CN119588436A

CN119588436A - A semi-homogeneous anion selective exchange membrane and its preparation method and application

Info

Publication number: CN119588436A
Application number: CN202411930168.2A
Authority: CN
Inventors: 熊冠东; 姜其斌; 徐劲峰; 姜强
Original assignee: Wuhan Danyuange New Membrane Material Co ltd
Current assignee: Wuhan Danyuange New Membrane Material Co ltd
Priority date: 2024-12-25
Filing date: 2024-12-25
Publication date: 2025-03-11

Abstract

The present invention relates to the technical field of resin-based composite membrane materials, and in particular to a semi-homogeneous anion selective exchange membrane and a preparation method and application thereof. The method comprises: uniformly mixing linear low-density polyethylene, an ion exchange resin containing a quaternary ammonium functional group, a resin containing an amide group and an auxiliary agent in a predetermined ratio, and then sequentially performing melt mixing, extrusion film forming and soaking to obtain a semi-homogeneous anion selective exchange membrane. The semi-homogeneous anion selective exchange membrane prepared by the present invention has low resistance, high migration number, and has the properties of heat resistance, oxidation resistance, and good dimensional stability.

Description

Semi-homogeneous anion selective exchange membrane and preparation method and application thereof

Technical Field

The invention relates to the technical field of resin-based composite membrane materials, in particular to a semi-homogeneous anion selective exchange membrane, a preparation method and application thereof.

Background

Ion exchange membranes are an important ion separation material in the purification or treatment of water, food, beverages, chemicals and wastewater and in the facilities for fractionation, migration consumption and electrical regeneration, particularly in electrodialysis and Electrodeionization (EDI) facilities, and are classified into homogeneous ion exchange membranes and heterogeneous ion exchange membranes according to the difference in ion exchange membrane structures. Ion exchange membrane materials are also divided into anionic ion exchange membrane materials and anionic ion exchange membrane materials, homogeneous membranes referring to the entirety of the membrane, excluding any support materials that can be used to enhance strength, are membranes made from reactive polymers that contain ion exchange functionality. Homogeneous membranes tend to be relatively difficult to manufacture, they use hazardous materials during manufacture, and in addition, they are difficult to chemically modify, each modification requiring a change in the basic chemical nature of the membrane, while homogeneous membranes also tend to have limited physical strength and often require a screen or cloth to support because the polymer produced cannot easily combine the desired physical and electrochemical properties to perform effectively in the manufactured device. Heterogeneous membranes are composed of a composite material containing ion exchange resins to deliver electrochemical properties and a binder to impart physical strength and integrity to the delivery, and are typically formed by fusion of a base membrane material and ion exchange resins. Typical heterogeneous membranes may be heterogeneous membranes produced by a paste-like process, current heterogeneous membranes often have poor electrochemical performance.

U.S. patent No. 5037858 discloses an anion selective polymer prepared from a concentrated solution of N, N ' -methylenebisacrylamide, wherein the anion exchange membrane material is designed to incorporate a positive nitrogen ion center, but a single choice of N, N ' -methylenebisacrylamide is used, which is easily separated out during the engineering application of the membrane material, thereby resulting in functional attenuation of the membrane material after a period of operation, and in addition, the use of N, N ' -methylenebisacrylamide by the membrane material has a certain toxicity and is not suitable for use in products and devices requiring high water quality.

U.S. patent No. 7087654B2 discloses an ion exchange and electrochemical method and apparatus employing a one-step quaternization and polymerization of anion selective polymers, which also uses the anion exchange function of the positive nitrogen ion center, which is also in the form of a homogeneous membrane material which is difficult to chemically modify, each modification requiring a change in the basic chemical properties of the membrane, and which has limited physical strength and is relatively costly. The procedures are complicated.

U.S. patent No. 5137925A discloses an anion exchange membrane material with improved fouling properties, wherein the base membrane material used by the anion exchange membrane material is polyvinyl chloride, and meanwhile, an anion homogeneous membrane material with a positive nitrogen ion center and unsaturated double bonds introduced into a high molecular structure is irreversible, and meanwhile, the homogeneous membrane material is difficult to chemically modify, and the basic chemical properties of the membrane need to be changed every modification, and moreover, the physical strength of the homogeneous membrane material is limited, and the cost is relatively high. The procedures are complicated.

U.S. patent No. 4373031a discloses a membrane material for synthesizing an anion exchange polymer using a di-tertiary amine, in which the di-tertiary amine material has a certain toxicity and a certain solubility in hot water, so that the use of the membrane material is suitably performed at a relatively low temperature. And the homogeneous film has no support layer and the physical properties are not very good.

U.S. patent No. 4374720a discloses the synthesis of a water-soluble cross-linking agent and its use in the manufacture of anionic polymers, in which chloroform is used in the preparation of anionic polymers, which is also a homogeneous membrane material, which has been in phase-out in the current membrane material preparation process. The method uses a single ion exchange group positive nitrogen ion center group, and the polymer has certain water solubility. The sheet resistance and ion mobility are not good for the present invention. The ion exchange activity and capacity of the anion exchange membrane material are inferior to those of quaternary ammonium salt type ion exchange groups.

Chinese patent CN 115028956A discloses an anion exchange membrane, a preparation method, and preparation and application of an alkaline anion exchange membrane, in which the preparation of a polycationic polymer is also performed, the anion exchange membrane and the alkaline anion exchange membrane provided by the invention have high ion conductivity, obvious hydrophilic-hydrophobic microphase separation structure and excellent chemical stability, and have good application prospects in the field of anion exchange membrane fuel cells. The solvent of the copolymer solution used in the patent is chloroform, methylene dichloride or tetrahydrofuran, and the anion exchange membrane material uses N-methylpiperidine, N, N' -dimethylpiperazine and N, N-dimethylhexadecylamine, which all enhance the ion exchange capacity, but have larger toxicity, and the monomer substances have certain solubility under the condition of higher temperature, and are used in the field of anion exchange membrane materials and have certain limitation in the technical field of pure water preparation.

In order to overcome the problems existing in the preparation and application processes of the anion exchange membrane material, a new ion exchange membrane is needed to be proposed so as to solve the problems.

Disclosure of Invention

In order to solve the problems, the invention provides a semi-homogeneous anion selective exchange membrane, a preparation method and application thereof, and the invention provides the following technical scheme:

The invention discloses a preparation method of a semi-homogeneous anion selective exchange membrane, which comprises the steps of uniformly mixing linear low-density polyethylene, ion exchange resin containing quaternary ammonium functional groups, resin containing amide groups and an auxiliary agent according to a preset proportion, and then sequentially carrying out melt mixing, extrusion film forming and soaking to obtain the semi-homogeneous anion selective exchange membrane.

Further, melting, mixing and extruding to form a film at 150-180 ℃;

the extrusion film forming speed is controlled to be 0.5-0.8m/min;

The soaking condition is that soaking in sodium chloride solution with mass fraction of 4-5% at 23-25deg.C for 46-50 hr.

Further, the semi-homogeneous anion selective exchange membrane comprises, by weight, 1 to 1.1 parts of linear low density polyethylene, 0.85 to 1.0 parts of ion exchange resin containing quaternary ammonium functional groups, 0.1 to 0.22 parts of resin containing amide groups and 0.03 to 1.0 part of auxiliary agent.

Further, the linear low density polyethylene is obtained by copolymerizing propylene, butene, 4-methyl-1-pentene, hexene or octene;

Wherein the relative molecular weight of the linear low-density polyethylene is 5-10 ten thousand, the density is 0.915-0.935 g/cm ³, and the melting point is 115-120 ℃.

Further, the ion exchange resin containing quaternary ammonium functional groups has a water content of less than 15%;

ion exchange resins containing quaternary ammonium functionality include polystyrene quaternary ammonium anion resins, beaded polystyrene anion exchange resins, and styrene divinylbenzene copolymerized anion exchange resins.

Further, the amount of the amide group-containing resin is 1 to 20% by weight based on the weight of the linear low density polyethylene;

The amide group-containing resin includes polyamide resin and/or polyester polyurethane resin.

Further, the polyamide resin has a relative molecular mass of 8000 to 12000, an acid value of <10mgKOH/g, an amine value of <5mgKOH/g, a softening point temperature of 130 to 140 ℃, an average particle diameter of 25.+ -. 5 μm, and/or,

The polyester polyurethane resin has a relative molecular mass of 5000-12000, an acid value of 30-35mgKOH/g, a glass transition temperature of 40-65 ℃, a softening point temperature of 80-95 ℃ and a melting temperature of 150-160 ℃.

Further, the auxiliary agent comprises calcium stearate and n-stearyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, wherein,

The weight ratio of the calcium stearate to the n-stearyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate is (0.1-0.5) to (0.2-0.5).

The invention also provides a semi-homogeneous anion-selective exchange membrane prepared by the method, and the thickness of the semi-homogeneous anion-selective exchange membrane is 0.20mm-1.00mm.

The invention also provides the use of a semi-homogeneous anion selective exchange membrane as described above in electrodialysis and electrodeionization apparatus.

The invention has the technical effects and advantages that:

the invention provides development and industrialization of a semi-homogeneous membrane material, a semi-homogeneous ion exchange membrane is between a homogeneous membrane and a heterogeneous membrane, a part of fixed groups of the semi-homogeneous ion exchange membrane are combined with a membrane matrix in a chemical bond way, and the electrochemical performance of the membrane is also between that of the homogeneous membrane and the heterogeneous membrane. A part of the fixed groups of the membrane are combined with the polymer matrix in a physical form, and the other part of the fixed groups are combined with the polymer matrix in a chemical bond, so that the membrane has the characteristics of heterogeneous membranes and homogeneous membranes.

The polyamide resin or the polyester polyurethane resin with low molecular weight and amide groups contains positively charged nitrogen atom centers, can provide weak-electric ion exchange groups, can also act as a lubricant to reduce the required extrusion or forming temperature, and is insoluble in water, so that the thermal damage to the ion exchange resin in the thermoforming process is reduced. The membrane material not only combines the advantages of a homogeneous membrane and a heterogeneous membrane, but also has higher high migration number of more than 96 percent, and the membrane surface resistance of less than 12 omega cm ², temperature resistance, oxidation resistance, high strength and the like. Is a membrane material with better engineering application. The test result shows that the membrane surface resistance and migration number of the semi-homogeneous ion exchange membrane material prepared by the invention are improved greatly, and the membrane is also used for electrochemical equipment, such as alkali/chlorine electrolysis equipment, electrophoretic paint purification equipment, electro-organic synthesis equipment and the like, and is particularly suitable for electrodialysis and Electrodeionization (EDI) equipment.

The main materials used in the invention are low molecular weight polyamide resin and (or) polyester polyurethane resin which have lubricating effect on processability, so that the processing performance of linear low density polyethylene is improved, the lubricating processability of LLDPE and anion exchange resin in the process of mixing and forming films is improved, and meanwhile, selective ion exchange groups containing charge positive can be provided, and the effect of anion exchange resin can be also achieved. The ion exchange active point of the anion exchange membrane material is effectively improved, the surface is soaked in the ion exchange resin in the activation process by adding the amide resin, and the specific surface area is larger, so that more ion exchange resin materials are exposed in the treatment fluid in the equipment using the membrane, therefore, the ion exchange membrane material can obtain excellent ion exchange performance within the thickness range of 0.20mm-1.00mm, and meanwhile, the membrane surface resistance of the anion exchange membrane material is lower and the migration number is higher by adding the amide resin.

The anion exchange membrane material has stronger anion adsorption and exchange capacity, thus forming the anion semi-homogeneous phase selective exchange membrane with amido and quaternary ammonium functional groups, in a word, the anion semi-homogeneous anion exchange membrane material has the advantages of low membrane resistance, high migration number, temperature resistance, oxidation resistance, good dimensional stability and the like.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

FIG. 1 is a sample drawing of an extrusion molding process using 10% low molecular weight polyamide resin according to example 1 of the present application;

FIG. 2 is a sample view of the extrusion molding process of example 2 of the present application using 10% low molecular weight polyester polyurethane resin;

FIG. 3 is a sample of an extrusion molding process using 5% low molecular weight polyamide resin +5% polyester polyurethane resin in accordance with example 3 of the present application;

FIG. 4 is a sample of the extrusion molding process of example 4 of the present application without using low molecular weight polyamide resin and polyester polyurethane resin;

FIG. 5 is a sample of the prior art comparative example 5 of the present application, which was a foreign company without adding resin during extrusion molding.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In order to solve the defects in the prior art, the invention discloses a semi-homogeneous anion selective exchange membrane, which comprises, by weight, 1-1.1 parts of Linear Low Density Polyethylene (LLDPE), 0.85-1.0 parts of ion exchange resin containing quaternary ammonium functional groups, 0.1-0.22 parts of resin containing amide groups and 0.03-1.0 part of auxiliary agent (the formula of the auxiliary agent contains 0.1-0.5 part of calcium stearate and 0.2-0.5 part of n-octadecyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate).

In one embodiment of the invention, the linear low density polyethylene is produced by copolymerization of propylene, butene, 4-methyl-1 pentene, hexene or octene, and the like. These mixed monomers undergo free radical polymerization with short chain branching in the polymer to form a combination of linear and low density, and LLDPE film materials of this type have smoothness and hydrophobicity which allow for simplified filling of ion exchange resins and elimination of extractables in the adhesive during the preparation of the ion exchange film materials, which is an advantage for use in electrodeionization devices to produce ultrapure water. Is an ideal base membrane material for preparing high-quality ion exchange membrane materials.

In one embodiment of the invention, the anion exchange resin containing quaternary ammonium functionality has a moisture content of 10-20%, preferably less than 15%, such as the anion exchange resin material used is a beaded polystyrene quaternary ammonium anion resin containing 8-10% DVB copolymerized from styrene, divinylbenzene, a white powder in appearance, a size of about 50 μm, a functionality of NH ₄ ⁺, and a moisture content of 10-20%.

Ion exchange resins containing quaternary ammonium functionality also include beaded polystyrene anion exchange resins and styrene divinylbenzene copolymerized anion exchange resins. Wherein, the bead polystyrene anion exchange resin has the size of 300-1200 mu m, and the anion active group is chloride ion;

The anion exchange resin for styrene divinylbenzene copolymerization can be macroporous styrene divinylbenzene copolymerization anion exchange resin of DuPont company, the size is 650-820 μm, and the anion active group is chloride ion.

In one embodiment of the invention, the amide group-containing resin is used in an amount of 1 to 20 parts by weight of the linear low density polyethylene, and the amide group-containing resin includes a polyamide resin and/or a polyester urethane resin. Among them, polyamide resins having low molecular weight and containing amide groups are resins which can be melt-processed at relatively low temperatures and are obtained by ring-opening polymerization of caprolactam. The main technical index of the low molecular weight polyamide resin is that the relative molecular weight is generally about 1 ten thousand, the preferable relative molecular weight is 8000-12000, the acid value is controlled to be less than 10mgKOH/g, the amine value is controlled to be less than 5mgKOH/g, the softening point temperature is 130-140 ℃, and the average grain diameter is 25+/-5 mu m. This low melting point property allows him to melt at a lower temperature than other polymeric materials, and is easier to handle and process.

The polyester polyurethane resin is a resin material with excellent heat insulation performance, chemical resistance, good electrical performance, easy processing and low water absorption rate of hard polyurethane, and is prepared by condensation polymerization of isocyanate MDI and polyester polyol. The relative molecular weight is 5000-12000, the acid value is controlled at 30-35mgKOH/g, the glass transition temperature is 40-65 ℃, the softening point is 80-95 ℃, and the optimal melting temperature is 150-160 ℃. The amide resin brings about a new weak-electropositive nitrogen atom center and has a weak anion exchange function under certain conditions. The ion exchange and migration capacity of the anion selective exchange membrane can be improved, and the membrane resistance can be reduced. As with the low molecular weight polyamide resins described above, the polyester polyurethane resins used provide chemically bonded ion exchange groups and also serve as a base film material and as a lubricant during the preparation and formation of the base film material. We can also use either or a combination of these two water-insoluble amide-based resin materials containing positive nitrogen ion centers.

In one embodiment of the invention, the auxiliary comprises calcium stearate and n-stearyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, wherein the weight ratio of calcium stearate to n-stearyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate is (0.1-0.5): 0.2-0.5.

Anion exchange membranes are ion exchange membrane materials that selectively allow anions to permeate and adsorb while blocking and rejecting other cations, quaternary ammonium functional group anion exchange is the usual way of exchange for anion membrane materials, and the exchange membrane materials of the present invention are ion exchange membrane materials in which a membrane-like polymer matrix is physically immobilized in addition to an exchange form in which a quaternary ammonium functional group is bound, and also in which a polymer matrix is chemically immobilized in combination with an amide group. Known as semi-homogeneous anion selective exchange membrane materials. Preferably, the raw material composition of the invention mainly uses Linear Low Density Polyethylene (LLDPE) with relative molecular weight of 5-10 ten thousand, density of 0.915-0.935 g/cm ³ and melting point of 115-120 ℃ and ion exchange resin containing quaternary ammonium functional groups, and in order to further improve the performance of anion selective exchange membrane, the invention also uses low molecular weight polyamide resin and (or) polyester polyurethane resin containing amide groups, which have similar melt forming processing temperature as LLDPE, and the two amide group-containing resins have the common characteristics that the amide groups containing nitrogen positive ion center are added on a polymer frame and have ion exchange function under certain conditions. The amide group-containing resin has a molding processing temperature and moldability similar to those of linear low density polyethylene LLDPE, and is insoluble in water. The resin containing amide groups can provide amide groups with weak electric positive property, and provide anion exchange active points in the base film material, so that the anion exchange film material has stronger anion adsorption and exchange capacity, and especially has higher exchange capacity for weak electrolyte ions. The modified polyamide resin can also be used as a base film material, and improves the lubricating processability in the process of mixing LLDPE and quaternary ammonium functional group anion exchange resin, so that the quaternary ammonium functional group-containing anion exchange resin is easier to uniformly disperse in LLDPE/low molecular weight polyamide resin and/or polyester polyurethane resin matrix in simple extrusion processing equipment used by us. In addition, since the resin containing an amide group contains a large number of polar groups. The ion exchange resin wets the surface in the activation process, the specific surface area of the matrix film material is larger, so that more ion exchange resin materials can be exposed in the treatment fluid of equipment using the film, therefore, the ion exchange film material has excellent ion exchange performance within the thickness of 0.20-1.00mm, the film surface resistance of the semi-homogeneous anion exchange film material is lower, the migration number is higher, and the semi-homogeneous anion exchange film material has the performances of temperature resistance, oxidation resistance, good dimensional stability and the like.

The semi-homogeneous anion selective exchange membrane material provided by the invention has a relatively large specific surface area and rich ion exchange active points, so that the semi-homogeneous anion selective exchange membrane material has stronger adsorption and exchange capacity in the aspect of ion exchange. The membrane material has the properties of high selectivity, low ion diffusion resistance, high physical strength, good chemical resistance and the like while isolating gas permeation and water permeation. In addition, such film materials are not used or harmful substances are generated during the preparation process. The membrane material is easy to manufacture and process, and has low processing cost, and meanwhile, the assembly preparation technology of the membrane has simple technical process and low cost. In addition to raw material costs, the films of the present invention are manufactured using the steps of formulation, extrusion or heat treatment and brine conditioning, all using standard low cost manufacturing equipment. Can be realized without special equipment design and upgrading.

The semi-homogeneous anion selective exchange membrane is applied to electrodialysis and electrodeionization equipment, and is widely applied to the fields of semiconductors, biological medicines, petrifaction, thermal power generation, zero pollution emission, brackish water and sea water desalination and the like for preparing pure water and/or ultrapure water.

The invention also provides a preparation method of the semi-homogeneous anion selective exchange membrane, which comprises the following steps of uniformly mixing linear low-density polyethylene, ion exchange resin containing quaternary ammonium functional groups, resin containing amide groups and auxiliary agent according to a preset proportion, and sequentially carrying out melt mixing, extrusion film forming and soaking to obtain the semi-homogeneous anion selective exchange membrane.

In one embodiment of the invention, in the preparation process, firstly, linear Low Density Polyethylene (LLDPE), ion exchange resin containing quaternary ammonium functional groups, polyamide resin (or) with low molecular weight containing amide groups, polyester polyurethane resin (or) and auxiliary agent are smelted and mixed according to a certain proportion, then the mixture is extruded by a screw extruder, a die with required thickness is arranged at the tail end of the extruder, pulling-up is carried out, soaking adjustment and film activation treatment are carried out by using a sodium chloride solution with the mass fraction of 5% at 25 ℃, and the soaking condition is that the mixture is soaked in a sodium chloride solution with the mass fraction of 4-5% at 23-25 ℃ for 46-50 hours. Preferably, the linear low density polyethylene, anion exchange resin and amide group-containing resin are mixed and dried according to the mass ratio of 100:85-95:5-20, extrusion processing is carried out by using an extruder, the extrusion speed is controlled to be 0.5-0.8m/min in the processing process, smelting and film forming are carried out within the range of 150-180 ℃, the thickness of the extruded film is set to be 0.20-1.00mm, after film forming, the film material is placed into a sodium chloride solution with the mass fraction of 5% at 25 ℃ for 48 hours, so as to regulate and activate the film, and the obtained semi-homogeneous anion selective exchange film with amide groups and quaternary ammonium functional groups is obtained.

The semi-homogeneous anion selective exchange membrane is free from using or generating harmful substances in the production and preparation process, the selected amide group-containing resin has proper glass transition temperature and softening point temperature, and the addition of the amide group-containing resin can reduce the extrusion molding temperature required by the membrane material in the smelting and mixing processing process of LLDPE and the ion exchange resin, so that the thermal damage to the ion exchange resin in the thermoforming process is reduced, and the method is simple, effective and low in cost. The anion exchange membrane material can easily modify membrane chemical substances, and any commercially available ion exchange resin can be used as an ion exchange active point, so that the anion exchange membrane material is a semi-homogeneous anion selective exchange membrane material with high efficiency and good performance.

The technical scheme of the invention will be further described with reference to the specific embodiments.

Example 1

450 Parts of linear low density polyethylene (model LLDPEDFDA-9085), 550 parts of anion exchange resin, 45 parts of polyamide resin with low molecular weight containing amido, 0.2 part of calcium stearate and 0.5 part of n-octadecyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1076) are weighed, mixed and dried, extruded by an extruder, extrusion speed is controlled to be 0.5-0.8m/min in the processing process, smelting and film forming are carried out within the range of 150-180 ℃, the film thickness after the extrusion film forming is 0.72mm, and the film material is put into sodium chloride solution with the mass fraction of 5% at 25 ℃ for soaking for 48 hours, so as to adjust and activate the film, and the obtained semi-homogeneous anion selective exchange film (figure 1) with amido and quaternary ammonium functional groups is obtained.

Example 2

450 Parts of linear low density polyethylene (model LLDPEDFDA-9085), 550 parts of anion exchange resin, 45 parts of polyester polyurethane resin, 0.2 part of calcium stearate and 0.5 part of 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propanoic acid n-stearyl alcohol ester (antioxidant 1076) are weighed, mixed and dried, extrusion processing is carried out by using an extruder, the extrusion speed is controlled to be 0.5-0.8m/min in the processing process, smelting and film forming are carried out within the range of 150-180 ℃, the film thickness after extrusion film forming is 0.72mm, and the film material is put into a sodium chloride solution with the mass fraction of 5% at 25 ℃ to be soaked for 48 hours, so as to adjust and activate the film, thus obtaining the semi-homogeneous anion selective exchange film (figure 2) with amide groups and quaternary ammonium functional groups.

Example 3

450 Parts of linear low density polyethylene (model LLDPEDFDA-9085), 550 parts of anion exchange resin, 22.5 parts of polyamide resin with low molecular weight containing amido, 22.5 parts of polyester polyurethane resin, 0.2 part of calcium stearate and 0.5 part of n-octadecyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1076) are weighed, mixed and dried, extrusion processing is carried out by using an extruder, the extrusion speed is controlled to be 0.5-0.8m/min in the processing process, smelting and film forming are carried out within the range of 150-180 ℃, the film thickness after the extrusion film forming is 0.72mm, the film material is put into a sodium chloride solution with the mass fraction of 5% at 25 ℃ for soaking for 48 hours, so as to adjust and activate the film, and the obtained semi-homogeneous anion selective exchange film (figure 3) with amido and quaternary ammonium functional groups.

Comparative example 1

450 Parts of linear low density polyethylene (model LLDPEDFDA-9085), 550 parts of anion exchange resin, 0.2 part of calcium stearate and 0.5 part of n-stearyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1076) are weighed, mixed and dried, extruded by an extruder, extrusion speed is controlled to be 0.5-0.8m/min in the processing process, smelting and film forming are carried out within the range of 150-180 ℃, the film thickness after film forming by extrusion is 0.72mm, and the film material is placed into a sodium chloride solution with the mass fraction of 5% at 25 ℃ to be soaked for 48 hours, so that the film is regulated and activated, and the obtained semi-homogeneous anion selective exchange film with amide groups and quaternary ammonium functional groups (figure 4).

Comparative example 2

The IONPURE company heterogeneous anion exchange membrane material is purchased on the market.

The heterogeneous anion exchange membrane materials (FIG. 5) of examples 1-3, comparative example 1 and the existing IONPURE company on the market were analyzed, and the comparative indexes were mainly examined as film thickness, ion exchange capacity mmol/g, internal resistance (Ω. CM ²) and migration in%. The results of the tests for the main ion exchange capacity and effect evaluation are shown in tables 1-2.

TABLE 1 anionic semi-homogeneous anion exchange resin Membrane Material formulation, unit, parts

Table 2 the performance analysis of the anionic semi-homogeneous anion exchange membrane material is as follows:

The ion exchange capacity, internal resistance in membrane surface and migration number of the membrane material are tested, and the test results (table 2) show that the addition of the polyamide resin and/or the polyester polyurethane resin with low molecular weight containing amide groups can reduce the internal resistance of the ion exchange membrane material and improve the migration number. In the anion exchange resin with polyethylene as base film material, the internal resistance of the film is higher, and an auxiliary agent capable of improving the processing is added, but the internal resistance of the film surface is not improved. Table 2 contains a typical comparison of the values of the different manufacturers' commercial anion exchange membrane materials compared to the present invention. As can be seen from Table 2, the internal resistance of the semipermeable membrane prepared by the method is smaller than or equal to that of the heterogeneous anion exchange membrane material of the IONPURE company, and the internal resistance is low, which indicates that the total water treatment process of the membrane material is greatly reduced in power consumption and slightly improved in migration number. The anion exchange membrane material ion exchange membranes related to the present invention have similar permeation selectivities and permeabilities to other commercially available membranes, and the semi-homogeneous membranes prepared according to the present invention have lower internal membrane resistances and higher ion transfer numbers at substantially the same membrane thicknesses and ion exchange resin ratios.

The main materials used in the present invention, such as linear low density polyethylene, anion exchange resin, low molecular weight polyamide resin and/or polyester polyurethane resin, are all commercially available. Wherein the low molecular weight polyamide resin and/or the polyester polyurethane resin are/is used for setting the technical index of the product according to the requirement. The use and type of such materials should not be construed as limiting the invention in any way due to slight variations in their technical specifications, but rather should be construed in a manner consistent with the meaning of such terms in the context of this specification and the relevant art and should not be construed in an idealized or overly formal sense unless expressly so defined herein. These and other objects and features of the present invention are more fully described in the following detailed description of the invention in the accompanying drawings.

It should be noted that the foregoing description is only a preferred embodiment of the present invention, and although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood that modifications, equivalents, improvements and modifications to the technical solution described in the foregoing embodiments may occur to those skilled in the art, and all modifications, equivalents, and improvements are intended to be included within the spirit and principle of the present invention.

Claims

1. A method for preparing a semi-homogeneous anion-selective exchange membrane, the method comprising:

The preparation method comprises the steps of uniformly mixing linear low-density polyethylene, ion exchange resin containing quaternary ammonium functional groups, resin containing amide groups and an auxiliary agent according to a preset proportion, and sequentially carrying out melt mixing, extrusion film forming and soaking to obtain the semi-homogeneous anion selective exchange membrane.

2. A process for preparing a semi-homogeneous anion-selective exchange membrane according to claim 1,

Melting, mixing and extruding to form a film at 150-180 ℃;

the extrusion film forming speed is controlled to be 0.5-0.8m/min;

3. A process for preparing a semi-homogeneous anion-selective exchange membrane according to claim 1,

The semi-homogeneous anion selective exchange membrane comprises, by weight, 1-1.1 parts of linear low density polyethylene, 0.85-1.0 parts of ion exchange resin containing quaternary ammonium functional groups, 0.1-0.22 parts of resin containing amide groups and 0.03-1.0 part of auxiliary agent.

4. The method for preparing a semi-homogeneous anion-selective exchange membrane according to claim 1, wherein the linear low density polyethylene is obtained by copolymerizing propylene, butene, 4-methyl-1-pentene, hexene or octene;

5. The method for preparing a semi-homogeneous anion selective exchange membrane according to claim 1, wherein the water content of the ion exchange resin containing quaternary ammonium functional groups is 10 to 20%;

6. The method for preparing a semi-homogeneous anion exchange membrane according to claim 1, wherein the amount of the amide group-containing resin is 1 to 20% by weight based on the linear low density polyethylene;

7. The method for producing a semi-homogeneous anion-selective exchange membrane according to claim 6, wherein the polyamide resin has a relative molecular mass of 8000 to 12000, an acid value of <10mgKOH/g, an amine value of <5mgKOH/g, a softening point temperature of 130 to 140℃and an average particle diameter of 25.+ -. 5. Mu.m, and/or,

8. The method for preparing a semi-homogeneous anion-selective exchange membrane according to claim 1, wherein the auxiliary agent comprises calcium stearate and n-stearyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, wherein,

9. A semi-homogeneous anion-selective exchange membrane prepared by the process according to any one of claims 1 to 8, wherein the semi-homogeneous anion-selective exchange membrane has a thickness of 0.20mm to 1.00mm.

10. Use of a semi-homogeneous anion selective exchange membrane according to claim 9 in electrodialysis and electrodeionization apparatus.