Modified polyacrylonitrile polymer for functional fibers and method for preparing the same
By using a pipeline static mixer and a specific chain extender during the modification process of polyacrylonitrile fibers, the problem of low functional group content after modification of polyacrylonitrile fibers was solved, thereby improving their application effect in the field of ion exchange fibers.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-12-09
- Publication Date
- 2026-06-09
AI Technical Summary
In the existing technology, the modified polyacrylonitrile fiber has a low content of functional groups, which limits its application in the field of ion exchange fibers, and the cyano hydrolysis reaction is inefficient and difficult to control.
A polyacrylonitrile polymer with high molecular weight and appropriate number of functional groups is prepared by using a static pipe mixer for thorough dispersion, introducing comonomers, and controlling monomer temperature and using specific chain extenders. This polymer is suitable for dry acrylonitrile spinning processes.
This improves the performance of polyacrylonitrile fibers in the field of ion exchange fibers, enhances the content of functional groups, and meets the high carboxyl content requirements of modified functional fibers.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of polyacrylonitrile polymer synthesis technology, specifically to polyacrylonitrile polymers for modified functional fibers and their preparation methods. Background Technology
[0002] Ion exchange fibers are a new type of fibrous ion exchange material developed based on ion exchange resins. Research on them began in the 1950s. As an ion exchange material, it contains fixed ions and mobile ions with opposite signs to the fixed ions. When it comes into contact with a solution containing dissociable compounds, the mobile ions can exchange with ions of the same sign in the solution, hence the name ion exchange fiber.
[0003] Ion exchange fibers are new functional materials with specific properties developed based on ion exchange resin products. It can be said that ion exchange fibers can better replace ion exchange resins in almost any field. Due to their large specific surface area and the fact that they can be applied in various forms (such as non-woven fabrics and membranes), ion exchange fibers have unique advantages in areas where the use of ion exchange resins is difficult.
[0004] The matrix materials for preparing ion exchange fibers can be divided into natural fibers and synthetic fibers. Natural fibers mainly include natural facial fibers and cellulose fibers. Depending on the raw materials, synthetic fibers can be classified as polyvinyl alcohol fibers, polyacrylonitrile fibers, polyethylene fibers, polypropylene fibers, and polyvinyl chloride fibers.
[0005] The cyano groups in polyacrylonitrile fibers have high chemical reactivity and can be converted into carboxyl groups through hydrolysis to prepare cation exchange resins. However, the hydrolysis of cyano groups is inefficient, the reaction process is difficult to control, and the modified polymer has a low carboxyl content, resulting in a low number of effective groups that can be introduced in subsequent modifications, thus limiting its applications.
[0006] Chinese patent application CN117986439A, published on May 7, 2024, discloses a ternary functionalized acrylonitrile polymer and its preparation method. The polymerizing monomers include acrylonitrile, a first monomer, and a second monomer. The first monomer is an unsaturated organic acid, and the second monomer includes one or more of butadiene, isoprene, and isoprene in any proportion. However, it suffers from the problem of low content of functional groups after modification. Summary of the Invention
[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing polyacrylonitrile polymer for modified functional fibers. After sufficient dispersion by a pipeline static mixer, a comonomer is introduced, and by controlling the monomer temperature and introducing a specific chain extender, a polyacrylonitrile with a relatively high molecular weight and an appropriate number of functional groups is prepared, thereby preparing ion exchange fibers with excellent properties.
[0008] Another objective of this invention is to provide a modified functional fiber polyacrylonitrile polymer, wherein the acrylic acid mass percentage is more than 3.0%, the Mn is 40,000 to 60,000, the molecular weight distribution is 2.5 to 3.5, and the polyacrylonitrile copolymer is suitable for dry acrylonitrile spinning process. The solution concentration is 25% to 28%, which effectively improves the performance of polyacrylonitrile fibers in the field of ion exchange fibers.
[0009] This invention is achieved using the following technical solution:
[0010] The method for preparing the modified functional fiber polyacrylonitrile polymer includes the following steps:
[0011] (1) The first monomer and the second monomer are added to a pipeline static mixer and dispersed to obtain mixture A;
[0012] (2) Preparation of chain extender emulsion system: Prepare an emulsifier aqueous solution with a mass concentration of 1 to 5%, and then prepare a uniform emulsion with a chain extender mass percentage of 0.1% to 20% by water, emulsifier aqueous solution and chain extender; mix and stir until the chain extender emulsion has no obvious layering phenomenon;
[0013] (3) Add water to the polymerization reactor, heat up, start stirring, add oxidant and reducing agent, and at the same time add mixture A and prepared chain extender emulsifier at 20℃~30℃. The material stays in the reactor for 40~60min. Add terminator to obtain slurry.
[0014] (4) The slurry obtained in step (3) is placed in a mixing tank, and then the polymer is obtained by centrifugation, washing and drying.
[0015] The first monomer is acrylonitrile, and the second monomer is one of sorbic acid, butenoic acid, acrylic acid, itaconic acid, and 4-pentenoic acid.
[0016] The first monomer has a mass fraction of 80%–95%, and the second monomer has a mass fraction of 2%–10%.
[0017] The aforementioned static pipeline mixer is one of the following: SV type mixer, SX type mixer, and SL type mixer with a cooling water jacket.
[0018] The oxidant is one of potassium persulfate, ammonium persulfate, or hydrogen peroxide; the reducing agent is one of sodium bisulfite or sodium metabisulfite; and the terminating agent is EDTA.
[0019] The emulsifier is polyvinyl alcohol with a degree of polymerization of 400-1000 and a degree of alcoholysis of 35%-70%.
[0020] The amount of oxidant used is 0.1-1% of the total mass fraction of monomers, and the amount of reducing agent used is 1-7% of the total mass fraction of monomers; the initial aqueous phase temperature in the polymerization reactor is 50℃-65℃, and the reaction temperature in the polymerization reactor is 50℃-65℃.
[0021] The chain extender is one, two or more of diene or polyene monomers, small molecule compounds or oligomers in any proportion.
[0022] The chain extender is one or two of the following: a mixture of diallyl phthalate and diallyl maleate or a mixture of divinylbenzene and ethylene glycol dimethacrylate; the mass ratio of diallyl phthalate to diallyl maleate is (2-4):(0-2); the mass ratio of the diallyl maleate mixture or divinylbenzene to ethylene glycol dimethacrylate is (0-3):(2-3); the amount of chain extender, based on pure chain extender, accounts for 500-2000 ppm of the total monomer.
[0023] The modified functional fiber polyacrylonitrile polymer is prepared by the above-described method for preparing the modified functional fiber polyacrylonitrile polymer.
[0024] Compared with the prior art, the beneficial effects of the present invention are:
[0025] (1) The modified functional fiber polyacrylonitrile polymer prepared by the present invention has an acrylic acid mass percentage of more than 3.0%, Mn of 40,000 to 60,000, and a molecular weight distribution of 2.5 to 3.5. It is a polyacrylonitrile copolymer suitable for dry acrylonitrile spinning process. The concentration of the prepared solution is 25% to 28%, which effectively improves the application effect of polyacrylonitrile fiber in the field of ion exchange fiber.
[0026] (2) After being fully dispersed by a static mixer in a pipeline, a comonomer is introduced, and a polyacrylonitrile with a relatively high molecular weight and an appropriate number of functional groups is prepared by controlling the monomer temperature at 20-30℃ and introducing a specific chain extender, thereby preparing an ion exchange fiber with excellent properties. Detailed Implementation
[0027] The present invention will be further described below with reference to the embodiments, but these embodiments do not limit the implementation of the present invention.
[0028] Example 1
[0029] A method for preparing polyacrylonitrile polymer for modified functional fibers includes the following steps:
[0030] (1) Acrylonitrile and sorbic acid are added to an SV type mixer with a cooling water jacket in proportion and dispersed to obtain mixture A;
[0031] (2) Preparation of chain extender emulsion system: Polyvinyl alcohol with a degree of polymerization of 400 and a degree of alcoholysis of 35% is prepared into an emulsion with a mass concentration of 1%. Then, water, polyvinyl alcohol aqueous solution and chain extender are used to prepare a uniform emulsion with a chain extender mass percentage of 10%. The mixture is stirred until the chain extender emulsion has no obvious layering phenomenon. The amount of chain extender is 500 ppm of the total monomer based on pure chain extender. The chain extender is prepared by mixing diallyl phthalate and diallyl maleate in a mass ratio of 3:1.
[0032] (3) Add 280g of water to the polymerization reactor, heat to 55℃, start stirring, add potassium persulfate and sodium metabisulfite in proportion, and add mixture A and prepared chain extender emulsion at 30℃. The reaction temperature is 55℃, the material stays in the reactor for 40min, add terminating agent EDTA, and obtain slurry.
[0033] (4) The slurry obtained in step (3) is placed in a mixing tank, and then the polymer is obtained by centrifugation, washing and drying.
[0034] The specific formula is shown in Table 1.
[0035] Example 2
[0036] A method for preparing polyacrylonitrile polymer for modified functional fibers includes the following steps:
[0037] (1) Acrylonitrile and 4-pentenoic acid were added to an SX-type mixer with a cooling water jacket in proportion and dispersed to obtain mixture A;
[0038] (2) Preparation of chain extender emulsion system: Polyvinyl alcohol with a degree of polymerization of 600 and a degree of hydrolysis of 45% is prepared into an emulsion with a mass concentration of 2%. Then, water, polyvinyl alcohol aqueous solution and chain extender are used to prepare a uniform emulsion with a chain extender mass percentage of 1%. The mixture is stirred until the chain extender emulsion has no obvious layering phenomenon. The chain extender is diallyl phthalate. The amount of chain extender is 800 ppm of the total monomer based on pure chain extender.
[0039] (3) Add 280g of water to the polymerization reactor, heat to 65℃, start stirring, add potassium persulfate and sodium metabisulfite in proportion, and add mixture A and prepared chain extender emulsion at 25℃. The reaction temperature is 65℃, the material stays in the reactor for 40min, add terminating agent EDTA, and obtain slurry.
[0040] (4) The slurry obtained in step (3) is placed in a mixing tank, and then the polymer is obtained by centrifugation, washing and drying.
[0041] The specific formula is shown in Table 1.
[0042] Example 3
[0043] A method for preparing polyacrylonitrile polymer for modified functional fibers includes the following steps:
[0044] (1) Acrylonitrile and acrylic acid are added to an SL-type mixer with a cooling water jacket in proportion and dispersed to obtain mixture A;
[0045] (2) Preparation of chain extender emulsion system: Polyvinyl alcohol with a degree of polymerization of 800 and a degree of alcoholysis of 60% is prepared into an emulsion with a mass concentration of 3%. Then, water, polyvinyl alcohol aqueous solution and chain extender are used to prepare a uniform emulsion with a chain extender mass percentage of 20%. The mixture is stirred until the chain extender emulsion has no obvious layering phenomenon. The amount of chain extender is 1000 ppm of the total monomer based on pure chain extender. The chain extender is prepared by mixing divinylbenzene and ethylene glycol dimethacrylate at a mass ratio of 2:3.
[0046] (3) Add 280g of water to the polymerization reactor, heat to 60℃, start stirring, add potassium persulfate and sodium metabisulfite in proportion, and add mixture A and prepared chain extender emulsion at 20℃. The reaction temperature is 60℃, the material stays in the reactor for 40min, add terminating agent EDTA, and obtain slurry.
[0047] (4) The slurry obtained in step (3) is placed in a mixing tank, and then the polymer is obtained by centrifugation, washing and drying.
[0048] The specific formula is shown in Table 1.
[0049] Example 4
[0050] A method for preparing polyacrylonitrile polymer for modified functional fibers includes the following steps:
[0051] (1) Acrylonitrile and acrylic acid are added to an SV type mixer with a cooling water jacket in proportion and dispersed to obtain mixture A;
[0052] (2) Preparation of chain extender emulsion system: Polyvinyl alcohol with a degree of polymerization of 900 and a degree of alcoholysis of 65% is prepared into an emulsion with a mass concentration of 4%. Then, water, polyvinyl alcohol aqueous solution and chain extender are used to prepare a uniform emulsion with a chain extender mass percentage of 8%. The mixture is stirred until the chain extender emulsion has no obvious layering phenomenon. The amount of chain extender used is 1500 ppm of the total monomer based on pure chain extender. The chain extender is ethylene glycol dimethacrylate.
[0053] (3) Add 280g of water to the polymerization reactor, heat to 50℃, start stirring, add ammonium persulfate and sodium bisulfite in proportion, and add mixture A and prepared chain extender emulsion at 25℃. The reaction temperature is 50℃, the material stays in the reactor for 40min, add terminating agent EDTA, and obtain slurry.
[0054] (4) The slurry obtained in step (3) is placed in a mixing tank, and then the polymer is obtained by centrifugation, washing and drying.
[0055] The specific formula is shown in Table 1.
[0056] Example 5
[0057] A method for preparing polyacrylonitrile polymer for modified functional fibers includes the following steps:
[0058] (1) Acrylonitrile and acrylic acid are added to an SV type mixer with a cooling water jacket in proportion and dispersed to obtain mixture A;
[0059] (2) Preparation of chain extender emulsion system: Polyvinyl alcohol with a degree of polymerization of 1000 and a degree of alcoholysis of 70% is prepared into an emulsion with a mass concentration of 5%. Then, water, polyvinyl alcohol aqueous solution and chain extender are used to prepare a uniform emulsion with a chain extender mass percentage of 15%. The mixture is stirred until the chain extender emulsion has no obvious layering phenomenon. The amount of chain extender is 2000 ppm of the total monomer based on pure chain extender. The chain extender is prepared by mixing diallyl phthalate, diallyl maleate, divinylbenzene and ethylene glycol dimethacrylate in a mass ratio of 2:1:2:3.
[0060] (3) Add 280g of water to the polymerization reactor, heat to 55℃, start stirring, add hydrogen peroxide and sodium metabisulfite in proportion, and add mixture A and prepared chain extender emulsion at 30℃. The reaction temperature is 55℃, the material stays in the reactor for 40min, add terminating agent EDTA, and obtain slurry.
[0061] (4) The slurry obtained in step (3) is placed in a mixing tank, and then the polymer is obtained by centrifugation, washing and drying.
[0062] The specific formula is shown in Table 1.
[0063] Comparative Example 1
[0064] 280g of water was added to the polymerization reactor, and the temperature was raised to 55℃. Stirring was then started. Oxidizing agent and reducing agent were added sequentially through different pipes. Polyvinyl alcohol with a degree of polymerization of 2000 and a degree of alcoholysis of 80% was selected as the emulsifier and added to the reactor. The reaction temperature was controlled at 60℃ and the residence time in the reactor was 50min. Terminator was added through the overflow port. The slurry was then placed in a mixing tank, and the polymer was obtained by centrifugation, washing with water, and drying. The polymer was then modified. The specific formulation is shown in Table 1.
[0065] Comparative Example 2
[0066] 260g of water was added to the polymerization reactor, and the temperature was raised to 60℃. Stirring was then started. Oxidizing agent and reducing agent were added sequentially through different pipes. The acrylonitrile temperature was controlled at 35℃ and the acrylic acid temperature at 37℃. The mixture was then introduced into the reaction vessel, and the reaction temperature was controlled at 65℃. The residence time in the vessel was 60min. Terminator was added through the overflow port. The slurry was then placed into a mixing tank, and the polymer was obtained by centrifugation, washing with water, and drying. The polymer was then modified. The specific formulation is shown in Table 1.
[0067] Comparative Example 3
[0068] 280g of water was added to a 500L polymerization reactor, and the temperature was raised to 60℃. Stirring was then started. Oxidizing agent and reducing agent were added sequentially through different pipes. The acrylonitrile temperature was controlled at 27℃ and the acrylic acid temperature at 35℃. The mixture was then introduced into the reaction vessel, and the reaction temperature was controlled at 55℃. The residence time in the vessel was 60min. Terminating agent was added through the overflow port. The slurry was then placed into a mixing tank, and the polymer was obtained by centrifugation, washing with water, and drying. The polymer was then modified. The specific formulation is shown in Table 1.
[0069] Comparative Example 4
[0070] 320g of water was added to a 500L polymerization reactor, and the temperature was raised to 55℃. Stirring was then started. Oxidizing agent and reducing agent were added sequentially through different pipes. After controlling the temperature of acrylonitrile and acrylic acid at 35℃, the mixture was introduced into the reactor through a static mixer. The reaction temperature was controlled at 60℃, and the residence time in the reactor was 50min. Terminator was added through the overflow port. The slurry was then placed into a mixing tank, and the polymer was obtained by centrifugation, washing with water, and drying. The polymer was then modified. The specific formulation is shown in Table 1.
[0071] Table 1. Specific formulations of Examples 1-5 and Comparative Examples 1-4
[0072]
[0073] The polymer test data obtained in Examples 1-5 and Comparative Examples 1-4 are shown in Table 2.
[0074] Table 2. Polymer test data obtained from Examples 1-5 and Comparative Examples 1-4.
[0075]
[0076]
[0077] As can be seen from Table 2, the preparation method can meet the requirements of industrial production. The prepared polymer has a high acrylic acid mass percentage, with the acrylic acid content in the polymer reaching more than 3%. After modification, the functionality of the polymer can be greatly increased, meeting the requirement of high carboxyl content for modified functional fibers.
Claims
1. A method for preparing a polyacrylonitrile polymer for modified functional fibers, characterized in that, Includes the following steps: (1) The first monomer and the second monomer are added to a pipeline static mixer and dispersed to obtain mixture A; (2) Preparation of chain extender emulsion system: Prepare an emulsifier aqueous solution with a mass concentration of 1 to 5%, and then prepare a uniform emulsion with a chain extender mass percentage of 0.1% to 20% by water, emulsifier aqueous solution and chain extender; mix and stir until the chain extender emulsion has no obvious layering phenomenon; (3) Add water to the polymerization reactor, heat up, start stirring, add oxidant and reducing agent, and at the same time add mixture A and prepared chain extender emulsifier at 20℃~30℃. The material stays in the reactor for 40~60min. Add terminator to obtain slurry. (4) The slurry obtained in step (3) is placed in a mixing tank, and then the polymer is obtained by centrifugation, washing and drying.
2. The method for preparing the modified functional fiber polyacrylonitrile polymer according to claim 1, characterized in that, The first monomer is acrylonitrile, and the second monomer is one of sorbic acid, butenoic acid, acrylic acid, itaconic acid, and 4-pentenoic acid.
3. The method for preparing the modified functional fiber polyacrylonitrile polymer according to claim 1, characterized in that, The first monomer has a mass fraction of 80%–95%, and the second monomer has a mass fraction of 2%–10%.
4. The method for preparing the modified functional fiber polyacrylonitrile polymer according to claim 1, characterized in that, The aforementioned static pipeline mixer is one of the following: SV type mixer, SX type mixer, and SL type mixer with a cooling water jacket.
5. The method for preparing the modified functional fiber polyacrylonitrile polymer according to claim 1, characterized in that, The oxidant is one of potassium persulfate, ammonium persulfate, or hydrogen peroxide; the reducing agent is one of sodium bisulfite or sodium metabisulfite; and the terminating agent is EDTA.
6. The method for preparing the modified functional fiber polyacrylonitrile polymer according to claim 1, characterized in that, The emulsifier is polyvinyl alcohol with a degree of polymerization of 400-1000 and a degree of alcoholysis of 35%-70%.
7. The method for preparing the modified functional fiber polyacrylonitrile polymer according to claim 1, characterized in that, The amount of oxidant used is 0.1-1% of the total mass fraction of monomers, and the amount of reducing agent used is 1-7% of the total mass fraction of monomers; the initial aqueous phase temperature in the polymerization reactor is 50℃-65℃, and the reaction temperature in the polymerization reactor is 50℃-65℃.
8. The method for preparing the modified functional fiber polyacrylonitrile polymer according to claim 1, characterized in that, The chain extender is one, two or more of diene or polyene monomers, small molecule compounds or oligomers in any proportion.
9. The method for preparing the modified functional fiber polyacrylonitrile polymer according to claim 1, characterized in that, The chain extender is one or two of the following: a mixture of diallyl phthalate and diallyl maleate or a mixture of divinylbenzene and ethylene glycol dimethacrylate; the mass ratio of diallyl phthalate to diallyl maleate is (2-4):(0-2); the mass ratio of divinylbenzene to ethylene glycol dimethacrylate is (0-3):(2-3); the amount of chain extender, based on pure chain extender, accounts for 500-2000 ppm of the total monomer.
10. A polyacrylonitrile polymer for modified functional fibers, characterized in that, It is prepared by the method for preparing the modified functional fiber polyacrylonitrile polymer according to any one of claims 1-9.