A recyclable, environmentally dry gelatin / cellulose-based thermal insulation cooler, its green preparation method, and its application.

Abstract

This invention discloses a recyclable, environmentally dry gelatin / cellulose-based thermal insulation cooler, its green preparation method, and its application. The green preparation method of the recyclable, environmentally dry gelatin / cellulose-based thermal insulation cooler is as follows: dissolving gelatin in water to obtain a gelatin solution; mixing the gelatin solution with a cellulose dispersion to obtain a gelatin / cellulose mixture; adding functional fillers to the gelatin / cellulose mixture and dispersing them evenly to obtain a foam precursor solution; adding sodium dodecyl sulfate to the foam precursor solution and then stirring it at high speed to obtain wet foam; gelling the wet foam to obtain a wet foam gel; and naturally drying the wet foam gel to obtain the gelatin / cellulose-based thermal insulation cooler. The thermal insulation cooler prepared by this invention has advantages such as low density, high porosity, uniformly distributed small pore size, high solar reflectivity and infrared emissivity, and low thermal conductivity. Furthermore, it can be recycled and reused, and the entire process is environmentally friendly, non-toxic, and does not require drying equipment.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials technology, specifically relating to a recyclable, environmentally dry gelatin / cellulose-based heat insulation cooler and its green preparation method and application. Background Technology

[0002] Social and economic development has led to an increase in global energy consumption, with buildings and housing accounting for a large proportion of this. Traditional thermal control systems often require substantial energy consumption, which not only exacerbates global resource and environmental problems but also contributes to more frequent extreme weather events. Therefore, developing a low-energy, sustainable thermal control technology is of great significance.

[0003] Porous materials, due to their excellent properties such as low density, high porosity, and thermal insulation, are widely used in building insulation, packaging, and biomedicine. Lightweight porous materials that combine thermal insulation and radiative cooling properties have become a highly regarded new type of building thermal management material in recent years due to their superior thermal management performance and multifunctional integration capabilities. Applying them to building envelopes can not only suppress heat conduction and convection from the external thermal environment to the building interior, but also minimize the absorption of sunlight, thereby reducing building energy consumption.

[0004] Developing high-performance aerogel coolers using green and simple manufacturing methods remains a challenge. Traditional gels struggle to form aerogels through natural drying due to capillary forces caused by the surface tension of water, which lead to wrinkling and collapse of the pore walls. Currently, most thermal insulation cooler manufacturing involves specific drying processes (such as supercritical drying and freeze-drying) to eliminate the negative impact of surface tension on the aerogel microstructure during drying. However, these drying methods are unsuitable for large-scale production of thermal insulation coolers due to the high cost of drying equipment, the complexity of the drying process, and high energy consumption. Summary of the Invention

[0005] In order to solve the problems mentioned in the background art, the present invention aims to provide a recyclable, environmentally dry gelatin / cellulose-based heat insulation cooler, its green preparation method and application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On one hand, the present invention provides a green preparation method for a recyclable, environmentally dry gelatin / cellulose-based heat-insulating cooler, comprising the following steps:

[0007] (1) Dissolve gelatin in water to obtain a gelatin solution, and mix the gelatin solution with a cellulose dispersion to obtain a gelatin / cellulose mixture;

[0008] (2) The functional filler is added to the gelatin / cellulose mixture and dispersed evenly to obtain a foam precursor solution;

[0009] (3) Sodium dodecyl sulfate is added to the foam precursor solution to obtain a mixture, and the mixture is stirred at high speed to foam to obtain wet foam;

[0010] (4) The wet foam is gelled to obtain wet foam gel, and the wet foam gel is naturally dried to obtain a recyclable, environmentally dry gelatin / cellulose-based heat insulation cooler.

[0011] Furthermore, the gelatin described in step (1) has an adhesive strength ≥ 240g Bloom;

[0012] And / or, the cellulose dispersion in step (1) is a nanocellulose dispersion.

[0013] Furthermore, the nanocellulose dispersion is at least one of bacterial nanocellulose dispersion, cellulose nanocrystal dispersion, cellulose nanofiber dispersion, and microfibrillated cellulose dispersion.

[0014] Further, the mass concentration of gelatin in the gelatin / cellulose mixture in step (1) is 2%~10%;

[0015] And / or, the mass concentration of cellulose in the gelatin / cellulose mixture in step (1) is 0.1%~1%.

[0016] Further, step (1) specifically involves: dissolving gelatin in water at 40°C to 80°C to obtain a gelatin solution, and mixing the gelatin solution with a cellulose dispersion at 40°C to 60°C to obtain a gelatin / cellulose mixture.

[0017] Furthermore, the functional filler in step (2) includes at least one of boron nitride, titanium dioxide, and microencapsulated phase change functional materials;

[0018] And / or, the mass concentration of the functional filler in the foam precursor liquid in step (2) is 0%~20%.

[0019] Furthermore, the microencapsulated phase change functional material includes at least one of paraffin phase change microcapsules and hydrated salt phase change microcapsules.

[0020] Further, the mass concentration of sodium dodecyl sulfate in the mixture described in step (3) is 0.01%~0.03%;

[0021] And / or, the temperature of the high-speed stirring foaming in step (3) is 40°C~60°C, the speed of the high-speed stirring foaming is 10000rpm~20000rpm, and the time of the high-speed stirring foaming is 5min~10min.

[0022] Further, the method for gelling the wet foam in step (4) to obtain wet foam gel is as follows: pour the wet foam into a mold and cool it at room temperature for 20 min to 30 min to obtain wet foam gel.

[0023] On the other hand, the present invention provides a recyclable, environmentally dry gelatin / cellulose-based heat-insulating cooler, which is prepared by any of the preparation methods described above.

[0024] On the other hand, the present invention provides an application of the above-described recyclable, environmentally dry gelatin / cellulose-based thermal insulation cooler in the preparation of energy-saving building materials, infrared thermal stealth materials, cold chain transportation packaging materials, and food storage materials.

[0025] This invention uses gelatin as the matrix for constructing a porous thermal insulation cooler, cellulose as a reinforcing phase to regulate the structure and stability of the foam, and sodium dodecyl sulfate as a surfactant. Appropriate amounts of functional fillers with high light reflectivity (such as boron nitride, titanium dioxide, and microencapsulated phase change functional materials) can be added to enhance the thermal insulation and cooling effect. By introducing a large number of air bubbles into the mixed slurry to form a sufficiently stable foam structure, the robust gas-liquid interface of the foam provides strong mechanical support, thus maintaining a good porous structure even during direct drying. To address the foam instability mechanism, the composition and content of the precursor liquid are modified, and the properties of the precursor liquid are controlled by changing the temperature to obtain a relatively stable foam structure. The thermally reversible gelation behavior of gelatin is utilized to rapidly transform wet foam into a gel, achieving long-term stability of the wet foam. The nanofiber network of cellulose not only helps improve the stability of the gas-liquid interface but also enhances the rigidity of the interfacial film, restricting bubble diffusion and the free movement of gelatin molecular chains, thus reducing foam instability. Thanks to the synergistic stabilizing effect of gelatin, cellulose, and surfactants, the heat-insulating cooler successfully maintained a relatively uniform porous structure after natural drying.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The gelatin / cellulose-based heat insulation cooler of the present invention can be formed by direct casting and natural drying without the need for expensive drying equipment. The preparation process is simple, green, environmentally friendly and non-toxic, and low in cost, which can realize the large-scale preparation of heat insulation coolers.

[0028] (2) The gelatin / cellulose-based heat insulation cooler of the present invention obtains a uniform porous structure through the synergistic effect of gelatin and cellulose, which has extremely low density, high porosity, uniformly distributed small pore size, high solar reflectivity and infrared emissivity, and low thermal conductivity.

[0029] (3) The gelatin / cellulose-based heat insulation cooler of the present invention has the ability to be recycled and reused. The raw materials used are environmentally friendly, renewable, and widely available, and have no harm to the environment and health.

[0030] (4) The gelatin / cellulose-based heat insulation cooler of the present invention has strong adaptability and compatibility, and can be functionalized by introducing various fillers such as nanoparticles and phase change materials.

[0031] (5) The gelatin / cellulose-based heat insulation cooler of the present invention has dual functions of heat insulation and radiation cooling, and can be used for energy-saving building thermal management, infrared thermal stealth, cold chain transportation packaging, food insulation, etc. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a cross-sectional electron microscope image of the gelatin / cellulose-based heat insulation cooler prepared in Example 1 of the present invention;

[0034] Figure 2 A photographic schematic diagram illustrating the load-bearing capacity of the gelatin / cellulose-based heat-insulating cooler prepared in Example 1 of the present invention;

[0035] Figure 3 This is a schematic diagram of the closed-loop recycling process of the gelatin / cellulose-based heat insulation cooler prepared in Example 1 of the present invention;

[0036] Figure 4 A comparison of the mechanical and thermal conductivity properties of the gelatin / cellulose-based thermal insulation cooler prepared in Example 1 of this invention before and after recycling.

[0037] Figure 5 This is a cross-sectional electron microscope image of the phase change functionalized gelatin / cellulose-based thermal insulation cooler prepared in Example 2 of the present invention;

[0038] Figure 6 The DSC heating and cooling curves of the phase change functionalized gelatin / cellulose-based thermal insulation cooler prepared in Example 2 of this invention are shown.

[0039] Figure 7A photographic schematic diagram illustrating the load-bearing capacity of the phase change functionalized gelatin / cellulose-based thermal insulation cooler prepared in Example 2 of the present invention;

[0040] Figure 8 This is a cross-sectional electron microscope image of the phase change functionalized gelatin / cellulose-based thermal insulation cooler prepared in Example 3 of the present invention;

[0041] Figure 9 This is a cross-sectional electron microscope image of the boron nitride-functionalized gelatin / cellulose-based thermal insulation cooler prepared in Example 4 of the present invention;

[0042] Figure 10 This is a cross-sectional electron microscope image of the titanium dioxide-functionalized gelatin / cellulose-based thermal insulation cooler prepared in Example 5 of the present invention;

[0043] Figure 11 This is a cross-sectional electron microscope image of the gelatin foam prepared in Comparative Example 1 of the present invention;

[0044] Figure 12 This is a cross-sectional electron microscope image of the gelatin foam prepared in Comparative Example 2 of the present invention. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] Preparation of gelatin / cellulose-based heat-insulating coolers:

[0048] (1) Add gelatin (gel strength of 240g Bloom) to deionized water and stir to dissolve under water bath heating at 40°C to prepare a gelatin solution with a mass concentration of 10%; use deionized water to dilute the concentration of cellulose nanofiber dispersion to 1%; mix the 10% gelatin solution and the 1% cellulose nanofiber dispersion at a volume ratio of 1:1 at 40°C to prepare a gelatin / cellulose mixture, that is, the mass concentrations of gelatin and cellulose nanofiber in the gelatin / cellulose mixture are 5% and 0.5%, respectively.

[0049] (2) Sodium dodecyl sulfate was added to the gelatin / cellulose mixture to obtain a mixture with a sodium dodecyl sulfate mass concentration of 0.01%. The mixture was stirred at 12000 rpm at 40°C for 10 min to obtain wet foam.

[0050] (3) The wet foam was poured into the corresponding mold and cooled at room temperature for 30 minutes to obtain a stable wet foam gel. The obtained wet foam gel was then placed in a cool and ventilated environment to air dry naturally to obtain a gelatin / cellulose-based heat insulation cooler. The average pore size of the gelatin / cellulose-based heat insulation cooler was 104.8 ± 32.7 μm, and the density was 0.019 g / cm³. -3 It has a porosity of 98.6%, a solar reflectance of 84.5%, an infrared emissivity of 84.4%, and a thermal conductivity of 45.9 mW / m² measured using a thermal constant analyzer. -1 K -1 Gelatin / cellulose-based insulating coolers possess a certain degree of thermal insulation due to their relatively low thermal conductivity. Their relatively high solar reflectivity and infrared emissivity also provide a degree of radiative cooling.

[0051] Electron microscopy was performed on the cross-section of the gelatin / cellulose-based heat insulation cooler, and the results are as follows: Figure 1 As shown. From Figure 1 As can be seen from the example, Example 1 successfully obtained a uniform porous foam structure.

[0052] The load-bearing capacity of the gelatin / cellulose-based thermal insulation cooler was tested, and the results are as follows: Figure 2 As shown. From Figure 2 As can be seen, a sample weighing only 0.056g can support a 500g weight without significant deformation.

[0053] The gelatin / cellulose-based thermal insulation cooler was redissolved in 40°C water to obtain a precursor solution (the mass concentrations of gelatin and cellulose in the precursor solution were 5% and 0.5%, respectively). The solution was then stirred at 12000 rpm at 40°C for 10 minutes to obtain wet foam. The wet foam was poured into a mold and cooled at room temperature for 30 minutes to obtain a wet foam gel. The wet foam gel was then allowed to dry naturally to obtain the recovered gelatin / cellulose-based thermal insulation cooler. A schematic diagram of the closed-loop recycling process of the gelatin / cellulose-based thermal insulation cooler is shown below. Figure 3 As shown.

[0054] Mechanical and thermal conductivity properties of gelatin / cellulose-based insulating coolers and recycled gelatin / cellulose-based insulating coolers were tested, and the results are as follows: Figure 4 As shown. From Figure 4 As can be seen, its mechanical and thermal properties remain basically unchanged before and after recycling.

[0055] Example 2

[0056] Preparation of phase change functionalized gelatin / cellulose-based thermal insulation coolers:

[0057] (1) Add gelatin (gel strength of 240g Bloom) to deionized water and stir to dissolve under water bath heating at 40°C to prepare a gelatin solution with a mass concentration of 10%; use deionized water to dilute the concentration of cellulose nanofiber dispersion to 1%; mix the 10% gelatin solution and the 1% cellulose nanofiber dispersion at a volume ratio of 1:1 at 40°C to prepare a gelatin / cellulose mixture, that is, the mass concentrations of gelatin and cellulose nanofiber in the gelatin / cellulose mixture are 5% and 0.5%, respectively.

[0058] (2) Add the paraffin phase change microcapsules with a phase change temperature of 37°C to the gelatin / cellulose mixture and stir evenly under a water bath heating condition of 40°C to prepare a foam precursor solution with a paraffin phase change microcapsule mass concentration of 10%.

[0059] (3) Sodium dodecyl sulfate was added to the foam precursor solution to obtain a mixture. The mass concentration of sodium dodecyl sulfate in the mixture was 0.01%. The mixture was stirred at 12000 rpm at 40°C for 10 min to obtain wet foam.

[0060] (4) The wet foam was poured into the corresponding mold and cooled at room temperature for 30 minutes to obtain a stable wet foam gel. The obtained wet foam gel was placed in a cool and ventilated environment to dry naturally, thus obtaining a phase change functionalized gelatin / cellulose-based heat insulation cooler. The phase change functionalized gelatin / cellulose-based heat insulation cooler had an average pore size of 101.27 ± 38.5 μm and a density of 0.086 g / cm³. -3 It has a porosity of 91.8%, a solar reflectance of 86.7%, an infrared emissivity of 89.2%, and a thermal conductivity of 60.6 mW / m² measured using a thermal constant analyzer. -1 K -1 Compared to Example 1, the addition of paraffin phase change microcapsules improved both solar reflectivity and infrared emissivity.

[0061] Scanning electron microscopy was performed on the cross-section of a phase change functionalized gelatin / cellulose-based thermal insulation cooler, and the results are as follows: Figure 5 As shown. From Figure 5 As can be seen from the example, Example 2 also successfully obtained a uniform porous foam structure.

[0062] DSC testing was performed on the phase change functionalized gelatin / cellulose-based insulating cooler, and the results are as follows: Figure 6 As shown. From Figure 6 As can be seen, the melting enthalpy of the phase change functionalized gelatin / cellulose-based insulating cooler is 128.8 J g. -1 The enthalpy of crystallization is 127.0 J / g. -1Example 2, based on Example 1, introduces a phase change functional filler, thus possessing a certain phase change capability.

[0063] The load-bearing capacity of phase change functionalized gelatin / cellulose-based insulating coolers was tested, and the results are as follows: Figure 7 As shown. From Figure 7 As can be seen, a sample weighing only 0.24g can support a 1kg weight without significant deformation.

[0064] Example 3

[0065] Preparation of phase change functionalized gelatin / cellulose-based thermal insulation coolers:

[0066] (1) Add gelatin (gel strength of 240g Bloom) to deionized water and stir to dissolve it under water bath heating at 40°C to prepare a gelatin solution with a mass concentration of 14%; use deionized water to dilute the concentration of cellulose nanofiber dispersion to 1%; mix the gelatin solution with a mass concentration of 14% and the cellulose nanofiber dispersion with a mass concentration of 1% at a volume ratio of 1:1 at 40°C to prepare a gelatin / cellulose mixture, that is, the mass concentrations of gelatin and cellulose nanofiber in the gelatin / cellulose mixture are 7% and 0.5%, respectively.

[0067] (2) Add the paraffin phase change microcapsules with a phase change temperature of 37°C to the gelatin / cellulose mixture and stir evenly under a water bath heating condition of 40°C to prepare a foam precursor solution with a paraffin phase change microcapsule mass concentration of 15%.

[0068] (3) Sodium dodecyl sulfate was added to the foam precursor solution to obtain a mixture. The mass concentration of sodium dodecyl sulfate in the mixture was 0.01%. The mixture was stirred at 12000 rpm at 40°C for 10 min to obtain wet foam.

[0069] (4) The wet foam was poured into the corresponding mold and cooled at room temperature for 30 minutes to obtain a stable wet foam gel. The obtained wet foam gel was placed in a cool and ventilated environment to dry naturally, thus obtaining a phase change functionalized gelatin / cellulose-based heat insulation cooler. The phase change functionalized gelatin / cellulose-based heat insulation cooler had an average pore size of 90.7±32.6μm and a density of 0.122g / cm³. -3 Its porosity is 88.2%, and its thermal conductivity, measured using a thermal constant analyzer, is 70.0 mW / m². -1 K -1 .

[0070] Scanning electron microscopy was performed on the cross-section of a phase change functionalized gelatin / cellulose-based thermal insulation cooler, and the results are as follows: Figure 8 As shown. From Figure 8As can be seen from the example, Example 3 successfully obtained a uniform porous foam structure.

[0071] Example 4

[0072] Preparation of boron nitride functionalized gelatin / cellulose-based thermal insulation coolers:

[0073] (1) Add gelatin (gel strength of 240g Bloom) to deionized water and stir to dissolve under water bath heating at 40°C to prepare a gelatin solution with a mass concentration of 10%; use deionized water to dilute the concentration of cellulose nanofiber dispersion to 1%; mix the 10% gelatin solution and the 1% cellulose nanofiber dispersion at a volume ratio of 1:1 at 40°C to prepare a gelatin / cellulose mixture, that is, the mass concentrations of gelatin and cellulose nanofiber in the gelatin / cellulose mixture are 5% and 0.5%, respectively.

[0074] (2) Add boron nitride to the gelatin / cellulose mixture and stir evenly under a 40°C water bath heating condition to prepare a foam precursor solution with a boron nitride mass concentration of 1%.

[0075] (3) Sodium dodecyl sulfate was added to the foam precursor solution to obtain a mixture. The mass concentration of sodium dodecyl sulfate in the mixture was 0.01%. The mixture was stirred at 12000 rpm at 40°C for 5 minutes to obtain wet foam.

[0076] (4) Pour the wet foam into the corresponding mold and cool it at room temperature for 30 minutes to obtain a stable wet foam gel. Place the obtained wet foam gel in a cool and ventilated environment to dry naturally to obtain a boron nitride-functionalized gelatin / cellulose-based heat insulation cooler. The density of the boron nitride-functionalized gelatin / cellulose-based heat insulation cooler is 0.025 g cm³. -3 It has a porosity of 98.3% and an average pore size of 90.2±32.1μm. Boron nitride not only has a unique two-dimensional layered structure, but also good mechanical strength, chemical inertness, and dense barrier pathways. When combined with gelatin, it can effectively enhance the properties of gelatin foam in these aspects, while perfectly maintaining the electrical insulation of the material, thus broadening its application scenarios.

[0077] Scanning electron microscopy was performed on the cross-section of a boron nitride-functionalized gelatin / cellulose-based thermal insulation cooler, and the results are as follows: Figure 9 As shown. From Figure 9 As can be seen, Example 4 successfully obtained a uniform porous foam structure. By further magnifying its pore wall structure, it can be observed that sheet-like boron nitride is attached to the pore walls.

[0078] Example 5

[0079] Preparation of gelatin / cellulose-based thermal insulation coolers functionalized with nano-titanium dioxide:

[0080] (1) Add gelatin (gel strength of 240g Bloom) to deionized water and stir to dissolve under water bath heating at 40°C to prepare a gelatin solution with a mass concentration of 14%; use deionized water to dilute the concentration of bacterial nanocellulose dispersion to 1%; mix the 14% gelatin solution and the 1% bacterial nanocellulose dispersion at a volume ratio of 1:1 at 40°C to prepare a gelatin / cellulose mixture, that is, the mass concentrations of gelatin and bacterial nanocellulose in the gelatin / cellulose mixture are 7% and 0.5%, respectively.

[0081] (2) Add nano-titanium dioxide to the gelatin / cellulose mixture and stir evenly under a 40°C water bath heating condition to prepare a foam precursor solution with a nano-titanium dioxide mass concentration of 1%.

[0082] (3) Sodium dodecyl sulfate was added to the foam precursor solution to obtain a mixture. The mass concentration of sodium dodecyl sulfate in the mixture was 0.01%. The mixture was stirred at 12000 rpm at 40°C for 5 minutes to obtain wet foam.

[0083] (4) Pour the wet foam into the corresponding mold and cool it at room temperature for 30 minutes to obtain a stable wet foam gel. Place the obtained wet foam gel in a cool and ventilated environment to dry naturally to obtain a nano-titanium dioxide functionalized gelatin / cellulose-based heat insulation cooler. The density of the nano-titanium dioxide functionalized gelatin / cellulose-based heat insulation cooler is 0.024 g cm³. -3 The porosity is 98.6%, and the average pore size is 108.7±35.9μm. The unique physicochemical properties of nano-titanium dioxide at the nanoscale can be used as a reinforcing filler dispersed in a gelatin matrix. Its nanoparticle structure can also greatly enhance the light scattering effect of the foam and improve the light reflectivity of the foam.

[0084] Scanning electron microscopy was performed on the cross-section of a gelatin / cellulose-based thermal insulation cooler functionalized with nano-titanium dioxide. The results are as follows: Figure 10 As shown. From Figure 10 As can be seen, Example 5 successfully obtained a uniform porous foam structure. By further magnifying its pore wall structure, the presence of granular nano-titanium dioxide can be observed.

[0085] Comparative Example 1

[0086] Preparation of gelatin foam:

[0087] (1) Add gelatin (gel strength of 240g Bloom) to deionized water and stir to dissolve under 40°C water bath heating to prepare a gelatin solution with a mass concentration of 5%.

[0088] (2) A 5% gelatin solution was directly stirred at 12,000 rpm at 40°C for 10 minutes to obtain wet foam.

[0089] (3) Pour the wet foam into the corresponding mold and cool it at room temperature for 30 minutes to obtain a stable wet foam gel; place the obtained wet foam gel in a cool and ventilated environment to dry naturally to obtain gelatin foam. The average pore size of the gelatin foam is 384.8±174.1μm, and the density is 0.037g / cm³. -3 The porosity is 97.6%.

[0090] Electron microscopy was performed on the cross-section of the gelatin foam, and the results are as follows: Figure 11 As shown. From Figure 11 As can be seen, unlike the uniform structures obtained in Examples 1 to 5, Comparative Example 1 shows a relatively large and non-uniform porous structure, indicating that it is difficult to maintain a uniform foam structure in the absence of cellulose and sodium dodecyl sulfate.

[0091] Comparative Example 2

[0092] Preparation of gelatin foam:

[0093] (1) Add gelatin (gel strength of 240g Bloom) to deionized water and stir to dissolve under 40°C water bath heating to prepare a gelatin solution with a mass concentration of 10%.

[0094] (2) A 10% gelatin solution was directly stirred at 40°C and 12000 rpm for 10 minutes to obtain wet foam.

[0095] (3) Pour the wet foam into the corresponding mold and cool it at room temperature for 30 minutes to obtain a stable wet foam gel; place the obtained wet foam gel in a cool and ventilated environment to dry naturally to obtain gelatin foam. The average pore size of the gelatin foam is 335.6±116.3μm, and the density is 0.034g / cm³. -3 The porosity is 97.4%.

[0096] Electron microscopy was performed on the cross-section of the gelatin foam, and the results are as follows: Figure 12 As shown. From Figure 12 As can be seen, compared to Comparative Example 1, although the pore size in Comparative Example 2 was adjusted to some extent, some relatively large pores still remained, and the pore structure was still uneven. This indicates that even increasing the foam concentration has a limited effect on adjusting the foam structure, and it is impossible to obtain the uniform porous structure shown in Examples 1 to 5.

[0097] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A green preparation method for a recyclable, environmentally dry gelatin / cellulose-based thermal insulation cooler, characterized in that, Includes the following steps: (1) Dissolve gelatin in water to obtain a gelatin solution, and mix the gelatin solution with a cellulose dispersion to obtain a gelatin / cellulose mixture; (2) The functional filler is added to the gelatin / cellulose mixture and dispersed evenly to obtain a foam precursor solution; (3) Sodium dodecyl sulfate is added to the foam precursor solution to obtain a mixture, and the mixture is stirred at high speed to foam to obtain wet foam; (4) The wet foam is gelled to obtain wet foam gel, and the wet foam gel is naturally dried to obtain a recyclable, environmentally dry gelatin / cellulose-based heat insulation cooler.

2. The preparation method according to claim 1, characterized in that, The gelatin described in step (1) has a glue strength ≥ 240gBloom; And / or, the cellulose dispersion in step (1) is a nanocellulose dispersion.

3. The preparation method according to claim 2, characterized in that, The nanocellulose dispersion is at least one of bacterial nanocellulose dispersion, cellulose nanocrystal dispersion, cellulose nanofiber dispersion, and microfibrillated cellulose dispersion.

4. The preparation method according to claim 1, characterized in that, The mass concentration of gelatin in the gelatin / cellulose mixture in step (1) is 2%~10%; And / or, the mass concentration of cellulose in the gelatin / cellulose mixture in step (1) is 0.1%~1%.

5. The preparation method according to claim 1, characterized in that, The functional filler mentioned in step (2) includes at least one of boron nitride, titanium dioxide, and microencapsulated phase change functional materials; And / or, the mass concentration of the functional filler in the foam precursor liquid in step (2) is 0%~20%.

6. The preparation method according to claim 5, characterized in that, The microencapsulated phase change functional material includes at least one of paraffin phase change microcapsules and hydrated salt phase change microcapsules.

7. The preparation method according to claim 1, characterized in that, The mass concentration of sodium dodecyl sulfate in the mixture described in step (3) is 0.01%~0.03%; And / or, the temperature of the high-speed stirring foaming in step (3) is 40°C~60°C, the speed of the high-speed stirring foaming is 10000rpm~20000rpm, and the time of the high-speed stirring foaming is 5min~10min.

8. The preparation method according to claim 1, characterized in that, The method for gelling the wet foam in step (4) to obtain wet foam gel is as follows: pour the wet foam into a mold and cool it at room temperature for 20 min to 30 min to obtain wet foam gel.

9. A recyclable, environmentally dry gelatin / cellulose-based insulating cooler, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 8.

10. The application of the recyclable, environmentally dry gelatin / cellulose-based thermal insulation cooler of claim 9 in the preparation of energy-saving building materials, infrared thermal stealth materials, cold chain transportation packaging materials, and food storage materials.

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