Radiation refrigeration regenerated cellulose-containing fiber imitating human epidermis wrinkle structure, fabric and preparation and application of radiation refrigeration regenerated cellulose-containing fiber

Abstract

The invention relates to a radiation refrigeration regenerated cellulose-containing fiber imitating a human epidermis wrinkle structure, a fabric and preparation and application of the radiation refrigeration regenerated cellulose-containing fiber imitating the human epidermis wrinkle structure, and the radiation refrigeration regenerated cellulose-containing fiber imitating the human epidermis wrinkle structure is prepared through mechanical stirring and hydrogen bond interaction after cellulose is dissolved by alkali urea for the first time and then a nano material is compounded. The invention provides a potential personal thermal management material, and provides a feasible new thought for application of regenerated cellulose fibers in the field of radiation refrigeration.

Description

Technical Field

[0001] The present invention belongs to the field of functional fibers, and particularly relates to a radiative cooling regenerated cellulose fiber, fabric with a structure imitating human epidermal wrinkles, and their preparation and application. Background Art

[0002] Passive daytime radiative cooling (PDRC) is an efficient zero - energy cooling technology that radiates heat into outer space using the atmospheric transparency window, thereby achieving passive cooling. The characteristics of PDRC materials are high emissivity in the atmospheric transparency spectrum (8 - 13 μm) range and high reflectivity in the solar spectrum band (0.25 - 2.5 μm) range. These properties enable the material to exhibit radiative cooling performance during the day. The potential applications of this technology have been demonstrated, including reducing building energy consumption, developing smart textiles, and solutions for keeping food fresh. In particular, radiative cooling fabrics achieve zero - energy consumption in hot outdoor environments, thus reducing the dependence of personal heat management on air conditioners and other high - energy - consuming refrigeration devices. Currently, the research on radiative cooling fabrics has used polymers, including polyethylene terephthalate, polyvinylidene fluoride, cellulose, etc. The molecular bond vibration wavelengths of these polymers are in the range of 8 - 13 μm, and they have the advantages of simple processing, low cost, and high emissivity. However, these polymers are more extracted from petroleum products and inevitably cause pollution during the production process. Obviously, in the field of PDRC applications, it is still an urgent task to develop radiative cooling fabrics that meet the standards of human comfort, durability, renewability, and sustainability.

[0003] In addition, studies have shown that polymers exposed to a large amount of solar heat radiation (about 1000 W·m -2 ) will reduce their thermoregulation efficacy due to internal structural disorder. In addition to utilizing the inherent properties of materials, spectral characteristic structures are also an important research field. In recent years, designing bionic structures has become a common method to improve the scattering efficiency of materials. Natural organisms such as silver ants and butterflies regulate their body temperature by changing their physical properties to adapt to the surrounding environment. Researchers have used a template - assisted process to add aluminum oxide (Al2O3) to polydimethylsiloxane (PDMS) to prepare a flexible PDRC film with a triangular cross - section on the surface. In addition, the human skin is an extraordinary biological structure that has the ability to regulate body temperature when its temperature is higher than the surrounding environment. This is achieved by adopting a three - layer structure that can spontaneously transfer heat to the surrounding environment through radiation. Studies have shown that from the perspective of the skin epidermal structure, a replicated skin epidermal structure RC fabric can be manufactured by mixing various nanoparticles to prepare a photon coating (RC) and coating it on the fabric surface.

[0004] However, current research on cellulose-based radiative cooling fabrics mainly focuses on preparation through surface synthesis and fabric coating. These methods can endow the fabric with radiative cooling performance by forming a thin film on the fabric surface. However, the thickness of the coating and the weak interfacial interaction with the fabric will not only affect the mechanical properties of the fabric but also reduce the softness, breathability, and moisture permeability of the fabric, thus affecting the wearable performance of the fabric. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a radiative cooling regenerated cellulose fiber, fabric with a structure imitating human epidermal wrinkles, and their preparation and application, particularly a radiative cooling regenerated cellulose fiber with a structure imitating human epidermal wrinkles, which can generate structural influence and hydrogen bond interaction between materials to endow the fiber with application stability, and its preparation and application.

[0006] The present invention provides a regenerated cellulose-containing material, which is a regenerated cellulose material with a wrinkled structure on the surface or a regenerated cellulose / nanomaterial composite material with a wrinkled structure on the surface.

[0007] The nanomaterial is one or more of nano-silica particles, nano-TiO₂, and nano-ZnO; the surface wrinkled structure is a micro-nano wrinkled structure.

[0008] Furthermore, for the surface wrinkled structure, the average surface wrinkled height is 0.5 - 2.5 μm.

[0009] The micro-nano wrinkled structure simulates the structural characteristics of high emissivity of the human epidermis in the atmospheric window and improves the scattering efficiency of the fiber in the visible light band.

[0010] Furthermore, the nanomaterial is nanoparticles, and the average particle size of the nanoparticles is 400 - 600 nm.

[0011] The strong hydrogen bond formed between the hydroxyl groups of the regenerated cellulose fiber and the hydroxyl groups of the nanomaterial (such as silica particles) enhances the mechanical properties of the fiber and provides weavability.

[0012] Furthermore, the regenerated cellulose-containing material is prepared from a regenerated cellulose solution obtained by purifying dissolving pulp from wood and containing nanoparticles. Under the condition of wet spinning, a composite fiber with high reflectivity and high emissivity is formed by regenerating the gel.

[0013] The present invention provides a preparation method of a regenerated cellulose-containing material, including:

[0014] Dissolve cellulose in an alkali-urea solution, add nanomaterials, mix to obtain a spinning solution, conduct wet spinning, wash, and freeze-dry to obtain a regenerated cellulose-containing material; wherein the nanomaterial is 0 - 150% of the mass of cellulose.

[0015] Alternatively, dissolve cellulose in an alkali-urea solution, add nanomaterials and mix them, then add a crosslinking agent for crosslinking to obtain a spinning solution, perform wet spinning, wash, and freeze-dry to obtain a regenerated cellulose material-containing product; the nanomaterials account for 0-150% of the mass of cellulose.

[0016] The mixing is to obtain a spinning solution by ultrasonic dispersion and stirring.

[0017] Preferably, the nanomaterials account for 5-120% of the mass of cellulose.

[0018] Optionally, if the nanomaterials account for 0%, 10%, 20%, 30%, 40%, 50% of the mass of cellulose.

[0019] By adjusting the mixing ratio of the materials, the solvent replacement rate of the fiber in the coagulation bath is regulated, thereby producing different degrees of wrinkling effects.

[0020] Preferably, the concentration of cellulose in the spinning solution is 4-9 wt.%.

[0021] Preferably, the cellulose is cellulose with a methyl cellulose content of 92-96%, and further preferably, the cellulose is wood cellulose.

[0022] Further, the preparation method of the cellulose includes: subjecting the wood to hot water pretreatment and / or cooking in a mixed solution containing sodium hydroxide and sodium sulfite, washing, then bleaching with a sodium hypochlorite solution until the pulp becomes white, and then performing cold alkali extraction and washing to obtain cellulose (cellulose with a methyl cellulose content of 92-96%).

[0023] The wood includes at least one of basswood and balsa wood; the concentration of sodium hydroxide in the mixed solution of sodium hydroxide and sodium sulfite is 40-70 g / L, and the concentration of sodium sulfite is 26-46 g / L; the mass ratio of the mixed solution to the wood is 10:1; the mass percentage concentration of the sodium hypochlorite solution is 0.5-5 wt.%; the mass percentage concentration of the sodium hydroxide solution in the cold alkali extraction is 5-15 wt.%.

[0024] Preferably, the reaction temperature of the wood in the hot water pretreatment is 170-200 °C, and the time is 2-4 h; the wood reacts and is washed in the mixed solution of sodium hydroxide and sodium sulfite, where the reaction temperature is 150-170 °C and the time is 1-3 h; the washing is washing with deionized water 3-5 times.

[0025] Preferably, the cellulose is dissolved in an alkali-urea solution, where the dissolution temperature is -5 to 5 °C; the concentration of the cellulose solution is 4-9 wt.%.

[0026] Preferably, the crosslinking agent is one of epichlorohydrin, glutaraldehyde, and citric acid; the concentration of the crosslinking agent in the spinning solution is 0.05-5 wt.%.

[0027] Preferably, the crosslinking is carried out at -5°C to 5°C for 0.5-2 h.

[0028] The wet spinning is to extrude the spinning solution into the phytic acid coagulation bath through a syringe.

[0029] Preferably, the process parameters of the wet spinning are as follows: the inner diameter of the needle is 250-500 μm, the spinning speed is 80-150 μL / min; the coagulation bath used is a phytic acid solution; the concentration of the phytic acid solution is 15-25 wt.%.

[0030] The present invention provides a fabric, which is a fabric woven from a raw material containing any of the regenerated cellulose materials or a raw material containing a regenerated cellulose material prepared by any of the methods.

[0031] The weaving method can be a woven structure or a knitted structure.

[0032] The present invention provides an application of any of the regenerated cellulose materials, a regenerated cellulose material prepared by any of the methods, or the fabric in the field of radiative cooling.

[0033] The present invention solves the problem that current traditional regenerated cellulose fibers have high absorption of sunlight. Inspired by the epidermal structure of the human body, by using the intermolecular vibration of cellulose and highly reflective nanomaterials such as silica nanoparticles, a bionic composite regenerated cellulose fiber with good air permeability, moisture permeability, abrasion resistance, and radiative cooling performance is constructed into a fabric, which has important practical significance for the development of the bio-based fabric field. The present invention provides a method for simulating the human epidermal structure to enhance the optical properties of materials in the visible light spectrum. By incorporating silica nanoparticles into the cellulose solution and using the dense surface structure formed during the regeneration and spinning process, a composite fiber with bionic surface wrinkles is prepared. This fiber utilizes the hydrogen bond interaction between cellulose and nanoparticles to enhance the mechanical properties of the fiber and combines the excellent spectral selectivity of both, enabling the woven fabric to reflect more sunlight and radiate heat to outer space in the actual environment.

[0034] The present invention uses wood (such as basswood), removes lignin, hemicellulose, etc. in the wood through treatment to obtain cellulose with a high methyl cellulose content. By using an alkali-urea solution to isolate the hydrogen bond interaction between cellulose molecules at low temperature, cellulose is dissolved to obtain a regenerated cellulose solution. At the same time, nanomaterials (silica particles) are dispersed in the cellulose solvent, and cellulose and nanomaterials (silica) are mixed together by low-temperature freezing and high-speed mechanical stirring to obtain a regenerated cellulose / nanomaterial mixed solution. Then, through the wet spinning method, the barrier between cellulose chains is removed by acid-base neutralization, and cellulose molecules are re-bonded together through hydrogen bonds, and form hydrogen bond interactions with the hydroxyl groups of nanomaterials (silica). The pleats formed by the solidification of the double-diffusion effect during cellulose regeneration, combined with the hindering effect of nanomaterials (silica), make the surface wrinkles larger and enhance the mechanical properties of the fibers, increase the specific surface area of the fibers, and thus increase the scattering efficiency of the fibers. The fibers are woven into fabrics by different weaving methods for application tests of radiative cooling. This kind of fabric not only utilizes the chemical structure of cellulose itself and the excellent spectral selectivity of nanomaterials (silica nanoparticles), but also utilizes the surface structure after their synergistic regeneration, which increases the scattering path of light, improves the reflectivity of sunlight, and helps to enhance the emissivity of the atmospheric window. In addition, the raw materials required by this method are simple and easy to obtain, the preparation method is simple and feasible, the cost is low and environmentally friendly, it is a very promising personal thermal management material, and at the same time provides a feasible new idea for the field of regenerated cellulose fibers.

[0035] Beneficial effects

[0036] (1) The present invention provides a method for preparing a radiative cooling regenerated cellulose fiber with an excellent biocompatibility and radiative cooling effect, imitating the epidermal fold structure of the human body, and provides a new idea for the field of regenerated cellulose fibers;

[0037] (2) There is currently no report on studying the influence of adjusting the concentration of nanomaterials such as silica on the surface wrinkles of cellulose fibers. The present invention provides a new idea for the application of regenerated cellulose fibers and at the same time provides a new idea for the construction of bio-based fabrics;

[0038] (3) The existing preparation of cellulose-based fabrics for radiative cooling mainly involves synthesizing nanoparticles on the surface or spraying radiative cooling fillers. However, the thickness of the coating and the interfacial force with the fabric still affect the wearability and stability of the fabric. Inspired by the human epidermal structure, the present invention continuously spun to prepare cooling regenerated cellulose / nanomaterial (silica nanoparticles) fibers. The biomimetic micro-nano structure of this fiber is the result of restricted solution gelation, thus forming a wrinkled surface with an increased specific surface area. By systematically adjusting the concentration of silica nanoparticles, radiative cooling fibers with high reflectivity and high emissivity were prepared. The adhesion of the nanomaterial (silica) to the fiber was enhanced through the hydrogen bonding formed between cellulose and the nanomaterial (silica), reducing losses and enhancing the mechanical properties of the fiber, making it capable of being woven;

[0039] (4) Most of the fiber raw materials prepared in the present invention are derived from biomass materials, which are widely sourced and easily available. This not only achieves better biocompatibility effects but also greatly promotes the high-quality and high-value conversion of biomass materials.

[0040] (5) The radiative cooling fabric woven in the present invention has a reflectivity of 81 - 93% in the solar band and an emissivity of 0.93 - 0.98 in the atmospheric window band, and can achieve a cooling effect of 3 - 8 °C lower than the ambient temperature.

[0041] (6) The raw materials required by the method of the present invention are simple and easily available, the preparation method is simple and feasible, the cost is low and environmentally friendly. It is a very promising personal thermal management material, and at the same time provides a feasible new idea for the application of regenerated cellulose fibers in the field of radiative cooling. Description of the Drawings

[0042] Figure 1 It is a comparative infrared spectrum diagram of the wood cellulose prepared in Example 1 and Example 4 and the fibers prepared in Example 1, Example 2 and Example 3; among which (a) is the infrared spectrum diagram of the wood cellulose before and after purification, and (b) is the infrared spectrum diagram of the composite fiber;

[0043] Figure 2 It is a comparative SEM diagram of the wood cellulose prepared in Example 1 and Example 4 and the fibers prepared in Example 1 and Example 2; among which (a) is the SEM diagram of the wood cellulose before purification, (b) is the SEM diagram of the wood cellulose after purification; (c) is the SEM diagram of the regenerated cellulose fiber without adding silica; (d) is the SEM diagram of the regenerated cellulose fiber adding silica;

[0044] Figure 3 It is the AFM diagram of the composite fibers prepared in Example 1 and Example 2; among which (a) is the AFM diagram of the regenerated cellulose fiber without adding silica, and (b) is the AFM diagram of the regenerated cellulose fiber adding silica;

[0045] Figure 4 Test results of the mechanical properties of the composite fibers prepared in Example 1, Example 2, Example 3 and Example 4;

[0046] Figure 5 Research on the radiative cooling performance of the composite fiber fabrics prepared in Example 1, Example 2 and Example 4; among which (a) is the reflectivity test of the fabric at a wavelength of 0.25 - 2.5 μm; (b) is the emissivity test of the fabric at a wavelength of 8 - 13 μm;

[0047] Figure 6 Schematic diagram of the synthesis and characterization of the present invention. Detailed implementation manners

[0048] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0049] Example 1

[0050] (1) Preparation of wood cellulose: Take 50 g of sodium hydroxide and 34 g of sodium sulfite and put them into a beaker. Add 1000 ml of deionized water and stir evenly, then add 100 g of Tilia wood (each piece has a size of 3 cm * 3 cm * 2 mm) and react at 160 °C for 3 h. The obtained product is repeatedly washed with three times of deionized water, and then bleached with sodium hypochlorite solution by heating until the wood becomes white to obtain white wood. Take 80 g of sodium hydroxide, add 920 ml of deionized water and stir evenly, then add 100 g of the above-obtained white wood and react at 45 °C for 0.5 h, and then repeatedly wash with deionized water and dry to obtain wood cellulose with a methyl cellulose content of 92%;

[0051] (2) Radiative cooling regenerated cellulose fiber imitating the epidermal fold structure of the human body: Dissolve 9 g of cellulose in 100 ml of alkaline urea solution at -5 °C to obtain a spinning solution. During the wet spinning process, the prepared composite solution is extruded into a 15% phytic acid coagulation bath at a needle size of 500 μm at a rate of 80 μL / min. After washing with deionized water, wet composite fibers are obtained, and then freeze-dried to obtain regenerated wood cellulose fibers, fibers with an average surface fold height of 0.5 μm are obtained, and then a functional fabric is obtained by weaving. The reflectivity in the solar band reaches 77%, and the emissivity is 0.93.

[0052] Example 2

[0053] (1) Preparation of wood cellulose: The same as in Example 1;

[0054] (2)Radiative cooling regenerated cellulose fiber imitating the epidermal fold structure of the human body: Dissolve 6 g of cellulose in 100 ml of alkaline urea solution at 5 °C. At the same time, disperse 2 g of silica nanoparticles with an average particle size of 500 nm in 100 ml of alkaline urea solution by ultrasonic dispersion, and then obtain a composite solution through high-speed stirring and mixing. During the wet spinning process, the prepared composite solution is extruded into a 20% phytic acid coagulation bath at a rate of 120 μL / min with a needle size of 500 μm. After washing with deionized water, wet composite fibers are obtained, and then freeze-dried to obtain radiative cooling regenerated cellulose fibers imitating the epidermal fold structure of the human body. Fibers with an average surface fold height of 1.35 μm are obtained, and then functional fabrics are obtained by weaving. The reflectivity reaches 81% in the solar band, and the emissivity is 0.97.

[0055] Example 3

[0056] (1)Preparation of wood cellulose: The same as in Example 1;

[0057] (2)Radiative cooling regenerated cellulose fiber imitating the epidermal fold structure of the human body: Dissolve 6 g of cellulose in 100 ml of alkaline urea solution at 0 °C. At the same time, disperse 2 g of silica nanoparticles with an average particle size of 500 nm in 100 ml of alkaline urea solution by ultrasonic dispersion, and then obtain a composite solution through high-speed stirring and mixing. Add 0.7 ml of epichlorohydrin at -5 °C and crosslink for 2 h, and centrifuge to obtain a pre-crosslinked composite solution. During the wet spinning process, the prepared composite solution is extruded into a 20% phytic acid coagulation bath at a rate of 100 μL / min with a needle size of 400 μm. After washing with deionized water, wet composite fibers are obtained, and then freeze-dried to obtain radiative cooling regenerated cellulose fibers imitating the epidermal fold structure of the human body. Fibers with an average surface fold height of 1.35 μm are obtained, and then functional fabrics are obtained by weaving. The reflectivity reaches 81% in the solar band, and the emissivity is 0.97.

[0058] Example 4

[0059] (1)Preparation of wood cellulose: Put 50 g of sodium hydroxide and 34 g of sodium sulfite into a beaker, add 1000 ml of deionized water, stir evenly, and then add 100 g of Tilia wood (each piece with a size of 3 cm * 3 cm * 2 mm) and react at 170 °C for 2.5 h. The obtained product is repeatedly washed with three times of deionized water, and then bleached with 1000 ml of 2% sodium hypochlorite solution at 40 °C until the wood turns white to obtain white wood. Put 100 g of sodium hydroxide into 900 ml of deionized water, stir evenly, add 100 g of the above-obtained white wood, react at 45 °C for 0.5 h, and then repeatedly wash with deionized water and dry to obtain wood cellulose with a methyl cellulose content of 94%.

[0060] (2)Radiative cooling regenerated cellulose fiber imitating the epidermal fold structure of the human body: Dissolve 6 g of cellulose in 100 ml of alkaline urea solution at 0 °C. At the same time, disperse 6 g of silica nanoparticles with an average particle size of 400 nm in 100 ml of alkaline urea solution by ultrasonic dispersion, and then obtain a composite solution by high-speed stirring and mixing. Add 0.5 ml of epichlorohydrin at -5 °C and crosslink for 2 h, and centrifuge to obtain a pre-crosslinked composite solution. During the wet spinning process, the prepared composite solution is extruded into a 20% phytic acid coagulation bath at a needle size of 500 μm at a rate of 120 μL / min. After washing with deionized water, wet composite fibers are obtained, and then freeze-dried to obtain a radiative cooling regenerated cellulose fiber imitating the epidermal fold structure of the human body, obtaining fibers with an average surface fold height of 1.5 μm. Then, a functional fabric is obtained by weaving, with a reflectivity of 93% and an emissivity of 0.98 in the solar band.

[0061] Product Structure and Performance Characterization:

[0062] The following will illustrate the structure and performance of the radiative cooling regenerated cellulose fiber imitating the epidermal fold structure of the human body in the present invention through infrared spectroscopy, scanning electron microscopy, mechanical properties, reflectivity, and emissivity tests.

[0063] 1. Infrared Spectroscopy (FTIR)

[0064] Figure 1 (a) shows the infrared spectra of wood cellulose before and after purification. Compared with wood, the peak intensities of the characteristic peaks of lignin and hemicellulose gradually disappear at 1520 cm -1 and 1730 cm -1 , indicating the success of purifying wood cellulose, which is beneficial for subsequent improvement of cellulose solubility and fiber mechanical strength, etc.; Figure 1 (b) shows the infrared spectra of the fibers in Example 1, Example 2, and Example 3. Compared with Example 1, the Si-O-Si of silica is increased in Example 2 and shifted from 850 cm -1 to 1020 cm -1 , indicating a strong intermolecular hydrogen bond interaction between cellulose and silica; compared with Example 2, a strong sharp peak appears at 1363 cm -1 in Example 3, indicating the stretching vibration absorption peak of CH-O-CH generated between epichlorohydrin and the hydroxyl groups of cellulose. Based on the above analysis, it is considered that the radiative cooling regenerated cellulose fiber imitating the epidermal fold structure of the human body is successfully prepared.

[0065] 2. Scanning Electron Microscopy (SEM)

[0066] Figure 2(a, b) are the scanning electron microscope images of wood cellulose before and after purification. Compared with the unpurified wood, after treatment, the lignin and hemicellulose in the wood block are dissolved out, and the structure changes from a network where the three are interconnected to aggregated cellulose fibers, greatly promoting the infiltration of the solvent components and the dissolution of cellulose. Figure 2 (c, d) are the scanning electron microscope images of the fiber in Example 1 and Example 4 respectively. After adding silica, the surface of the fiber changes from a mostly porous network structure to a wrinkled micro-structure with uniformly distributed nanoparticles. Based on the above analysis, it is considered that the preparation of the radiative cooling regenerated cellulose fiber imitating the epidermal wrinkled structure of the human body is successful.

[0067] 3. Atomic Force Microscope (AFM)

[0068] Measure the height of the wrinkles on the fiber surface, and obtain the height change map by using the interaction force between the atomic force probe and the surface wrinkled structure. Figure 3 a is for Example 1 and Figure 3 b is for Example 2, showing the change map of the wrinkle height on the fiber surface before and after adding silica. After adding silica, the wrinkle height on the fiber surface increases from the original 0.5 μm to 1.35 μm, increasing the specific surface area of the fiber, enlarging the area for reflecting sunlight, and improving the scattering efficiency of the fiber.

[0069] 4. Mechanical Property Test

[0070] Select fibers with similar diameters, and use an electronic universal testing machine to stretch the fibers at a stretching speed of 2 mm / min, and record the real-time changes in mechanical properties. Figure 4 Shows the comparison of the mechanical properties of Example 1 and Example 2 before and after adding silica. After adding silica, the mechanical properties of the fiber decrease, but only by 6 MPa, and the strain change is not significant. The comparison of the mechanical property changes of Example 2 and Example 3 with and without crosslinking and Example 3 shows that after introducing chemical crosslinking through pre-crosslinking with chemical bonds, the mechanical properties of the fiber increase from 16 MPa to 22.5 MPa, and the strain increases from 20% to 23.5%. The comparison of the mechanical property changes of Example 4 with an increased silica concentration shows that after adding particles, the mechanical properties of the fiber decrease from 22.5 MPa to 12 MPa, and the strain remains unchanged. Therefore, in summary, the mechanical properties are improved after introducing chemical crosslinking, but the addition of silica will reduce the mechanical properties to a certain extent, but it does not affect the weavability and improves the reflectivity of the fabric, enabling the radiative cooling performance of the cellulose-based fabric.

[0071] 5. Measurement of Reflectivity and Emissivity

[0072] By weaving the fibers of the three examples, the reflectivity of the fabric in the visible light band and the emissivity in the atmospheric window band are respectively measured on an ultraviolet-visible-near-infrared spectrometer and an infrared spectrometer with a gold integrating sphere. As Figure 5As shown in a, the average reflectance of Examples 1 to 4 is 77%, 81% and 93% respectively. Among them, the composite fiber in Example 4 has the highest reflectance, indicating that silica can effectively increase the specific surface area of the fiber, thereby increasing the scattering efficiency in the solar band. From Figure 5 As shown in b, due to the chemical structure of cellulose itself, the emissivity of the three fibers changes little, increasing from 0.93 to 0.98.

Claims

1. A regenerated cellulose-containing material, characterized in that: The regenerated cellulose-containing material is a regenerated cellulose material having a corrugated structure on the surface or a regenerated cellulose / nano material composite material having a corrugated structure on the surface.

2. The regenerated cellulose-containing material according to claim 1, characterized in that: The nano material is one or more of nano silicon dioxide, nano TiO2 and nano ZnO; the surface wrinkle structure is a micro-nano level wrinkle structure.

3. A method for preparing a regenerated cellulose-containing material, comprising: Dissolving cellulose in an alkaline urea solution, adding nanomaterials, mixing to obtain a spinning solution, performing wet spinning, washing, and freeze drying to obtain a regenerated cellulose-containing material; The nanomaterial is 0-150% of the mass of cellulose; Or dissolve cellulose in an alkaline urea solution, add nanomaterials to mix, then add a crosslinking agent to crosslink to obtain a spinning solution, perform wet spinning, wash, freeze-dry, and obtain a regenerated cellulose-containing material; wherein the nanomaterials account for 0-150% of the mass of the cellulose.

4. The preparation method according to claim 3, characterized in that: The concentration of cellulose in the spinning solution is 4-9wt.%; The cellulose is cellulose with a methylcellulose content of 92-96%.

5. The preparation method according to claim 4, characterized in that: The preparation method of cellulose comprises: pre-treating wood with hot water and / or boiling in a mixed solution containing sodium hydroxide and sodium sulfite, washing, then bleaching with sodium hypochlorite solution until the pulp becomes white, and then extracting with cold alkali and washing to obtain cellulose.

6. The preparation method according to claim 3, characterized in that: The cellulose is dissolved in an alkaline urea solution, wherein the dissolution temperature is -5-5°C; the concentration of the cellulose solution is 4-9 wt.%.

7. The preparation method according to claim 3, characterized in that: The cross-linking agent is one or more of epichlorohydrin, glutaraldehyde and citric acid; the concentration of the cross-linking agent in the spinning solution is 0.05-5wt.%.

8. The preparation method according to claim 3, characterized in that: The process parameters of the wet spinning method are as follows: the inner diameter of the needle is 250-500 μm, the spinning speed is 80-150 μL / min; the coagulation bath is a phytic acid solution; wherein the concentration of the phytic acid solution is 15-25 wt.%; The mixing is to obtain the spinning solution by ultrasonic dispersion and stirring; The cross-linking is a cross-linking reaction at -5°C to 5°C for 0.5-2h.

9. A fabric, characterized in that: The fabric is a fabric woven from a raw material containing the regenerated cellulose material according to any one of claims 1-2 or the regenerated cellulose material prepared by the method according to any one of claims 3-8.

10. Use of the regenerated cellulose-containing material according to any one of claims 1 to 2, the regenerated cellulose-containing material prepared by the method according to any one of claims 3 to 8, or the fabric according to claim 9 in the field of radiant cooling.

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