阅读说明：本技术 一种聚四氟乙烯基均相阴离子交换膜及其制备方法 (polytetrafluoroethylene-based homogeneous anion exchange membrane and preparation method thereof ) 是由 余莉 祖拜代·图尔荪麦麦提 马媛媛 郭超 于 2019-09-16 设计创作，主要内容包括：本发明公开了一种聚四氟乙烯基均相阴离子交换膜及其制备方法,其原料按重量比份包括：四氟乙烯80-100份、超疏水性含氟共聚物5-20份、增塑剂10-25份、活化剂1-2份、交联剂0.8-2份、引发剂0.5-0.8份和水余量,本发明涉及膜材料技术领域。该聚四氟乙烯基均相阴离子交换膜及其制备方法,聚四氟乙烯乳液配制方法简单可控,制备的聚四氟乙烯基均相阴离子交换膜具有超高疏水性,能够有效降低水渗透率,提高电渗析分离盐的效率,制备的聚四氟乙烯基均相阴离子交换膜能在酸环境中长期稳定运行,制备的聚四氟乙烯基阴离子交换膜,每天运行6h,连续运行六个月,NaCl的脱盐率达到99.8％以上,出水可满足要求。(The invention discloses a polytetrafluoroethylene-based homogeneous anion exchange membrane and a preparation method thereof, wherein the polytetrafluoroethylene-based homogeneous anion exchange membrane comprises the following raw materials in parts by weight: 80-100 parts of tetrafluoroethylene, 5-20 parts of super-hydrophobic fluorine-containing copolymer, 10-25 parts of plasticizer, 1-2 parts of activating agent, 0.8-2 parts of cross-linking agent, 0.5-0.8 part of initiator and the balance of water. The preparation method of the polytetrafluoroethylene-based homogeneous anion exchange membrane is simple and controllable, the prepared polytetrafluoroethylene-based homogeneous anion exchange membrane has ultrahigh hydrophobicity, the water permeability can be effectively reduced, the salt electrodialysis separation efficiency is improved, the prepared polytetrafluoroethylene-based homogeneous anion exchange membrane can stably operate in an acid environment for a long time, the prepared polytetrafluoroethylene-based anion exchange membrane operates for 6 hours every day and continuously operates for six months, the desalination rate of NaCl reaches more than 99.8%, and the effluent can meet the requirements.)

1. A polytetrafluoroethylene-based homogeneous anion exchange membrane, characterized in that: the raw materials comprise the following components in parts by weight: 80-100 parts of tetrafluoroethylene, 5-20 parts of super-hydrophobic fluorine-containing copolymer, 10-25 parts of plasticizer, 1-2 parts of activating agent, 0.8-2 parts of cross-linking agent, 0.5-0.8 part of initiator and the balance of water, wherein the raw materials of the super-hydrophobic fluorine-containing copolymer comprise the following components in parts by weight: 20-50 parts of methyl methacrylate, 25-40 parts of perfluoroalkyl methacrylate, 15-30 parts of hydroxyethyl methacrylate and 15-40 parts of dibenzyl trithioester.

2. a polytetrafluoroethylene-based homogeneous anion exchange membrane according to claim 1, wherein: the plasticizer is dioctyl phthalate.

3. A polytetrafluoroethylene-based homogeneous anion exchange membrane according to claim 1, wherein: the cross-linking agent is ethylene glycol dimethacrylate.

4. A polytetrafluoroethylene-based homogeneous anion exchange membrane according to claim 1, wherein: the initiator is one or the combination of two groups of dibenzoyl peroxide or azobisisobutyronitrile.

5. a polytetrafluoroethylene-based homogeneous anion exchange membrane according to claim 1, wherein: the activator is 1% HCl.

6. A preparation method of a polytetrafluoroethylene-based homogeneous anion exchange membrane is characterized by comprising the following steps: the method specifically comprises the following steps:

s1, preparation of super-hydrophobic fluorine-containing copolymer: firstly, dissolving methyl methacrylate, perfluoroalkyl methacrylate and hydroxyethyl methacrylate in corresponding weight ratio into cyclohexanone, performing ultrasonic treatment for 1h to completely and uniformly mix the perfluoroalkyl methacrylate, then adding dibenzyltrithioester in corresponding weight ratio, introducing nitrogen for protection, performing oil bath reaction at a constant temperature of 70 ℃ for 36h, obtaining a polymer after cyclohexane is precipitated, dissolving the polymer in acetone, and filtering to obtain the super-hydrophobic fluorine-containing copolymer after cyclohexane is completely precipitated;

S2, preparing polytetrafluoroethylene emulsion: introducing nitrogen into the reaction kettle, removing air in the kettle, then adding a plasticizer into the kettle, sequentially adding an activating agent, a cross-linking agent, an initiator and water, cooling, vacuumizing, adding tetrafluoroethylene and the super-hydrophobic fluorine-containing copolymer prepared in the step S1, keeping the temperature and the pressure in the kettle while stirring, filtering, washing and drying after the polymerization reaction is finished to obtain polytetrafluoroethylene powder, dissolving the polytetrafluoroethylene powder in water to prepare polytetrafluoroethylene emulsion, and standing the emulsion after ultrasonic treatment;

s3, preparation of the coating: paving a polyester film on a smooth bright aluminum plate, placing kraft paper on the polyester film, uniformly coating the polytetrafluoroethylene emulsion, covering another polyester film on the slurry, uniformly rolling the polyester film by using a rubber roller, placing the kraft paper on the kraft paper, uniformly coating the polytetrafluoroethylene emulsion, covering the polyester film on the kraft paper, uniformly rolling the polyester film by using the rubber roller, repeatedly operating the steps, and finally covering another bright aluminum plate to obtain a stack of coatings;

s4, forming of base film: putting the stack of coatings obtained in the step S3 in a press, pressurizing to 0.20MPa, heating at 100 ℃ for 1h, heating at 80 ℃ for 6h, cooling, taking out, and peeling to obtain a base film;

S5, soaking of the base film: soaking the base film in 0.1mol/L sulfuric acid and 5% aniline for 1h, and cleaning with clear water;

s6, washing of base membrane: washing the base film obtained in the step S5 with ethanol, extracting the environment-friendly plasticizer, and then cleaning with clear water;

s7, base film reaction treatment: soaking the basement membrane obtained in the step S6 in 250g/L trimethylamine aqueous solution, reacting for 20-24h at 30-35 ℃, taking out, and cleaning with clear water;

S8, forming a polytetrafluoroethylene-based homogeneous anion exchange membrane: and (4) putting the membrane obtained in the step S7 into 0.1mol/L acid solution of camphorsulfonic acid, p-toluenesulfonic acid or dodecylbenzenesulfonic acid, soaking for 12h, taking out, and washing with clear water to obtain the polytetrafluoroethylene-based homogeneous anion exchange membrane.

7. the method of preparing a polytetrafluoroethylene-based homogeneous anion exchange membrane according to claim 6, wherein: the viscosity of the polytetrafluoroethylene emulsion prepared in the step S2 is 2000-3500 cps.

8. The method of preparing a polytetrafluoroethylene-based homogeneous anion exchange membrane according to claim 6, wherein: in the step S2, the temperature in the kettle is 55-80 ℃, and the pressure in the kettle is 0.5-2.8 MPa.

Technical Field

the invention relates to the technical field of membrane materials, in particular to a polytetrafluoroethylene-based homogeneous anion exchange membrane and a preparation method thereof.

Background

the anion exchange membrane is a high molecular polymer membrane which contains basic active groups and has selective permeability to anions, is also called an ion selective permeability membrane, and consists of three parts: the polymer main chain with fixed groups, namely a polymer matrix (also called a base film), positively charged active groups (namely cations) and anions which can move freely on the active groups, and the nature of the anion exchange membrane is an alkaline electrolyte and has a selective permeability effect on anions, so the anion exchange membrane is also called an ion selective permeability membrane, generally expressed as-NH₃ ⁺、-NR₂H⁺or-PR₃ ⁺the cations are used as active exchange groups, OH < - > is generated at a cathode and is used as a carrier, and the carrier moves to an anode through the selective permeability of an anion exchange membrane.

at present, the research of the homogeneous phase ion exchange membrane in China is still in a primary stage, the nation pays high attention to the problems of energy conservation and environmental protection, and particularly the requirements of multiple aspects such as zero emission of high-salt-content wastewater, zero emission in the industrial production process and the like are higher and higher at present, so that the ion exchange membrane with simple process, energy conservation and strong pollution resistance attracts wide attention and is developed as the main direction of future research, the preparation method of the ion exchange membrane is always the key direction of research, the research on the preparation process of the anion exchange membrane has great economic value, and the application of the ion exchange membrane in the aspects of water treatment and electrodialysis can greatly save energy and protect the environment.

the homogeneous anion exchange membrane is influenced by the aspects of technology, cost and the like in practical application, is really put into production and use in a small number, the membrane preparation technology in China is still to be perfected, and most of the membranes used at present depend on import, so that the research and the research on the preparation and the modification of the membranes are still needed.

disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a polytetrafluoroethylene-based homogeneous anion exchange membrane and a preparation method thereof, wherein the anion exchange membrane is formed by tetrafluoroethylene, a hydrophobic polymer and an additive through a pressurized thermal phase conversion method, and then polyaniline is added to prepare the hydrophobic and acid-resistant anion exchange membrane through chemical reaction.

(II) technical scheme

in order to achieve the purpose, the invention is realized by the following technical scheme: a polytetrafluoroethylene-based homogeneous anion exchange membrane comprises the following raw materials in parts by weight: 80-100 parts of tetrafluoroethylene, 5-20 parts of super-hydrophobic fluorine-containing copolymer, 10-25 parts of plasticizer, 1-2 parts of activating agent, 0.8-2 parts of cross-linking agent, 0.5-0.8 part of initiator and the balance of water, wherein the raw materials of the super-hydrophobic fluorine-containing copolymer comprise the following components in parts by weight: 20-50 parts of methyl methacrylate, 25-40 parts of perfluoroalkyl methacrylate, 15-30 parts of hydroxyethyl methacrylate and 15-40 parts of dibenzyl trithioester.

preferably, the plasticizer is dioctyl phthalate, and the dioctyl phthalate belongs to an environment-friendly plasticizer, so that the flexibility of the formed film can be improved, and the formed film is facilitated.

preferably, the crosslinking agent is ethylene glycol dimethacrylate.

Preferably, the initiator is one or a combination of two of dibenzoyl peroxide and azobisisobutyronitrile.

Preferably, the activator is 1% HCl.

The invention also discloses a preparation method of the polytetrafluoroethylene-based homogeneous anion exchange membrane, which comprises the following steps:

S1, preparation of super-hydrophobic fluorine-containing copolymer: firstly, dissolving methyl methacrylate, perfluoroalkyl methacrylate and hydroxyethyl methacrylate in corresponding weight ratio into cyclohexanone, performing ultrasonic treatment for 1h to completely and uniformly mix the perfluoroalkyl methacrylate, then adding dibenzyltrithioester in corresponding weight ratio, introducing nitrogen for protection, performing oil bath reaction at a constant temperature of 70 ℃ for 36h, obtaining a polymer after cyclohexane is precipitated, dissolving the polymer in acetone, and filtering to obtain the super-hydrophobic fluorine-containing copolymer after cyclohexane is completely precipitated;

S2, preparing polytetrafluoroethylene emulsion: introducing nitrogen into the reaction kettle, removing air in the kettle, then adding a plasticizer into the kettle, sequentially adding an activating agent, a cross-linking agent, an initiator and water, cooling, vacuumizing, adding tetrafluoroethylene and the super-hydrophobic fluorine-containing copolymer prepared in the step S1, keeping the temperature and the pressure in the kettle while stirring, filtering, washing and drying after the polymerization reaction is finished to obtain polytetrafluoroethylene powder, dissolving the polytetrafluoroethylene powder in water to prepare polytetrafluoroethylene emulsion, and standing the emulsion after ultrasonic treatment;

s3, preparation of the coating: paving a polyester film on a smooth bright aluminum plate, placing kraft paper on the polyester film, uniformly coating the polytetrafluoroethylene emulsion, covering another polyester film on the slurry, uniformly rolling the polyester film by using a rubber roller, placing the kraft paper on the kraft paper, uniformly coating the polytetrafluoroethylene emulsion, covering the polyester film on the kraft paper, uniformly rolling the polyester film by using the rubber roller, repeatedly operating the steps, and finally covering another bright aluminum plate to obtain a stack of coatings;

S4, forming of base film: putting the stack of coatings obtained in the step S3 in a press, pressurizing to 0.20MPa, heating at 100 ℃ for 1h, heating at 80 ℃ for 6h, cooling, taking out, and peeling to obtain a base film;

s5, soaking of the base film: soaking the base film in 0.1mol/L sulfuric acid and 5% aniline for 1h, and cleaning with clear water;

s6, washing of base membrane: washing the base film obtained in the step S5 with ethanol, extracting the environment-friendly plasticizer, and then cleaning with clear water;

S7, base film reaction treatment: soaking the basement membrane obtained in the step S6 in 250g/L trimethylamine aqueous solution, reacting for 20-24h at 30-35 ℃, taking out, and cleaning with clear water;

s8, forming a polytetrafluoroethylene-based homogeneous anion exchange membrane: and (4) putting the membrane obtained in the step S7 into 0.1mol/L acid solution of camphorsulfonic acid, p-toluenesulfonic acid or dodecylbenzenesulfonic acid, soaking for 12h, taking out, and washing with clear water to obtain the polytetrafluoroethylene-based homogeneous anion exchange membrane.

preferably, the viscosity of the polytetrafluoroethylene emulsion prepared in step S2 is 2000-3500cps, and too high viscosity results in too thick film formation, and too low viscosity makes it difficult to form a film, so the selection of the viscosity of the emulsion is particularly critical.

Preferably, in the step S2, the temperature in the kettle is 55-80 ℃, and the pressure in the kettle is 0.5-2.8 MPa.

(III) advantageous effects

The invention provides a polytetrafluoroethylene-based homogeneous anion exchange membrane and a preparation method thereof. Compared with the prior art, the method has the following beneficial effects:

(1) The polytetrafluoroethylene-based homogeneous anion exchange membrane and the preparation method thereof comprise the following raw materials in parts by weight: 80-100 parts of tetrafluoroethylene, 5-20 parts of super-hydrophobic fluorine-containing copolymer, 10-25 parts of plasticizer, 1-2 parts of activating agent, 0.8-2 parts of cross-linking agent, 0.5-0.8 part of initiator and the balance of water, wherein the raw materials of the super-hydrophobic fluorine-containing copolymer comprise the following components in parts by weight: the homogeneous anion exchange membrane is prepared by forming a membrane by tetrafluoroethylene, a hydrophobic polymer and an additive through a pressurized thermal phase conversion method, adding polyaniline, and performing chemical reaction to prepare a hydrophobic and acid-resistant anion exchange membrane.

(2) The polytetrafluoroethylene-based homogeneous anion exchange membrane and the preparation method thereof have the advantage that the prepared polytetrafluoroethylene-based homogeneous anion exchange membrane can stably run in an acid environment for a long time.

(3) The polytetrafluoroethylene homogeneous anion exchange membrane prepared by the preparation method runs for 6 hours every day and continuously runs for six months, the desalination rate of NaCl reaches over 99.8 percent, and the effluent can meet the requirement.

Drawings

FIG. 1 is a flow chart of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the embodiment of the present invention provides three technical solutions: a preparation method of a polytetrafluoroethylene-based homogeneous anion exchange membrane specifically comprises the following embodiments: