Preparation method and application of high-modulus heterocyclic aramid fiber

Abstract

The application discloses a preparation method and application of high-modulus heterocyclic aramid fiber, and comprises the following steps: adding a solvent and a cosolvent into a reaction kettle; reducing the temperature of the reaction kettle to-5-5 DEG C, adding p-phenylenediamine and 2-(4-aminophenyl)-5-aminobenzimidazole, and stirring and dissolving; adding p-phthaloyl chloride into the reaction kettle twice, and then increasing the reaction temperature to room temperature after reaction; adding the remaining p-phthaloyl chloride for reaction until a viscous heterocyclic aramid stock solution is obtained; performing spinning after defoaming and filtering of the heterocyclic aramid stock solution, and performing spinning through stretching and heat treatment to obtain the high-modulus heterocyclic aramid fiber. The reaction temperature and the adding amount of p-phthaloyl chloride are controlled, the prepared heterocyclic aramid fiber has excellent breaking strength, breaking elongation and initial modulus, and can be widely applied to the processing and manufacturing of materials and composite materials in the fields of aerospace, national defense and military industry, civil safety protection equipment, building engineering, automobile manufacturing and communication systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of fiber-reinforced composite materials, and more specifically, relates to a preparation method and application of high-modulus heterocyclic aramid fiber. Background Art

[0002] Aramid fibers are primarily classified into three types: meta-aramid, para-aramid, and heterocyclic aramid. Heterocyclic aramid, also known as aramid III or heterocyclic aromatic polyamide fiber, refers to high-performance fibers made by incorporating heterocyclic structural units into traditional aramid structures. Compared to standard aramid, heterocyclic aramid offers advantages such as superior mechanical properties, chemical stability, thermal stability, flame retardancy, and optoelectronic properties. It is primarily used in aerospace, defense, civilian safety equipment, construction, automotive manufacturing, and communications systems.

[0003] Heterocyclic aramid fibers are often used in the manufacture of composite materials. Increasing the modulus of the fiber can enhance the overall performance of the composite material, such as increasing the tensile strength and modulus of the composite material, making it more adaptable to various complex application environments. Increasing the modulus of heterocyclic aramid fibers can enhance their resistance to deformation, allowing the material to maintain a more stable shape when subjected to stress, thereby improving the overall structural strength and durability. High-modulus heterocyclic aramid fibers can meet the needs of more high-end applications. For example, in the aerospace field, high-modulus fibers can withstand greater mechanical loads, help reduce the weight of aircraft, and improve flight efficiency. Therefore, the preparation of high-modulus heterocyclic aramid fibers has become a hot spot in the development of the heterocyclic aramid fiber industry. Summary of the Invention

[0004] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0005] In order to achieve these objects and other advantages according to the present invention, a method for preparing a high modulus heterocyclic aramid fiber is provided, comprising the following steps:

[0006] Step 1: adding solvent and cosolvent into the reactor;

[0007] Step 2: Lower the temperature of the reaction kettle to -5 to 5°C, add p-phenylenediamine and 2-(4-aminophenyl)-5-aminobenzimidazole, and stir to dissolve;

[0008] Step 3: Add terephthaloyl chloride to the reactor in two portions, with the first portion being 80-90% of the total molar amount. After reacting for 6-18 hours, raise the reaction temperature to room temperature. Add the remaining terephthaloyl chloride and continue reacting until a viscous heterocyclic aramid stock solution is obtained.

[0009] Step four, the heterocyclic aramid dope is degassed, filtered, and then spun into fibers, which are stretched and heat treated to obtain high modulus heterocyclic aramid fibers.

[0010] Preferably, in the step one, the solvent is N,N-dimethylacetamide or N-methyl pyrrolidone; the cosolvent is lithium chloride, sodium acetate or lithium acetate; wherein the cosolvent accounts for 1.5-3.0% of the mass of the solvent.

[0011] Preferably, the solvent, p-phenylenediamine, 2-(4-aminophenyl)-5-aminobenzimidazole, and terephthaloyl chloride are used in a ratio of 1000-3000 g: 0.1-0.5 mol: 0.2-0.5 mol: 0.3-1.0 mol.

[0012] Preferably, in the step one, the reactor also includes modified nano-aluminum oxide powder and surfactant sodium dodecyl sulfate, and the modified nano-aluminum oxide powder, sodium dodecyl sulfate, and solvent are used in a ratio of 1-10 g: 0.5-2 g: 1000-3000 g.

[0013] Preferably, the preparation method of the modified nano-aluminum oxide powder comprises:

[0014] S1, dispersing nano-aluminum oxide powder with a particle size of 20-50 nm in deionized water to obtain a suspension, adding polyethylene glycol-600 to the suspension, coating the nano-aluminum oxide powder, and then ultrasonic dispersing for 10-20 min at an ultrasonic frequency of 30-50 kHz after adding polyethylene glycol-600, and standing for 2-12 h to obtain a dispersion;

[0015] S2, adding graphene powder to the dispersion, stirring and heating to 30-60℃, maintaining for 20-30 min, then heating to 80-90℃, maintaining for 5-10 min, and then cooling to room temperature and standing for 2-4 h to obtain a mixed dispersion;

[0016] S3, evaporating and concentrating the mixed dispersion, filtering, and then washing and drying the precipitate to obtain a solid powder;

[0017] S4, vacuum heat treating the solid powder at a vacuum degree less than 0.02 Pa and a heat treatment temperature of 200-400℃ for 5-20 min, and then cooling to room temperature to obtain the modified nano-aluminum oxide powder.

[0018] Preferably, in the S1, the nano-aluminum oxide powder, polyethylene glycol-600, and deionized water are used in a ratio of 2-10 g: 1-5 mL: 250-300 mL.

[0019] Preferably, in the S2, the D90 particle size of the graphene powder is 0.3 μm, and the mass ratio of the graphene powder to the nano-aluminum oxide powder is 1-3:2-10.

[0020] Preferably, in the step four, the drawing amount of the jet in the coagulation bath is 120-150%, the coagulation bath temperature is 20-60℃, the jet cap hole diameter is 0.05-0.15 mm, and the hole number is 100-500 holes.

[0021] Preferably, in the step four, the heat treatment temperature is 200-400℃.

[0022] The application of a high-modulus heterocyclic aramid fiber to the processing and manufacturing of materials and composite materials in the fields of aerospace, national defense and military industry, civil safety protection equipment, construction engineering, automobile manufacturing and communication systems.

[0023] The application has at least the following beneficial effects: the heterocyclic aramid fiber prepared from p-phenylenediamine and 2-(4-aminophenyl)-5-aminobenzimidazole as raw materials by controlling the reaction temperature and the addition amount of terephthaloyl chloride exhibits excellent breaking strength, breaking elongation and initial modulus, and can be widely applied to the processing and manufacturing of materials and composite materials in the fields of aerospace, national defense and military industry, civil safety protection equipment, construction engineering, automobile manufacturing and communication systems.

[0024] The polyethylene glycol-600 and the graphene-coated modified nano-aluminum oxide powder are added to the heterocyclic aramid stock solution, the modified nano-aluminum oxide powder is uniformly dispersed in the heterocyclic aramid stock solution by the dispersion of sodium dodecyl sulfate, the uniformity of the dispersion of the modified nano-aluminum oxide powder in the reaction system is improved, the uniformity of the distribution of the modified nano-aluminum oxide powder in the heterocyclic aramid fiber is improved, and the spinning difficulty is reduced.

[0025] Other advantages, objects, and features of the application will be in part apparent and in part pointed out hereinafter. DETAILED DESCRIPTION

[0026] The application will be further described in detail below so that those skilled in the art can implement it according to the description.

[0027] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0028] Example 1

[0029] The embodiment provides a preparation method of high-modulus heterocyclic aramid fiber, and comprises the following steps:

[0030] Step one, 3000g of N,N-dimethylacetamide is added into a reaction kettle as a solvent, and 60g of lithium acetate is added as a cosolvent;

[0031] Step two, the temperature of the reaction kettle is reduced to 0 DEG C, 21.6g of p-phenylenediamine and 67.2g of 2-(4-aminophenyl)-5-aminobenzimidazole are added and stirred and dissolved;

[0032] Step three, 101.5g of terephthaloyl chloride is added into the reaction kettle in two times, 81.2g is added in the first time, the reaction temperature is increased to 25 DEG C after 12 hours, and the remaining 20.3g of terephthaloyl chloride is added for reaction until a viscous heterocyclic aramid stock solution is obtained;

[0033] Step four, the heterocyclic aramid stock solution is subjected to atmospheric pressure defoaming for 6h, filtration and spinning, the spinning is subjected to stretching and heat treatment, and high-modulus heterocyclic aramid fiber is obtained, wherein the stretching amount of the spinning in the coagulation bath is 120%, the coagulation bath temperature is 40 DEG C, the spinning cap hole diameter is 0.10mm, the hole number is 300, and the heat treatment temperature is 250 DEG C.

[0034] Embodiment 2

[0035] The embodiment provides a preparation method of high-modulus heterocyclic aramid fiber, and comprises the following steps:

[0036] Step one, 2500g of N,N-dimethylacetamide is added into a reaction kettle as a solvent, and 37.5g of lithium acetate is added as a cosolvent;

[0037] Step two, the temperature of the reaction kettle is reduced to 5 DEG C, 32.4g of p-phenylenediamine and 44.8g of 2-(4-aminophenyl)-5-aminobenzimidazole are added and stirred and dissolved;

[0038] Step three, 60.9g of terephthaloyl chloride is added into the reaction kettle in two times, 55.2g is added in the first time, the reaction temperature is increased to 25 DEG C after 12 hours, and the remaining 11.7g of terephthaloyl chloride is added for reaction until a viscous heterocyclic aramid stock solution is obtained;

[0039] Step four, the heterocyclic aramid stock solution is subjected to atmospheric pressure defoaming for 6h, filtration and spinning, the spinning is subjected to stretching and heat treatment, and high-modulus heterocyclic aramid fiber is obtained, wherein the stretching amount of the spinning in the coagulation bath is 120%, the coagulation bath temperature is 40 DEG C, the spinning cap hole diameter is 0.10mm, the hole number is 300, and the heat treatment temperature is 250 DEG C.

[0040] Embodiment 3

[0041] The embodiment provides a preparation method of high-modulus heterocyclic aramid fiber, and comprises the following steps:

[0042] Step one, 2000g of N,N-dimethylacetamide is added into a reaction kettle as a solvent, and 50g of lithium acetate is added as a cosolvent;

[0043] Step two, the temperature of the reaction kettle is reduced to-5 DEG C, 10.8g of p-phenylenediamine and 44.8g of 2-(4-aminophenyl)-5-aminobenzimidazole are added and stirred and dissolved;

[0044] Step three, 60.9g of terephthaloyl chloride is added into the reaction kettle in two times, 55.2g is added in the first time, and after 12 hours of reaction, the reaction temperature is increased to 25 DEG C; the remaining 11.7g of terephthaloyl chloride is added for reaction until a viscous heterocyclic aramid stock solution is obtained;

[0045] Step four, the heterocyclic aramid stock solution is subjected to atmospheric pressure defoaming for 6h, filtration and spinning, and the spinning capillary is subjected to stretching and heat treatment, so that the high-modulus heterocyclic aramid fiber is obtained; wherein the stretching amount of the spinning capillary in the coagulation bath is 120%, the coagulation bath temperature is 50 DEG C, the spinning capillary hole diameter is 0.10mm, the hole number is 100, and the heat treatment temperature is 300 DEG C.

[0046] Embodiment 4

[0047] The embodiment provides a preparation method of high-modulus heterocyclic aramid fiber, and different from embodiment 1, 2g of modified nano-aluminum oxide powder and 1g of sodium dodecyl sulfate are added in step one; wherein the preparation method of the modified nano-aluminum oxide powder comprises the following steps:

[0048] S1, 10g of nano-aluminum oxide powder with a particle size of 20-50nm is dispersed in 250mL of deionized water to obtain a suspension, 2mL of polyethylene glycol-600 is added to the suspension, the nano-aluminum oxide powder is coated, after the addition of the polyethylene glycol-600, ultrasonic dispersion is carried out at an ultrasonic frequency of 30kHz for 20min, and standing is carried out for 12h to obtain a dispersion liquid;

[0049] S2, 2g of graphene powder with a D90 particle size of 0.3um is added into the dispersion liquid, stirring is carried out to increase the temperature to 60 DEG C, after heat preservation for 30min, the temperature is increased to 90 DEG C, heat preservation is carried out for 5min, then the temperature is cooled to room temperature, and standing is carried out for 3h to obtain a mixed dispersion liquid;

[0050] S3, the mixed dispersion liquid is subjected to evaporation concentration, the precipitate is washed and dried after filtration to obtain a solid powder;

[0051] S4, vacuum heat treatment is performed on the solid powder, the vacuum degree is less than 0.02 Pa, the heat treatment temperature is 200℃, the heat treatment time is 20 min, and the modified nano-alumina powder is obtained after cooling to room temperature.

[0052] The method and process parameters of the remaining steps of this embodiment are the same as those of embodiment 1.

[0053] Embodiment 5

[0054] The preparation method of the high modulus heterocyclic aramid fiber provided in this embodiment is different from that of embodiment 1 in that 5g of modified nano-alumina powder and 1.5g of sodium dodecyl sulfate are added in step one; wherein the preparation method of the modified nano-alumina powder comprises:

[0055] S1, disperse 10g of nano-alumina powder with a particle size of 20-50nm in 250mL of deionized water to obtain a suspension, add 2mL of polyethylene glycol-600 to the suspension, coat the nano-alumina powder, and after adding the polyethylene glycol-600, ultrasonically disperse at a frequency of 40kHz for 15min, stand for 12h to obtain a dispersion liquid;

[0056] S2, add 2.5g of graphene powder with a D90 particle size of 0.3μm to the dispersion liquid, stir to heat to 50℃, heat for 20-30min, then heat to 90℃, heat for 5min, then cool to room temperature, stand for 4h to obtain a mixed dispersion liquid;

[0057] S3, evaporate and concentrate the mixed dispersion liquid, wash and dry the precipitate after filtration to obtain a solid powder;

[0058] S4, vacuum heat treatment is performed on the solid powder, the vacuum degree is less than 0.02 Pa, the heat treatment temperature is 300℃, the heat treatment time is 10 min, and the modified nano-alumina powder is obtained after cooling to room temperature.

[0059] The method and process parameters of the remaining steps of this embodiment are the same as those of embodiment 1.

[0060] Embodiment 6

[0061] The preparation method of the high modulus heterocyclic aramid fiber provided in this embodiment is different from that of embodiment 1 in that 10g of modified nano-alumina powder and 2g of sodium dodecyl sulfate are added in step one; wherein the preparation method of the modified nano-alumina powder comprises:

[0062] S1, 10 g of nano-alumina powder with a particle size of 20-50 nm was dispersed in 250 mL of deionized water to obtain a suspension, 3 mL of polyethylene glycol-600 was added to the suspension, the nano-alumina powder was coated, after the addition of polyethylene glycol-600, ultrasonic dispersion was carried out at a frequency of 50 kHz for 20 min, and the dispersion liquid was obtained after standing for 12 h;

[0063] S2, 3 g of graphene powder was added to the dispersion liquid, stirred and heated to 60℃, and then heated to 90℃ for 10 min, and then cooled to room temperature, and then stood for 4 h to obtain a mixed dispersion liquid;

[0064] S3, the mixed dispersion liquid was evaporated and concentrated, and the precipitate was washed and dried after filtration to obtain a solid powder;

[0065] S4, the solid powder was subjected to vacuum heat treatment, the vacuum degree was less than 0.02 Pa, the heat treatment temperature was 400℃, the heat treatment time was 20 min, and the modified nano-alumina powder was obtained after cooling to room temperature.

[0066] The methods and process parameters of the remaining steps of this example are the same as those of Example 1.

[0067] Comparative Example 1

[0068] The comparative example provides a preparation method of high modulus heterocyclic aramid fiber, which is different from Example 1 in that 5 g of nano-alumina powder with a particle size of 20-50 nm and 1.5 g of sodium dodecyl sulfate are added in step one. The preparation method and process parameters of the remaining steps of this comparative example are the same as those of Example 1.

[0069] Comparative Example 2

[0070] The comparative example provides a preparation method of high modulus heterocyclic aramid fiber, which is different from Example 1 in that 10 g of nano-alumina powder with a particle size of 20-50 nm and 2 g of sodium dodecyl sulfate are added in step one. The preparation method and process parameters of the remaining steps of this comparative example are the same as those of Example 4.

[0071] The breaking strength (determination method according to GB / T 19975-2005), elongation at break (determination method according to GJB 348-87), and initial modulus (determination method according to GB / T 42823-2023) of the high modulus heterocyclic aramid fibers prepared in Examples 1-6 and Comparative Examples 1-2 were measured, respectively, to obtain the following table:

[0072]

[0073] As can be seen from the above table, the high modulus heterocyclic aramid fibers prepared in Examples 1-6 all have high breaking strength, breaking elongation and initial modulus, and the breaking strength, breaking elongation and initial modulus of the heterocyclic aramid fibers prepared in Examples 4-6 are further improved because the modified nano-alumina powder is added to the heterocyclic aramid dope.

[0074] The number of devices and the scale of processes described herein are intended to illustrate the application. Applications, modifications and variations of the application will be apparent to those skilled in the art without departing from the general concept of the application.

[0075] While embodiments of the application have been disclosed in connection with the specified embodiments, as illustrated and described above, it will be readily apparent to those skilled in the art that various modifications can be made to the application without departing from the spirit and scope of the application as set forth in the claims and equivalent scope thereof.

Claims

1. A method of making high modulus heterocyclic aramid fiber, characterized by, It comprises the following steps: Step one, adding solvent and cosolvent into the reaction kettle; Step two, reducing the temperature of the reaction kettle to-5~5℃, adding p-phenylenediamine and 2-(4-aminophenyl)-5-aminobenzimidazole, and stirring to dissolve; Step three, adding terephthaloyl chloride into the reaction kettle twice, the first time adding 80~90% of the total molar amount, and after 6~18 hours of reaction, the reaction temperature is raised to room temperature; the remaining terephthaloyl chloride is added for reaction until a viscous heterocyclic aramid stock solution is obtained; Step four, degassing and filtering the heterocyclic aramid stock solution, and then spinning, stretching, and heat treating the jet to obtain high-modulus heterocyclic aramid fibers. In step one, the reaction kettle also contains modified nano-aluminum oxide powder and surfactant sodium dodecyl sulfate, and the use amount ratio of the modified nano-aluminum oxide powder, sodium dodecyl sulfate, and solvent is 1~10g:0.5~2g:1000~3000g. The preparation method of the modified nano-aluminum oxide powder comprises: S1, dispersing nano-aluminum oxide powder with a particle size of 20~50nm in deionized water to obtain a suspension, adding polyethylene glycol-600 to the suspension, coating the nano-aluminum oxide powder, and after adding polyethylene glycol-600, ultrasonic dispersion is carried out at an ultrasonic frequency of 30~50kHz for 10~20min, and then standing for 2~12h to obtain a dispersion liquid; the use amount ratio of the nano-aluminum oxide powder, polyethylene glycol-600, and deionized water is 2~10g:1~5mL:250~300mL; S2, adding graphene powder with a D90 particle size of 0.3μm to the dispersion liquid, the mass ratio of the graphene powder and the nano-aluminum oxide powder being 1~3:2~10, stirring to raise the temperature to 30~60℃, standing for 20~30min, then raising the temperature to 80~90℃, standing for 5~10min, then cooling to room temperature, and standing for 2~4h to obtain a mixed dispersion liquid; S3, evaporating and concentrating the mixed dispersion liquid, filtering, washing, and drying the precipitate to obtain a solid powder; S4, vacuum heat treating the solid powder, the vacuum degree being less than 0.02Pa, the heat treatment temperature being 200~400℃, and the heat treatment time being 5~20min, and then cooling to room temperature to obtain the modified nano-aluminum oxide powder; In step four, the stretching amount of the jet in the coagulation bath is 120%, the coagulation bath temperature is 20~60℃, the jet cap hole diameter is 0.05~0.15mm, and the number of holes is 100~500.

2. The method of making high modulus heterocyclic aramid fibers according to claim 1, wherein, In step one, the solvent is N,N-dimethylacetamide or N-methylpyrrolidone; the cosolvent is lithium chloride, sodium acetate, or lithium acetate; and the mass of the cosolvent accounts for 1.5~3.0% of the mass of the solvent.

3. The method of making high modulus heterocyclic aramid fiber according to claim 1, wherein, The use amount ratio of the solvent, p-phenylenediamine, 2-(4-aminophenyl)-5-aminobenzimidazole, and terephthaloyl chloride is 1000~3000g:0.1~0.5mol:0.2~0.5mol:0.3~1.0mol.

4. The method of making high modulus heterocyclic aramid fiber according to claim 1, wherein, In step four, the heat treatment temperature is 200~400℃.

5. Use of high modulus heterocyclic aramid fibers characterized in that, The high-modulus heterocyclic aramid fiber is prepared by the method of any one of claims 1-4, and is applied to the processing and manufacturing of materials and composite materials in the fields of aerospace, national defense and military industry, civil safety protection equipment, construction engineering, automobile manufacturing, and communication systems.

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