

[0012] Step 3: Place the treated oak wood in water and reversible thermochromic dye in sequence for vacuum treatment, let it stand, and repeat the above steps 2-5 times to obtain the reversible thermochromic energy storage floor.

[0013] Further, in step one, the fatty alcohol is selected from one of dodecanol, tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, or eicosyl alcohol; the alkane is selected from one of tetradecane, hexadecane, octadecane, eicosyl, or docosyl; the leucocyanide is 2-dibenzylamino-6-diethylaminofluorane; and the color developer is 4-benzyloxy-4'-hydroxydiphenyl sulfone.

[0014] Further, in step one, the mixing includes: first ultrasonically mixing the fatty alcohol, the alkane and the leucoant at 50-120°C for 5-60 minutes, then adding the color developer and continuing to mix at 50-90°C for 5-120 minutes.

[0015] Further, in step one, the mass ratio of fatty alcohol to alkane in the composite solvent is (3:2) to (9:1).

[0016] The mass ratio of the luminescent agent, the color developer, and the composite solvent is 1:(0.5~2):(20~140).

[0017] Furthermore, in step two, the mass fraction of the sodium chlorite solution is 1%-10%.

[0018] Further, in step two, the oak is soaked in the sodium chlorite solution at 70-80°C for 0.5-2 hours; and soaked in the ethanol solution for 5-120 minutes.

[0019] Furthermore, in step two, the treated oak is stored in an ethanol solution for later use.

[0020] Furthermore, in step three, the vacuum degree of the vacuuming process is -0.01 MPa to -0.1 MPa, and the time for each vacuuming process is 7-10 minutes.

[0021] Furthermore, in step three, the "resting" refers to letting the pressure return to normal for 1-10 minutes.

[0022] Furthermore, in step three, the mass ratio of the treated oak to the reversible thermochromic dye is 1:0.05-1:100.

[0023] On the other hand, the present invention also provides a reversible thermochromic energy storage floor, which is prepared by the above-described preparation method.

[0024] The principle of this invention is as follows:

[0025] Regarding substrate treatment, addressing the impregnation challenge caused by the high density of oak, this invention employs a mild sodium chlorite solution for selective lignin removal. Oak, as a non-fast-growing hardwood, possesses high density, corrosion resistance, high dimensional stability, and excellent mechanical properties, making it ideal for direct use as indoor flooring. However, its high density makes it difficult for dyes to directly impregnate the interior of oak. Oak is primarily composed of cellulose, hemicellulose, and lignin, with lignin acting as a binder filling the cellulose skeleton. By controlling the treatment time and temperature, only a certain thickness of lignin on the surface of the oak can be removed, providing ample impregnation space for the dye while completely preserving the internal lignin and cellulose skeleton, ensuring excellent mechanical strength of the finished product. Compared to other lignin removal methods such as sulfate and hydrogen peroxide methods, the sodium chlorite method does not require high temperature and pressure conditions, causes less damage to hemicellulose, and removes lignin more thoroughly and gently. Figure 12 As shown in (b), after the lignin is removed from oak, the lignin is eliminated, leaving a cellulose skeleton (containing cellulose and hemicellulose), which appears white. This is because, of the three major elements of wood, only lignin has color; as Figure 12 As shown in (c), when the cellulose framework is soaked in alcohol, the refractive index error between the two is less than 0.01, the light transmittance is greatly improved, which in turn causes the lignin-free layer to become transparent, revealing the pattern of the middle layer and ensuring the aesthetics in the colorless state.

[0026] In terms of dye formulation, in order to improve the latent heat value of wood, this invention uses ultrasonic blending to make hexadecane and dodecanol uniformly mixed. While ensuring high latent heat capacity (up to 40 J / g or more), it effectively reduces the phase change temperature of the composite solvent. Finally, leuco and chromogenic agents are added, and a high latent heat reversible thermochromic dye is successfully prepared.

[0027] In terms of process integration, the preparation of similar reversible thermochromic woods often employs methods such as surface spraying or impregnation. However, surface spraying typically results in a low latent heat value (up to approximately 30 J / g) and only a thin layer of material covering the surface, leading to poor stability. While impregnation allows for internal dye penetration, it often degrades the mechanical properties of fast-growing timber, making it difficult to meet practical application requirements. Improving mechanical properties necessitates additional vacuum pressure impregnation with resin, making the process quite complex. In contrast, this invention utilizes a subsequent vacuum impregnation process to fully penetrate the oak wood and fill the cellulose skeleton formed after lignin removal, thereby achieving a transparent wood effect. This allows the internal morphology of the oak wood to be fully revealed, ensuring its aesthetic appeal even in its colorless state.

[0028] Compared with the prior art, the advantages of the present invention are as follows:

[0029] 1. The reversible thermochromic energy storage floor prepared by the method of this invention has the characteristic of high latent heat, with an endothermic enthalpy change value ΔH. f and the exothermic enthalpy change ΔH c The latent heat capacity is 41.50 J / g and 40.98 J / g respectively. This represents a 534.37% increase compared to ordinary oak. This energy storage floor can absorb heat and lower the indoor temperature when the ambient temperature is high, improving the recycling of renewable energy. Furthermore, the energy storage floor itself can act as a temperature-regulating floor, raising the floor temperature and solving the problem of generally cool floor temperatures. When the indoor ambient temperature is low, the energy storage floor releases heat to raise the indoor temperature.

[0030] 2. The energy storage floor described in this invention exhibits excellent thermal stability, maintaining a latent heat capacity of 34.49 J / g after 50 thermal cycles, exceeding that of most reversible thermochromic woods that have not undergone thermal cycling; color difference ΔE * It has a value of 3.60, maintaining a noticeable color change;

[0031] 3. The color change response temperature range of the energy storage floor described in this invention is 19.45~27.65℃, which is suitable and has broad prospects for practical application. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0033] Figure 1The images show actual photographs of the reversible thermochromic energy storage floor prepared in Example 1 in a colorless state (a) and a colored state (b), and actual photographs of the reversible thermochromic energy storage floor after 50 thermal cycles in a colorless state (c) and a colored state (d).

[0034] Figure 2 The color difference (ΔE) of the reversible thermochromic energy storage floor prepared in Example 1 after 50 thermal cycles. * ) Change curve graph;

[0035] Figure 3 The following are DSC curves of the reversible thermochromic energy storage floor (a) prepared in Example 1, the energy storage floor after 50 thermal cycles (b), the original oak (c), and the reversible thermochromic dye (d).

[0036] Figure 4 XPS spectra of raw oak, lignin-free oak, reversible thermochromic energy storage floor, and energy storage floor after 50 thermal cycles.

[0037] Figure 5 A photograph of the sample prepared in Comparative Example 1 in the color development state;

[0038] Figure 6 A photograph of the sample prepared in Comparative Example 1 in its colorless state;

[0039] Figure 7 This is a photograph of the sample prepared in Comparative Example 2 in the color development state.

[0040] Figure 8 This is a photograph of the sample prepared in Comparative Example 2 in its colorless state.

[0041] Figure 9 This is a photograph of the sample prepared in Comparative Example 3 in the color development state.

[0042] Figure 10 This is a photograph of the sample prepared in Comparative Example 3 in its colorless state.

[0043] Figure 11 Photographs of the energy storage floor prepared in Comparative Example 4 in colorless state (a) and colored state (b);

[0044] Figure 12 Photos of untreated oak (a), lignin-free oak (b), and lignin-free oak soaked in alcohol (c). Detailed Implementation

[0045] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0046] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0047] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0048] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0049] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0050] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0051] Unless otherwise specified, all raw materials used in the following embodiments and comparative examples of this invention are commercially available products, and the source of these commercially available products does not affect the technical effect of this invention.

[0052] Unless otherwise specified, the atmospheric pressure involved in this invention is 101.325 kPa, and the room temperature involved is 25 ± 5 °C.

[0053] Example 1

[0054] This embodiment provides a method for preparing reversibly thermochromic oak, the steps of which are as follows:

[0055] Step 1: Pour 40g of dodecanol and 10g of hexadecane into a beaker and sonicate for 10 minutes. After that, add 0.5g of 2-dibenzylamino-6-diethylaminofluorane and stir at 90℃ for 0.5 hours. Then add 0.5g of 4-benzyloxy-4'-hydroxydiphenyl sulfone and continue stirring for 2 hours to obtain a reversible thermochromic dye.

[0056] Step 2: Place 60mm×60mm×4mm oak wood into a 5wt% sodium chlorite aqueous solution and soak at 80℃ for 2 hours. Then soak in 200ml of alcohol for 1 hour. Finally, store in alcohol for later use to obtain lignin-free oak wood.

[0057] Step 3: Place the removed lignin-free oak in distilled water and vacuum it to -0.08 MPa for 10 minutes. Then, remove it and place it in a petri dish with 20g of reversible thermochromic dye. Vacuum it to -0.08 MPa for 7 minutes, then allow it to stand at normal pressure for 7 minutes. Repeat the above steps 3 times. Wash the impregnated oak with alcohol and finally air dry it at room temperature to obtain reversible thermochromic oak.

[0058] The reversible thermochromic oak was subjected to multiple thermal cycling treatments. The specific steps were as follows: The prepared oak was individually placed into 7 cm × 10 cm sealed plastic bags and sealed. A vacuum drying oven was set to 60℃ to simulate a high-temperature environment, and a refrigerator was set to -18℃ to simulate a low-temperature environment. Each environment was used for 20 minutes, and data was recorded using a colorimeter during the process. One cycle of heating and cooling constituted one cycle, and a total of 50 cycles were performed.

[0059] The test results of the sample in Example 1 are analyzed as follows:

[0060] Figure 1 The images show the colorless (a) and colored (b) states of the reversible thermochromic oak obtained in Example 1. When the ambient temperature is increased (≥19.45℃), the reversible thermochromic oak displays the color and pattern of the intermediate layer, such as... Figure 1 As shown in (a); when the ambient temperature is lowered, the reversible thermochromic dye gradually solidifies within the oak, causing the oak to turn green, as shown in (a). Figure 1 As shown in (b); when the temperature rises again, the reversible thermochromic oak repeats the above-mentioned color change process. During this process, the colorless ΔE... * With a value of 11.49, the color change is clearly perceptible, demonstrating excellent color-changing effects.

[0061] After subjecting the reversible thermochromic oak obtained above to 50 thermal cycles, the following results were obtained: Figure 1 The images show actual specimens of colorless (c) and colored (d) states of reversible thermochromic oak; as can be seen from the images, after 50 thermal cycles, Figure 1(c) and Figure 1 (a) showed no significant change, indicating that thermal cycling had no significant effect on the colorless state; Figure 1 (d) compared with Figure 1 (b) shows obvious color fading, which is consistent with Figure 2 The color difference curves corroborate each other. Although the oak in the colored state showed obvious fading after 50 thermal cycles, it still exhibited a uniform green color compared to the colorless state, demonstrating good thermal stability.

[0062] Figure 2 The graph shows the color difference change curve of the reversible thermochromic oak obtained in Example 1 after 50 thermal cycles. It can be seen from the graph that before 20 thermal cycles, ΔE... * Relatively stable, with good cellulose skeleton coating. Color difference ΔE between 20 and 30 cycles. * The significant changes are due to several factors: thermal cycling weakens the coating capacity of the cellulose skeleton, leading to increased solvent leakage; and before 20 cycles, the leaked solvent does not affect the colorimetric reactions of the leucocyanide and developer. After 20 cycles, the remaining solvent cannot provide a sufficient environment for the leucocyanide lactone ring to close, resulting in a change in ΔE. * Significant changes occurred. After 30 thermal cycles, ΔE * The fluctuations gradually decreased.

[0063] As Figure 3 As shown in (a), the ΔH of reversible thermochromic oak f and ΔH c The values ​​are 41.50 J / g and 40.98 J / g, respectively. Figure 3 As shown in (d), the ΔH of reversible thermochromic dyes f and ΔH c The values ​​are 203.30 J / g and 199.80 J / g, respectively. Therefore, the ΔH value of reversible thermochromic oak compared to reversible thermochromic dyes can be obtained. f and ΔH c The percentages decreased by 79.59% and 79.49% respectively; this is due to the reduced proportion of reversible thermochromic dyes in reversible thermochromic oak. The initial endothermic and exothermic temperatures were 19.45℃ and 21.42℃, respectively, representing increases of 6.68℃ and 2.4℃ compared to the reversible thermochromic dye. This indicates that the difference in thermal conductivity of oak has a greater impact on the endothermic process and a smaller impact on the exothermic temperature, because oak also competes with the reversible thermochromic dye for heat during the heating process. For oak, such as... Figure 3 As shown in (c), the Cp of the original oak is 1.128 J / (g‧K), and the Δt is 5.37. Therefore, the ΔH of the original oak can be derived. c The ΔH value of reversibly thermochromic oak is 6.46 J / g, compared to that of original oak.c It has increased by 534.37%, possessing superior latent heat capacity.

[0064] Depend on Figure 3 As shown in (b), after 50 thermal cycles, the ΔH of the reversible thermochromic oak is... f and ΔH c The latent heat values ​​were 34.49 J / g and 34.21 J / g, respectively, which were 16.89% and 16.52% lower than those of the uncirculated reversible thermochromic oak. The decrease in latent heat value was mainly due to solvent leakage during the circulation process, which also indirectly proves that the cellulose and hemicellulose skeleton of oak has good coating ability. After 50 thermal cycles, the initial endothermic and exothermic temperatures of the reversible thermochromic oak were 17.75℃ and 29.17℃, respectively, a decrease of 1.7℃ and an increase of 0.07℃ compared to the original oak before 50 thermal cycles. This is because solvent leakage leads to a decrease in the solvent content of the reversible thermochromic oak, reducing the energy required for phase change. It may also be due to the oak framework's adsorption of leuco and chromogenic agents, resulting in a disproportionate leakage of these agents compared to the solvent leakage. This reduces the solvent content and increases the proportion of leuco and chromogenic agents, thus lowering the thermal conductivity of the reversible thermochromic oak. However, after 50 thermal cycles, the ΔH of the reversible thermochromic oak compared to the original oak... c The fact that it continues to improve indicates that it still possesses superior latent heat capacity.

[0065] Figure 4 The XPS spectra of the oak described in Example 1, the lignin-free oak, the reversibly thermochromic oak, and the reversibly thermochromic oak after 50 thermal cycles are shown. Here, 50 cycles refers to the reversibly thermochromic oak after 50 thermal cycles, and energy storage oak refers to the reversibly thermochromic oak.

[0066] like Figure 4 As shown, the carbon-to-oxygen ratio (C / O ratio) of oak is 4.29, that of lignin-free oak is 2.55, and that of reversibly thermochromic oak is also 2.55. After 50 thermal cycles, the C / O ratio of reversibly thermochromic oak is 2.91. The C / O ratio of lignin-free oak decreased by 1.74 compared to oak, indicating that lignin was successfully removed, more cellulose was exposed on the surface, the oxygen content increased, and the C / O ratio decreased. After impregnation with the reversibly thermochromic dye, the C / O ratio of the lignin-free group did not change. This is because the cellulose skeleton is supported during impregnation, leading to a decrease in the C / O ratio, but the presence of the reversibly thermochromic dye compensates for this loss. It may also be because most of the reversibly thermochromic dye penetrates into the oak, leaving relatively little residue on the surface. After 50 thermal cycles, the carbon-oxygen ratio of reversibly thermochromic oak increased by 0.93 compared to that of reversibly thermochromic oak. This is because oxidation occurred on the wood surface during the cycling process, resulting in an increase in oxygen-containing functional groups.

[0067] Comparative Example 1

[0068] Compared with Example 1, the only difference is that in the first step, 0.5g of 4-benzyloxy-4'-hydroxydiphenyl sulfone was replaced with 0.2g of 4-benzyloxy-4'-hydroxydiphenyl sulfone.

[0069] Figure 5 This is a reversible thermochromic oak in a color-developing state, with uneven color distribution, showing distinct dark green and light green areas. Figure 6 This refers to the colorless oak exhibiting reversible thermochromic chromic effects, showing no obvious green residue and demonstrating excellent color-changing properties. The ΔE value at this stage is... * The value was 10.96, which was 0.53 lower than that of Example 1.

[0070] This is because the reduced amount of 4-benzyloxy-4'-hydroxydiphenyl sulfone resulted in uneven distribution of 4-benzyloxy-4'-hydroxydiphenyl sulfone after impregnation into the oak, leading to poor color uniformity in the oak. However, this also ensured that the composite solvent had sufficient solubility to dissolve 4-benzyloxy-4'-hydroxydiphenyl sulfone and 2-dibenzylamino-6-diethylaminofluorane in the colorless state, thus resulting in no color residue and a good colorless effect.

[0071] Comparative Example 2

[0072] Compared with Example 1, the only difference is that in the first step, 40g of dodecanol and 10g of hexadecane are replaced with 64g of dodecanol and 16g of hexadecane.

[0073] like Figure 7 and Figure 8 The images show the color-developing and colorless effects of reversibly thermochromic oak. As can be seen from the images, the color effect is uneven in both the developed and colorless states.

[0074] On the one hand, the increased amount of composite solvent leads to uneven distribution of 2-dibenzylamino-6-diethylaminofluorane and 4-benzyloxy-4'-hydroxydiphenyl sulfone in the pigment, resulting in poor color uniformity of oak. At this point, ΔE * The value was 8.24, a decrease of 3.25 compared to Example 1. The total amount of composite solvent increased, the color became lighter, and the poor uniformity led to a decrease in ΔE. * The color decreases rapidly. On the other hand, it is because 2-dibenzylamino-6-diethylaminofluorane and 4-benzyloxy-4'-hydroxydiphenyl sulfone are difficult to distribute freely after entering the wood in areas where dyes are abundant. This causes the local concentration of 2-dibenzylamino-6-diethylaminofluorane and 4-benzyloxy-4'-hydroxydiphenyl sulfone to exceed the solubility of the composite solvent, resulting in precipitation. Consequently, the color darkens in some areas even when the dye is colorless.

[0075] Comparative Example 3

[0076] Compared with Example 1, the only difference is that in the first step, 40g of dodecanol and 10g of hexadecane are replaced with 2.5g of dodecanol and 47.5g of hexadecane.

[0077] Figure 9 and Figure 10 The images show the color-developed and colorless diagrams of reversibly thermochromic oak. As can be seen from the images, in the color-developed state, there is a slight difference in color depth between the lower left and lower right corners. In the colorless state, the center is white, while other areas are darker. In this case, ΔE... * The value was 10.74, a decrease of 1.02 compared to Example 1. Considering the overall visual effect, Example 1 showed a better color rendering and colorless state.

[0078] Comparative Example 4

[0079] Compared with Example 1, the only difference is that the second step is omitted.

[0080] like Figure 11 As shown in (a), the morphology of untreated oak is illustrated. Figure 11 As shown in (b), by omitting the lignin removal step and directly impregnating the surface with dye, only the less dense areas were dyed, resulting in a green color; the vast majority remained undyed. Overall, the color was very uneven and unattractive; compared to Example 1... Figure 1 The comparison between (a) and (b) confirms the difficulty of impregnating oak and the indispensability of lignin removal.

[0081] Comparative Example 5

[0082] Compared to Example 1, the only difference is that the sodium chlorite aqueous solution was replaced with an equal amount of choline chloride solution and sodium sulfite solution. Different lignin removal methods affect the reversible thermochromic oak ΔE. * The impacts are shown in Table 1;

[0083] Table 1. Effects of different lignin removal methods on the ΔE of reversibly thermochromic oak. * Impact

[0084] choline chloride Sodium sulfite Example 1 (Sodium chlorite) NaOH <![CDATA[ΔE * ]]> 8.86 9.56 11.49 5.35

[0085] As shown in Table 1, ΔE in Example 1 * The efficiency of lignin removal was improved by 2.63% compared to the choline chloride method, 1.93% compared to the sodium sulfite method, and 6.14% compared to the NaOH method. This is because, under the same time and temperature conditions, sodium chlorite has a higher lignin removal efficiency, resulting in greater dye penetration and better color change. ΔE * Larger. The above data fully demonstrates the superiority of sodium chlorite in removing lignin.

[0086] Comparative Example 6

[0087] Compared with Example 1, the only difference is that vacuum impregnation was replaced by surface spraying and impregnation methods. The latent heat values ​​of reversible thermochromic oak under different preparation methods are shown in Table 2.

[0088] Table 2. Latent heat values ​​of reversibly thermochromic oak under different preparation methods

[0089] Surface spraying method Room temperature impregnation method Example 1 Example 1 (after 50 thermal cycles) <![CDATA[ΔH f ]]> 31.42 J / g 29.43 J / g 41.50 J / g 34.49 J / g <![CDATA[ΔH c ]]> 30.81 J / g 27.57 J / g 40.98 J / g 34.21 J / g

[0090] As shown in Table 2, the ΔH of the surface spraying method f The thermal conductivity decreased by 10.08 J / g compared to Example 1, and still decreased by 3.07 J / g compared to Example 1 after 50 thermal cycles. The room temperature impregnation method resulted in reductions of 12.07 J / g and 5.06 J / g, respectively. In summary, the reversible thermochromic oak prepared using the method of this invention exhibits excellent heat storage capacity and good stability, exceeding most similar studies.

[0091] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0092] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0093] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a reversible thermochromic energy storage floor, characterized in that, Specifically, the steps include the following: Step 1: Preparation of reversible thermochromic dyes: A reversible thermochromic dye is obtained by ultrasonically mixing fatty alcohol, alkane, leuco agent and chromogenic agent in a certain mass ratio; wherein the fatty alcohol and alkane constitute a composite solvent. Step 2: Pre-treatment of oak: The oak wood was soaked in sodium chlorite solution and ethanol solution in turn to obtain the treated oak wood. Step 3: Place the treated oak wood in water and reversible thermochromic dye in sequence for vacuum treatment, let it stand, and repeat the above steps 2-5 times to obtain the reversible thermochromic energy storage floor.

2. The method for preparing a reversible thermochromic energy storage floor as described in claim 1, characterized in that, In step one, the fatty alcohol is selected from one of dodecanol, tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, or eicosyl alcohol; the alkane is selected from one of tetradecane, hexadecane, octadecane, eicosyl, or docosyl; the leucocyanide is 2-dibenzylamino-6-diethylaminofluorane; and the color developer is 4-benzyloxy-4'-hydroxydiphenyl sulfone.

3. The method for preparing a reversible thermochromic energy storage floor as described in claim 1, characterized in that, In step one, the mixing includes: first, ultrasonically mixing the fatty alcohol, the alkane and the leucoant at 50-120°C for 5-60 minutes, then adding the color developer and continuing to mix at 50-90°C for 5-120 minutes.

4. The method for preparing a reversible thermochromic energy storage floor as described in claim 1, characterized in that, In step one, the mass ratio of fatty alcohol to alkane in the composite solvent is (3:2) to (9:1). The mass ratio of the luminescent agent, the color developer, and the composite solvent is 1:(0.5~2):(20~140).

5. The method for preparing a reversible thermochromic energy storage floor as described in claim 1, characterized in that, In step two, the sodium chlorite solution has a mass fraction of 1%-10%.

6. The method for preparing a reversible thermochromic energy storage floor as described in claim 1, characterized in that, In step two, the oak is soaked in the sodium chlorite solution at 70-80°C for 0.5-2 hours; and soaked in the ethanol solution for 5-120 minutes. The treated oak was stored in an ethanol solution for later use.

7. The method for preparing a reversible thermochromic energy storage floor as described in claim 1, characterized in that, In step three, the vacuum level of the vacuuming process is -0.01 MPa to -0.1 MPa, and the time for each vacuuming process is 7-10 minutes.

8. The method for preparing a reversible thermochromic energy storage floor as described in claim 1, characterized in that, In step three, the "resting" refers to letting the pressure return to normal for 1-10 minutes.

9. The method for preparing a reversible thermochromic energy storage floor as described in claim 1, characterized in that, In step three, the mass ratio of the treated oak to the reversible thermochromic dye is 1:0.05-1:

100.

10. A reversible thermochromic energy storage floor, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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