Total heat exchange membrane and preparation method and application thereof

Abstract

The invention relates to a total heat exchange membrane as well as a preparation method and application thereof. The total heat exchange membrane comprises a porous supporting layer and a compact functional layer arranged on at least one side of the porous supporting layer, the material of the compact functional layer comprises a combination of a one-dimensional nanofiber material and a block copolymer. According to the total heat exchange membrane provided by the invention, all the components are synergistically compounded according to a specific ratio, so that the total heat exchange membrane has good heat resistance, the heat shrinkage after being placed at 150 DEG C for 1.5 h is less than or equal to 3%, the heat shrinkage after being placed at 180 DEG C for 1 h is less than or equal to 8%, the total heat exchange membrane can be normally used at industrial high temperature, meanwhile, the moisture permeability of the total heat exchange membrane is relatively high, the air permeability is greater than or equal to 31,000 sec / 100mL, and the moisture permeability is greater than or equal to 1360g / m < 2 >. 24h.

Description

A full heat exchange membrane and its preparation method and application Technical Field

[0001] The present application relates to the field of heat exchange membrane technology, for example, a full heat exchange membrane and its preparation method and application. Background Art

[0002] Currently, heat exchange membranes are mostly of three types: paper-based, aluminum foil and polymer-based. Among them, aluminum foil heat exchange membranes can only achieve sensible heat exchange and have low enthalpy thermal efficiency; paper-based heat exchange membranes are prone to mildew and have a short service life; currently, polymer-based heat exchange membranes are mainly used, which can achieve full heat exchange of latent heat and sensible heat, have high selective permeability to water molecules, and have good barrier properties to other gases, and can achieve higher enthalpy thermal efficiency.

[0003] The full heat exchange membrane is a heat recovery device when the air is replaced. It is mostly used in buildings and structures designed for living scenarios. The operating temperature is mostly below 50°C. However, in industrial scenarios, the operating temperature sometimes reaches above 150°C. The functional layer membranes of the currently common polymer-based full heat exchange membranes will melt or shrink significantly above this temperature and cannot be used normally under such high temperature conditions. This limits the use of the full heat exchange membrane. Therefore, it is urgent to develop a full heat exchange membrane with good heat resistance and moisture permeability, and meet the application requirements in industrial scenarios above 150°C.

[0004] Summary of the Invention

[0005] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0006] The present application provides a full heat exchange membrane, a preparation method and application thereof. Through the selection and design of membrane materials, the obtained full heat exchange membrane has good heat resistance and moisture permeability, high full heat exchange efficiency, and can meet the conditions of use above 150°C. Even if used under conditions as high as 180°C, it will not melt, and the thermal shrinkage rate is also low.

[0007] In a first aspect, the present application provides a full heat exchange membrane, which includes a porous support layer and a dense functional layer arranged on at least one side of the porous support layer; the material of the dense functional layer includes a combination of one-dimensional nanofiber material and block copolymer.

[0008] The full heat exchange membrane provided by the present application has a one-dimensional nanofiber material in the membrane material as the main membrane-forming structure, which has a rigid structure and good heat resistance. The gaps between the one-dimensional nanofiber materials are filled by block copolymers, which provide diffusion and mass transfer channels for water molecules. Moreover, through the interaction with the porous support layer, the adhesion between the dense functional layer and the porous support layer and the structural integration of the membrane are improved, thereby giving the full heat exchange membrane better overall heat resistance.

[0009] The following are optional technical solutions for this application, but are not intended to limit the technical solutions provided in this application. Through the following optional technical solutions, the objectives and beneficial effects of this application can be better achieved and realized.

[0010] In one embodiment, the surface of the one-dimensional nanofiber material is modified to contain polar groups, and the polar groups include any one of hydroxyl groups, carboxyl groups, sulfonic acid groups, or amino groups.

[0011] The surface of the one-dimensional nanofiber material has been modified to contain polar groups, which give it sites for water molecules to contact, absorb and transfer mass. It can also form a compact structure with good heat resistance through hydrogen bond stacking. At the same time, the polar groups grafted on the one-dimensional nanofiber material become sites for water molecules to bind, effectively improving the effective area and mass transfer efficiency of water molecules.

[0012] In one embodiment, the degree of modification functionalization of the one-dimensional nanofiber material is 20-45%, for example, it can be 20%, 22%, 24%, 26%, 28%, 30%, 33%, 35%, 38%, 40%, 42%, 45% or any two thereof.

[0013] The appropriate degree of modification and functionalization will be more conducive to the hydrogen bonding and stacking between one-dimensional nanofiber materials, further improving the density and heat resistance of one-dimensional nanofiber materials, and also conducive to the dispersion and membrane preparation of one-dimensional nanofiber materials during the membrane making process. At the same time, it ensures appropriate water molecule receiving sites, which is more conducive to the preparation of highly moisture-permeable full heat exchange membranes.

[0014] In the present application, the degree of modified functionalization is tested by a nuclear magnetic resonance method. The specific operation is as follows: tetramethylsilane (TMS) is selected as the internal standard, deuterated chloroform (d-CDCl3) and deuterated dimethyl sulfoxide (d6-DMSO) are used as test solvents, and the test is performed on a nuclear magnetic resonance instrument (Bruker AVANCEIII400). The test parameters are a frequency of 250 MHz and a temperature of 26°C. The area of ​​the characteristic peak of the modified functional group in the obtained nuclear magnetic resonance spectrum is integrated, and the degree of modified functionalization is calculated by the following formula: Degree of modified functionalization = Integral area of ​​characteristic peak of modified functional group / total integrated area) × 100%.

[0015] In the present application, there is no particular limitation on the modification treatment method of the one-dimensional nanofiber material, as long as it is a grafting method known in the art. For example, dichloromethane and sulfur trioxide are mixed to treat the one-dimensional nanofiber material to make it sulfonate; sodium hydroxide and chloroacetic acid are mixed to treat the one-dimensional nanofiber material to make it carboxylate, etc.

[0016] In the present application, there is no particular limitation on the aspect ratio of the one-dimensional nanofiber material.

[0017] In one embodiment, the aspect ratio of the one-dimensional nanofiber material is (10-50):1, for example, it can be 10:1, 15:1, 18:1, 20:1, 25:1, 28:1, 30:1, 35:1, 38:1, 40:1, 45:1, 48:1, 50:1 or a range consisting of any two thereof.

[0018] Controlling the appropriate aspect ratio of one-dimensional nanofiber materials is more conducive to film formation, and the one-dimensional nanofiber materials are fully stacked through hydrogen bonding, which significantly improves the heat resistance of the membrane.

[0019] In the present application, there is no particular limitation on the length of the one-dimensional nanofiber material, but the length is also related to the performance of the full heat exchange membrane.

[0020] In one embodiment, the length of the one-dimensional nanofiber material is 100-500 nm, for example, it can be 100 nm, 150 nm, 180 nm, 200 nm, 250 nm, 280 nm, 300 nm, 350 nm, 380 nm, 400 nm, 450 nm, 480 nm, 500 nm or a range consisting of any two thereof.

[0021] There is no particular limitation on the material of the one-dimensional nanofibers in this application.

[0022] In one embodiment, the one-dimensional nanofiber material includes at least one of an inorganic nanofiber material or an organic nanofiber material.

[0023] In one embodiment, the inorganic nanofiber material includes any one of silicon carbide nanowires, silicon carbide nanotubes, titanium dioxide nanorods, aluminum oxide nanorods, silicon dioxide nanorods, calcium sulfate nanorods, or hydroxyapatite nanowires, or a combination of at least two thereof.

[0024] In one embodiment, the organic nanofiber material includes any one of polyimide nanofibers, polyethylene terephthalate nanofibers, cellulose nanofibers, or aramid nanofibers, or a combination of at least two thereof.

[0025] In one embodiment, the block copolymer comprises at least one of an AB block copolymer, an ABA block copolymer, or a BAB block copolymer.

[0026] In one embodiment, the A segment in the block copolymer includes any one of a polyacrylic acid segment, a polyacrylamide segment, a polyethyleneimine segment, a polyvinyl alcohol segment, a polyoxyethylene segment, a polyvinyl pyrrolidone segment, a cellulose segment, a chitosan segment or a sulfonated polyetheretherketone segment.

[0027] In one embodiment, the polyacrylic acid segment includes any one of a polyacrylic acid segment, a polyhydroxyethyl acrylate segment, a polymethacrylic acid segment, and a polyhydroxyethyl methacrylate segment.

[0028] In one embodiment, the polyacrylamide-based segment includes a polyacrylamide segment or a polymethacrylamide segment.

[0029] In one embodiment, the cellulose segment includes any one of a hydroxypropyl methylcellulose segment, a hydroxymethyl cellulose segment, a hydroxyethyl cellulose segment or a hydroxyethyl methyl cellulose segment.

[0030] In one embodiment, the B segment in the block copolymer includes any one of a fluorine-containing polymer segment, a vinyl aromatic polymer segment, a polyamide segment, a polyurethane segment, a polyacrylate segment, or a polyester segment.

[0031] In one embodiment, the fluorine-containing polymer segment includes a polyvinylidene fluoride segment or a polytetrafluoroethylene segment.

[0032] In one embodiment, the vinyl aromatic polymer segment comprises a polystyrene segment or a poly(4-methylstyrene) segment.

[0033] In one embodiment, the polyamide segment includes any one of a polyhexamethylene adipamide segment, a polyamide 6 segment, a polyamide 66 segment, a polyamide 10 segment, a polyamide 12 segment, a polyhexamethylene sebacamide segment, a polydecane sebacamide segment, or a polyhexamethylene terephthalamide segment.

[0034] In one embodiment, the polyacrylate segment includes any one of a poly(tert-butyl acrylate) segment, a poly(tert-butyl methacrylate) segment, a poly(methyl acrylate) segment, and a poly(methyl methacrylate) segment.

[0035] In one embodiment, the polyester segment includes a polycaprolactone segment or a polylactide segment.

[0036] The A segment described in the present application is a polymer segment containing a polar hydrophilic group, which is conducive to the formation of hydrogen bonds. The B segment is a flexible segment containing a weakly polar hydrophobic group, which is conducive to the formation of van der Waals forces. The joint action of the A segment and the B segment is conducive to the block copolymer to interact with the one-dimensional nanofiber material through hydrogen bonds and van der Waals forces to form a better bond, good compatibility, and dense film formation; at the same time, after film formation, the strong hydrogen bonding effect of the A segment is adjusted by the B segment to a certain extent. The influence on the mass transfer of water molecules ensures the smooth transmission and mass transfer of water molecules in the membrane, provides a channel for the diffusion and mass transfer of water molecules, and makes the full heat exchange membrane have higher moisture permeability and full heat exchange efficiency; in addition, the block copolymer has a certain adhesion to the porous support layer, which can increase the interaction between the dense functional layer and the porous support layer and the degree of integration of the full heat exchange membrane, further improving the heat resistance of the membrane.

[0037] In the present application, there is no particular limitation on the molecular weight ratio of the A segment to the B segment in the block copolymer.

[0038] In one embodiment, the molecular weight ratio of the A segment to the B segment in the block copolymer is 1:(1-4), for example, it can be 1:1, 1:1.2, 1:1.4, 1:1.6, 1:2, 1:2.4, 1:2.6, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8, 1:4 or a range consisting of any two thereof.

[0039] Controlling the molecular weight ratio of the A segment to the B segment in the block copolymer, that is, making the mass percentage of the non-polar group segment in the polymer higher than that of the polar group segment, is more conducive to the formation of a relatively stable entanglement effect.

[0040] In one embodiment, the block copolymer has a molecular weight of 20-500 KDa, for example, 20 KDa, 50 KDa, 100 KDa, 150 KDa, 200 KDa, 250 KDa, 300 KDa, 350 KDa, 400 KDa, 450 KDa, 500 KDa, or any two thereof.

[0041] The AB block copolymer described in the present application can be obtained by purchasing a commercially available reagent product, or by following the conventional experimental steps or conditions described in the literature in the art.

[0042] In the present application, there is no particular restriction on the mass ratio of the one-dimensional nanofiber material to the block copolymer.

[0043] In one embodiment, the mass ratio of the one-dimensional nanofiber material to the block copolymer is (1-4):1, for example, it can be 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1 or a range consisting of any two of them.

[0044] Controlling the mass ratio of one-dimensional nanofiber material to block copolymer within a certain ratio range is beneficial to further improving the heat resistance of the full heat exchange membrane and the diffusion and mass transfer efficiency of water molecules, and significantly improving the moisture permeability and full heat exchange efficiency.

[0045] In one embodiment, the block copolymer is an AB block copolymer.

[0046] In one embodiment, the AB block copolymer includes any one or a combination of at least two of polyacrylic acid-polystyrene block copolymer, polyoxyethylene-polystyrene block copolymer, polyoxyethylene-polyurethane block copolymer, polyvinyl alcohol-polystyrene block copolymer, polyoxyethylene-polyamide 6 block copolymer, polyvinyl pyrrolidone-polyhexamethylene terephthalamide block copolymer, sulfonated polyetheretherketone-polyamide 66 block copolymer, polyoxyethylene-polyt-butyl acrylate block copolymer, polyvinylpyrrolidone-polyt-butyl acrylate block copolymer or sulfonated polyetheretherketone-polyt-butyl acrylate block copolymer.

[0047] The AB block copolymer ensures better integrity of the chain segments, thereby further enhancing the interaction between the block copolymer and the one-dimensional nanofiber material, and further improving the performance of the full heat exchange membrane.

[0048] In one embodiment, the porous support layer comprises a polymer porous membrane.

[0049] In the present application, there is no particular limitation on the material of the polymer porous membrane.

[0050] In one embodiment, the polymer porous membrane includes any one of a polyolefin membrane, a polyester membrane, a polyvinylidene fluoride membrane, or a polystyrene membrane.

[0051] In one embodiment, the polyolefin film includes any one of a polyethylene film, a polypropylene film, a polybutylene film, and a polypentene film.

[0052] In one embodiment, the polyester film includes any one of a polyethylene terephthalate film, a polycarbonate film, a polylactide film, and a polycaprolactone film.

[0053] In the present application, there is no particular limitation on the thickness of the polymer porous membrane, but the thickness is also related to the performance of the total heat exchange membrane.

[0054] In one embodiment, the thickness of the polymer porous membrane is 5-50 μm, for example, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or a range consisting of any two thereof.

[0055] In one embodiment, the thickness of the polymer porous membrane is 8-35 μm, for example, it can be 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, 32 μm, 35 μm or a range consisting of any two of them.

[0056] In the present application, there is no particular limitation on the porosity and air permeability of the polymer porous membrane.

[0057] In one embodiment, the porosity of the polymer porous membrane is 20-80%, for example, it can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or any two thereof.

[0058] In one embodiment, the air permeability of the polymer porous membrane is 50-1000s / 100cc, for example, it can be 50s / 100cc, 100s / 100cc, 150s / 100cc, 200s / 100cc, 250s / 100cc, 300s / 100cc, 350s / 100cc, 400s / 100cc, 450s / 100cc, 500s / 100cc, 550s / 100cc, 600s / 100cc, 700s / 100cc, 800s / 100cc, 900s / 100cc, 1000s / 100cc or a range consisting of any two of them.

[0059] In one embodiment, the total heat exchange membrane satisfies at least one of the following:

[0060] a) The thickness of the total heat exchange membrane is 9-60 μm, for example, it can be 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm or a range consisting of any two thereof.

[0061] b) The thermal shrinkage of the full heat exchange membrane after being placed at 150° C. for 1.5 hours is ≤20%, for example, it can be 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20% or a range consisting of any two thereof.

[0062] c) the thermal shrinkage of the full heat exchange membrane after being placed at 180° C. for 1 hour is ≤35%, for example, it can be 0, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35% or a range consisting of any two thereof.

[0063] d) the air permeability of the total heat exchange membrane is ≥20,000 s / 100 mL, for example, it can be 35,000 s / 100 mL, 34,000 s / 100 mL, 33,000 s / 100 mL, 32,000 s / 100 mL, 31,000 s / 100 mL, 30,000 s / 100 mL, 29,000 s / 100 mL, 28,000 s / 100 mL, 27,000 s / 100 mL, 26,000 s / 100 mL, 25,000 s / 100 mL, 24,000 s / 100 mL, 23,000 s / 100 mL, 22,000 s / 100 mL, 21,000 s / 100 mL, 20,000 s / 100 mL, or a range consisting of any two of them.

[0064] e) The moisture permeability of the full heat exchange membrane is ≥1020g / m 2 24h, for example, 1020g / m 2 24h, 1050g / m 2 24h, 1100g / m 2 24h, 1150g / m 2 24h, 1200g / m 2 24h, 1250g / m 2 24h, 1300g / m 2 24h, 1350g / m 2 24h, 1400g / m 2 24h, 1450g / m 2 24h, 1500g / m 2 24 hours or a combination of both.

[0065] In the second aspect, the present application provides a method for preparing the full heat exchange membrane as described in the first aspect, the preparation method comprising: mixing a one-dimensional nanofiber material, a block copolymer and a solvent to obtain a nanofiber dispersion, coating the nanofiber dispersion on at least one side of a porous support layer, and obtaining the full heat exchange membrane after drying.

[0066] The mixing method may be a known method, for example, a ball mill, a bead mill, a sand mill, a roller mill, a homogenizer, an ultrasonic homogenizer, a high-pressure homogenizer, an ultrasonic device, a paint shaker, etc. The mixing may also be performed by combining the above-mentioned multiple mixing devices to perform dispersion in stages.

[0067] In one embodiment, the solvent includes any one of water, N-methylpyrrolidone, acetone or ethanol, or a combination of at least two thereof.

[0068] In one embodiment, based on the mass of the nanofiber dispersion as 100%, the mass of the one-dimensional nanofiber material is 1-15%, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or a range consisting of any two thereof.

[0069] The coating method can be performed by a known method, such as dip coating, gravure coating, slot die coating, blade coating, comma coating, kiss coating, roller coating, rod coating, blow coating, spin coating, screen printing, inkjet printing, pad printing or other types of printing.

[0070] In one embodiment, the drying temperature is 50-85°C, for example, it can be 50°C, 55°C, 58°C, 60°C, 65°C, 68°C, 70°C, 75°C, 78°C, 80°C, 85°C or any two thereof.

[0071] In one embodiment, the drying time is 0.5-5 min, for example, it can be 0.5 min, 0.6 min, 0.8 min, 1 min, 1.2 min, 1.4 min, 1.6 min, 1.8 min, 2 min, 3 min, 4 min, 5 min or a range consisting of any two thereof.

[0072] The drying method can be carried out using known methods, such as hot air drying, contact drying or a combination thereof.

[0073] In one embodiment, the raw materials for preparing the total heat exchange membrane further include an auxiliary agent.

[0074] It should be noted that the auxiliary agents can be appropriately selected for use or not, and can be used alone or in combination according to the preparation of the full heat exchange membrane.

[0075] The following are non-limiting examples of adjuvants and the amounts of adjuvants added that can be used in this application.

[0076] In one embodiment, the auxiliary agent includes any one of a surfactant, a dispersant, a thickener, or a defoaming agent, or a combination of at least two thereof.

[0077] In one embodiment, the surfactant comprises any one or a combination of at least two of long-chain fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers, fatty acid polyoxyethylene esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, or polyethers. In one embodiment, based on 100% by mass of the one-dimensional nanofiber material, the mass of the surfactant is 0.1-1%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or a range consisting of any two thereof.

[0078] In one embodiment, the dispersant includes any one of sodium hydroxymethyl cellulose, sodium polyacrylate, or ammonium polyacrylate, or a combination of at least two thereof.

[0079] In one embodiment, based on the mass of the one-dimensional nanofiber material being 100%, the mass of the dispersant is 1-5%, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or a range consisting of any two thereof.

[0080] In one embodiment, the thickener includes any one or a combination of at least two of carboxymethyl starch, alginate, cationic starch, gelatin, methyl cellulose, hydroxyethyl cellulose, methyl hydroxypropyl cellulose or guar gum.

[0081] In one embodiment, based on the mass of the one-dimensional nanofiber material being 100%, the mass of the thickener is 0.3-1%, for example, it can be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% or a range consisting of any two thereof.

[0082] In one embodiment, the defoaming agent includes any one of polyether-modified silicone, polyether-modified mineral oil, or polysiloxane, or a combination of at least two thereof.

[0083] In one embodiment, based on the mass of the one-dimensional nanofiber material as 100%, the mass of the defoaming agent is 0.2-3%, for example, it can be 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.5%, 2.8%, 3% or a range consisting of any two of them.

[0084] In a third aspect, the present application provides an application of the full heat exchange membrane as described in the first aspect or the full heat exchange membrane obtained by the preparation method of the full heat exchange membrane as described in the second aspect in an exhaust gas heat recovery device.

[0085] Compared with the related art, this application has the following beneficial effects:

[0086] The full heat exchange membrane provided by this application has high full heat exchange efficiency and good heat resistance. The thermal shrinkage after being placed at 150°C for 1.5 hours is ≤3%, and the thermal shrinkage after being placed at 180°C for 1 hour is ≤8%. It can be used normally under industrial high temperatures. At the same time, its moisture permeability is high, with air permeability ≥31000sec / 100mL and moisture permeability ≥1360g / m 2 ·24h.

[0087] Still other aspects will become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0088] To facilitate understanding of the present application, the present application lists the following examples. Those skilled in the art should understand that the examples are only provided to help understand the present application and should not be considered as specific limitations of the present application.

[0089] The sources of some components in the Examples and Comparative Examples are as follows. Components for which specific experimental steps or conditions are not specified in the Examples or Comparative Examples can be obtained by following the conventional experimental steps or conditions described in the relevant art.

[0090] (1) Surface sulfonated cellulose nanofibers: 200 nm in length, with an aspect ratio of 10. The preparation method is as follows: 1 g of cellulose nanofibers is dispersed in 100 mL of dichloromethane, 15 g of sulfur trioxide is added, and the mixture is reacted at 26° C. for 30 min. The surface sulfonated cellulose nanofibers are then centrifuged to obtain the surface sulfonated cellulose nanofibers.

[0091] Surface-sulfonated cellulose nanofibers of other different lengths and aspect ratios in the embodiments can be prepared by referring to the above preparation method.

[0092] (2) Surface carboxylated cellulose nanofibers: 200 nm in length, aspect ratio of 10, prepared as follows: 2 g of cellulose nanofibers were soaked in 100 mL of pure water for 12 h, and 12 g of sodium hydroxide was added; chloroacetic acid was added in multiple portions, with the amount added being 70% of the amount of sodium hydroxide, stirred for 1 hour, filtered, rinsed with pure water, and ball-milled to obtain the surface carboxylated cellulose nanofibers.

[0093] (3) A polyacrylic acid-polystyrene block copolymer (molecular weight of 150 KDa, molecular weight ratio of polyacrylic acid segment to polystyrene segment of 1:2), the preparation method of which comprises: using 0.1 mmol of ethyl 2-bromoisobutyrate as an initiator, 0.05 mmol of cuprous bromide as a catalyst, 0.05 mmol of N,N,N,N,N-pentamethyldiethylenetriamine as a ligand, and 80 mmol of monomer acrylic acid, in 100 mL of toluene solvent, performing ATRP reaction under anhydrous and oxygen-free conditions, the reaction temperature being 70° C., the reaction time being 5 h, to obtain a polyacrylic acid precursor, the conversion rate of acrylic acid being 86.7%, and then adding 100 mmol of styrene monomer to continue initiating polymerization, the reaction time being 5 h, the conversion rate of styrene monomer being 96%, to obtain the polyacrylic acid-polystyrene block copolymer.

[0094] Other polyacrylic acid-polystyrene block copolymers in the examples can be prepared by referring to the above preparation method by adjusting the amount of monomers and initiators added.

[0095] (4) A polyoxyethylene-polystyrene block copolymer (molecular weight of 150 KDa, molecular weight ratio of polyoxyethylene segment to polystyrene segment of 1:2), the preparation method of which comprises: reacting 0.1 mmol of polyoxyethylene monomethoxy ether (50 KDa) and 0.1 mmol of 2-bromoisobutyryl chloride in 50 mL of dichloromethane for 30 min at 0°C to obtain a macromolecular initiator polyoxyethylene bromide. ATRP reaction is carried out in 100 mL of toluene solvent under anhydrous and oxygen-free conditions using 0.1 mmol of polyoxyethylene bromide as an initiator, 0.05 mol of cuprous bromide as a catalyst, 0.05 mmol of N,N,N,N,N-pentamethyldiethylenetriamine as a ligand, and 100 mmol of monomeric styrene to obtain the polyoxyethylene-polystyrene block copolymer, with a styrene conversion rate of 96%.

[0096] Other polyoxyethylene-polystyrene block copolymers in the examples can be prepared by referring to the above preparation method by adjusting the amount of monomers and initiators added.

[0097] (5) Polyoxyethylene-polyurethane block copolymer (molecular weight of 200 KDa, molecular weight ratio of polyoxyethylene segment to polyurethane segment of 1:2), the preparation method of which comprises: adding 0.1 mmol of polyoxyethylene monomethoxy ether (66.6 KDa) as an initiator and 0.1 mmol of stannous octoate as a catalyst to 300 mL of acetone solvent, then adding 8 mmol of 1,6-hexamethylene diisocyanate monomer and 8 mmol of polylactide (2 KDa), reacting under reflux for 7 h at a reaction temperature of 70°C to obtain the polyoxyethylene-polyurethane block copolymer, and the conversion rate of 1,6-hexamethylene diisocyanate was 83.3%.

[0098] (6) Polyacrylic acid-polystyrene-polyacrylic acid block copolymer (molecular weight of 150 KDa, ratio of the total molecular weight of the polyacrylic acid segment to the molecular weight of the polystyrene segment of 1:2): ATRP reaction was carried out in 100 mL of toluene solvent under anhydrous and oxygen-free conditions using 0.1 mmol of ethyl 2-bromoisobutyrate as initiator, 0.05 mmol of cuprous bromide as catalyst, 0.05 mmol of N,N,N,N,N-pentamethyldiethylenetriamine as ligand, and 40 mmol of monomeric acrylic acid. The reaction time was 5 h and the reaction temperature was 70°C to obtain a polyacrylic acid precursor with an acrylic acid conversion of 86.7%. Then, 100 mmol of styrene monomer was added to continue initiating polymerization for 5 h. The conversion of styrene was 96%, to obtain a polyacrylic acid-polystyrene block copolymer. 40 mmol of monomeric acrylic acid was then added and reacted for 5 h to obtain the polyacrylic acid-polystyrene-polyacrylic acid block copolymer with an acrylic acid conversion of 86.7%.

[0099] (7) Polyvinyl alcohol-polystyrene block copolymer (molecular weight of 450 KDa, molecular weight ratio of polyvinyl alcohol segment to polystyrene segment of 1:2), the preparation method of which comprises: using 0.1 mmol of ethyl 2-bromoisobutyrate as an initiator, 0.05 mmol of cuprous bromide as a catalyst, 0.05 mmol of N,N,N,N,N-pentamethyldiethylenetriamine as a ligand, and 120 mmol of monomer vinyl acetate, in 100 mL of toluene solvent, carrying out ATRP reaction under anhydrous and oxygen-free conditions for 5 h at a reaction temperature of 70°C to obtain a polyvinyl acetate precursor, with a vinyl acetate conversion rate of 95%; then, adding 100 mmol of styrene monomer to continue initiating polymerization, the reaction time is 5 h, and the styrene conversion rate is 96%, thereby obtaining a polyvinyl acetate-polystyrene block copolymer. The obtained polyvinyl acetate-polystyrene block copolymer was alcoholyzed according to the following ratio: polyvinyl acetate-polystyrene block copolymer: sodium hydroxide: methanol: water (mass ratio 100:200:2:0.2) to obtain the polyvinyl alcohol-polystyrene block copolymer.

[0100] (8) Polyethylene film: purchased from Xingyuan Materials, with a thickness of 20 μm, a porosity of 48%, and an air permeability of 180 s / 100 cc;

[0101] (9) Polyacrylic acid: molecular weight 50 KDa, purchased from Aladdin Reagent;

[0102] (10) Polystyrene: molecular weight 100 KDa, purchased from Aladdin Reagent;

[0103] (11) Acrylic acid-styrene random copolymer: 0.1 mmol of ethyl 2-bromoisobutyrate was used as an initiator, 0.1 mmol of cuprous bromide was used as a catalyst, 0.05 mmol of N,N,N,N,N-pentamethyldiethylenetriamine was used as a ligand, 80 mmol of monomeric acrylic acid and 100 mmol of monomeric styrene were simultaneously added to 100 mL of toluene solvent, and ATRP reaction was carried out under anhydrous and oxygen-free conditions for 5 h at a reaction temperature of 70°C to obtain the acrylic acid-styrene random copolymer.

[0104] Example 1

[0105] A full heat exchange membrane and a preparation method thereof, wherein the full heat exchange membrane comprises a porous support layer and a dense functional layer arranged on at least one side of the porous support layer, wherein the porous support layer is a polyethylene membrane, and the material of the dense functional layer comprises surface sulfonated cellulose nanofibers (length 200nm, aspect ratio 10, surface sulfonation degree 30%) and polyacrylic acid-polystyrene block copolymer (molecular weight 150KDa, molecular weight ratio of polyacrylic acid segment to polystyrene segment 1:2) in a mass ratio of 2:1.

[0106] The preparation method comprises: mixing surface-sulfonated cellulose nanofibers (length 200 nm, aspect ratio 10, surface sulfonation degree 30%), polyacrylic acid-polystyrene block copolymer (molecular weight 150 kDa, molecular weight ratio of polyacrylic acid segment to polystyrene segment 1:2), sodium polyacrylate, and water to obtain a nanofiber dispersion, wherein, based on the mass of the nanofiber dispersion being 100%, the mass of the surface-sulfonated cellulose nanofibers is 4%, the mass of the polyacrylic acid-polystyrene block copolymer is 2%, and the mass of the sodium polyacrylate is 0.2%. The nanofiber dispersion is then applied to one side of a polyethylene film and dried at 70°C for 5 minutes to obtain the total heat exchange membrane, which has a thickness of 12 μm.

[0107] Example 2

[0108] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that the surface sulfonated cellulose nanofibers are replaced with an equal amount of surface carboxylated cellulose nanofibers (length 200 nm, aspect ratio 10, surface carboxylation degree 30%). Other raw materials, process steps and parameters are the same as those in Example 1.

[0109] Example 3

[0110] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that an equal amount of polyacrylic acid-polystyrene block copolymer is replaced by a polyoxyethylene-polystyrene block copolymer (molecular weight of 150 KDa, and a molecular weight ratio of polyoxyethylene segments to polystyrene segments of 1:2). Other raw materials, process steps and parameters are the same as those in Example 1.

[0111] Example 4

[0112] A full heat exchange membrane and a preparation method thereof, which differs from Example 3 only in that an equal amount of a polyoxyethylene-polystyrene block copolymer (molecular weight of 150 KDa, a molecular weight ratio of the polyoxyethylene segment to the polystyrene segment of 1:2) is replaced by a polyoxyethylene-polystyrene block copolymer (molecular weight of 200 KDa, a molecular weight ratio of the polyoxyethylene segment to the polystyrene segment of 1:2); other raw materials, process steps and parameters are the same as those in Example 3.

[0113] Example 5

[0114] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 in that surface sulfonated cellulose nanofibers (length 200 nm, aspect ratio 10, surface sulfonation degree 30%) and polyacrylic acid-polystyrene block copolymer (molecular weight 150 KDa, molecular weight ratio of polyacrylic acid segment to polystyrene segment 1:2) are replaced by equal amounts of surface sulfonated cellulose nanofibers (length 300 nm, aspect ratio 15, surface sulfonation degree 30%) and polyoxyethylene-polyurethane block copolymer (molecular weight 200 KDa, molecular weight ratio of polyoxyethylene segment to polyurethane segment 1:2), respectively. Other raw materials, process steps and parameters are the same as those in Example 1.

[0115] Example 6

[0116] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that a polyacrylic acid-polystyrene block copolymer (molecular weight of 150 KDa, a molecular weight ratio of polyacrylic acid segments to polystyrene segments of 1:2) is replaced in equal amounts by a polyvinyl alcohol-polystyrene block copolymer (molecular weight of 450 KDa, a molecular weight ratio of polyvinyl alcohol segments to polystyrene segments of 1:2); other raw materials, process steps, and parameters are the same as those in Example 1.

[0117] Example 7

[0118] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 in that surface sulfonated cellulose nanofibers (length 200 nm, aspect ratio 10, surface sulfonation degree 30%) and polyacrylic acid-polystyrene block copolymer (molecular weight 150 KDa, molecular weight ratio of polyacrylic acid segment to polystyrene segment 1:2) are replaced by equal amounts of surface sulfonated cellulose nanofibers (length 200 nm, aspect ratio 15, surface sulfonation degree 30%) and polyacrylic acid-polystyrene block copolymer (molecular weight 70 KDa, molecular weight ratio of polyacrylic acid segment to polystyrene segment 1:2), respectively. Other raw materials, process steps and parameters are the same as those in Example 1.

[0119] Example 8

[0120] A full heat exchange membrane and a preparation method thereof, which differs from Example 7 only in that an equal amount of a polyacrylic acid-polystyrene block copolymer (molecular weight of 70 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 1:2) is replaced by a polyacrylic acid-polystyrene block copolymer (molecular weight of 100 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 1:2); other raw materials, process steps and parameters are the same as those in Example 7.

[0121] Example 9

[0122] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that the surface sulfonated cellulose nanofibers are replaced with cellulose nanofibers (length 200 nm, aspect ratio 10) in equal amounts, and other raw materials, process steps and parameters are the same as those in Example 1.

[0123] Example 10

[0124] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that surface sulfonated cellulose nanofibers (length 200 nm, aspect ratio 10, surface sulfonation degree 30%) are replaced by equal amounts of surface sulfonated cellulose nanofibers (length 200 nm, aspect ratio 10, surface sulfonation degree 10%). Other raw materials, process steps and parameters are the same as those in Example 1.

[0125] Example 11

[0126] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that surface sulfonated cellulose nanofibers (length 200 nm, aspect ratio 10, surface sulfonation degree 30%) are replaced by an equal amount of surface sulfonated cellulose nanofibers (length 200 nm, aspect ratio 10, surface sulfonation degree 60%). Other raw materials, process steps and parameters are the same as those in Example 1.

[0127] Example 12

[0128] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that surface sulfonated cellulose nanofibers (length 200 nm, aspect ratio 10, surface sulfonation degree 30%) are replaced by an equal amount of surface sulfonated cellulose nanofibers (length 600 nm, aspect ratio 30, surface sulfonation degree 30%). Other raw materials, process steps and parameters are the same as those in Example 1.

[0129] Example 13

[0130] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that surface sulfonated cellulose nanofibers (length 200 nm, aspect ratio 10, surface sulfonation degree 30%) are replaced by an equal amount of surface sulfonated cellulose nanofibers (length 100 nm, aspect ratio 5, surface sulfonation degree 30%). Other raw materials, process steps and parameters are the same as those in Example 1.

[0131] Example 14

[0132] A full heat exchange membrane and a preparation method thereof, which differs from Example 12 only in that the surface sulfonated cellulose nanofibers (length 600 nm, aspect ratio 30, surface sulfonation degree 30%) are replaced by an equal amount of surface sulfonated cellulose nanofibers (length 600 nm, aspect ratio 60, surface sulfonation degree 30%). Other raw materials, process steps and parameters are the same as those in Example 12.

[0133] Example 15

[0134] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that an equal amount of a polyacrylic acid-polystyrene block copolymer (molecular weight of 150 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 1:2) is replaced by a polyacrylic acid-polystyrene block copolymer (molecular weight of 10 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 1:2); other raw materials, process steps and parameters are the same as those in Example 1.

[0135] Example 16

[0136] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that an equal amount of a polyacrylic acid-polystyrene block copolymer (molecular weight of 150 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 1:2) is replaced by a polyacrylic acid-polystyrene block copolymer (molecular weight of 700 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 1:2); other raw materials, process steps and parameters are the same as those in Example 1.

[0137] Example 17

[0138] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that an equal amount of a polyacrylic acid-polystyrene block copolymer (molecular weight of 150 KDa, a molecular weight ratio of polyacrylic acid segments to polystyrene segments of 1:2) is replaced by a polyacrylic acid-polystyrene block copolymer (molecular weight of 150 KDa, a molecular weight ratio of polyacrylic acid segments to polystyrene segments of 1:5); other raw materials, process steps, and parameters are the same as those in Example 1.

[0139] Example 18

[0140] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that an equal amount of a polyacrylic acid-polystyrene block copolymer (molecular weight of 150 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 1:2) is replaced by a polyacrylic acid-polystyrene block copolymer (molecular weight of 150 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 2:1); other raw materials, process steps and parameters are the same as those in Example 1.

[0141] Example 19

[0142] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that a polyacrylic acid-polystyrene block copolymer (molecular weight 150 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 1:2) is replaced in equal amounts by a polyacrylic acid-polystyrene-polyacrylic acid block copolymer (molecular weight 150 KDa, a total molecular weight ratio of the polyacrylic acid segment to the molecular weight of the polystyrene segment of 1:2); other raw materials, process steps, and parameters are the same as those in Example 1.

[0143] Example 20

[0144] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that a polyacrylic acid-polystyrene block copolymer (molecular weight 150 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 1:2) is replaced in equal amounts by a polystyrene-polyacrylic acid-polystyrene block copolymer (molecular weight 150 KDa, a molecular weight ratio of the polyacrylic acid segment to the total molecular weight of the polystyrene segment of 1:2); other raw materials, process steps, and parameters are the same as those in Example 1.

[0145] Comparative Example 1

[0146] A full heat exchange membrane and a preparation method thereof, which differs from Example 9 only in that the material of the dense functional layer does not contain polyacrylic acid-polystyrene block copolymer; that is, the nanofiber dispersion does not contain polyacrylic acid-polystyrene block copolymer, and other raw materials, process steps and parameters are the same as Example 9.

[0147] Comparative Example 2

[0148] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that the material of the dense functional layer does not contain surface sulfonated cellulose nanofibers; that is, the nanofiber dispersion does not contain surface sulfonated cellulose nanofibers, and other raw materials, process steps and parameters are the same as those in Example 1.

[0149] Comparative Example 3

[0150] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that a polyacrylic acid-polystyrene block copolymer (molecular weight 150 KDa, a molecular weight ratio of polyacrylic acid segments to polystyrene segments of 1:2) is replaced in equal amounts by a mixture of polyacrylic acid (molecular weight 50 KDa) and polystyrene (molecular weight 100 KDa), wherein the mass ratio of polyacrylic acid to polystyrene is 1:1. Other raw materials, process steps, and parameters are the same as those in Example 1.

[0151] Comparative Example 4

[0152] A full heat exchange membrane and a preparation method thereof, which differs from Example 1 only in that an equal amount of a polyacrylic acid-polystyrene block copolymer (molecular weight of 150 KDa, a molecular weight ratio of the polyacrylic acid segment to the polystyrene segment of 1:2) is replaced by an acrylic acid-styrene random copolymer. Other raw materials, process steps and parameters are the same as those in Example 1.

[0153] Performance testing:

[0154] (1) Air permeability test: Air permeability test is carried out in accordance with GB / T36363-2018 standard;

[0155] (2) Moisture permeability test: Moisture permeability test is carried out in accordance with GB / T1037-2021 standard;

[0156] (3) Thermal shrinkage test: Thermal shrinkage test is carried out in accordance with GB / T36363-2018 standard.

[0157] The full heat exchange membranes provided in Examples 1-20 and Comparative Examples 1-4 were subjected to air permeability tests, moisture permeability tests, and thermal shrinkage tests at 150°C / 1.5h and 180°C / 1h, respectively. The results are shown in Table 1:

[0158] Table 1

[0159] As can be seen from Table 1, the full heat exchange membranes provided in Examples 1-20 of the present application have low thermal shrinkage rates at 150°C and 180°C, wherein the thermal shrinkage rate at 150°C / 1.5h is less than 20%, and the thermal shrinkage rate at 180°C / 1h is ≤35%; while the full heat exchange membranes provided in Examples 1-8 have further reduced thermal shrinkage rates at 150°C and 180°C, wherein the thermal shrinkage rate at 150°C is ≤3%, and the thermal shrinkage rate at 180°C is ≤8%, and the air permeability of the full heat exchange membrane is ≥31000s / 100mL, and the moisture permeability is ≥1360g / m 2 24h, with higher moisture permeability.

[0160] From the comparison of Examples 1-20 and Comparative Examples 1-2, it can be seen that if the dense functional layer does not contain block copolymers, a dense film layer cannot be formed, and high gas barrier and low thermal shrinkage effects cannot be achieved; if it does not contain one-dimensional nanofiber materials, the heat resistance of the membrane deteriorates significantly and cannot be used in working conditions with higher temperatures.

[0161] From the comparison of Examples 1-20 and Comparative Examples 3-4, it can be seen that in the dense functional layer, the polymer must be a block copolymer, so that it can form a strong interaction with the one-dimensional nanofiber material and the porous support layer, thereby improving the degree of integration of the overall structure of the membrane and improving the heat resistance of the membrane. Therefore, whether it is replaced with a polymer mixture or a random copolymer, the above technical effects cannot be achieved.

[0162] It can be seen from Examples 9-18 that the modification treatment of the one-dimensional nanofiber material, the degree of modification functionalization, the aspect ratio, the molecular weight of the block copolymer, and the molecular weight ratio of the A segment and the B segment in the block copolymer will have a certain impact on the heat resistance and moisture permeability of the membrane.

[0163] The applicant declares that while the above-mentioned embodiments are used to illustrate the detailed process equipment and process flow of the present application, the present application is not limited to the above-mentioned detailed process equipment and process flow, which does not mean that the present application must rely on the above-mentioned detailed process equipment and process flow in order to be implemented. Those skilled in the art should understand that any improvements to the present application, equivalent replacements for the raw materials of the present application's products, addition of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present application.

Claims

1. A total heat exchange membrane, wherein, The total heat exchange membrane includes a porous support layer and a dense functional layer disposed on at least one side of the porous support layer; The material of the dense functional layer includes a combination of one-dimensional nanofiber material and block copolymer.

2. The total heat exchange membrane according to claim 1, wherein The surface of the one-dimensional nanofiber material is modified to contain polar groups, and the polar groups include any one of hydroxyl group, carboxyl group, sulfonic acid group or amino group.

3. The total heat exchange membrane according to claim 1 or 2, wherein The modification functionalization degree of the one-dimensional nanofiber material is 20-45%.

4. The total heat exchange membrane according to any one of claims 1-3, wherein, The aspect ratio of the one-dimensional nanofiber material is (10-50):1; Optionally, the length of the one-dimensional nanofiber material is 100-500 nm; Optionally, the one-dimensional nanofiber material includes at least one of inorganic nanofiber material or organic nanofiber material; Optionally, the inorganic nanofiber material includes any one or a combination of at least two of silicon carbide nanowires, silicon carbide nanotubes, titanium dioxide nanorods, aluminum oxide nanorods, silicon dioxide nanorods, calcium sulfate nanorods or hydroxyapatite nanowires; Optionally, the organic nanofiber material includes any one or a combination of at least two of polyimide nanofibers, polyethylene terephthalate nanofibers, cellulose nanofibers or aramid nanofibers.

5. The total heat exchange membrane according to any one of claims 1-4, wherein, The block copolymer includes at least one of AB block copolymer, ABA block copolymer or BAB block copolymer; Optionally, the A chain segment in the block copolymer includes any one of polyacrylic acid chain segment, polyacrylamide chain segment, polyethyleneimine chain segment, polyvinyl alcohol chain segment, polyethylene oxide chain segment, polyvinylpyrrolidone chain segment, cellulose chain segment, chitosan chain segment or sulfonated polyether ether ketone chain segment; Optionally, the polyacrylic acid chain segment includes any one of polyacrylic acid chain segment, polyacrylic acid hydroxyethyl ester chain segment, polymethacrylic acid chain segment or polymethacrylic acid hydroxyethyl ester chain segment; Optionally, the polyacrylamide chain segment includes polyacrylamide chain segment or polymethacrylamide chain segment; Optionally, the cellulose chain segment includes any one of hydroxypropyl methyl cellulose chain segment, hydroxymethyl cellulose chain segment, hydroxyethyl cellulose chain segment or hydroxyethyl methyl cellulose chain segment; Optionally, the B chain segment in the block copolymer includes any one of fluoropolymer chain segment, vinyl aromatic polymer chain segment, polyamide chain segment, polyurethane chain segment, polyacrylate chain segment or polyester chain segment; Optionally, the fluoropolymer chain segment includes polyvinylidene fluoride chain segment or polytetrafluoroethylene chain segment; Optionally, the vinyl aromatic polymer chain segment includes polystyrene chain segment or poly(4-methylstyrene) chain segment; Optionally, the polyamide chain segment includes any one of polyhexamethylene adipamide chain segment, polyamide 6 chain segment, polyamide 66 chain segment, polyamide 10 chain segment, polyamide 12 chain segment, polydecamethylene adipamide chain segment, polydecamethylene sebacamide chain segment or poly(p-phenylene terephthalamide) chain segment; Optionally, the polyacrylate chain segment includes any one of tert-butyl acrylate chain segment, tert-butyl methacrylate chain segment, methyl acrylate chain segment or methyl methacrylate chain segment; Optionally, the polyester chain segment includes polycaprolactone chain segment or polylactide chain segment.

6. The total heat exchange membrane according to claim 5, wherein, The molecular weight ratio of the A segment to the B segment in the block copolymer is 1∶(1 - 4); Optionally, the molecular weight of the block copolymer is 20 - 500 KDa; Optionally, the mass ratio of the one-dimensional nanofiber material to the block copolymer is (1 - 4)∶1.

7. The total heat exchange membrane according to claim 5 or 6, wherein The block copolymer is an AB block copolymer; Optionally, the AB block copolymer includes any one or a combination of at least two of polyacrylic acid-polystyrene block copolymer, polyethylene oxide-polystyrene block copolymer, polyethylene oxide-polyurethane block copolymer, polyvinyl alcohol-polystyrene block copolymer, polyethylene oxide-polyamide 6 block copolymer, polyvinylpyrrolidone-polyhexamethylene terephthalamide block copolymer, sulfonated polyether ether ketone-polyamide 66 block copolymer, polyethylene oxide-tert-butyl acrylate block copolymer, polyvinylpyrrolidone-tert-butyl acrylate block copolymer, or sulfonated polyether ether ketone-tert-butyl acrylate block copolymer.

8. The total heat exchange membrane according to any one of claims 1-7, wherein, The porous support layer includes a polymer porous membrane; Optionally, the polymer porous membrane includes any one of polyolefin membranes, polyester membranes, polyvinylidene fluoride membranes, or polystyrene membranes; Optionally, the thickness of the polymer porous membrane is 5 - 50 μm, and further optionally 8 - 35 μm; Optionally, the porosity of the polymer porous membrane is 20 - 80%; Optionally, the air permeability of the polymer porous membrane is 50 - 1000 s / 100 cc.

9. The total heat exchange membrane according to any one of claims 1-8, wherein, The total heat exchange membrane satisfies at least one of the following: a) The thickness of the total heat exchange membrane is 9 - 60 μm; b) The thermal shrinkage of the total heat exchange membrane when placed at 150 °C for 1.5 h is ≤20%; c) The thermal shrinkage of the total heat exchange membrane when placed at 180 °C for 1 h is ≤35%; d) The air permeability of the total heat exchange membrane is ≥20000 s / 100 mL; e) The moisture permeability of the total heat exchange membrane ≥ 1020 g / m 2 ·24 h.

10. A method for preparing an all-heat exchange membrane according to any one of claims 1-9, comprising: The one-dimensional nanofiber material, the block copolymer, and a solvent are mixed to obtain a nanofiber dispersion liquid, and the nanofiber dispersion liquid is coated on at least one side of the porous support layer, and after drying, the total heat exchange membrane is obtained.

11. The preparation method according to claim 10, wherein, The solvent includes any one or a combination of at least two of water, N-methylpyrrolidone, acetone, or ethanol.

12. The preparation method according to claim 10 or 11, wherein, Based on the mass of the nanofiber dispersion liquid being 100%, the mass of the one-dimensional nanofiber material is 1 - 15%.

13. The preparation method according to any one of claims 10 to 12, wherein, The drying temperature is 50 - 85 °C; Optionally, the drying time is 0.5 - 5 min.

14. The preparation method according to any one of claims 10-13, wherein, The preparation raw materials of the total heat exchange membrane further include additives; Optionally, the additives include any one or a combination of at least two of surfactants, dispersants, thickeners, or defoamers; Optionally, the surfactants include any one or a combination of at least two of long-chain fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers, fatty acid polyoxyethylene esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, or polyethers; Optionally, based on the mass of the one-dimensional nanofiber material being 100%, the mass of the surfactant is 0.1 - 1%; Optionally, the dispersants include any one or a combination of at least two of sodium carboxymethyl cellulose, sodium polyacrylate, or ammonium polyacrylate; Optionally, based on the mass of the one-dimensional nanofiber material being 100%, the mass of the dispersant is 1-5%; Optionally, the thickener includes any one or a combination of at least two of carboxymethyl starch, alginate, cationic starch, gelatin, methylcellulose, hydroxyethyl cellulose, methyl hydroxypropyl cellulose, or guar gum; Optionally, based on the mass of the one-dimensional nanofiber material being 100%, the mass of the thickener is 0.3-1%; Optionally, the defoamer includes any one or a combination of at least two of polyether-modified silicone, polyether-modified mineral oil, or polysiloxane; Optionally, based on the mass of the one-dimensional nanofiber material being 100%, the mass of the defoamer is 0.2-3%.

15. Application of a total heat exchange membrane according to any one of claims 1-9 or a total heat exchange membrane obtained by the preparation method of a total heat exchange membrane according to any one of claims 10-14 in an exhaust gas heat recovery device.