A method for preparing polyphenylene sulfide-based chelated fibers

Abstract

This invention discloses a method for preparing polyphenylene sulfide (PPS)-based chelated fibers. PPS fibers are added to a reactor, and a solvent is added to allow them to swell fully. A crosslinking agent and a catalyst are then added to carry out the reaction. The resulting product is treated to obtain crosslinked PPS fibers. The crosslinked PPS fibers are then added to a solvent to swell, followed by the addition of a nitrifying agent to carry out the reaction. The product is then treated to obtain modified nitrated fiber PPS-NO2. The modified nitrated fiber PPS-NO2 is then added to a solvent to swell, followed by the addition of a reducing agent to carry out a reduction reaction. The product is then treated to obtain amino-based PPS-NH2. The amino-based PPS-NH2 is then added to a solvent, followed by the addition of a functional monomer to carry out a grafting reaction, yielding the product, polyphenylene sulfide-based chelated fibers. Using this invention to prepare chelated functional fibers effectively avoids the drawbacks of using highly carcinogenic substances such as chloromethyl ether in existing technologies. Furthermore, the polyphenylene sulfide-based chelated fibers prepared by this invention exhibit good stability and acid and alkali resistance.

Description

I. Technical Field:

[0001] This invention relates to a method for preparing chelated fibers, and more particularly to a method for preparing polyphenylene sulfide-based chelated fibers. II. Background Technology:

[0002] Chelating fibers are a type of adsorption and separation functional fiber material with coordinating chelating groups, and are a novel adsorption and separation material developed in recent years. According to conventional classification methods, chelating fibers and ion-exchange fibers are generally referred to as ion-exchange fibers. Similar to ion-exchange resin materials, the matrix used in fibrous adsorption materials is an organic polymer, and the process of matrix modification to obtain active functional groups with ion-exchange and chelating properties is essentially the same for both. Chelating fibers possess the advantages of ion-exchange fibers, while also having advantages not found in other ion-exchange fibers, such as high selectivity for ion adsorption and higher adsorption capacity. Compared with chelating resins, chelating fibers have advantages such as a larger effective specific surface area, faster exchange and elution rates, easier regeneration, diverse application forms, usability in both liquid and gas phases, and lower fluid resistance.

[0003] Chelated fibers can be viewed as consisting of two parts: a matrix fiber and chelating groups attached to it. Matrix fibers include polypropylene, polyvinyl alcohol, acrylic fiber, and polyphenylene sulfide, while chelating groups include various types such as amine oximes, amides, amino groups, thiourea, and imidazoles. Different matrix fibers, using different methods to attach various chelating groups, can yield chelated fibers with different properties. Due to their superior physical and chemical properties, chelated fibers have wide applications in areas such as metal resource protection, water treatment, and marine resource utilization.

[0004] Currently, there are two main methods for preparing chelated fibers: chemical grafting and irradiation grafting. Chemical grafting is widely used. However, current chemical grafting methods still face some problems. For example, the crosslinking agent currently used in PPS-based fibers is the highly carcinogenic methylating agent chloromethyl ether, which causes serious environmental pollution. Therefore, researching new alternatives to the highly carcinogenic chloromethyl ether to prepare chelated fibers with comparable functionality is of great significance. III. Summary of the Invention:

[0005] The technical problem this invention aims to solve is: to overcome the technical difficulties in the preparation of chelated fibers, such as the use of toxic and harmful raw materials (chloromethyl methyl ether) and the complexity of reaction steps, this invention provides a novel method for preparing polyphenylene sulfide-based chelated fibers. Using this invention to prepare polyphenylene sulfide-based chelated fibers solves the problem of serious environmental pollution caused by the use of the highly carcinogenic methylating agent chloromethyl ether as a crosslinking agent in chemical grafting methods. Furthermore, by utilizing the reducible nature of nitro groups, nitro groups are reduced to amino groups, and functional monomers are grafted onto the amino groups, thereby obtaining a novel polyphenylene sulfide-based chelated fiber.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a method for preparing polyphenylene sulfide-based chelated fibers, the method comprising the following steps:

[0008] a. Add polyphenylene sulfide fiber to a reaction vessel, then add solvent to allow it to fully swell (the swelling time is 6-12 hours). After swelling, add crosslinking agent and catalyst and stir or ultrasonically disperse evenly. Then heat to 70-80℃ and react at this temperature for 12-48 hours. After the reaction is complete, cool to room temperature, filter, and filter out the product. The product is then subjected to alcohol washing, acid boiling, water washing, and drying to obtain crosslinked polyphenylene sulfide fiber, i.e., crosslinked PPS fiber.

[0009] b. Add the cross-linked PPS fibers obtained in step a to the solvent and allow them to swell completely. After swelling, add the nitrifying agent and stir or ultrasonically disperse evenly. Then heat to 40-60℃ and react at this temperature for 1-6 hours. After the reaction is complete, cool to room temperature, filter, and filter out the product. Wash the product with alcohol, water, and dry it in sequence to obtain modified nitrated fiber PPS-NO2.

[0010] Modified nitrocellulose PPS-NO2 was placed in a container and a solvent was added to swell it. Then a reducing agent was added and the mixture was heated to 50-100℃ and reacted for 1-6 hours. After the reaction was completed, the mixture was cooled to room temperature and filtered. The product was then subjected to alcohol washing, acid boiling, water washing and drying to obtain amino polyphenylene sulfide fiber PPS-NH2.

[0011] c. Place the obtained amino polyphenylene sulfide fiber PPS-NH2 in a container, add solvent A; then add the functional monomer, and heat to 60-120℃ for 4-6 hours; after the reaction is completed, cool to room temperature, filter, and wash the product with alcohol, water and dry in sequence to obtain PPS-based chelated functional fiber, i.e., polyphenylene sulfide-based chelated fiber.

[0012] According to the above-described method for preparing polyphenylene sulfide-based chelated fibers, in step a, the mass-to-volume ratio of the polyphenylene sulfide fiber to the solvent is 1 g: 50-100 mL, the molar ratio of the polyphenylene sulfide fiber to the crosslinking agent is 1: 0.5-8, and the molar ratio of the polyphenylene sulfide fiber to the catalyst is 1: 1.2-2.2.

[0013] According to the above-described method for preparing polyphenylene sulfide-based chelated fibers, the solvent in step a is 1,2-dichloroethane; the catalyst is anhydrous aluminum trichloride, anhydrous ferric trichloride, or anhydrous tin tetrachloride; and the crosslinking agent is at least one of dimethoxymethane, ethylene glycol dimethyl ether, and 1,4-dimethoxybenzene.

[0014] According to the above-mentioned method for preparing polyphenylene sulfide-based chelated fibers, the specific operation process of sequentially washing the obtained product with alcohol, boiling with acid, washing with water and drying in step a is as follows: the obtained product is sequentially washed with anhydrous ethanol, boiled in HCl solution with a concentration of 1-2 mol / L at 50°C for 5-6 hours, washed with water until neutral, and then vacuum dried at 50-60°C to constant weight.

[0015] According to the above-described method for preparing polyphenylene sulfide-based chelated fibers, the solvent in step b is 1,2-dichloroethane; the nitrating agent is a mixture of concentrated sulfuric acid and concentrated nitric acid, wherein the molar ratio of concentrated nitric acid to concentrated sulfuric acid is 1:3 to 7 (in the mixture, concentrated sulfuric acid is the functionalizing agent and nitric acid is the acidifying agent); the reducing agent is stannous chloride or reduced iron powder (wherein, when stannous chloride is used as the reducing agent, concentrated hydrochloric acid needs to be added as a catalyst; when reduced iron powder is used as the reducing agent, ammonium chloride needs to be added as a catalyst).

[0016] According to the above-described method for preparing polyphenylene sulfide-based chelated fibers, the mass-to-volume ratio of the cross-linked PPS fiber to the solvent in step b is 1 g: 50-100 mL, and the molar ratio of the cross-linked PPS fiber to the nitrifying agent is 1: 0.5-2.

[0017] The mass-to-volume ratio of the modified nitrated cellulose PPS-NO2 to the solvent is 1g:50-100mL, and the mass-to-volume ratio of the modified nitrated PPS-NO2 fiber to the reducing agent is 1:1-5.

[0018] According to the above-described method for preparing polyphenylene sulfide-based chelated fibers, the specific process of sequentially washing the obtained product with alcohol, water, and drying in step b is as follows: the obtained product is sequentially washed with anhydrous ethanol, then washed with water until neutral, and then vacuum dried to constant weight under a vacuum of 0.08 MPa and a drying temperature of 50–60°C; the specific process of sequentially washing the product with alcohol, acid boiling, water washing, and drying is as follows: the obtained product is sequentially washed with anhydrous ethanol, boiled in a 1–2 mol / L HCl solution at 50°C for 5–6 hours, washed with water until neutral, and then vacuum dried to constant weight under a vacuum of 0.08 MPa and a drying temperature of 50–60°C.

[0019] According to the above-described method for preparing polyphenylene sulfide-based chelated fibers, in step c, the mass-to-volume ratio of the amino-polyphenylene sulfide fiber PPS-NH2 to solvent A is 1 g: 50-100 mL, and the molar ratio of the amino-polyphenylene sulfide fiber PPS-NH2 to the functional monomer is 1: 1-10.

[0020] According to the above-mentioned method for preparing polyphenylene sulfide-based chelated fibers, solvent A in step c is 1,2-dichloroethane or hydrochloric acid; the functional monomer is at least one of sodium chloroacetate, phosphorous acid, and 2-chlorobenzothiazole (wherein, when grafting phosphorous acid, hydrochloric acid is used as solvent, trioxymethylene reacts with amino groups to generate a methylamino intermediate, which then reacts with phosphorous acid to obtain the target product; when grafting sodium chloroacetate and 2-chlorobenzothiazole, 1,2-dichloroethane is used as solvent).

[0021] According to the above-mentioned method for preparing polyphenylene sulfide-based chelated fibers, the specific process of washing the product with alcohol, water and drying in step c is as follows: the obtained product is washed with anhydrous ethanol and water until neutral, and then vacuum dried to constant weight under vacuum conditions of 0.08 MPa and drying temperature of 50-60℃.

[0022] The positive and beneficial effects of this invention are:

[0023] 1. The technical solution of this invention is the first to crosslink the fiber matrix by Friedel-Crafts alkylation reaction of the crosslinking agent and the benzene ring, and then introduce nitro groups on the benzene ring by using a mixed acid nitrification reagent, reduce the introduced nitro groups to amino groups, and graft functional monomers onto the amino groups to obtain novel chelated functional fibers.

[0024] 2. The technical solution of this invention uses inexpensive and readily available industrial raw materials such as polyphenylene sulfide fiber, nitric acid, and concentrated sulfuric acid, avoiding the use of a strong carcinogen (chloromethyl methyl ether). Therefore, it has the advantages of being environmentally friendly and having significant economic benefits, and is conducive to environmental protection.

[0025] 3. The technical solution of this invention simplifies the existing nitration reaction and allows for better control of the reaction process. This invention employs a new preparation method, resulting in a simple reaction process, convenient operation, short reaction time, low energy consumption, easy processing, and minimal pollution.

[0026] 4. The polyphenylene sulfide-based chelating functional fiber synthesized in this invention has a positive effect on Cu. 2+ Cr 6+ Ni 2+ Plasma exhibits remarkable adsorption performance, retaining 95% of its initial adsorption capacity even after five adsorption-desorption cycles.

[0027] 5. This invention obtains a series of fibers with chelating function by changing the reagents used, providing a completely new approach to the preparation of chelated fibers.

[0028] In summary, this invention has significant economic and social benefits. IV. Description of the attached drawings:

[0029] Figure 1(a) Original matrix fiber; (b) Scanning electron microscope images of the polyphenylene sulfide sodium acetate chelating functional fiber prepared in Example 1.

[0030] Depend on Figure 1 As can be seen, the original matrix fiber surface is smooth, while the chelated functional fiber surface becomes rough after a series of reactions, and deposits begin to appear on the fiber surface, proving that the reaction was successful.

[0031] Figure 2 (c) Original matrix fiber; (d) Scanning electron microscope images of polyphenylene sulfide-based thiazole chelating functional fibers prepared in Example 5.

[0032] Depend on Figure 2 As can be seen, the original matrix fiber surface is smooth, while the chelated functional fiber surface becomes rough after a series of reactions, and deposits begin to appear on the fiber surface, proving that the reaction was successful.

[0033] Figure 3 The FT-IR spectra of polyphenylene sulfide fiber (PPS) and the polyphenylene sulfide-based phosphoric acid chelating functional fiber prepared in Example 3 are shown in the present invention.

[0034] pass Figure 3 The FT-IR shows that in the range of 3000–3500 cm⁻¹ -1 An absorption peak for the stretching vibration of OH appears at 1160 cm⁻¹. -1 The presence of a bending vibration absorption peak at P=O indicates that chloromethylphosphoric acid has been successfully grafted onto the fiber.

[0035] Figure 4 A schematic diagram of the reaction for preparing sodium polyphenylene sulfide acetate chelating functional fibers in Example 1 of this invention.

[0036] Figure 5 A schematic diagram of the reaction for preparing polyphenylene sulfide-based phosphoric acid chelating functional fibers in Example 3 of this invention.

[0037] Figure 6 A schematic diagram of the reaction for preparing polyphenylene sulfide-based thiazole chelating functional fibers in Example 5 of this invention.

[0038] Figure 7 The polyphenylene sulfide sodium acetate type chelating functional fiber prepared in Example 1 of this invention supports Ni 2+ Adsorption performance diagram;

[0039] Depend on Figure 7 It can be seen that the polyphenylene sulfide sodium acetate chelating functional fiber prepared in Example 1 still has good adsorption performance after five desorption and regeneration cycles.

[0040] Figure 8 The polyphenylene sulfide-based phosphoric acid chelating functional fiber prepared in Example 3 of this invention has a positive effect on Cr.6+ Adsorption performance diagram;

[0041] Depend on Figure 8 It can be seen that the polyphenylene sulfide-based phosphoric acid chelating functional fiber prepared in Example 3 still has good adsorption performance after five desorption and regeneration cycles.

[0042] Figure 9 The polyphenylene sulfide-based thiazole chelating fiber prepared in Example 5 of this invention has a positive effect on Cu. 2+ Adsorption performance diagram;

[0043] Depend on Figure 9 It can be seen that the polyphenylene sulfide-based thiazole chelating fiber prepared in Example 5 still has good adsorption performance after five desorption and regeneration cycles. V. Detailed Implementation Methods:

[0044] The present invention will be further illustrated below with reference to the embodiments, but this does not limit the scope of protection of the technical solution of the present invention.

[0045] Example 1:

[0046] The present invention discloses a method for preparing sodium polyphenylene sulfide acetate-type chelating functional fibers, the detailed steps of which are as follows:

[0047] a. First, weigh 0.43 g (0.004 mol) of polyphenylene sulfide (PPS) fiber and add it to a reaction flask. Then, add 43 mL of 1,2-dichloroethane and let it swell for 12 h. After swelling, add 2.83 mL (0.032 mol) of dimethoxymethane and 1.17 g (0.0088 mol) of anhydrous aluminum trichloride and stir until homogeneous. Then, heat to 70 °C and react at this temperature for 24 h. After the reaction is complete, cool to room temperature, filter, and filter out the product. Wash the product with anhydrous ethanol, boil it in 2 mol / L HCl solution at 50 °C for 6 h, wash it with water until neutral, and vacuum dry it to constant weight (vacuum degree: 0.08 MPa, drying temperature: 60 °C, drying time: 24 h). After drying, cross-linked polyphenylene sulfide fiber is obtained (the modified fiber has a 2% weight increase compared to the original polyphenylene sulfide fiber).

[0048] b. The obtained cross-linked polyphenylene sulfide fiber was added to 43 mL of 1,2-dichloroethane and allowed to swell for 12 h. After swelling, 5 mL of mixed acid was added and stirred evenly (the mixed acid was a mixture of concentrated sulfuric acid and concentrated nitric acid in a molar ratio of 3:1). The mixture was then heated to 60 °C and reacted for 1 h at this temperature. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the obtained product was filtered out. The obtained product was washed successively with anhydrous ethanol and water until neutral, and then vacuum dried to constant weight (vacuum degree of 0.08 MPa, drying temperature of 60 °C, drying time of 24 h). After drying, modified nitrated PPS-NO2 fiber was obtained.

[0049] Modified nitrated PPS-NO2 fibers were placed in 30 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 1 g of stannous chloride and 20 mL of concentrated hydrochloric acid were added as reducing agent, and the mixture was heated to 90 °C for 5 h for reduction reaction. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain the product. The product was washed with anhydrous ethanol, then boiled with 1 mol / L hydrochloric acid at 50 °C for 5 h, washed with water until neutral, and vacuum dried to constant weight (vacuum degree 0.08 MPa, drying temperature 60 °C, drying time 24 h). After drying, amino polyphenylene sulfide fibers PPS-NH2 were obtained (the fiber weight increased by 16% compared to before the reaction).

[0050] c. The obtained amino-polyphenylene sulfide fiber PPS-NH2 was placed in 50 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 4.6 g of sodium chloroacetate was added, and the mixture was heated to 100 °C and reacted for 5 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the product was obtained. The product was washed successively with anhydrous ethanol and water until neutral, and finally vacuum dried to constant weight (vacuum degree: 0.08 MPa, drying temperature: 60 °C, drying time: 24 h). After drying, sodium chloroacetate polyphenylene sulfide chelated functional fiber was obtained (the fiber weight increased by 35.8% compared to before the reaction).

[0051] The fiber prepared in Example 1 of this invention was subjected to elemental analysis (EA) data analysis. The analysis results are detailed in Table 1. The data in Table 1 show that sodium chloroacetate was successfully grafted onto the polyphenylene sulfide fiber.

[0052] Table 1. Elemental analysis (EA) data of the fiber prepared in Example 1 of this invention.

[0053]

[0054] Example 2:

[0055] The present invention discloses a method for preparing sodium polyphenylene sulfide acetate-type chelating functional fibers, the detailed steps of which are as follows:

[0056] a. First, weigh 1.5 g (0.014 mol) of polyphenylene sulfide (PPS) fiber and add it to a reaction flask. Then, add 150 mL of 1,2-dichloroethane and let it swell for 12 h. After swelling, add 8.5 mL (0.11 mol) of dimethoxymethane and 4.1 g (0.03 mol) of anhydrous aluminum trichloride and stir until homogeneous. Then, heat to 70 °C and react at this temperature for 24 h. After the reaction is complete, cool to room temperature, filter, and filter out the product. Wash the product with anhydrous ethanol, boil it in 1 mol / L HCl solution at 50 °C for 5 h, wash it with water until neutral, and then vacuum dry it to constant weight (vacuum degree: 0.08 MPa, drying temperature: 60 °C, drying time: 24 h). After drying, dimethoxymethane crosslinked PPS fiber is obtained (the modified fiber has a 3% weight increase compared to the original PPS fiber).

[0057] b. The obtained dimethoxymethane-crosslinked polyphenylene sulfide fiber was added to 150 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 15 mL of mixed acid was added and stirred evenly (the mixed acid was a mixture of concentrated sulfuric acid and concentrated nitric acid in a molar ratio of 3:1). The mixture was then heated to 60 °C and reacted for 1 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the obtained product was filtered out. The obtained product was washed successively with anhydrous ethanol and water until neutral, and then vacuum dried to constant weight (vacuum degree of 0.08 MPa, drying temperature of 60 °C, drying time of 24 h). After drying, modified nitrated PPS-NO2 fiber was obtained.

[0058] The obtained modified nitrated PPS-NO2 fiber was placed in 90 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 3.5 g of reducing agent, reducing iron powder, and 1 g of catalyst, ammonium chloride were added, and the temperature was raised to 80 °C for a reduction reaction for 3 h. After the reaction was completed, the product was cooled to room temperature and filtered to obtain the product. The product was washed with anhydrous ethanol, then boiled with 1 mol / L hydrochloric acid at 50 °C for 5 h, washed with water until neutral, and vacuum dried to constant weight (vacuum degree of 0.08 MPa, drying temperature of 60 °C, drying time of 24 h). After drying, amino polyphenylene sulfide fiber PPS-NH2 was obtained (the fiber weight increased by 14.6% compared to before the reaction).

[0059] c. The obtained amino-polyphenylene sulfide fiber PPS-NH2 was placed in 50 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 10 g of sodium chloroacetate was added, and the mixture was heated to 100 °C and reacted for 5 h. After the reaction was completed, the mixture was cooled to room temperature, filtered to obtain the product, and washed successively with anhydrous ethanol and water until neutral. The product was then vacuum dried to constant weight (vacuum degree: 0.08 MPa, drying temperature: 60 °C, drying time: 24 h). After drying, sodium chloroacetate polyphenylene sulfide chelated functional fiber was obtained (the fiber weight increased by 33.7% compared to before the reaction).

[0060] Example 3:

[0061] The present invention discloses a method for preparing polyphenylene sulfide-based phosphoric acid chelating functional fibers, the detailed steps of which are as follows:

[0062] a. First, weigh 1 g (0.0093 mol) of polyphenylene sulfide (PPS) fiber and add it to a reaction flask. Then, add 100 mL of 1,2-dichloroethane and let it swell for 12 h. After swelling, add 5.6 mL (0.074 mol) of dimethoxymethane and 1.38 g (0.01 mol) of anhydrous aluminum trichloride and stir until homogeneous. Then, heat to 70 °C and react at this temperature for 24 h. After the reaction is complete, cool to room temperature, filter, and filter out the product. Wash the product with anhydrous ethanol, boil it in 1 mol / L HCl solution at 50 °C for 5 h, wash it with water until neutral, and then vacuum dry it to constant weight (vacuum degree: 0.08 MPa, drying temperature: 60 °C, drying time: 24 h). After drying, dimethoxymethane crosslinked PPS fiber is obtained (the modified fiber has a weight increase of 3.1% compared to the original PPS fiber).

[0063] b. The obtained cross-linked polyphenylene sulfide fiber was added to 100 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 10 mL of mixed acid was added and stirred evenly (the mixed acid was a mixture of concentrated sulfuric acid and concentrated nitric acid in a molar ratio of 3:1). The mixture was then heated to 60 °C and reacted for 1 h at this temperature. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the obtained product was filtered out. The obtained product was washed successively with anhydrous ethanol and water until neutral, and then vacuum dried to constant weight (vacuum degree of 0.08 MPa, drying temperature of 60 °C, drying time of 24 h). After drying, modified nitrated PPS-NO2 fiber was obtained.

[0064] The obtained modified nitrated PPS-NO2 fiber was placed in 30 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 2.2 g of stannous chloride and 40 mL of concentrated hydrochloric acid were added as reducing agent, and the temperature was raised to 90 °C for a reduction reaction for 5 h. After the reaction was completed, the product was cooled to room temperature and filtered to obtain the product. The product was washed with anhydrous ethanol, then boiled with 1 mol / L hydrochloric acid at 50 °C for 5 h, washed with water until neutral, and vacuum dried to constant weight (vacuum degree of 0.08 MPa, drying temperature of 60 °C, drying time of 24 h) to obtain amino polyphenylene sulfide fiber PPS-NH2 (the fiber weight increased by 14.9% compared to before the reaction).

[0065] c. The obtained amino-polyphenylene sulfide fiber PPS-NH2 was placed in 110 mL of hydrochloric acid, and 6.05 g of phosphorous acid and 2.1 g of paraformaldehyde were added. The mixture was heated to 100 °C and reacted for 5 h. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain the product. The product was washed successively with anhydrous ethanol and water until neutral, and then vacuum dried to constant weight (vacuum degree of 0.08 MPa, drying temperature of 60 °C, drying time of 24 h). After drying, polyphenylene sulfide-based phosphoric acid chelating functional fiber was obtained (the fiber weight increased by 41.6% compared with that before the reaction).

[0066] Example 4:

[0067] The present invention discloses a method for preparing polyphenylene sulfide-based phosphoric acid chelating functional fibers, the detailed steps of which are as follows:

[0068] a. First, weigh 1.9 g (0.018 mol) of polyphenylene sulfide (PPS) fiber and add it to a reaction flask. Then, add 190 mL of 1,2-dichloroethane and let it swell for 12 h. After swelling, add 11 mL (0.14 mol) of dimethoxymethane and 5.3 g (0.03 mol) of anhydrous aluminum trichloride and stir until homogeneous. Then, heat to 70 °C and react at this temperature for 24 h. After the reaction is complete, cool to room temperature, filter, and filter out the product. Wash the product with anhydrous ethanol, boil it in 1 mol / L HCl solution at 50 °C for 5 h, wash it with water until neutral, and vacuum dry it to constant weight (vacuum degree: 0.08 MPa, drying temperature: 60 °C, drying time: 24 h). After drying, dimethoxymethane crosslinked PPS fiber is obtained (the modified fiber has a weight increase of 2.8% compared to the original PPS fiber).

[0069] b. The cross-linked polyphenylene sulfide fiber obtained above was added to 200 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 20 mL of mixed acid was added and stirred evenly (the mixed acid was a mixture of concentrated sulfuric acid and concentrated nitric acid in a molar ratio of 3:1). The mixture was then heated to 60 °C and reacted at this temperature for 1 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the obtained product was filtered out. The obtained product was washed successively with anhydrous ethanol and water until neutral, and then vacuum dried to constant weight (vacuum degree of 0.08 MPa, drying temperature of 60 °C, drying time of 24 h). After drying, modified nitrated PPS-NO2 fiber was obtained.

[0070] Modified nitrated PPS-NO2 fibers were placed in 60 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 5 g of reducing agent (reducing iron powder) and 1.5 g of catalyst (ammonium chloride) were added, and the mixture was heated to 80 °C for a reduction reaction for 3 h. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain the product. The product was washed with anhydrous ethanol, then boiled in 1 mol / L hydrochloric acid at 50 °C for 5 h, washed with water until neutral, and vacuum dried to constant weight (vacuum degree: 0.08 MPa, drying temperature: 60 °C, drying time: 24 h). After drying, amino polyphenylene sulfide fibers PPS-NH2 were obtained (the fiber weight increased by 15.5% compared to before the reaction).

[0071] c. The obtained amino-polyphenylene sulfide fiber PPS-NH2 was placed in 200 mL of hydrochloric acid, and then 10 g of phosphorous acid and 4.5 g of trioxymethylene were added. The mixture was heated to 100 °C and reacted for 5 h. After the reaction was completed, the mixture was cooled to room temperature, filtered to obtain the product, and washed successively with anhydrous ethanol and water until neutral. The product was then vacuum dried to constant weight (vacuum degree of 0.08 MPa, drying temperature of 60 °C, drying time of 24 h). After drying, polyphenylene sulfide-based phosphoric acid chelated functional fiber was obtained (the fiber weight increased by 38.8% compared with that before the reaction).

[0072] Example 5:

[0073] The present invention discloses a method for preparing polyphenylene sulfide-based thiazole chelating functional fibers, the detailed steps of which are as follows:

[0074] a. First, weigh 0.51 g (0.0047 mol) of polyphenylene sulfide (PPS) fiber and add it to a reaction flask. Then, add 50 mL of 1,2-dichloroethane and let it swell for 12 h. After swelling, add 3.4 mL (0.0376 mol) of dimethoxymethane and 2.7 g (0.02 mol) of anhydrous aluminum trichloride and stir until homogeneous. Then, heat to 70 °C and react at this temperature for 24 h. After the reaction is complete, cool to room temperature, filter, and filter out the product. Wash the product with anhydrous ethanol, boil it in 1 mol / L HCl solution at 50 °C for 5 h, wash it with water until neutral, and vacuum dry it to constant weight (vacuum degree: 0.08 MPa, drying temperature: 60 °C, drying time: 24 h). After drying, dimethoxymethane crosslinked PPS fiber is obtained (the modified fiber has a weight increase of 2.1% compared to the original PPS fiber).

[0075] b. The obtained cross-linked polyphenylene sulfide fiber was added to 50 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 5 mL of mixed acid was added and stirred evenly (the mixed acid was a mixture of concentrated sulfuric acid and concentrated nitric acid in a molar ratio of 3:1). The mixture was then heated to 60 °C and reacted at this temperature for 1 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the obtained product was filtered out. The obtained product was washed successively with anhydrous ethanol and water until neutral, and then vacuum dried to constant weight (vacuum degree of 0.08 MPa, drying temperature of 60 °C, drying time of 24 h). After drying, modified nitrated PPS-NO2 fiber was obtained.

[0076] Modified nitrated PPS-NO2 fibers were placed in 30 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 1.1 g of stannous chloride and 22 mL of concentrated hydrochloric acid were added as reducing agent, and the mixture was heated to 90 °C for 5 h for reduction reaction. After the reaction was completed, the mixture was cooled to room temperature, filtered to obtain the product, washed with anhydrous ethanol, boiled with 1 mol / L hydrochloric acid at 50 °C for 5 h, washed with water until neutral, and vacuum dried to constant weight (vacuum degree 0.08 MPa, drying temperature 60 °C, drying time 24 h). After drying, amino polyphenylene sulfide fibers PPS-NH2 were obtained (the fiber weight increased by 15.2% compared to before the reaction).

[0077] c. The obtained amino-based polyphenylene sulfide fiber PPS-NH2 was placed in 55 mL of 1,2-dichloroethane and allowed to swell for 12 h. Then, 4 g of 2-chlorobenzothiazole was added, and the mixture was heated to 100 °C and reacted for 5 h. After the reaction was completed, the mixture was cooled to room temperature, filtered to obtain the product, and washed successively with anhydrous ethanol and water until neutral. The product was then vacuum dried to constant weight (vacuum degree 0.08 MPa, drying temperature 60 °C, drying time 24 h). After drying, polyphenylene sulfide-based thiazole chelating functional fiber was obtained (the fiber weight increased by 42.9% compared to before the reaction).

Claims

1. A method for preparing polyphenylene sulfide-based chelated fibers, characterized in that, The preparation method includes the following steps: a. Add polyphenylene sulfide fiber to a reaction vessel, then add solvent to allow it to swell fully. After swelling, add crosslinking agent and catalyst and stir or ultrasonically disperse evenly. Then heat to 70-80℃ and react at this temperature for 12-48 hours. After the reaction is complete, cool to room temperature, filter, filter out the product, and then wash the product with alcohol, acid, water and dry it in sequence to obtain crosslinked polyphenylene sulfide fiber, i.e., crosslinked PPS fiber. The crosslinking agent is at least one of dimethoxymethane, ethylene glycol dimethyl ether and 1,4-dimethoxybenzene; b. Add the cross-linked PPS fibers obtained in step a to the solvent and allow them to swell completely. After swelling, add the nitrifying agent and stir or ultrasonically disperse evenly. Then heat to 40-60℃ and react at this temperature for 1-6 hours. After the reaction is complete, cool to room temperature, filter, and filter out the product. Wash the product with alcohol, water, and dry it in sequence to obtain modified nitrated fiber PPS-NO2. Modified nitrocellulose PPS-NO2 was placed in a container and a solvent was added to swell it. Then a reducing agent was added and the mixture was heated to 50-100℃ and reacted for 1-6 hours. After the reaction was completed, the mixture was cooled to room temperature and filtered. The product was then subjected to alcohol washing, acid boiling, water washing and drying to obtain amino polyphenylene sulfide fiber PPS-NH2. c. Place the obtained amino polyphenylene sulfide fiber PPS-NH2 in a container, add solvent A; then add the functional monomer, and heat to 60-120℃ for 4-6 hours; after the reaction is completed, cool to room temperature, filter, and wash the product with alcohol, water and dry in sequence to obtain PPS-based chelated functional fiber, i.e., polyphenylene sulfide-based chelated fiber. The solvent A is 1,2-dichloroethane or hydrochloric acid; the functional monomer is at least one of sodium chloroacetate, phosphorous acid, and 2-chlorobenzothiazole; wherein, when grafting phosphorous acid, hydrochloric acid is used as the solvent, and paraformaldehyde reacts with an amino group to generate a methylamino intermediate, which then reacts with phosphorous acid to obtain the target compound; when grafting sodium chloroacetate and 2-chlorobenzothiazole, 1,2-dichloroethane is used as the solvent.

2. The method for preparing polyphenylene sulfide-based chelated fibers according to claim 1, characterized in that: In step a, the mass-to-volume ratio of the polyphenylene sulfide fiber to the solvent is 1 g: 50-100 mL, the molar ratio of the polyphenylene sulfide fiber to the crosslinking agent is 1: 0.5-8, and the molar ratio of the polyphenylene sulfide fiber to the catalyst is 1: 1.2-2.

2.

3. The method for preparing polyphenylene sulfide-based chelated fibers according to claim 1, characterized in that: The solvent in step a is 1,2-dichloroethane; the catalyst is anhydrous aluminum trichloride, anhydrous ferric trichloride, or anhydrous tin tetrachloride.

4. The method for preparing polyphenylene sulfide-based chelated fibers according to claim 1, characterized in that, The specific operation process of sequentially washing the obtained product with alcohol, boiling with acid, washing with water and drying in step a is as follows: the obtained product is washed sequentially with anhydrous ethanol, boiled in HCl solution with a concentration of 1-2 mol / L at 50°C for 5-6 hours, washed with water until neutral, and then vacuum dried at 50-60°C to constant weight.

5. The method for preparing polyphenylene sulfide-based chelated fibers according to claim 1, characterized in that, The solvents used in step b are all 1,2-dichloroethane; the nitrating agent is a mixture of concentrated sulfuric acid and concentrated nitric acid, with a molar ratio of concentrated nitric acid to concentrated sulfuric acid of 1:3 to 7; and the reducing agent is stannous chloride or reduced iron powder.

6. The method for preparing polyphenylene sulfide-based chelated fibers according to claim 1, characterized in that, In step b, the mass-to-volume ratio of the cross-linked PPS fiber to the solvent is 1 g: 50-100 mL, and the molar ratio of the cross-linked PPS fiber to the nitrifying agent is 1: 0.5-2. The mass-to-volume ratio of the modified nitrated cellulose PPS-NO2 to the solvent is 1g:50-100mL, and the mass-to-volume ratio of the modified nitrated PPS-NO2 fiber to the reducing agent is 1:1-5.

7. The method for preparing polyphenylene sulfide-based chelated fibers according to claim 1, characterized in that, The specific process of sequentially washing the obtained product with alcohol, water, and drying in step b is as follows: the obtained product is washed sequentially with anhydrous ethanol, then washed with water until neutral, and then vacuum dried to constant weight under a vacuum of 0.08 MPa and a drying temperature of 50–60°C; the specific process of sequentially washing the product with alcohol, acid boiling, water washing, and drying is as follows: the obtained product is washed sequentially with anhydrous ethanol, boiled in 1–2 mol / L HCl solution at 50°C for 5–6 h, washed with water until neutral, and then vacuum dried to constant weight under a vacuum of 0.08 MPa and a drying temperature of 50–60°C.

8. The method for preparing polyphenylene sulfide-based chelated fibers according to claim 1, characterized in that: In step c, the mass-to-volume ratio of the amino polyphenylene sulfide fiber PPS-NH2 to solvent A is 1 g: 50-100 mL, and the molar ratio of the amino polyphenylene sulfide fiber PPS-NH2 to the functional monomer is 1: 1-10.

9. The method for preparing polyphenylene sulfide-based chelated fibers according to claim 1, characterized in that, The specific process of washing the product with alcohol, water and drying in step c is as follows: the obtained product is washed with anhydrous ethanol and water until neutral, and then vacuum dried to constant weight under vacuum conditions of 0.08 MPa and drying temperature of 50-60℃.

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