Flame-retardant and bacteriostatic wave-absorbing PET fiber and preparation method thereof

Abstract

The application discloses a kind of flame-retardant bacteriostatic wave-absorbing PET fibers and preparation method thereof, the fiber includes fiber body and is arranged on the bacteriostatic wave-absorbing layer of fiber body surface, fiber body is skin-core composite structure, from inside to outside includes core layer and flame-retardant wave-absorbing barrier layer in sequence;Flame-retardant wave-absorbing barrier layer is the raw material of flame-retardant wave-absorbing mixture, includes the following components by weight parts:PET polyester chip 100, flame retardant 9-15, flame-retardant wave-absorbing particle 22-40, compatible agent 1.5-4.The bacteriostatic wave-absorbing layer in the application can provide excellent electromagnetic wave absorption capacity through the bacteriostatic wave-absorbing particle therein, can realize effective protection to electromagnetic pollution, and also can provide excellent antibacterial performance through active oxygen generated under light and / or electromagnetic wave irradiation.Flame-retardant wave-absorbing barrier layer can provide good reflection and absorption electromagnetic wave capacity in addition to being able to improve flame-retardant performance through the flame-retardant wave-absorbing particle therein.

Description

Technical Field

[0001] This invention relates to the field of polyester fiber materials, and in particular to a flame-retardant and antibacterial microwave-absorbing PET fiber and its preparation method. Background Technology

[0002] PET fiber (polyester, polyethylene terephthalate), commonly known as "polyester," has advantages such as high breaking strength and elastic modulus, moderate resilience, excellent heat setting effect, good abrasion resistance, and stable chemical properties. It has wide applications in the manufacture of home textiles and industrial textiles.

[0003] Ordinary polyester fiber is a flammable fiber. Adding flame-retardant components can improve its flame-retardant properties, thereby enhancing the safety of the fiber. For example, patent CN112831863B discloses a flame-retardant polyester fiber and its preparation process, and patent CN109881289B discloses a method for preparing flame-retardant and smoke-suppressing PET fiber.

[0004] However, with the enrichment and expansion of applications for polyester fibers, more and more requirements are being placed on the functions of polyester fibers, such as electromagnetic shielding performance and antibacterial performance.

[0005] With the widespread use of electronic devices, the harm caused to the human body by electromagnetic waves in daily life has attracted increasing attention. Therefore, the development of electromagnetic shielding materials with electromagnetic wave shielding properties to reduce radiation and enhance human protection is of great significance and has promising application prospects. Iron oxide (Fe3O4) has high saturation magnetization, coercivity, and resistivity, which can act as a magnetic loss agent for electromagnetic waves. Furthermore, iron oxide is abundant, inexpensive, and easy to synthesize, making it a commonly used magnetic loss-type absorbing material. For example, patent CN118727436B discloses a magnetic composite fiber cloth with electromagnetic shielding properties and its preparation method, which uses iron oxide to modify the fiber cloth, giving it electromagnetic wave shielding performance. However, single-material absorbing materials have simple loss mechanisms and low absorption efficiency, making it difficult to meet application requirements.

[0006] Antibacterial polyester fibers can effectively reduce bacterial growth and harm to human health. Traditional methods typically involve adding antibacterial agents, such as silver or copper, as illustrated by a method for preparing copper oxide antibacterial fibers disclosed in patent CN105401245B. However, uneven dispersion of the antibacterial agent within the fiber can affect its antibacterial performance and may also compromise fiber strength.

[0007] Therefore, it is now necessary to improve existing technologies to provide more reliable solutions. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a flame-retardant and antibacterial microwave-absorbing PET fiber and its preparation method, in order to address the shortcomings of the prior art.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a flame-retardant and antibacterial microwave-absorbing PET fiber is provided, comprising a fiber body and an antibacterial microwave-absorbing layer disposed on the surface of the fiber body. The fiber body is a core-sheath composite structure, comprising a core layer and a flame-retardant microwave-absorbing barrier layer from the inside out. The raw material of the flame-retardant microwave-absorbing barrier layer is a flame-retardant microwave-absorbing mixture, comprising the following components by weight: 100 parts of PET polyester chips, 9-15 parts of flame retardant, 22-40 parts of flame-retardant microwave-absorbing particles, and 1.5-4 parts of compatibilizer.

[0010] The flame-retardant microwave absorbing particles are prepared through the following steps:

[0011] S1-1, Preparation of carboxylated graphene oxide;

[0012] S1-2. Zinc oxide-hybridized iron oxide is loaded onto carboxylated graphene oxide to obtain composite microwave absorbing particles;

[0013] S1-3. Polyaniline hybridization treatment is applied to the composite microwave absorbing particles to obtain flame-retardant microwave absorbing particles.

[0014] The antibacterial absorbing layer is obtained by coating the surface of the fiber body with antibacterial absorbing particles. The preparation method of the antibacterial absorbing particles includes the following steps:

[0015] S2-1, Preparation of partially oxidized Ti3C2T X MXene;

[0016] S2-2, Preparation of Ni hybrid carbon dots;

[0017] S2-3, Partially oxidize Ti3C2T x MXene and Ni-hybridized carbon dots self-assemble to obtain antibacterial and microwave absorbing particles.

[0018] Preferably, the fiber body is prepared by a core-sheath composite spinning process using PET polyester chips as the core material and a flame-retardant and microwave-absorbing mixture as the sheath material.

[0019] The antibacterial absorbing layer is obtained by coating the surface of the fiber body with antibacterial absorbing particles through an impregnation process. The specific impregnation process is as follows:

[0020] Antibacterial absorbing particles are dispersed in deionized water to obtain an antibacterial absorbing particle dispersion. The fiber body is ultrasonically washed in deionized water, dried, immersed in the antibacterial absorbing particle dispersion, dried, and this process is repeated several times to form an antibacterial absorbing layer on the surface of the fiber body.

[0021] Preferably, the impregnation process used to prepare the antibacterial absorbing layer is as follows:

[0022] Add antibacterial absorbing particles to deionized water and ultrasonically disperse for 1-4 hours to prepare an antibacterial absorbing particle dispersion with a concentration of 5-20 mg / mL. Ultrasonically wash the fiber body in deionized water for 0.5-2 hours, remove it and dry it at 80-120℃ for 1-4 hours, place it in the antibacterial absorbing particle dispersion, immerse it at 50-70℃ for 10-30 minutes, remove it and dry it at 80-120℃ for 1-4 hours to complete one immersion. Repeat the immersion 2-8 times to form an antibacterial absorbing layer on the surface of the fiber body.

[0023] Preferably, the flame-retardant microwave absorbing particles are prepared through the following steps:

[0024] S1-1. Add graphene oxide to a mixture of H2O2 and nitric acid, heat and stir under reflux, filter, wash with deionized water until neutral, and dry to obtain carboxylated graphene oxide.

[0025] S1-2. Carboxylated graphene oxide and urea were added to deionized water and ultrasonically dispersed to obtain a graphene dispersion. PVP, FeCl2, FeCl3, and ZnSO4 were added to a mixed solvent of deionized water and ethylene glycol in a volume ratio of 1:1 and stirred. The resulting mixture was added to the graphene dispersion under stirring. The product was transferred to a reaction vessel and reacted at 190-240℃ for 6-24 hours. After centrifugation, washing, and vacuum drying, composite microwave absorbing particles were obtained.

[0026] S1-3. Disperse the composite microwave absorbing particles in deionized water, add aniline, stir, add ammonium persulfate, adjust the pH of the reaction system to 2-3, stir the reaction, centrifuge, wash, and vacuum dry to obtain flame-retardant microwave absorbing particles.

[0027] Preferably, the flame-retardant microwave absorbing particles are prepared through the following steps:

[0028] S1-1. Take 2g of graphene oxide and add it to a mixture of 50mL of 20wt% H2O2 and 100mL of 60wt% nitric acid. Stir and reflux at 80℃ for 6h, filter, wash with deionized water until neutral, and dry to obtain carboxylated graphene oxide.

[0029] S1-2. Take 1g of carboxylated graphene oxide and 4.5g of urea and add them to 100mL of deionized water. Disperse the mixture by ultrasonication for 1h to obtain a graphene dispersion. Add 1g of PVP, 0.381g of FeCl2, 0.972g of FeCl3, and 0.322g of ZnSO4 to a mixed solvent of 100mL of deionized water and ethylene glycol in a volume ratio of 1:1. Stir for 15min. Add the resulting mixture to the graphene dispersion under stirring. Stir for 1h. Transfer the resulting product to a reaction vessel and react at 220℃ for 12h. Centrifuge, wash, and vacuum dry to obtain composite microwave absorbing particles.

[0030] S1-3. Take 0.2g of composite microwave absorbing particles and add them to 100mL of deionized water. Disperse them by sonication for 45min. Add 0.35g of aniline and stir for 1h. Add 0.85g of ammonium persulfate at 5℃ and adjust the pH of the reaction system to 2 with 30wt% hydrochloric acid. Stir the reaction at room temperature for 8h. Centrifuge, wash, and vacuum dry to obtain flame-retardant microwave absorbing particles.

[0031] Preferably, the antibacterial absorbing particles are prepared through the following steps:

[0032] S2-1, Ti3C2T X MXene was calcined in air at 250-400℃ for 2-4 hours and then ground to obtain partially oxidized Ti3C2T. x MXene;

[0033] S2-2. Add nickel sulfate hexahydrate, glucose, polyethyleneimine, dithiodibenzoic acid and 4-methoxypyridine to deionized water, stir, adjust pH to 9, heat and stir to react, transfer the obtained precursor to a reaction vessel, react at 230-250℃ for 5-20h, centrifuge, wash, and vacuum dry to obtain Ni hybrid carbon dots.

[0034] S2-3. Add Ni-hybridized carbon dots to hydrochloric acid, sonicate, filter, wash the solid product with deionized water until neutral, and then disperse it in deionized water to obtain a carbon dot dispersion; partially oxidize Ti3C2T x MXene was dispersed in deionized water to obtain an MXene dispersion;

[0035] The carbon dot dispersion was added to the MXene dispersion under stirring. The mixture was stirred continuously, allowed to stand, filtered, washed, and freeze-dried to obtain antibacterial and microwave-absorbing particles.

[0036] Preferably, the antibacterial absorbing particles are prepared through the following steps:

[0037] S2-1, Ti3C2T XMXene was calcined in air at 350°C for 3 hours and then ground to obtain partially oxidized Ti3C2T. x MXene;

[0038] S2-2. 524 mg nickel sulfate hexahydrate, 600 mg glucose, 350 mg polyethyleneimine, 306 mg dithiodibenzoic acid and 218 mg 4-methoxypyridine were added to 150 mL of deionized water and stirred for 30 min. Then the pH was adjusted to 9 with 1 mol / L sodium hydroxide solution and stirred at 60 °C for 4 h. The resulting precursor was transferred to a reaction vessel and reacted at 230 °C for 10 h. After centrifugation, washing and vacuum drying, Ni hybrid carbon dots: Ni-CDs were obtained.

[0039] S2-3. Add 1.5g of Ni hybrid carbon dots to 80mL of 1mol / L hydrochloric acid, sonicate at 60℃ for 1h, filter, wash the solid product with deionized water until neutral, then add to 50mL of deionized water and sonicate for 1.5h to obtain a carbon dot dispersion; add 1g of partially oxidized Ti3C2T x MXene was added to 50 mL of deionized water and ultrasonically dispersed for 2 h to obtain an MXene dispersion.

[0040] The carbon dot dispersion was added to the MXene dispersion under stirring. The mixture was stirred continuously at 1000 rpm for 10 h, then allowed to stand for 2 h, filtered, washed, and freeze-dried to obtain antibacterial absorbing particles.

[0041] Preferably, the compatibilizer is one or more of EEA (ethylene-ethyl acrylate), EVA (ethylene-vinyl acetate copolymer), and maleic anhydride-grafted polyolefin elastomer (maleic anhydride-grafted POE).

[0042] The flame retardant is one or more of ammonium polyphosphate, trihydroxyethyl phosphate, phenylphosphonic acid, and trihydroxymethylphosphonic acid oxide.

[0043] The present invention also provides a method for preparing the flame-retardant and antibacterial microwave-absorbing PET fiber as described above, comprising the following steps:

[0044] Step 1: Mix PET polyester chips, flame retardant, flame retardant microwave absorbing particles, and compatibilizer evenly to obtain a flame retardant microwave absorbing mixture;

[0045] Step 2: PET polyester chips as core material and flame-retardant microwave-absorbing mixture as sheath material are added to their respective screw extruders for melt extrusion, and then the fiber body is prepared by core-sheath composite spinning process.

[0046] Step 3: An antibacterial and microwave-absorbing layer is formed by impregnating the fiber body with antibacterial and microwave-absorbing particles, and finally the flame-retardant and antibacterial microwave-absorbing PET fiber is obtained.

[0047] Preferably, in step 2, the mass ratio of the skin layer material to the core layer material is 1:9 to 3.5:6.5; the melt extrusion temperature corresponding to the core layer material is 260-290℃, and the melt extrusion temperature corresponding to the skin layer material is 250-290℃.

[0048] The spinning process parameters are: spinning temperature 260-280℃, spinning speed 2000-4500m / min, side blowing temperature 10-30℃, and side blowing speed 0.2-1m / s.

[0049] The beneficial effects of this invention are:

[0050] This invention provides a flame-retardant and antibacterial microwave-absorbing PET fiber, which has a multi-layered composite structure consisting of a core layer, a flame-retardant microwave-absorbing barrier layer, and an antibacterial microwave-absorbing layer, from the inside out. The antibacterial microwave-absorbing layer provides excellent electromagnetic wave absorption capabilities through its antibacterial microwave-absorbing particles, effectively protecting against electromagnetic pollution. It also provides excellent antibacterial properties through the active oxygen generated under light and / or electromagnetic wave irradiation. The flame-retardant microwave-absorbing barrier layer, through its flame-retardant microwave-absorbing particles, not only enhances flame-retardant performance but also provides good electromagnetic wave reflection and absorption capabilities. This allows the portion of incident electromagnetic waves not absorbed by the antibacterial microwave-absorbing layer to be absorbed and reflected by the flame-retardant microwave-absorbing barrier layer. This multiple reflection and absorption between the antibacterial and flame-retardant microwave-absorbing layers significantly improves electromagnetic wave shielding capabilities and reduces electromagnetic wave transmission. On the other hand, the flame-retardant microwave absorbing barrier layer can also block the active oxygen generated in the antibacterial microwave absorbing layer through its antibacterial absorbing particles, preventing active oxygen from entering the core layer and causing aging and degradation of the polyester in the core layer. Furthermore, the flame-retardant microwave absorbing barrier layer also improves the mechanical strength and antistatic properties of the fiber.

[0051] The Ni-hybridized carbon dots in the antibacterial absorbing layer of this invention can not only absorb electromagnetic waves, but also generate active oxygen with antibacterial properties under the action of electromagnetic waves, which is beneficial to the fiber's performance. The antibacterial absorbing particles of this invention contain Ni-hybridized carbon dots and partially oxidized Ti3C2T... x The combination with MXene enables the antibacterial and microwave-absorbing layer on the fiber surface prepared by it to generate active oxygen with antibacterial ability under light or electromagnetic radiation, which can endow the fiber with excellent antibacterial and antimicrobial properties. Attached Figure Description

[0052] Figure 1 The infrared absorption spectrum of the flame-retardant microwave-absorbing particles prepared in Example 1;

[0053] Figure 2 The infrared absorption spectrum of the antibacterial absorbing particles prepared in Example 1;

[0054] Figure 3 These are the results of electromagnetic shielding performance tests.

[0055] Figure 4 The results are the overall shielding effectiveness degradation rate test results;

[0056] Figure 5 This is the result of the limiting oxygen index test;

[0057] Figure 6 The results show the antibacterial performance of the antibacterial absorbing particles.

[0058] Figure 7 The results are from the antibacterial performance test of the fiber;

[0059] Figure 8 The results show the singlet oxygen generation capacity of the antibacterial absorbing particles prepared in Example 1 under different conditions.

[0060] Figure 9 The results of singlet oxygen generation tests on the antibacterial absorbing particles prepared in Examples 1-4 and Comparative Examples 4-6;

[0061] Figure 10 This is the result of the fracture strength test. Detailed Implementation

[0062] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0063] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0064] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available. For examples where specific conditions are not specified, conventional conditions or conditions recommended by the manufacturer are followed. For reagents or instruments whose manufacturers are not specified, they are all commercially available products.

[0065] This invention provides a flame-retardant and antibacterial microwave-absorbing PET fiber, characterized in that it comprises a fiber body and an antibacterial microwave-absorbing layer disposed on the surface of the fiber body. The fiber body has a core-sheath composite structure, comprising a core layer and a flame-retardant microwave-absorbing barrier layer from the inside out. The raw material of the flame-retardant microwave-absorbing barrier layer is a flame-retardant microwave-absorbing mixture, comprising the following components by weight: 100 parts of PET polyester chips, 9-15 parts of flame retardant, 22-40 parts of flame-retardant microwave-absorbing particles, and 1.5-4 parts of compatibilizer.

[0066] In this invention, flame-retardant microwave absorbing particles are prepared through the following steps:

[0067] S1-1, Preparation of carboxylated graphene oxide:

[0068] Take 1-4g of graphene oxide and add it to a mixture of 25-100mL of 20wt% H2O2 and 50-200mL of 60wt% nitric acid. Stir and reflux at 70-90℃ for 3-12h, filter, wash with deionized water until neutral, and dry to obtain carboxylated graphene oxide.

[0069] S1-2. Zinc oxide-hybridized iron oxide is loaded onto carboxylated graphene oxide to obtain composite microwave absorbing particles:

[0070] Take 0.5-2g of carboxylated graphene oxide and 2.2-9g of urea and add them to 50-200mL of deionized water. Disperse the mixture by ultrasonication for 0.5-2h to obtain a graphene dispersion. Add 0.5-2g of PVP, 0.2-0.6g of FeCl2, 0.5-2g of FeCl3, and 0.15-0.65g of ZnSO4 to a mixed solvent of 50-200mL of deionized water and ethylene glycol in a volume ratio of 1:1. Stir for 5-30min. Add the resulting mixture to the graphene dispersion while stirring. Stir for 0.5-2h. Transfer the resulting product to a reaction vessel and react at 190-240℃ for 6-24h. Centrifuge, wash, and vacuum dry to obtain composite microwave absorbing particles.

[0071] S1-3. The composite microwave absorbing particles are subjected to polyaniline hybridization treatment to obtain flame-retardant microwave absorbing particles:

[0072] Take 0.1-0.4g of composite microwave absorbing particles and add them to 50-200mL of deionized water. Disperse them ultrasonically for 30-90min. Add 0.15-0.7g of aniline and stir for 0.5-2h. Add 0.4-1.7g of ammonium persulfate at 2-10℃ and adjust the pH of the reaction system to 2-3 with 30wt% hydrochloric acid. Stir the reaction at room temperature for 4-16h. Centrifuge, wash, and vacuum dry to obtain flame-retardant microwave absorbing particles.

[0073] In this invention, the antibacterial absorbing layer is obtained by coating the surface of the fiber body with antibacterial absorbing particles. The preparation method of the antibacterial absorbing particles includes the following steps:

[0074] S2-1, Preparation of partially oxidized Ti3C2T X MXene:

[0075] Ti3C2T X MXene was calcined in air at 250-400℃ for 2-4 hours and then ground to obtain partially oxidized Ti3C2T. x MXene;

[0076] Among them, Ti3C2T X MXene can be obtained from commercially available products or by traditional etching methods. For example, in some embodiments, it is prepared as follows: 1.35 g of LiF is added to 25 mL of 9 M HCl solution and stirred for 30 min to obtain an etching solution; 2 g of Ti3AlC2 is added to the etching solution, and the mixture is stirred at 45 °C for 48 h. After the reaction, the product is washed with deionized water by centrifugation until the pH of the supernatant is 6, and then dried under vacuum at 60 °C for 12 h to obtain Ti3C2T. X MXene;

[0077] S2-2, Preparation of Ni-hybridized carbon dots:

[0078] Add 250-1050 mg of nickel sulfate hexahydrate, 300-1200 mg of glucose, 175-700 mg of polyethyleneimine, 150-612 mg of dithiodibenzoic acid, and 100-250 mg of 4-methoxypyridine to 50-300 mL of deionized water, stir for 15-60 min, then adjust the pH to 9 with 0.5-2 mol / L sodium hydroxide solution, stir and react at 50-70 °C for 2-8 h, transfer the obtained precursor to a reaction vessel, react at 230-250 °C for 5-20 h, centrifuge, wash, and vacuum dry to obtain Ni hybrid carbon dots: Ni-CDs;

[0079] S2-3, Partially oxidize Ti3C2T x MXene self-assembles with Ni-hybridized carbon dots to obtain antibacterial and microwave absorbing particles:

[0080] Add 0.75-3 g of Ni hybrid carbon dots to 40-160 mL of 0.5-2 mol / L hydrochloric acid, sonicate at 50-70 °C for 0.5-2 h, filter, wash the solid product with deionized water until neutral, then add 25-100 mL of deionized water and sonicate for 1-3 h to obtain a carbon dot dispersion; add 0.5-2 g of partially oxidized Ti3C2T x Add MXene to 25-100 mL of deionized water and sonicate for 1-4 h to obtain MXene dispersion;

[0081] The carbon dot dispersion was added to the MXene dispersion under stirring. The mixture was stirred continuously at 500-2000 rpm for 5-20 hours, then allowed to stand for 1-4 hours, filtered, washed, and freeze-dried to obtain antibacterial absorbing particles.

[0082] In this invention, the fiber body is prepared by using PET polyester chips as the core material and flame-retardant microwave-absorbing mixture as the sheath material through a core-sheath composite spinning process.

[0083] The antibacterial absorbing layer is obtained by coating the surface of the fiber body with antibacterial absorbing particles through an impregnation process. The specific impregnation process is as follows:

[0084] Add antibacterial absorbing particles to deionized water and ultrasonically disperse for 1-4 hours to prepare an antibacterial absorbing particle dispersion with a concentration of 5-20 mg / mL. Ultrasonically wash the fiber body in deionized water for 0.5-2 hours, remove it and dry it at 80-120℃ for 1-4 hours, place it in the antibacterial absorbing particle dispersion, immerse it at 50-70℃ for 10-30 minutes, remove it and dry it at 80-120℃ for 1-4 hours to complete one immersion. Repeat the immersion 2-8 times to form an antibacterial absorbing layer on the surface of the fiber body.

[0085] Invention Mechanism:

[0086] 1. Overall Mechanism: The flame-retardant and antibacterial absorbing PET fiber prepared by this invention has a multi-layer composite structure consisting of a core layer, a flame-retardant absorbing barrier layer, and an antibacterial absorbing layer, arranged sequentially from the inside out. The core layer is the main structure of the PET fiber, while the flame-retardant and antibacterial absorbing barrier layers are functional structural layers formed by sequentially covering the core layer. The antibacterial absorbing layer provides excellent electromagnetic wave absorption capabilities through its antibacterial absorbing particles, effectively protecting against electromagnetic pollution. It also provides excellent antibacterial properties through the active oxygen generated under light and / or electromagnetic radiation. The flame-retardant absorbing barrier layer, through its flame-retardant absorbing particles, not only enhances flame-retardant performance but also provides good electromagnetic wave reflection and absorption capabilities. This allows the portion of the incident electromagnetic wave not absorbed by the antibacterial absorbing layer to be absorbed and reflected by the flame-retardant absorbing barrier layer, resulting in multiple reflections and absorptions between the antibacterial and flame-retardant absorbing layers. Ultimately, this significantly improves the electromagnetic wave shielding capability and reduces the amount of electromagnetic wave transmission. On the other hand, the flame-retardant microwave absorbing barrier layer can also block the active oxygen generated in the antibacterial microwave absorbing layer through its antibacterial absorbing particles, preventing active oxygen from entering the core layer and causing aging and degradation of the polyester in the core layer. Furthermore, the flame-retardant microwave absorbing barrier layer also improves the mechanical strength and antistatic properties of the fiber. The following is a further analysis and explanation of the preparation and mechanism of action of the antibacterial absorbing particles in the antibacterial microwave absorbing layer and the flame-retardant microwave absorbing barrier layer.

[0087] 2. Preparation and mechanism of action of antibacterial absorbing particles:

[0088] 2-1. Preparation mechanism:

[0089] First, the Ti3C2T X MXene was calcined at high temperature in air. By controlling the calcination temperature and time, partial oxidation was achieved, causing the Ti in it to be oxidized to TiO2, thus obtaining Ti3C2T with in-situ supported TiO2. XMXene material, the TiO2 obtained in this way can be uniformly distributed in Ti3C2T X MXene exhibits good dispersibility and more uniform particle size in its layered structure.

[0090] Then, using nickel sulfate hexahydrate as the nickel source and glucose, polyethyleneimine, dithiodibenzoic acid and 4-methoxypyridine as the composite carbon source, a nickel oxide-doped carbon dot, namely a Ni-hybridized carbon dot, was synthesized by hydrothermal method.

[0091] Finally, Ni hybrid carbon dots were assembled onto partially oxidized Ti3C2T. x On MXene, antibacterial absorbing particles were obtained: Ni hybrid carbon dots were first impregnated in hydrochloric acid under ultrasonic treatment. Through the reaction of hydrochloric acid with nickel oxide, a large amount of Ni was generated on the Ni hybrid carbon dots. 2+ Then, Ni hybrid carbon dots were combined with partially oxidized Ti3C2T x MXene is mixed in solution and partially oxidizes Ti3C2T x The negatively charged hydroxyl groups and fluoride ions contained in MXene react with Ni 2+ The electrostatic coupling effect, and the partial oxidation of Ti3C2T x The physical adsorption of the layered structure in MXene enables Ni hybrid carbon dots to connect and assemble onto partially oxidized Ti3C2T. x On MXene, uniform loading is achieved to obtain antibacterial and microwave-absorbing particles.

[0092] 2-2. Main mechanism of action:

[0093] Ti3C2T x MXene is a two-dimensional nanolayered material with a large specific surface area and a multilayer structure. It also has excellent electromagnetic shielding and wave absorption properties. The inherent polarization and dipole polarization caused by surface defects can efficiently dissipate electromagnetic wave energy (Zhang Hengyu. Research on MXene-based flexible and efficient wave-absorbing textile materials [D]. Donghua University, 2024.).

[0094] In this invention, Ti3C2T x MXene, as a matrix material for antibacterial and microwave-absorbing particles, provides excellent microwave absorption performance. Furthermore, by partially oxidizing it, a matrix of Ti3C2T... xAfter TiO2 is formed in situ on MXene, firstly, TiO2 can not only optimize impedance matching, but also effectively prevent stacking and provide a heterogeneous interface, providing a conductive path for charge carriers and further improving absorption characteristics; secondly, TiO2 is an excellent photosensitive material that can generate electron-hole pairs under light. The electrons after the transition react with the substrate (such as H2O, O) to produce reactive oxygen species, such as singlet oxygen (¹O2), superoxide radical (O2⁻), hydroxyl radical (OH·), etc. Reactive oxygen species have strong oxidizing properties and can destroy cell membranes, proteins and DNA structures, thus exhibiting excellent antibacterial ability.

[0095] The Ni hybrid carbon dots prepared in this invention exhibit a unique microwave absorption response characteristic. Upon absorbing electromagnetic waves, they can efficiently generate reactive oxygen species. This is because, after absorbing electromagnetic waves, the internal electrons of the Ni hybrid carbon dots undergo energy level transitions, jumping from low-energy orbitals to high-energy orbitals. The transitioned electrons react with oxygen molecules (O2) or water molecules (H2O) to generate singlet oxygen (¹O2), superoxide radicals (O2⁻), and hydroxyl radicals (OH·).

[0096] In other words, Ni hybrid carbon dots can not only absorb electromagnetic waves, but also generate active oxygen with antibacterial properties under the influence of electromagnetic waves, which is beneficial to the fiber's performance. In this invention, Ni hybrid carbon dots react with partially oxidized Ti3C2T... x The combination with MXene enables the antibacterial and microwave-absorbing layer on the fiber surface prepared by it to generate active oxygen with antibacterial ability under light or electromagnetic radiation, which can endow the fiber with excellent antibacterial and antimicrobial properties.

[0097] The Ni doped in the carbon dots is nickel oxide nanoparticles that are uniformly hybridized with the carbon dots during a high-temperature and high-pressure hydrothermal reaction. The nickel oxide nanoparticles can further improve the microwave absorption performance. The main mechanisms of action include: nickel oxide reduces the reflection of electromagnetic waves on the material surface by adjusting the conductivity and dielectric constant of the composite material, improves the impedance matching characteristics, and allows more electromagnetic waves to enter the material and be consumed. The polar molecular structure of nickel oxide generates dipole polarization under an alternating electromagnetic field, which can consume electromagnetic energy (Wang Huiya. Preparation of biomass porous carbon / nickel oxide composite material and its microwave absorption performance study [D]. Yunnan University, 2019.).

[0098] Partial oxidation of Ti3C2T x MXene provides good loading for Ni hybrid carbon dots, enabling better uniform distribution of Ni hybrid carbon dots and partial oxidation of Ti3C2T. x MXene can provide electron transport and improve electron-hole separation efficiency, thereby enhancing the microwave absorption performance of Ni hybrid carbon dots and their catalytic ability to generate active oxygen under electromagnetic wave excitation.

[0099] 3. Preparation and Mechanism of Action of Flame-Retardant and Microwave-Absorbing Mixtures:

[0100] 3-1. Preparation mechanism:

[0101] First, graphene oxide is oxidized using a mixture of H2O2 and nitric acid to enrich the carboxyl groups on its surface, thus obtaining carboxylated graphene oxide.

[0102] Then, zinc oxide-hybridized iron(III) oxide was deposited in situ on carboxylated graphene oxide using a one-pot hydrothermal method to obtain composite microwave absorbing particles; due to the abundant carboxyl groups on the surface, they can attract Fe... 2+ Fe 3+ The presence of Zn ions facilitates the deposition of zinc oxide-hybridized iron tetroxide on graphene oxide.

[0103] Finally, in-situ polymerization was used to graft polyaniline onto the composite microwave absorbing particles to obtain flame-retardant microwave absorbing particles.

[0104] 3-2. Mechanism of action:

[0105] Fe3O4 possesses high saturation magnetization, coercivity, and resistivity, making it a commonly used magnetic loss-type microwave absorbing material (Pan Hong, Hu Lei, Xu Lihui, et al. Green low-temperature method for preparing Fe3O4 and its composite material microwave absorption performance [J]. Materials Engineering, 2025, 53(4): 150-162.). However, the loss mechanism of single-material microwave absorbing materials is simple, and the microwave absorption efficiency is low, making it difficult to meet the application requirements. In this invention, by hybridizing ZnO into Fe3O4, the dielectric loss is improved through its polarization effect and interfacial polarization energy, thereby enhancing the microwave absorption performance (Wang S, Li D, Zhou Y, et al. Hierarchical Ti3C2TxMXene / Ni Chain / ZnO Array Hybrid Nanostructures on Cotton Fabric for Durable Self-Cleaning and Enhanced Microwave Absorption [J]. ACS nano, 2020(7): 14.). Furthermore, loading zinc oxide hybrid iron oxide with carboxylated graphene oxide can further enhance the wave absorption performance. This is mainly due to the excellent conductivity of graphene oxide itself, which achieves electromagnetic wave absorption through the synergistic effect of conductivity loss and polarization loss. Conductive materials have the effect of reflecting and guiding electromagnetic waves. Current and magnetic polarization opposite to the electromagnetic field are generated inside the conductive material, which reflects or absorbs part of the electromagnetic waves, reducing the amount of electromagnetic waves transmitted, thereby achieving shielding (Hao Xiuyang, Yun Gaojie. Types and product standards of anti-electromagnetic radiation textiles [J]. Light Textile Industry and Technology, 2013, 2: 42-43).

[0106] On the other hand, graphene oxide has excellent mechanical and temperature properties. When added to the flame-retardant and microwave-absorbing barrier layer, it can help improve the tensile strength and toughness of the fiber. Furthermore, graphene oxide can enhance the barrier performance of the flame-retardant and microwave-absorbing barrier layer against active oxygen, preventing active oxygen from entering the core layer and accelerating polymer aging, thus preventing damage to the main structure of the polyester fiber. This is because graphene oxide has a two-dimensional sheet structure, which can form a dense barrier, effectively extending the path of oxygen and corrosive media to penetrate the polymer and reducing the penetration rate.

[0107] In this invention, grafting polyaniline onto composite microwave absorbing particles enhances conductivity, modulates dielectric properties, and optimizes electromagnetic wave reflection loss. The positive charges on the molecular chains induce dipole interactions, forming polaron conductive channels. This structural change significantly improves the material's ability to attenuate electromagnetic waves. Simultaneously, polyaniline grafting also improves uniform dispersion in flame-retardant microwave absorbing mixtures; and the increased conductivity also enhances the antistatic properties of the fibers.

[0108] 4. The mechanism of cooperation between the antibacterial absorbing layer and the flame-retardant absorbing barrier layer:

[0109] In the preparation process of the antibacterial absorbing layer, the combination of the two can facilitate the formation of the antibacterial absorbing layer: Ti3C2T in the antibacterial absorbing particles X The MXene surface contains abundant fluoride ions and hydroxyl groups, and the carbon dots in the antibacterial microwave absorbing particles contain a large number of carboxyl groups and hydroxyl groups. The polyaniline segments in the flame-retardant microwave absorbing barrier layer contain a large number of positively charged nitrogen atoms, which enables the antibacterial microwave absorbing particles to assemble and coat the surface of the flame-retardant microwave absorbing barrier layer through electrostatic coupling, forming an antibacterial microwave absorbing layer.

[0110] Coordination in mechanism of action:

[0111] 1. The antibacterial absorbing layer provides antibacterial properties by generating reactive oxygen species (ROS) under light and / or magnetic irradiation. However, these ROS attack polymer chains, causing them to break and accelerating polymer aging. Therefore, if a large amount of ROS enters the core layer, which forms the main structure of PET fibers, it can easily accelerate the aging of the PET fibers, damaging their mechanical properties and ultimately affecting the overall strength of the fibers. This invention effectively overcomes this problem by using a flame-retardant absorbing barrier layer. The flame-retardant absorbing barrier layer forms a physical barrier, effectively preventing ROS from entering the core layer, thus resolving the adverse effects of ROS.

[0112] 2. The antibacterial absorbing layer has excellent wave absorption performance. The remaining part of the incident electromagnetic wave after being absorbed by the antibacterial absorbing layer will be absorbed and reflected by the flame-retardant absorbing barrier layer. The reflected part will be absorbed or reflected again by the antibacterial absorbing layer. Thus, through the combination of the antibacterial absorbing layer and the flame-retardant absorbing barrier layer, multiple reflections and absorptions of electromagnetic waves can be achieved, which will ultimately significantly improve the electromagnetic wave shielding ability of the fiber and reduce the amount of electromagnetic wave transmission.

[0113] The above is the general concept of the present invention. Based on this, detailed embodiments and comparative examples are provided below to further illustrate the present invention.

[0114] Explanation of the main raw material sources in the examples and comparative examples:

[0115] Polyester chips (polyethylene terephthalate chips), model CB-602, relative viscosity 0.8 dl / g, acid value 35 mg KOH / g, Far Eastern Textile Industry (Shanghai) Co., Ltd.; vacuum dry at 120℃ for 6 hours before use;

[0116] Ammonium polyphosphate, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0117] EEA (ethylene-ethyl acrylate copolymer), Arkema EEA 8200 from France, purchased from Suzhou Guoyao New Materials Co., Ltd.

[0118] Graphene oxide, model MG-NGO-01, single-layer sheet diameter 50-500nm, Shanghai Maoguo Nanotechnology Co., Ltd.

[0119] PVP (Polyvinylpyrrolidone), Shanghai Hongzhuang Chemical Technology Co., Ltd.;

[0120] Aniline, Nanjing Furunda Chemical Co., Ltd.;

[0121] Ammonium persulfate, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0122] Polyethyleneimine, MW10000, Shanghai Youen Chemical Co., Ltd.;

[0123] Dithiodibenzoic acid, Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0124] 4-Methoxypyridine, Shanghai Hongzhuang Chemical Technology Co., Ltd.

[0125] Example 1

[0126] A flame-retardant and antibacterial microwave-absorbing PET fiber includes a fiber body and an antibacterial microwave-absorbing layer disposed on the surface of the fiber body. The fiber body has a core-sheath composite structure, which includes a core layer and a flame-retardant microwave-absorbing barrier layer from the inside to the outside. The fiber body is prepared by using PET polyester chips as the core layer material and a flame-retardant microwave-absorbing mixture as the sheath material through a core-sheath composite spinning process. The antibacterial microwave-absorbing layer is obtained by coating the surface of the fiber body with antibacterial microwave-absorbing particles.

[0127] The specific preparation method of this flame-retardant and antibacterial microwave-absorbing PET fiber is as follows:

[0128] Step 1: By weight, mix 100 parts of PET polyester chips, 13 parts of flame retardant, 28 parts of flame retardant microwave absorbing particles, and 3 parts of compatibilizer at 70°C and 500 rpm for 2 hours to obtain a flame retardant microwave absorbing mixture.

[0129] The flame retardant is ammonium polyphosphate, and the compatibilizer is EEA (ethylene-ethyl acrylate copolymer).

[0130] Step 2: PET polyester chips are added as the core material and flame-retardant microwave-absorbing mixture is added as the sheath material to their respective screw extruders for melt extrusion. The fiber body is then prepared using a core-sheath composite spinning process. The mass ratio of sheath material to core material is 2:8.

[0131] The melt extrusion temperature for the core layer material is 275℃, and the melt extrusion temperature for the skin layer material is 280℃.

[0132] The process parameters for core-sheath composite spinning are: spinning temperature 270℃, spinning speed 4000m / min, side blowing temperature 20℃, and side blowing speed 0.5m / s.

[0133] Step 3: An antibacterial and microwave-absorbing layer is formed by coating the fiber body surface with antibacterial and microwave-absorbing particles using an impregnation process.

[0134] Antibacterial and microwave-absorbing particles were added to deionized water and ultrasonically dispersed for 2 hours to prepare an antibacterial and microwave-absorbing particle dispersion with a concentration of 10 mg / mL. The fiber body was ultrasonically washed in deionized water for 1 hour, dried at 100°C for 2 hours, placed in the antibacterial and microwave-absorbing particle dispersion, immersed at 55°C for 20 minutes, removed and dried at 100°C for 2 hours to complete one immersion. The immersion was repeated 4 times to form an antibacterial and microwave-absorbing layer on the surface of the fiber body, and finally flame-retardant and antibacterial microwave-absorbing PET fiber was obtained.

[0135] In this example, the flame-retardant microwave absorbing particles are prepared through the following steps:

[0136] S1-1, Preparation of carboxylated graphene oxide:

[0137] Take 2g of graphene oxide and add it to a mixture of 50mL of 20wt% H2O2 and 100mL of 60wt% nitric acid. Stir and reflux at 80℃ for 6h, filter, wash with deionized water until neutral, and vacuum dry at 90℃ for 12h to obtain carboxylated graphene oxide.

[0138] S1-2. Zinc oxide-hybridized iron oxide is loaded onto carboxylated graphene oxide to obtain composite microwave absorbing particles:

[0139] 1g of carboxylated graphene oxide and 4.5g of urea were added to 100mL of deionized water and ultrasonically dispersed for 1h to obtain a graphene dispersion. 1g of PVP (polyvinylpyrrolidone), 0.381g of FeCl2, 0.972g of FeCl3, and 0.322g of ZnSO4 were added to a mixed solvent of 100mL of deionized water and ethylene glycol in a volume ratio of 1:1 and stirred for 15min. The resulting mixture was then added to the graphene dispersion under stirring and stirred for 1h. The resulting product was transferred to a reaction vessel and reacted at 220℃ for 12h. After cooling to room temperature, the product was centrifuged, washed with deionized water, and vacuum dried at 90℃ for 24h to obtain composite microwave absorbing particles.

[0140] S1-3. The composite microwave absorbing particles are subjected to polyaniline hybridization treatment to obtain flame-retardant microwave absorbing particles:

[0141] 0.2g of composite microwave absorbing particles were added to 100mL of deionized water and ultrasonically dispersed for 45min. 0.35g of aniline was added and stirred for 1h. 0.85g of ammonium persulfate was added at 5℃, and the pH of the reaction system was adjusted to 2 with 30wt% hydrochloric acid. The reaction was stirred at room temperature for 8h, centrifuged, and the solid product was washed with deionized water and vacuum dried at 80℃ for 24h to obtain flame-retardant microwave absorbing particles.

[0142] In this example, the antibacterial absorbing particles are prepared through the following steps:

[0143] S2-1, Preparation of partially oxidized Ti3C2T X MXene:

[0144] S2-1-1, Preparation of Ti3C2T X MXene:

[0145] Ti3C2T X MXene was prepared using a conventional etching method: 1.35 g of LiF was added to 25 mL of 9 M HCl solution and stirred for 30 min to obtain an etching solution; 2 g of Ti3AlC2 was added to the etching solution, and the mixture was stirred at 45 °C for 48 h. After the reaction, the product was washed with deionized water by centrifugation until the pH of the supernatant was 6, and then dried under vacuum at 60 °C for 12 h to obtain Ti3C2T. X MXene;

[0146] S2-1-2, Partial oxidation treatment:

[0147] Ti3C2T X MXene was calcined in air at 350°C for 3 hours, cooled to room temperature, and ground to obtain powdered partially oxidized Ti3C2T. x MXene;

[0148] S2-2, Preparation of Ni-hybridized carbon dots:

[0149] 524 mg nickel sulfate hexahydrate, 600 mg glucose, 350 mg polyethyleneimine, 306 mg dithiobenzoic acid and 218 mg 4-methoxypyridine were added to 150 mL of deionized water and stirred for 30 min. Then the pH was adjusted to 9 with 1 mol / L sodium hydroxide and the reaction was stirred at 60 °C for 4 h. The resulting precursor was transferred to a reaction vessel and reacted at 230 °C for 10 h. After cooling to room temperature, the product was separated by centrifugation. The solid product was washed with ethanol and deionized water in sequence and dried under vacuum at 80 °C for 12 h to obtain Ni hybrid carbon dots: Ni-CDs.

[0150] S2-3, Partially oxidize Ti3C2T x MXene self-assembles with Ni-hybridized carbon dots:

[0151] 1.5 g of Ni hybrid carbon dots were added to 80 mL of 1 mol / L hydrochloric acid, sonicated at 60 °C for 1 h, filtered, and the solid product was washed with deionized water until neutral. Then, it was added to 50 mL of deionized water and sonicated for 1.5 h to obtain a carbon dot dispersion.

[0152] 1g of partially oxidized Ti3C2T x MXene was added to 50 mL of deionized water and ultrasonically dispersed for 2 h to obtain an MXene dispersion.

[0153] The carbon dot dispersion was added to the MXene dispersion under stirring. The mixture was stirred continuously at 1000 rpm for 10 h, then allowed to stand for 2 h, filtered, and the solid product was washed with deionized water and freeze-dried to obtain antibacterial absorbing particles.

[0154] Reference Figure 1 The image shows the infrared absorption spectrum of the flame-retardant microwave-absorbing particles prepared in this embodiment. Figure 2 The infrared absorption spectrum of the antibacterial absorbing particles prepared in this embodiment illustrates the successful preparation of the two particles.

[0155] Example 2

[0156] The only difference between this example and Example 1 is:

[0157] Step 1 in this example is as follows: By weight, 100 parts of PET polyester chips, 13 parts of flame retardant, 24 parts of flame retardant microwave absorbing particles, and 3 parts of compatibilizer are mixed at 70°C and 500 rpm for 2 hours to obtain a flame retardant microwave absorbing mixture.

[0158] Example 3

[0159] The only difference between this example and Example 1 is:

[0160] Step S2-3 in this example is as follows:

[0161] 1.2 g of Ni hybrid carbon dots were added to 80 mL of 1 mol / L hydrochloric acid, sonicated at 60 °C for 1 h, filtered, and the solid product was washed with deionized water until neutral. Then, it was added to 50 mL of deionized water and sonicated for 1.5 h to obtain a carbon dot dispersion.

[0162] 1g of partially oxidized Ti3C2T x MXene was added to 50 mL of deionized water and ultrasonically dispersed for 2 h to obtain an MXene dispersion.

[0163] The carbon dot dispersion was added to the MXene dispersion under stirring. The mixture was stirred continuously at 1000 rpm for 10 h, then allowed to stand for 2 h, filtered, and the solid product was washed with deionized water and freeze-dried to obtain antibacterial absorbing particles.

[0164] Example 4

[0165] A flame-retardant and antibacterial microwave-absorbing PET fiber includes a fiber body and an antibacterial microwave-absorbing layer disposed on the surface of the fiber body. The fiber body has a core-sheath composite structure, which includes a core layer and a flame-retardant microwave-absorbing barrier layer from the inside to the outside. The fiber body is prepared by using PET polyester chips as the core layer material and a flame-retardant microwave-absorbing mixture as the sheath material through a core-sheath composite spinning process. The antibacterial microwave-absorbing layer is obtained by coating the surface of the fiber body with antibacterial microwave-absorbing particles.

[0166] The specific preparation method of this flame-retardant and antibacterial microwave-absorbing PET fiber is as follows:

[0167] Step 1: By weight, mix 100 parts of PET polyester chips, 13 parts of flame retardant, 28 parts of flame retardant microwave absorbing particles, and 3 parts of compatibilizer at 80°C and 600 rpm for 1.5 hours to obtain a flame retardant microwave absorbing mixture.

[0168] The flame retardant is ammonium polyphosphate, and the compatibilizer is EEA (ethylene-ethyl acrylate copolymer).

[0169] Step 2: PET polyester chips are added as the core material and flame-retardant microwave-absorbing mixture is added as the sheath material to their respective screw extruders for melt extrusion. The fiber body is then prepared using a core-sheath composite spinning process. The mass ratio of sheath material to core material is 2:8.

[0170] The melt extrusion temperature for the core layer material is 270℃, and the melt extrusion temperature for the skin layer material is 275℃.

[0171] The process parameters for core-sheath composite spinning are: spinning temperature 270℃, spinning speed 4000m / min, side blowing temperature 20℃, and side blowing speed 0.5m / s.

[0172] Step 3: An antibacterial and microwave-absorbing layer is formed by coating the fiber body surface with antibacterial and microwave-absorbing particles using an impregnation process.

[0173] Antibacterial and microwave-absorbing particles were added to deionized water and ultrasonically dispersed for 2 hours to prepare an antibacterial and microwave-absorbing particle dispersion with a concentration of 10 mg / mL. The fiber body was ultrasonically washed in deionized water for 1 hour, dried at 90°C for 3 hours, placed in the antibacterial and microwave-absorbing particle dispersion, immersed at 50°C for 20 minutes, removed and dried at 90°C for 3 hours to complete one immersion. The immersion was repeated 4 times to form an antibacterial and microwave-absorbing layer on the surface of the fiber body, and finally flame-retardant and antibacterial microwave-absorbing PET fiber was obtained.

[0174] The preparation methods for flame-retardant microwave absorbing particles and antibacterial microwave absorbing particles are the same as in Example 1.

[0175] Comparative Example 1

[0176] A PET fiber with a core-sheath composite structure, comprising a core layer and a flame-retardant layer from the inside out; it is prepared by a core-sheath composite spinning process using PET polyester chips as the core layer material and a flame-retardant mixture as the sheath layer material.

[0177] The specific preparation method of this PET fiber is as follows:

[0178] Step 1: By weight, mix 100 parts of PET polyester chips, 13 parts of flame retardant, and 3 parts of compatibilizer at 70°C and 500 rpm for 2 hours to obtain a flame retardant mixture.

[0179] The flame retardant is ammonium polyphosphate, and the compatibilizer is EEA (ethylene-ethyl acrylate copolymer).

[0180] Step 2: PET polyester chips are added to their respective screw extruders as core material and flame retardant mixture as sheath material for melt extrusion. The fiber body is then prepared using a core-sheath composite spinning process. The mass ratio of sheath material to core material is 2:8.

[0181] The melt extrusion temperature for the core layer material is 275℃, and the melt extrusion temperature for the skin layer material is 280℃.

[0182] The process parameters for core-sheath composite spinning are: spinning temperature 270℃, spinning speed 4000m / min, side blowing temperature 20℃, and side blowing speed 0.5m / s.

[0183] Comparative Example 2

[0184] The only difference between this example and Example 1 is:

[0185] In this example, ZnSO4 is not added in step S1-2 of the preparation of flame-retardant microwave absorbing particles.

[0186] Comparative Example 3

[0187] The only difference between this example and Example 1 is:

[0188] In this example, FeCl2 and FeCl3 are not added in step S1-2 of the preparation of flame-retardant microwave absorbing particles.

[0189] Comparative Example 4

[0190] The only difference between this example and Example 1 is:

[0191] The antibacterial absorbing particles in this example were prepared through the following steps:

[0192] S2-1, Preparation of Ti3C2T X MXene, the steps are the same as in Example 1;

[0193] S2-2, Prepare Ni hybrid carbon dots, the steps are the same as in Example 1;

[0194] S2-3, Ti3C2T x MXene self-assembles with Ni-hybridized carbon dots:

[0195] 1.5 g of Ni hybrid carbon dots were added to 80 mL of 1 mol / L hydrochloric acid, sonicated at 60 °C for 1 h, filtered, and the solid product was washed with deionized water until neutral. Then, it was added to 50 mL of deionized water and sonicated for 1.5 h to obtain a carbon dot dispersion.

[0196] 1g Ti3C2T x MXene was added to 50 mL of deionized water and ultrasonically dispersed for 2 h to obtain an MXene dispersion.

[0197] The carbon dot dispersion was added to the MXene dispersion under stirring. The mixture was stirred continuously at 1000 rpm for 10 h, then allowed to stand for 2 h, filtered, and the solid product was washed with deionized water and freeze-dried to obtain antibacterial absorbing particles.

[0198] Comparative Example 5

[0199] The only difference between this example and Example 1 is:

[0200] This example uses the partially oxidized Ti3C2T prepared in Example 1. X MXene acts as an antibacterial and microwave-absorbing particle.

[0201] Comparative Example 6

[0202] The only difference between this example and Example 1 is:

[0203] The antibacterial absorbing particles in this example were prepared through the following steps:

[0204] S2-1, Preparation of partially oxidized Ti3C2T X MXene, the steps are the same as in Example 1;

[0205] S2-2, Preparation of carbon dots:

[0206] 600 mg glucose, 350 mg polyethyleneimine, 306 mg dithiodibenzoic acid and 218 mg 4-methoxypyridine were added to 150 mL of deionized water and stirred for 30 min. The resulting precursor was transferred to a reaction vessel and reacted at 230 °C for 10 h. After cooling to room temperature, the mixture was filtered through a 0.22 μm filter membrane. The filtrate was dialyzed in deionized water for 24 h using a 1200 Da dialysis bag. The dialysate in the dialysis bag was then freeze-dried to obtain carbon dots.

[0207] S2-3, Partially oxidize Ti3C2T x MXene self-assembles with carbon dots:

[0208] Add 1.5g of carbon dots to 80mL of 1mol / L hydrochloric acid, sonicate at 60℃ for 1h, filter, wash the solid product with deionized water until neutral, then add 50mL of deionized water and sonicate for 1.5h to obtain carbon dot dispersion.

[0209] 1g of partially oxidized Ti3C2T x MXene was added to 50 mL of deionized water and ultrasonically dispersed for 2 h to obtain an MXene dispersion.

[0210] The carbon dot dispersion was added to the MXene dispersion under stirring. The mixture was stirred continuously at 1000 rpm for 10 h, then allowed to stand for 2 h, filtered, and the solid product was washed with deionized water and freeze-dried to obtain antibacterial absorbing particles.

[0211] Performance test examples

[0212] 1. Electromagnetic shielding performance

[0213] The fibers are woven into a shape measuring 25×12×1.0mm. 3 After constructing rectangular samples, the electromagnetic shielding performance of the samples in the frequency range of 8.2–12.4 GHz was tested using an Agilent N5230A vector network analyzer. The test results are shown in Table 1 below. Figure 3 As shown.

[0214] Table 1

[0215] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Total shielding effectiveness / dB 53 46 49 52 9 46 41 50 44 48

[0216] The test results show that Examples 1-4 all have good electromagnetic shielding performance. In Example 2, the decrease in the content of flame-retardant absorbing particles led to a reduction in electromagnetic shielding performance. In Example 3, the reduced proportion of Ni-hybridized carbon dots in the antibacterial absorbing particles also resulted in a certain decrease in electromagnetic shielding performance. Comparative Example 1, lacking flame-retardant absorbing particles and without an outer antibacterial absorbing layer, exhibited the largest decrease in electromagnetic shielding performance. The decrease in electromagnetic shielding performance in Comparative Example 2 indicates that doping the flame-retardant absorbing particles with ZnO can improve absorption performance; the decrease in Comparative Example 3 is attributed to the absence of iron(III) oxide in the flame-retardant absorbing particles; the results of Comparative Example 4 indicate that Ti3C2T x Titanium dioxide formed by partial oxidation of MXene has an improving effect on microwave absorption performance; the antibacterial microwave absorbing particles in Comparative Example 5 have no Ni-hybridized carbon dots, and their microwave absorption performance is significantly reduced; the reason for the decrease in microwave absorption performance in Comparative Example 6 is that the carbon dots are not hybridized with nickel oxide.

[0217] Further testing was conducted on the overall shielding effectiveness degradation rate of Examples 1-4 after 500 water washes. The test results are shown in Table 2 and... Figure 4 As shown:

[0218] Table 2

[0219] Example 1 Example 2 Example 3 Example 4 Total shielding effectiveness reduction rate / % 4.3 4.5 4.9 4.4

[0220] It can be seen that Examples 1-4 can still maintain high electromagnetic shielding performance after being washed with water.

[0221] 2. Flame retardant properties

[0222] The test was conducted according to standard GB / T 2406.2-2009, and the test results are shown in Table 3 below. Figure 5 As shown:

[0223] Table 3

[0224] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Limiting Oxygen Index (LOI) / % 37.5 34.1 36.4 37.3 21.7 35.7 36.9 37.3 36.6 37.2

[0225] The test results show that Examples 1-4 have good flame retardant properties.

[0226] 3. Antibacterial properties

[0227] According to GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Shaking method", the inhibition rate of the prepared sample against Escherichia coli ATCC 25922 was determined by shaking flask method.

[0228] (1) Antibacterial performance test of antibacterial absorbing particles:

[0229] The sample consisted of antibacterial absorbing particles prepared in Example 1. Bacteria and the antibacterial absorbing particles were mixed and cultured, with different conditions applied for 15 minutes every hour. After 24 hours of culture, the antibacterial rate was measured and calculated. Based on the treatment conditions, four groups of experiments were conducted:

[0230] Group 1: Individual lighting treatment;

[0231] Group 2: Individual electromagnetic wave irradiation treatment;

[0232] Group 3: Light treatment + electromagnetic wave irradiation treatment;

[0233] Group 4 (control group): No light exposure, no electromagnetic radiation;

[0234] The illumination conditions were as follows: 50W fluorescent lamp for 30 minutes, total incubation time 24 hours, with a distance of 30cm between the lamp and the sample. Electromagnetic radiation conditions were: 2000 MHz, 1W / m². 2 The distance between the sample and the sample is 40cm.

[0235] The test results are shown in Table 4 below. Figure 6 As shown:

[0236] Table 4

[0237] Group 1 Group 2 Group 3 Group 4 Antibacterial rate / % 89.6 74.2 99.5 38.3

[0238] The test results show that, compared with the control group, both light irradiation and electromagnetic wave irradiation treatment can significantly improve the antibacterial rate. Moreover, the antibacterial rate is the highest when both light irradiation and electromagnetic wave irradiation are applied simultaneously, indicating that both contribute to the antibacterial performance.

[0239] (2) Antibacterial properties test of fibers:

[0240] The samples were fibers prepared in Examples 1-4 and Comparative Examples 4-6. During the mixed culture of bacteria and fiber samples, light treatment and electromagnetic wave irradiation were applied every 1 hour (the light and electromagnetic wave irradiation conditions were the same as above). The treatment time was 15 minutes. After 24 hours of culture, the antibacterial rate was detected and calculated.

[0241] The test results are shown in Table 5 below. Figure 7 :

[0242] Table 5

[0243] Example 1 Example 2 Example 3 Example 4 Comparative Example 4 Comparative Example 5 Comparative Example 6 Antibacterial rate / % 99.5 99.4 97.2 99.2 92.0 93.6 95.8

[0244] 4. Singlet oxygen generation performance

[0245] The sample was added to deionized water and ultrasonically dispersed in air for 45 min to prepare a dispersion with a concentration of 1 mg / mL. The content of singlet oxygen generated after treatment under different conditions for 30 min was determined using a singlet oxygen fluorescent probe (SOSG, Shanghai Beyotime Biotechnology Co., Ltd., model S0067).

[0246] SOSG is a probe that binds highly selectively to singlet oxygen. Before reacting with singlet oxygen, SOSG itself exhibits weak blue fluorescence. After reacting with singlet oxygen, the resulting SOSG peroxide (SOSG-EP) emits green fluorescence. The maximum excitation wavelength is 504 nm, and the maximum emission wavelength is 525 nm. The ability to generate singlet oxygen is determined by detecting the intensity of the emission light at 525 nm; the greater the emission intensity, the stronger the ability to generate singlet oxygen.

[0247] (1) The sample was the antibacterial absorbing particles prepared in Example 1. The content of singlet oxygen generated after the dispersion was treated under different conditions for 30 min was measured, and the intensity of the emitted light at 525 nm was used for characterization:

[0248] Group 1: Individual lighting treatment;

[0249] Group 2: Individual electromagnetic wave irradiation treatment;

[0250] Group 3: Light treatment + electromagnetic wave irradiation treatment;

[0251] Group 4: No light exposure, no electromagnetic radiation;

[0252] The illumination conditions were as follows: 50W fluorescent lamp for 30 minutes, total incubation time 24 hours, with a distance of 30cm between the lamp and the sample. Electromagnetic radiation conditions were: 2000 MHz, 1W / m². 2 The distance between the sample and the sample is 40cm.

[0253] The test results are shown in Table 6 below. Figure 8 As shown:

[0254] Table 6

[0255] Group 1 Group 2 Group 3 Group 4 Fluorescence intensity (au) 8743 7255 9848 54

[0256] The test results show that singlet oxygen cannot be generated in the absence of light or electromagnetic radiation (its fluorescence value is the background fluorescence). The antibacterial absorbing particles can generate singlet oxygen under light or electromagnetic radiation alone. When light and electromagnetic radiation are applied simultaneously, the singlet oxygen yield is the highest. The results, combined with the antibacterial performance test, indicate that the antibacterial performance comes from the generated ROS.

[0257] (2) The samples were the antibacterial absorbing particles prepared in Examples 1-4 and Comparative Examples 4-6. The content of singlet oxygen produced after the dispersion was treated under the same conditions (simultaneous application of light and electromagnetic irradiation, with the light and electromagnetic irradiation conditions being the same as above) for 30 min was measured, and the intensity of the emitted light at 525 nm was used for characterization.

[0258] The test results are shown in Table 7 below. Figure 9 As shown:

[0259] Table 7

[0260] Example 1 Example 2 Example 3 Example 4 Comparative Example 4 Comparative Example 5 Comparative Example 6 Fluorescence intensity (au) 9848 9831 9622 9812 9102 9259 9475

[0261] The test results show that Examples 1-4 can efficiently produce singlet oxygen, while the decrease in singlet oxygen yield in Comparative Example 4 is attributed to Ti3C2T x MXene, without partial oxidation treatment, lacks the ability to generate singlet oxygen in titanium dioxide formed by partial oxidation treatment; the decrease in singlet oxygen yield in Comparative Example 5 further proves that Ni-hybridized carbon dots can generate singlet oxygen under electromagnetic irradiation; the results of Comparative Example 6 show that Ni hybridization treatment in carbon dots can improve the ability to generate singlet oxygen under electromagnetic irradiation.

[0262] 5. Fracture strength

[0263] The breaking strength of polyester fibers was measured according to the standard GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments". The test results are shown in Table 7 below. Figure 10 As shown:

[0264] Table 7

[0265] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Fracture strength (cN / detx) 3.28 3.03 3.24 3.27 2.94 3.21 3.17 3.27 3.22 3.25

[0266] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A flame-retardant and antibacterial microwave-absorbing PET fiber, characterized in that, It includes a fiber body and an antibacterial and microwave-absorbing layer disposed on the surface of the fiber body. The fiber body has a core-sheath composite structure, which includes a core layer and a flame-retardant and microwave-absorbing barrier layer from the inside to the outside. The raw material of the flame-retardant and microwave-absorbing barrier layer is a flame-retardant and microwave-absorbing mixture, which includes the following components by weight: 100 parts of PET polyester chips, 9-15 parts of flame retardant, 22-40 parts of flame-retardant and microwave-absorbing particles, and 1.5-4 parts of compatibilizer. The flame-retardant microwave absorbing particles are prepared through the following steps: S1-1, Preparation of carboxylated graphene oxide; S1-2. Zinc oxide-hybridized iron oxide is loaded onto carboxylated graphene oxide to obtain composite microwave absorbing particles; S1-3. Polyaniline hybridization treatment is applied to the composite microwave absorbing particles to obtain flame-retardant microwave absorbing particles. The antibacterial absorbing layer is obtained by coating the surface of the fiber body with antibacterial absorbing particles through an impregnation process. The antibacterial absorbing particles are prepared through the following steps: S2-1, Ti3C2T X MXene was calcined in air at 250-400℃ for 2-4 hours and then ground to obtain partially oxidized Ti3C2T. x MXene; S2-2. Add nickel sulfate hexahydrate, glucose, polyethyleneimine, dithiodibenzoic acid and 4-methoxypyridine to deionized water, stir, adjust pH to 9, heat and stir to react, transfer the obtained precursor to a reaction vessel, react at 230-250℃ for 5-20h, centrifuge, wash, and vacuum dry to obtain Ni hybrid carbon dots. S2-3. Add Ni-hybridized carbon dots to hydrochloric acid, sonicate, filter, wash the solid product with deionized water until neutral, and then disperse it in deionized water to obtain a carbon dot dispersion; partially oxidize Ti3C2T x MXene was dispersed in deionized water to obtain an MXene dispersion; The carbon dot dispersion was added to the MXene dispersion under stirring. The mixture was stirred continuously, allowed to stand, filtered, washed, and freeze-dried to obtain antibacterial and microwave-absorbing particles.

2. The flame-retardant and antibacterial microwave-absorbing PET fiber according to claim 1, characterized in that, The fiber body is prepared by a core-sheath composite spinning process using PET polyester chips as the core material and flame-retardant and microwave-absorbing mixture as the sheath material. The antibacterial absorbing layer is obtained by coating the surface of the fiber body with antibacterial absorbing particles through an impregnation process. The specific impregnation process is as follows: Antibacterial absorbing particles are dispersed in deionized water to obtain an antibacterial absorbing particle dispersion. The fiber body is ultrasonically washed in deionized water, dried, immersed in the antibacterial absorbing particle dispersion, dried, and this process is repeated several times to form an antibacterial absorbing layer on the surface of the fiber body.

3. The flame-retardant and antibacterial microwave-absorbing PET fiber according to claim 2, characterized in that, The impregnation process used to prepare the antibacterial absorbing layer is as follows: Add antibacterial absorbing particles to deionized water and ultrasonically disperse for 1-4 hours to prepare an antibacterial absorbing particle dispersion with a concentration of 5-20 mg / mL. Ultrasonically wash the fiber body in deionized water for 0.5-2 hours, remove it and dry it at 80-120℃ for 1-4 hours, place it in the antibacterial absorbing particle dispersion, immerse it at 50-70℃ for 10-30 minutes, remove it and dry it at 80-120℃ for 1-4 hours to complete one immersion. Repeat the immersion 2-8 times to form an antibacterial absorbing layer on the surface of the fiber body.

4. The flame-retardant and antibacterial microwave-absorbing PET fiber according to claim 1, characterized in that, Flame-retardant microwave absorbing particles are prepared through the following steps: S1-1. Add graphene oxide to a mixture of H2O2 and nitric acid, heat and stir under reflux, filter, wash with deionized water until neutral, and dry to obtain carboxylated graphene oxide. S1-2. Carboxylated graphene oxide and urea were added to deionized water and ultrasonically dispersed to obtain a graphene dispersion. PVP, FeCl2, FeCl3, and ZnSO4 were added to a mixed solvent of deionized water and ethylene glycol in a volume ratio of 1:1 and stirred. The resulting mixture was added to the graphene dispersion under stirring. The product was transferred to a reaction vessel and reacted at 190-240℃ for 6-24 hours. After centrifugation, washing, and vacuum drying, composite microwave absorbing particles were obtained. S1-3. Disperse the composite microwave absorbing particles in deionized water, add aniline, stir, add ammonium persulfate, adjust the pH of the reaction system to 2-3, stir the reaction, centrifuge, wash, and vacuum dry to obtain flame-retardant microwave absorbing particles.

5. The flame-retardant and antibacterial microwave-absorbing PET fiber according to claim 4, characterized in that, Flame-retardant microwave absorbing particles are prepared through the following steps: S1-1. Take 2g of graphene oxide and add it to a mixture of 50mL of 20wt% H2O2 and 100mL of 60wt% nitric acid. Stir and reflux at 80℃ for 6h, filter, wash with deionized water until neutral, and dry to obtain carboxylated graphene oxide. S1-2. Take 1g of carboxylated graphene oxide and 4.5g of urea and add them to 100mL of deionized water. Disperse the mixture by ultrasonication for 1h to obtain a graphene dispersion. Add 1g of PVP, 0.381g of FeCl2, 0.972g of FeCl3, and 0.322g of ZnSO4 to a mixed solvent of 100mL of deionized water and ethylene glycol in a volume ratio of 1:

1. Stir for 15min. Add the resulting mixture to the graphene dispersion under stirring. Stir for 1h. Transfer the resulting product to a reaction vessel and react at 220℃ for 12h. Centrifuge, wash, and vacuum dry to obtain composite microwave absorbing particles. S1-3. Take 0.2g of composite microwave absorbing particles and add them to 100mL of deionized water. Disperse them by sonication for 45min. Add 0.35g of aniline and stir for 1h. Add 0.85g of ammonium persulfate at 5℃ and adjust the pH of the reaction system to 2 with 30wt% hydrochloric acid. Stir the reaction at room temperature for 8h. Centrifuge, wash, and vacuum dry to obtain flame-retardant microwave absorbing particles.

6. The flame-retardant and antibacterial microwave-absorbing PET fiber according to claim 1, characterized in that, Antibacterial absorbing particles are prepared through the following steps: S2-1, Ti3C2T X MXene was calcined in air at 350°C for 3 hours and then ground to obtain partially oxidized Ti3C2T. x MXene; S2-2. 524 mg nickel sulfate hexahydrate, 600 mg glucose, 350 mg polyethyleneimine, 306 mg dithiodibenzoic acid and 218 mg 4-methoxypyridine were added to 150 mL of deionized water and stirred for 30 min. Then the pH was adjusted to 9 with 1 mol / L sodium hydroxide solution and stirred at 60 °C for 4 h. The resulting precursor was transferred to a reaction vessel and reacted at 230 °C for 10 h. After centrifugation, washing and vacuum drying, Ni hybrid carbon dots: Ni-CDs were obtained. S2-3. Add 1.5g of Ni hybrid carbon dots to 80mL of 1mol / L hydrochloric acid, sonicate at 60℃ for 1h, filter, wash the solid product with deionized water until neutral, then add 50mL of deionized water and sonicate for 1.5h to obtain carbon dot dispersion. 1g of partially oxidized Ti3C2T x MXene was added to 50 mL of deionized water and ultrasonically dispersed for 2 h to obtain an MXene dispersion. The carbon dot dispersion was added to the MXene dispersion under stirring. The mixture was stirred continuously at 1000 rpm for 10 h, then allowed to stand for 2 h, filtered, washed, and freeze-dried to obtain antibacterial absorbing particles.

7. The flame-retardant and antibacterial microwave-absorbing PET fiber according to claim 1, characterized in that, The compatibilizer is one or more of ethylene-ethyl acrylate, ethylene-vinyl acetate copolymer, and maleic anhydride-grafted polyolefin elastomer. The flame retardant is one or more of ammonium polyphosphate, trihydroxyethyl phosphate, phenylphosphonic acid, and trihydroxymethylphosphonic acid oxide.

8. A method for preparing flame-retardant and antibacterial microwave-absorbing PET fiber as described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Mix PET polyester chips, flame retardant, flame retardant microwave absorbing particles, and compatibilizer evenly to obtain a flame retardant microwave absorbing mixture; Step 2: PET polyester chips as core material and flame-retardant microwave-absorbing mixture as sheath material are added to their respective screw extruders for melt extrusion, and then the fiber body is prepared by core-sheath composite spinning process. Step 3: An antibacterial and microwave-absorbing layer is formed by impregnating the fiber body with antibacterial and microwave-absorbing particles, and finally the flame-retardant and antibacterial microwave-absorbing PET fiber is obtained.

9. The method for preparing flame-retardant and antibacterial microwave-absorbing PET fiber according to claim 8, characterized in that, In step 2, the mass ratio of the outer layer material to the core layer material is 1:9~3.5:6.5; the melt extrusion temperature corresponding to the core layer material is 260-290℃, and the melt extrusion temperature corresponding to the outer layer material is 250-290℃. The spinning process parameters are: spinning temperature 260-280℃, spinning speed 2000-4500m / min, side blowing temperature 10-30℃, and side blowing speed 0.2-1m / s.

Images