Total heat exchange membrane with Turing structure as well as preparation method and application of total heat exchange membrane

Abstract

The invention provides a polymer total heat exchange membrane with a Tailing structure and a preparation method and application thereof.The polymer total heat exchange membrane comprises a net-shaped porous supporting layer and a functional layer, and the functional layer is arranged on the single-side surface of the net-shaped porous supporting layer and fills at least part of pores of the net-shaped porous supporting layer; the functional layer is provided with an uneven Turing structure; the net-shaped porous supporting layer and the functional layer with the uneven Tailing structure are matched, so that the obtained polymer total heat exchange membrane has excellent moisture permeability and is suitable for being applied to a fresh air exchange system.

Description

Technical Field

[0001] The present invention belongs to the technical field of exchange membranes, and particularly relates to a total heat exchange membrane with a Turing structure, a preparation method thereof, and an application thereof. Background Art

[0002] According to the requirements of indoor air purification, the fresh air exchange system can not only continuously replace the indoor air, but also recover heat, and thus has received extensive attention. As a key material in the fresh air exchange system, the total heat exchange membrane plays a crucial role in energy recovery and air ventilation quality. The total heat exchange membrane needs to have highly selective gas permeation performance, high moisture permeability, and at the same time, the membrane structure should be resistant to water cleaning and have a long service life.

[0003] At present, the total heat exchange membranes commonly available on the market include paper exchange membranes, metal exchange membranes, and polymer membranes. Among them, the paper exchange membrane has poor gas selective permeability, which is not conducive to fresh air purification. At the same time, the paper exchange membrane is not resistant to water washing and has a very short service life. The metal exchange membrane can only perform sensible heat exchange and cannot perform latent heat exchange, resulting in a relatively low total heat exchange efficiency. Therefore, the paper exchange membrane and the metal exchange membrane can no longer meet the requirements and have gradually been phased out by the market.

[0004] The polymer membrane refers to a total heat exchange membrane based on polymers. It prepares a dense functional membrane by coating or composite coating a hydrophilic polymer as the main body on the surface of a porous support material, and has the characteristics of high gas selective permeability and excellent total heat exchange performance. However, due to the influence of the structure of the existing dense functional membrane, the total heat exchange efficiency is poor. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a polymer total heat exchange membrane with a Turing structure, a preparation method thereof, and an application thereof. By using a reticulated porous support layer and a functional layer with an uneven Turing structure in combination, the obtained polymer total heat exchange membrane has high moisture permeability and is suitable for application in the fresh air exchange system.

[0006] To achieve the purpose of the present invention, the following technical solutions are adopted:

[0007] In the first aspect, the present invention provides a polymer total heat exchange membrane with a Turing structure, and the polymer total heat exchange membrane includes a reticulated porous support layer and a functional layer;

[0008] The functional layer is disposed on a single-side surface of the reticulated porous support layer and fills at least part of the pores of the reticulated porous support layer, and the functional layer has an uneven Turing structure.

[0009] On the one hand, the reticulated porous support layer in the polymer total heat exchange membrane provided by the present invention has a relatively thin thickness, which basically does not affect the sensible heat exchange of the entire polymer total heat exchange membrane. At the same time, it also has a high porosity and a uniformly distributed nanoporous structure. Therefore, it not only has a low fresh air pressure drop, but also can improve the mass transfer rate of the gas contacting the functional membrane surface. In addition, the interior of the reticulated porous support layer is a reticulated through-porous structure, which increases the effective travel distance of gas molecules staying, diffusing and moving in the reticulated porous structure, enhances the effective collision between gas molecules and the functional layer, and thus can promote the enrichment of water molecules on the surface of the functional layer, contributing to improving the moisture permeability and enthalpy efficiency of the polymer total heat exchange membrane.

[0010] On the other hand, a functional layer is provided on one side surface and at least part of the pores of the reticulated porous support layer. Specifically, first, the structure of the functional layer is dense and has a relatively thin thickness, and also has a hydrophilic and polar chemical structure. Therefore, it has a high gas selective permeability and good gas barrier properties, can efficiently block the permeation of other gas molecules such as carbon dioxide, and can also significantly improve the mass transfer rate of water molecules in the functional layer, improving the latent heat exchange efficiency of the polymer total heat exchange membrane. When applied to a fresh air system, it can achieve the barrier between the exhausted air and the introduced fresh air, preventing the newly introduced air from being polluted by the indoor dirty air. Second, different from the functional layer structure of the traditional total heat exchange membrane, the functional layer of the polymer total heat exchange membrane provided in the present invention has a Turing structure. Microscopically, the Turing structure of the functional layer is uneven. The setting of the Turing structure greatly increases the surface area of the functional layer, effectively improving the contact sites for the diffusion of water vapor molecules, realizing efficient mass transfer and diffusion of water molecules, and thus significantly improving the moisture permeability and latent heat exchange efficiency of the polymer total heat exchange membrane.

[0011] In summary, the present invention combines a reticulated porous support layer with a functional layer having an uneven Turing structure. The functional layer is provided on one side surface of the reticulated porous support layer and fills at least part of the pores of the reticulated porous support layer, and the functional layer has an uneven Turing structure, so that the obtained polymer total heat exchange membrane has high moisture permeability and latent heat exchange efficiency and is suitable for application in a fresh air exchange system.

[0012] Although the present invention does not particularly limit the roughness and specific surface area increment of the functional layer in the provided polymer total heat exchange membrane, considering that the functional layer needs to have better moisture permeability and the polymer total heat exchange membrane containing it needs to have better enthalpy heat exchange efficiency, as a preferred technical solution of the present invention, the roughness of the functional layer ≥ 15 nm (such as 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm or the range composed of any two of them), and further preferably ≥ 25 nm.

[0013] As a preferred technical solution of the present invention, the specific surface area increment of the polymer total heat exchange membrane is ≥6%, such as 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or the range composed of any two of them, and further preferably ≥20%.

[0014] In the present invention, the "specific surface area increment" means the percentage increase of the difference between the specific surface area of the obtained polymer total heat exchange membrane with Turing structure and the specific surface area of the polymer total heat exchange membrane without Turing structure compared to the difference between the specific surface area of the polymer total heat exchange membrane without Turing structure and the specific surface area of the reticulated porous support layer; exemplarily, assuming the specific surface area of the reticulated porous support layer is A (m 2 / g), the specific surface areas of the polymer total heat exchange membrane with Turing structure and the polymer total heat exchange membrane without Turing structure further prepared therefrom are A1 (m 2 / g) and A2 (m 2 / g) respectively, then the specific surface area increment of the above polymer total heat exchange membrane with Turing structure = (A1 - A2) / (A2 - A) × 100%.

[0015] Preferably, the Turing structure of the functional layer has several protrusions.

[0016] Preferably, the number of protrusions per unit area in the functional layer is not less than 2 per μm 2 , for example, it can be 3 per μm 2 , 4 per μm 2 , 5 per μm 2 , 6 per μm 2 , 7 per μm 2 , 8 per μm 2 , 9 per μm 2 or the range composed of any two of them.

[0017] Preferably, each of the protrusions is octopus-like.

[0018] As a preferred technical solution of the present invention, defining the protrusions as octopus-like can make the formed Turing mechanism have greater roughness and specific surface area, thus further enhancing the moisture permeability of the functional layer, and further improving the enthalpy heat exchange efficiency of the polymer total heat exchange membrane; moreover, the anchor structure of the octopus-like protrusions can anchor on the surface of the reticulated porous support layer, making the combination of the functional layer and the reticulated porous support layer more firm. Even when applied in a humid environment for a long time, it can maintain the density and stability of the structure, is not easy to swell and fall off, and extends the service life.

[0019] It should be noted that the "protrusion" in the present invention refers to a regular dot-line structure formed by at least three extensions away from the surface of the reticulated porous support layer and converging with each other to form a protruding convergence point after a certain distance. The same meaning is expressed for the following identical expressions.

[0020] Furthermore, it should be noted that the "octopus-like" structure can also be referred to as the "umbrella bone-like" structure or the "radial" structure. Its name is only a description of this shape structure rather than a limitation.

[0021] Preferably, the reticulated porous support layer is a polymer porous membrane.

[0022] Preferably, the polymer porous membrane includes at least one of a polyolefin membrane, a polysulfone membrane, a cellulose acetate membrane, or a polyester membrane.

[0023] Although the present invention does not particularly limit the thickness of the reticulated porous support layer, preferably, the thickness of the reticulated porous support layer is defined as 6 - 30 μm. For example, it can be 8 μm, 11 μm, 13 μm, 15 μm, 17 μm, 19 μm, 21 μm, 23 μm, 25 μm, 27 μm, 29 μm, or the range composed of any two of them.

[0024] As a preferred technical solution, the present invention further defines the thickness of the reticulated porous support layer as 6 - 30 μm. Because a reticulated porous support layer with a suitable thickness can ensure that the polymer total heat exchange membrane has both a high packing density and a high mechanical strength, which is conducive to improving the heat exchange efficiency and enthalpy efficiency of the fresh air filter element. If the thickness of the reticulated porous support layer is less than 6 μm, it is not easy to form a reticulated porous support layer with high mechanical strength, resulting in relatively large air resistance and pressure drop, which is not conducive to the operation and enthalpy efficiency of the fresh air filter element. If the thickness of the reticulated porous support layer is greater than 30 μm, it will lead to a low packing density of the total heat exchange membrane, affecting the heat exchange efficiency of the fresh air filter element.

[0025] Although the present invention does not particularly limit the porosity of the reticulated porous support layer, preferably, the porosity of the reticulated porous support layer is defined as 30 - 75%. For example, it can be 40%, 50%, 60%, 70%, or the range composed of any two of them.

[0026] As a preferred technical solution of the present invention, the porosity of the reticulated porous support layer is further limited to 30-75%. Within this porosity range, it can ensure that there are enough pores in the reticulated porous support layer, thereby effectively increasing the diffusion and effective travel of gas molecules in the reticulated porous support layer, improving the heat exchange efficiency of the total heat exchange membrane, and also ensuring that the reticulated porous support layer has a low wind resistance and pressure drop. If the porosity of the reticulated porous support layer is lower than 30%, the increase in the diffusion and effective travel of gas molecules in the reticulated porous support layer is not obvious, and the improvement of the heat exchange efficiency of the polymer total heat exchange membrane is not obvious. If the porosity of the reticulated porous support layer is higher than 75%, it is easy to cause a large wind resistance and pressure drop of the reticulated porous support layer.

[0027] Although the present invention does not particularly limit the average pore diameter of the reticulated porous support layer, preferably, the average pore diameter of the reticulated porous support layer is limited to 10-80 nm, for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm or the range composed of any two of them.

[0028] As a preferred technical solution of the present invention, the present invention further limits the pore size distribution of the reticulated porous support layer to 10-80 nm. A suitable pore size is beneficial to form a dense functional layer to provide a suitable heat exchange area to ensure the heat exchange efficiency and gas barrier effect.

[0029] Although the present invention does not particularly limit the ratio of the pore diameter to the thickness of the reticulated porous support layer, preferably, the ratio of the pore diameter to the thickness of the reticulated porous support layer is limited to 1:(0.5-5), for example, it can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or the range composed of any two of them.

[0030] As a preferred technical solution of the present invention, the present invention further limits the ratio of the pore diameter to the thickness of the reticulated porous support layer to 1:(0.5-5). A suitable ratio of the pore diameter to the thickness is beneficial to the effective collision of gas molecules in the reticulated porous support layer, thereby ensuring the diffusion and movement of gas molecules, and then having a positive impact on the moisture permeability and enthalpy heat efficiency of the polymer total heat exchange membrane.

[0031] Preferably, the functional layer is provided on one side surface of the reticulated porous support layer by interfacial polymerization and fills at least part of the pores of the reticulated porous support layer.

[0032] In fact, the present invention does not particularly limit the preparation method of the functional layer. As long as the prepared functional layer can meet the above various characteristic ranges, the manufacturing method corresponding to the purpose can be freely selected, such as the interfacial polymerization method, the coating method, etc.

[0033] As a preferred technical solution of the present invention, in order to better control the thickness of the functional layer, it is defined that the functional layer is disposed on one side surface of the reticular porous support layer by interfacial polymerization and fills at least part of the pores of the reticular porous support layer; on the one hand, the method of interfacial polymerization is simple and easy to operate, facilitating large-scale continuous production; on the other hand, the interfacial polymerization reaction is controllable, and the thickness of the prepared functional layer is relatively thin. Compared with the traditional coated hydrophilic polymer functional film layer (generally with a thickness > 2μm), the functional layer can have a higher selective permeation rate of water vapor molecules, can efficiently block the permeation of other gas molecules such as carbon dioxide, and enables the obtained polymer total heat exchange membrane to have a higher latent heat exchange; in addition, the functional layer prepared by the method of interfacial polymerization has a three-dimensional chemical cross-linked structure, has good chemical stability and mechanical properties, and because the material of the functional layer is firmly combined with the porous support layer in the form of an interpenetrating network during the interfacial polymerization process, there is no problem of water absorption, swelling and shedding of the traditional hydrophilic polymer dense functional layer. In a humid environment for a long time, the chemical cross-linked structure remains stable, the functional film layer does not swell or shed, the structure remains dense, and its performance is basically not attenuated, and the service life is longer.

[0034] Preferably, the functional layer is a polyamide functional layer.

[0035] Although the present invention does not particularly limit the thickness of the functional layer, preferably, the thickness of the functional layer is defined as 10 - 800 nm, for example, it can be 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm or the range composed of any two of them.

[0036] In the second aspect, the present invention provides a method for preparing a polymer total heat exchange membrane having a Turing structure as described in the first aspect, and the preparation method includes: forming a functional layer having an uneven Turing structure on the outer surface and pores of the reticular porous support layer by interfacial polymerization to obtain the polymer total heat exchange membrane having a Turing structure.

[0037] In the preferred interfacial polymerization method of the present invention, there is no particular limitation on the preparation raw materials and the preparation method, as long as the diffusion rate difference between the aqueous phase monomer and the oil phase monomer in the interfacial polymerization reaction can be enlarged, the raw materials and methods corresponding to the purpose can be freely selected.

[0038] Preferably, the raw materials for preparing the functional layer include an oil-phase monomer, a water-phase monomer, and a hydrophilic polymer. Since the interfacial polymerization process is a reaction-diffusion process far from the thermodynamic equilibrium state, and the diffusion coefficients of the oil-phase monomer and the water-phase monomer in the medium are the same or close, a Turing structure cannot be formed, and the surface area of the functional layer cannot be increased. Therefore, in the present invention, a hydrophilic polymer is added to the raw materials for preparing the functional layer. The hydrophilic polymer can form hydrogen bond interactions with the water-phase monomer, which can reduce the molecular diffusion rate of the water-phase monomer in the medium, and then form a suitable diffusion coefficient difference with the oil-phase monomer (forming a diffusion coefficient difference of at least one order of magnitude). Through the synergistic effect, a diffusion-induced instability phenomenon occurs, and then a Turing structure can be formed by interfacial polymerization. The formation of the Turing structure significantly increases the specific surface area of the functional layer and the effective contact sites of water molecules, thereby effectively promoting the moisture permeability rate of the heat exchange membrane.

[0039] Preferably, the oil-phase monomer includes acyl chloride, and more preferably trimesoyl chloride.

[0040] Preferably, the water-phase monomer includes polyamine.

[0041] Preferably, the number-average molecular weight of the hydrophilic polymer is 4000 - 40000 Da, such as 10000 Da, 20000 Da, 30000 Da, or the range composed of any two of them.

[0042] Preferably, the hydrophilic polymer includes any one or a combination of at least two of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyethylene oxide (PEO), polymethyl methacrylate (PMMA), or polyethyleneimine (PEI).

[0043] In the present invention, since different hydrophilic polymers play different roles in controlling the diffusion of the water-phase monomer in the water phase, by adding different types of hydrophilic polymers, when the water-phase monomer diffuses to the oil phase side of the oil-water interface and undergoes an interfacial polymerization reaction, a bumpy Turing structure and a Turing structure with different specific surface areas can be formed, thereby effectively controlling the mass transfer diffusion of water molecules in the polymer total heat exchange membrane and improving the moisture permeability performance and enthalpy heat exchange efficiency of the heat exchange membrane.

[0044] In a specific embodiment of the present invention, when PVA is added to the aqueous solution, a "tubular-like" Turing structure (i.e., a convex long tubular structure) can be formed after subsequent interfacial polymerization. Its specific surface area is significantly enhanced compared with the spherical non-Turing structure, and the moisture permeability also increases.

[0045] In another specific embodiment of the present invention, a crosslinking agent is further added to the aqueous solution to form a hydrophilic polymer crosslinking network on the surface and at least part of the pores of the reticular porous support layer, thereby further restricting the diffusion rate of the aqueous monomer and further expanding the diffusion rate difference between the aqueous monomer and the oil-phase monomer in the subsequent interfacial polymerization reaction, thereby forming a Turing structure functional layer with several convex structures.

[0046] Here, a hydrophilic polymer containing an amino group (which can be a primary amine group or a secondary amine group), such as polyethyleneimine (PEI), is taken as an example to describe the formation process in detail: the crosslinking agent causes the hydrophilic polymer to form a hydrophilic polymer crosslinking network on the surface and at least part of the pores of the reticular porous support layer. The amino groups contained in the hydrophilic polymer network on the surface of the reticular porous support layer first undergo a crosslinking reaction with the polyacyl chloride to generate anchor points, and then the polyamine in the aqueous phase continues to undergo a polymerization reaction with the polyacyl chloride to form at least three extensions away from the surface of the reticular porous support layer from the anchor points. After a certain distance, they polymerize with each other to form convex convergence points, which are manifested as regular dot-line structures, i.e., protrusions, on the dense functional layer. This kind of Turing structure has a larger roughness and specific surface area, so it enhances the moisture permeability of the functional membrane, and further improves the enthalpy heat exchange efficiency of the total heat exchange membrane; at the same time, due to the existence of the anchor points, the dense functional layer of the Turing structure obtained by interfacial polymerization tightly anchors the reticular porous support layer, thereby significantly enhancing the structural stability of the total heat exchange membrane, its swelling resistance during use, and further improving the service life and cycle of the total heat exchange membrane.

[0047] Although the present invention does not particularly limit the type of the crosslinking agent, and any type corresponding to the purpose can be freely selected as long as it can cause the hydrophilic polymer to undergo a crosslinking reaction, preferably, it is defined that the crosslinking agent includes any one or a combination of at least two of glutaraldehyde, succinaldehyde or glutaric acid.

[0048] Preferably, the raw materials for preparing the functional layer further include an acid-binding agent and / or a surfactant.

[0049] Preferably, the acid-binding agent includes polyamine.

[0050] Preferably, the polyamine includes any one or a combination of at least two of triethylamine, diethylenetriamine or triethylenetetramine.

[0051] Preferably, the surfactant includes sodium dodecyl sulfate and / or sodium dodecylbenzenesulfonate.

[0052] Preferably, the method for forming the functional layer with the uneven Turing structure includes the following steps:

[0053] (1) Mix the aqueous monomer and the hydrophilic polymer in water to obtain an aqueous solution;

[0054] Mix the oil-phase monomer and the organic solvent to obtain an oil-phase solution;

[0055] (2) Immerse the reticulated porous support layer in the aqueous solution obtained in step (1), take it out, and make at least part of the pores of the reticulated porous support layer contain the aqueous solution to obtain a treated reticulated porous support layer;

[0056] (3) Coat the oil-phase solution obtained in step (1) on the surface of the treated reticulated porous support layer obtained in step (2), and through an interfacial polymerization reaction, form the functional layer with the uneven Turing structure.

[0057] In the present invention, the ways to adjust the Turing structure to have different roughnesses and specific surface area increments, in addition to obtaining by the above-mentioned method of using different hydrophilic polymers to affect the morphology of the Turing structure of the functional layer, can also consider controlling the concentration of the hydrophilic polymer added and regulating the temperature and reaction time of the interfacial polymerization within an appropriate range. Also, the formed Turing structure can be controlled to have different roughnesses and specific surface area increments. The improvement of roughness and specific surface area can promote the significant increase of the effective contact area and mass transfer area of gaseous water molecules, and thus effectively improve the moisture permeability and enthalpy heat exchange efficiency of the polymer total heat exchange membrane.

[0058] Although the present invention does not particularly limit the mass percentage content of the aqueous-phase monomer in the aqueous solution described in step (1), preferably, the mass percentage content of the aqueous-phase monomer in the aqueous solution described in step (1) is limited to 0.5-4%, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or the range composed of any two of them.

[0059] Although the present invention does not particularly limit the mass percentage content of the hydrophilic polymer in the aqueous solution described in step (1), preferably, the mass percentage content of the hydrophilic polymer in the aqueous solution described in step (1) is limited to 0.1-4%, for example, it can be 0.2%, 0.5%, 1%, 1.2%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or the range composed of any two of them.

[0060] Although the present invention does not particularly limit the mass percentage content of the oil-phase monomer in the oil-phase solution described in step (1), preferably, the mass percentage content of the oil-phase monomer in the oil-phase solution described in step (1) is limited to 0.02-1%, for example, it can be 0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8% or the range composed of any two of them.

[0061] In the present invention, the required common additives in the art can also be added according to corresponding requirements.

[0062] Preferably, a crosslinking agent is further added to the aqueous solution in step (1).

[0063] As a preferred technical solution of the present invention, during the process of immersing the reticulated porous support layer into the aqueous solution obtained in step (1), the aqueous solution will enter the pores of the reticulated porous support layer. At this time, the hydrophilic polymer is in a free and random thermal motion state, and through actions such as hydrogen bonding, it inhibits the diffusion rate of the aqueous monomers, reducing the diffusion rate of the aqueous monomers in the aqueous phase. Furthermore, a Turing structure such as a tubular shape can be formed. In comparison, the random thermal motion of the hydrophilic polymer has a limited inhibitory effect on the diffusion of the aqueous monomers. If crosslinking is carried out by adding a crosslinking agent to the aqueous solution, the hydrophilic polymer can be fixed in the pores of the reticulated porous support layer in the form of an interpenetrating network, restricting the random thermal motion of the hydrophilic polymer. This fixed hydrophilic polymer network has a stronger hydrogen bonding effect on the aqueous monomers and a stronger inhibitory effect on the diffusion of the aqueous monomers. As a result, the diffusion rate of the aqueous monomers is further reduced, leading to a greater difference in the diffusion rates between the aqueous monomers and the oil-phase monomers. Consequently, an octopus Turing structure different from the tubular structure can be formed.

[0064] Preferably, an acid-binding agent and / or a surfactant are further added to the aqueous solution in step (1).

[0065] As a preferred technical solution of the present invention, adding an acid-binding agent to the aqueous solution can make the interfacial polymerization reaction more complete, and thus the formed Turing structure is denser, thereby better increasing the roughness and specific surface increment of the functional layer.

[0066] As a preferred technical solution of the present invention, adding a surfactant to the aqueous solution can improve the interfacial phase compatibility between the functional layer formed by interfacial bonding and the reticulated porous support layer, and improve the adhesion between the functional layer and the reticulated porous support layer.

[0067] Although the present invention does not particularly limit the coating method in step (3), preferably, it is defined that the coating method in step (3) includes any one or a combination of at least two of spraying, pouring, roll coating, knife coating, or slot coating.

[0068] Although the present invention does not particularly limit the temperature of the interfacial polymerization in step (3), preferably, it is defined that the temperature of the interfacial polymerization in step (3) is 70 - 90 °C, for example, it can be 72 °C, 74 °C, 76 °C, 78 °C, 80 °C, 82 °C, 84 °C, 86 °C, 88 °C, or a range composed of any two of them.

[0069] Although the present invention does not particularly limit the time of the interfacial polymerization described in step (3), preferably, the time of the interfacial polymerization described in step (3) is limited to 3 to 180 s. For example, it can be 5 s, 10 s, 20 s, 40 s, 80 s, 100 s, 120 s, 140 s, 160 s, or the range composed of any two of them.

[0070] As a preferred technical solution of the present invention, the preparation method of the polymer total heat exchange membrane includes the following steps:

[0071] (1) Mix an aqueous monomer, a hydrophilic polymer, an acid-binding agent, and a surfactant in water to obtain an aqueous solution;

[0072] Mix an oil-phase monomer and an organic solvent to obtain an oil-phase solution;

[0073] (2) Immerse the reticulated porous support layer in small molecule alcohol, take it out and immerse it in the aqueous solution obtained in step (1), add a small molecule cross-linking agent for cross-linking, take it out, and remove the residual aqueous solution on the surface of the reticulated porous support membrane through a water removal roller to obtain a treated reticulated porous support layer;

[0074] (3) Coat the oil-phase solution obtained in step (1) on the surface of the treated reticulated porous support layer obtained in step (2), use a scraper or a water removal roller to remove the residual oil-phase solution on the surface of the reticulated porous support membrane, and through an interfacial polymerization reaction, form the functional layer with the uneven Turing structure on the surface of the reticulated porous support layer to obtain the polymer total heat exchange membrane.

[0075] In the third aspect, the present invention provides a fresh air exchange system, which includes the polymer total heat exchange membrane with a Turing structure as described in the first aspect or the polymer total heat exchange membrane prepared by the preparation method as described in the second aspect.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] The polymer total heat exchange membrane with a Turing structure provided by the present invention includes a reticulated porous support layer and a functional layer. The functional layer is provided on the single-side outer surface of the reticulated porous support layer and fills at least part of the pores of the reticulated porous support layer, and the functional layer has an uneven Turing structure; by using the reticulated porous support layer and the functional layer with an uneven Turing structure in combination, the obtained polymer total heat exchange membrane has high moisture permeability, and at the same time has high structural stability, and thus has a longer service life cycle, and is suitable for application in a fresh air exchange system. Description of the Drawings

[0078] Figure 1Scanning electron microscope image of one side surface of the functional layer in the polymer total heat exchange membrane provided for Example 1, with a magnification of 10K;

[0079] Figure 2 Scanning electron microscope image of one side surface of the functional layer in the polymer total heat exchange membrane provided for Example 4, with a magnification of 10K;

[0080] Figure 3 Scanning electron microscope image of one side surface of the functional layer in the polymer total heat exchange membrane provided for Comparative Example 1, with a magnification of 10K. Detailed implementation manners

[0081] The technical solutions of the present invention will be further described below through specific implementation manners. Those skilled in the art should understand that the described embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0082] Example 1

[0083] A polymer total heat exchange membrane with a Turing structure, which includes a reticular porous support layer and a functional layer. The functional layer is disposed on the single-side outer surface of the reticular porous support layer and fills at least part of the pores of the reticular porous support layer, and the functional layer has an uneven Turing structure;

[0084] Among them, the reticular porous support layer is a polyolefin membrane (Shenzhen Xingyuan Material Technology Co., Ltd., SW320H), with a thickness of 20 μm, a porosity of 50%, and an average pore diameter of 38 nm;

[0085] The functional layer is a polyamide functional layer, with a thickness of 140 nm, having a Turing structure similar to an octopus shape;

[0086] The preparation method of the polymer total heat exchange membrane provided in this example includes the following steps:

[0087] (1) Dissolve piperazine, triethylamine, sodium dodecylbenzenesulfonate, and polyethyleneimine (PEI, number average molecular weight of 10000 Da) in water to obtain an aqueous solution; the mass percentage content of PEI in the aqueous solution is 0.5%, the mass percentage content of piperazine is 2%, the mass percentage content of triethylamine is 2%, and the mass percentage content of sodium dodecylbenzenesulfonate is 0.2%;

[0088] Dissolve trimesoyl chloride in an isoparaffin reagent (Isopar G) to obtain an oil phase solution; the mass percentage content of trimesoyl chloride in the oil phase solution is 0.3%;

[0089] (2) Immerse the polyolefin membrane in ethanol for 30 s. After taking it out, transfer it into the aqueous solution obtained in step (1). After 10 min, add glutaraldehyde with a mass percentage of 0.05% relative to the aqueous solution, crosslink for 5 min, take it out, and remove the residual aqueous solution on the surface of the diaphragm through a water removal roller, so that at least part of the pores of the reticular porous support layer contain the aqueous solution, and the treated polyolefin membrane is obtained;

[0090] (3) Spray the oil phase solution obtained in step (1) on one surface of the treated polyolefin membrane obtained in step (2), and carry out an interfacial polymerization reaction at 80 °C for 30 s to form a functional layer with an uneven Turing structure on the surface of the polyolefin membrane, and the polymer total heat exchange membrane with a Turing structure is obtained.

[0091] Example 2

[0092] A polymer total heat exchange membrane with a Turing structure, which is different from Example 1 in that the mass percentage of PEI in the aqueous solution obtained in step (1) of the preparation method is 1%, so that the thickness of the obtained polyamide functional layer is 174 nm, and other substances, structures and preparation steps are all referred to Example 1.

[0093] Example 3

[0094] A polymer total heat exchange membrane with a Turing structure, which is different from Example 1 in that the reaction time of the interfacial polymerization in step (3) of the preparation method is 120 s, so that the thickness of the obtained polyamide functional layer is 701 nm, and other substances, structures and preparation steps are all referred to Example 1.

[0095] Example 4

[0096] A polymer total heat exchange membrane with a Turing structure, which includes a reticular porous support layer and a functional layer. The functional layer is arranged on the single-side outer surface of the reticular porous support layer and fills at least part of the pores of the reticular porous support layer, and the functional layer has an uneven Turing structure;

[0097] Among them, the reticular porous support layer is a polyolefin membrane (Shenzhen Xingyuan Materials Technology Co., Ltd., SW320H), with a thickness of 10 μm, a porosity of 50%, and a pore size distribution of 38 nm;

[0098] The functional layer is a polyamide functional layer, with a thickness of 136 nm and a tubular-like Turing structure;

[0099] The preparation method of the polymer total heat exchange membrane provided in this example includes the following steps:

[0100] (1) Dissolve piperazine, triethylamine, sodium dodecylbenzenesulfonate, and PVA (number-average molecular weight of 30,000 Da) in water to obtain an aqueous solution; the mass percentage content of PVA in the aqueous solution is 0.5%, the mass percentage content of piperazine is 2%, the mass percentage content of triethylamine is 2%, and the mass percentage content of sodium dodecylbenzenesulfonate is 0.2%;

[0101] Dissolve trimesoyl chloride in an isoparaffin reagent (Isopar G) to obtain an oil-phase solution; the concentration of trimesoyl chloride in the oil-phase solution is 0.3%;

[0102] (2) Immerse the polyolefin membrane in ethanol for 30 s, take it out, and remove the residual aqueous solution on the surface of the diaphragm through a water removal roller, so that at least part of the pores of the reticular porous support layer contain the aqueous solution, obtaining a treated polyolefin membrane;

[0103] (3) Spray the oil-phase solution obtained in step (1) on one side surface of the treated polyolefin membrane obtained in step (2), and carry out an interfacial polymerization reaction at 80 °C for 30 s to form a functional layer with an uneven Turing structure on the surface of the polyolefin membrane, obtaining the polymer total heat exchange membrane with a Turing structure.

[0104] Example 5

[0105] A polymer total heat exchange membrane with a Turing structure, which is different from Example 4 in that the mass percentage content of PVA in the aqueous solution obtained in the preparation method step (1) is 1%, so that the thickness of the obtained polyamide functional layer is 158 nm, and other substances, structures, and preparation steps are all referred to Example 4.

[0106] Example 6

[0107] A polymer total heat exchange membrane with a Turing structure, which is different from Example 4 in that the time of the interfacial polymerization reaction in the preparation method step (3) is 120 s, so that the thickness of the obtained polyamide functional layer is 830 nm, and other substances, structures, and preparation steps are all referred to Example 4.

[0108] Example 7

[0109] A polymer total heat exchange membrane with a Turing structure, which is different from Example 1 in that the reaction time of the interfacial polymerization in the preparation method step (3) is extended to 200 s, so that the thickness of the obtained polyamide functional layer is 900 nm, and other substances, structures, and preparation steps are all referred to Example 1.

[0110] Example 8

[0111] A polymer total heat exchange membrane with a Turing structure, which is different from that of Example 1 in that the thickness of the polyolefin membrane is 40 μm, and other substances, structures and preparation steps are all referred to Example 1.

[0112] Example 9

[0113] A polymer total heat exchange membrane with a Turing structure, which is different from that of Example 1 in that the thickness of the polyolefin membrane is 5 μm, and other substances, structures and preparation steps are all referred to Example 1.

[0114] Example 10

[0115] A polymer total heat exchange membrane with a Turing structure, which is different from that of Example 1 in that the porosity of the polyolefin membrane is 80%, and other substances, structures and preparation steps are all referred to Example 1.

[0116] Example 11

[0117] A polymer total heat exchange membrane with a Turing structure, which is different from that of Example 1 in that the porosity of the polyolefin membrane is 20%, and other substances, structures and preparation steps are all referred to Example 1.

[0118] Example 12

[0119] A polymer total heat exchange membrane with a Turing structure, which is different from that of Example 1 in that glutaraldehyde is not added for cross-linking in step (2), and other substances, structures and preparation steps are all referred to Example 1.

[0120] Comparative Example 1

[0121] A polymer total heat exchange membrane, which is different from that of Example 1 in that PVA is not added to the aqueous solution in step (1) of the preparation method, so that the obtained functional layer is spherical without a Turing structure, and other substances, structures and preparation steps are all referred to Example 1.

[0122] Performance test:

[0123] (1) Appearance morphology: The polymer total heat exchange membranes provided in Example 1, Example 4 and Comparative Example 1 were tested by a scanning electron microscope (Zeiss, Gemini360), and the scanning electron microscope images of the surface of the functional layer side of the polymer total heat exchange membranes provided in Example 1, 4 and Comparative Example 1 are respectively as Figures 1 to 3 shown;

[0124] From Figure 1 it can be seen that the functional layer of the polymer total heat exchange membrane provided in Example 1 is a Turing structure with a convex structure, where the convergence point is located at the highest point of the convexity, and the protruding fibers between multiple convexities intersect to form a network structure, presenting an overall "octopus"-like shape;

[0125] From Figure 2 It can be seen that the functional layer of the polymer total heat exchange membrane provided in Example 4 has a Turing structure of "tubular-like".

[0126] From Figure 3 It can be seen that the functional layer of the polymer total heat exchange membrane provided in Comparative Example 1 has a spherical structure of non-Turing structure.

[0127] (2) Specific surface area increment: Use a specific surface area and pore size analyzer (Beijing Jingwei Gaobo Science and Technology Co., Ltd., model JW-BK112) to measure the specific surface area of the reticulated porous support layer, the polymer total heat exchange membrane with a Turing structure provided in the examples, and the polymer total heat exchange membrane without a Turing structure provided in the comparative example, and then calculate the specific surface area increment of the polymer total heat exchange membrane;

[0128] The specific test method includes: cutting the polymer total heat exchange membrane and the reticulated porous support layer into slices and loading them into the sample tube, and then measuring the nitrogen adsorption amount;

[0129] The specific calculation method includes: specific surface area increment = (specific surface area of the polymer total heat exchange membrane with a Turing structure - specific surface area of the polymer total heat exchange membrane without a Turing structure) / (specific surface area of the total heat exchange membrane without a Turing structure - specific surface area of the reticulated porous support layer) × 100%.

[0130] (3) Surface roughness of the functional layer: Test by using an atomic force microscope (Bruker, model NanoWizard4XPbruker). The specific test method includes: drying the sample to be tested at 80 °C and then placing it on the sample stage of the atomic force microscope for testing to obtain the surface roughness of the sample to be tested.

[0131] (4) Moisture permeability rate: Test according to the method provided in the national standard "GB / T 2679.2 - 2015".

[0132] (5) Number of protrusions per unit area: Use SEM (Zeiss, model Gemini360), under the magnification condition of 10K times, count the number of convergence points in the 5×5μm area field of view, and then calculate the average number of convergence points per unit area (1μm 2 ) as the number of protrusions per unit area.

[0133] (6) Air permeability value and structural stability of the total heat exchange membrane: Test the air permeability value according to the method provided in the national standard "GB / T 36363 - 2018";

[0134] At 25°C, the polymer total heat exchange membrane was immersed in water for 300 days, and then tested and the air permeability value of the polymer total heat exchange membrane was recorded. The change rate of the air permeability value of the total heat exchange membrane was calculated by the following formula to characterize the structural stability of the total heat exchange membrane:

[0135] Change rate of air permeability value = (Air permeability value after 300 days of immersion - Air permeability value before immersion) / Air permeability value before immersion × 100%;

[0136] The evaluation criteria for structural stability are as follows: The absolute value of the change rate of the air permeability value < 2% indicates that the total heat exchange membrane has good structural stability, anti-swelling, and a good service life. The absolute value of the change rate of the air permeability value ≥ 2% indicates that the structural stability of the total heat exchange membrane is poor.

[0137] The total heat exchange membranes provided in Examples 1 to 12 and Comparative Examples 1 to 2 were tested according to the above test method, and the test results are shown in Table 1:

[0138] Table 1

[0139]

[0140] It can be seen from the data in Table 1 that:

[0141] The polymer total heat exchange membranes with Turing structures provided in Examples 1 to 12 have a higher moisture permeability rate (moisture permeability rate ≥ 930 g / m 2 / 24h) compared to the polymer total heat exchange membrane without a Turing structure provided in Comparative Example 1;

[0142] Among them, the polymer total heat exchange membranes with a raised structure (octopus-like) Turing structure functional layer provided in Examples 1 to 3 and Examples 7 to 11 have a lower change rate of air permeability value after 300 days of water immersion compared to the polymer total heat exchange membranes with a tubular-like Turing structure (without a raised structure) functional layer provided in Examples 4 to 6 and Example 12, and the polymer total heat exchange membrane without a Turing structure functional layer provided in Comparative Example 1.

[0143] The applicant declares that the present invention uses the above examples to illustrate a polymer total heat exchange membrane with a Turing structure and its preparation method and application, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of the raw materials selected for the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A polymer total heat exchange membrane with a Turing structure, characterized in that, The polymer total heat exchange membrane includes a reticular porous support layer and a functional layer; The functional layer is disposed on a single-side surface of the reticular porous support layer and fills at least part of the pores of the reticular porous support layer, and the functional layer has an uneven Turing structure.

2. The polymer total heat exchange membrane according to claim 1, characterized in that, The roughness of the functional layer ≥15 nm, preferably ≥25 nm; Preferably, the specific surface area increment of the polymer total heat exchange membrane ≥6%, more preferably ≥20%.

3. The polymer total heat exchange membrane according to claim 1 or 2, characterized in that The Turing structure of the functional layer has a number of protrusions; Preferably, the number of protrusions per unit area in the functional layer is not less than 2 / μm 2 ; Preferably, each of the protrusions is octopus-like.

4. The polymer total heat exchange membrane according to any one of claims 1 to 3, characterized in that The reticular porous support layer is a polymer porous membrane; Preferably, the polymer porous membrane includes at least one of a polyolefin membrane, a polysulfone membrane, a cellulose acetate membrane or a polyester membrane; Preferably, the thickness of the reticular porous support layer is 6-30 μm; Preferably, the porosity of the reticular porous support layer is 30-75%; Preferably, the average pore diameter of the reticular porous support layer is 10-80 nm; Preferably, the ratio of the average pore diameter to the thickness of the reticular porous support layer is 1:(0.5-5).

5. The polymer total heat exchange membrane according to any one of claims 1 to 4, characterized in that The functional layer is disposed on a single-side surface of the reticular porous support layer and fills at least part of the pores of the reticular porous support layer by means of interfacial polymerization.

6. The polymer total heat exchange membrane according to any one of claims 1 to 5, characterized in that The functional layer is a polyamide functional layer; Preferably, the thickness of the functional layer is 10-800 nm.

7. A method for preparing a polymer total heat exchange membrane with a Turing structure as described in any one of claims 1 to 6, characterized in that, The preparation method includes: forming a functional layer with an uneven Turing structure on the outer surface and at least part of the pores of the reticular porous support layer by means of interfacial polymerization to obtain the polymer total heat exchange membrane with a Turing structure.

8. The preparation method according to claim 7, characterized in that, The preparation raw materials of the functional layer include an oil-phase monomer, a water-phase monomer and a hydrophilic polymer; Preferably, the oil-phase monomer includes an acyl chloride, more preferably trimesoyl chloride; Preferably, the water-phase monomer includes a polyamine; Preferably, the number-average molecular weight of the hydrophilic polymer is 4000-40000 Da; Preferably, the hydrophilic polymer includes any one or a combination of at least two of polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, polymethyl methacrylate or polyethyleneimine; Preferably, the preparation raw materials of the functional layer further include a crosslinking agent; Preferably, the crosslinking agent includes any one or a combination of at least two of glutaraldehyde, succinaldehyde or glutaric acid; Preferably, the preparation raw materials of the functional layer further include an acid-binding agent and / or a surfactant; Preferably, the acid-binding agent includes a polyamine; Preferably, the polyamine includes any one or a combination of at least two of triethylamine, diethylenetriamine or triethylenetetramine; Preferably, the surfactant includes sodium dodecyl sulfate and / or sodium dodecylbenzenesulfonate.

9. The preparation method according to claim 7 or 8, characterized in that, The method for forming a functional layer with an uneven Turing structure includes the following steps: (1) Mix the water-phase monomer and the hydrophilic polymer in water to obtain a water-phase solution; Mix the oil-phase monomer and an organic solvent to obtain an oil-phase solution; (2) Immerse the reticular porous support layer in the aqueous solution obtained in step (1), take it out, and make at least part of the pores of the reticular porous support layer contain the aqueous solution to obtain a treated reticular porous support layer; (3) Coat the surface of the treated reticular porous support layer obtained in step (2) with the oil phase solution obtained in step (1), and form the functional layer with the uneven Turing structure through interfacial polymerization; Preferably, the mass percentage content of the aqueous phase monomer in the aqueous solution in step (1) is 0.5-4%; Preferably, the mass percentage content of the hydrophilic polymer in the aqueous solution in step (1) is 0.1-4%; Preferably, the mass percentage content of the oil phase monomer in the oil phase solution in step (1) is 0.02-1%; Preferably, a crosslinking agent is further added to the aqueous solution in step (1); Preferably, an acid-binding agent and / or a surfactant are further added to the aqueous solution in step (1). Preferably, the coating method in step (3) includes any one or a combination of at least two of spraying, pouring, roll coating, knife coating or slot coating; Preferably, the temperature of the interfacial polymerization in step (3) is 70-90°C; Preferably, the time of the interfacial polymerization in step (3) is 3-180 s.

10. A fresh air exchange system, characterized in that, The fresh air exchange system includes the polymer total heat exchange membrane with a Turing structure as described in any one of claims 1-6 or the polymer total heat exchange membrane prepared by the preparation method as described in any one of claims 7-9.

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