Wear-resistant liquid crystal polyarylester fiber and preparation method thereof

Abstract

The invention discloses a wear-resistant liquid crystal polyarylate fiber and a preparation method thereof, and the method comprises the following steps: S1, dopamine deposition polymerization: sequentially dissolving dopamine hydrochloride and hydrogen peroxide in a Tris buffer solution to obtain a mixed solution, rapidly immersing a liquid crystal polyarylate fiber in the mixed solution, and oscillating at the ambient temperature of 25 DEG C for 10-60 minutes to obtain a deposited fiber; s2, chain extension / cross-linking: wiping the deposited fibers, immersing the deposited fibers in a diethyl oxalate solution, and oscillating at 25 DEG C for 5-30 minutes to obtain the wear-resistant liquid crystal polyarylate fibers. According to the wear-resistant liquid crystal polyarylester fiber and the preparation method thereof provided by the invention, the dopamine is subjected to chain extension and cross-linking through the oxalate according to the characteristic that the amino can be quickly condensed with the oxalate, so that a thin layer of firm and smooth coating is formed on the liquid crystal polyarylester fiber, and the wear resistance of the liquid crystal polyarylester fiber is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-performance fibers, in particular to a wear-resistant liquid crystal polyarylate fiber and a preparation method thereof. BACKGROUND

[0002] Liquid crystal polyarylate fiber (TLCP) is a high-performance special fiber, the molecular chain of which is composed of rigid wholly aromatic structural units, and it is converted into a liquid crystal state when heated to a specific temperature, combining the fluidity of a liquid with the orderliness of a solid. During preparation, HBA, HNA and the like are used as monomers, and an oligomer is first prepared, followed by solid-phase polymerization to form a liquid crystal aromatic polyester, and then the fiber is prepared through melt spinning, drawing and heat treatment. The performance of the fiber is excellent, the molecular chain is rigid and straight, and the fiber is highly oriented during shaping. For example, the tensile strength of Vectran fiber is 5.8 GPa, and the modulus is 176 GPa, which is much higher than that of steel and aluminum. The strength retention rate of Vectran HT is more than 90% after 1000 hours of thermal load test at 200℃; the strength loss of Vectran fiber is small at -60℃, and the flexibility is good. In addition, it is resistant to chemical corrosion, suitable for chemical corrosion prevention; low creep (the creep rate of Vectran is 1 / 4 of Kevlar); low dielectric (2.6-3.0), low loss (less than 0.005); non-hygroscopic; excellent damping; self-extinguishing, microwave transparent and resistant to radiation. In application, it is used in the field of aerospace to realize weight reduction and efficiency improvement of aircraft structures and satellite support materials; in the field of electronics and electrical appliances to manufacture high-frequency electronic components to reduce signal loss; in the field of protection to make protective clothing and body armor to resist external forces; and in the field of medical treatment to manufacture stents and catheters, which have good biocompatibility and stable structure.

[0003] During spinning and shaping, the liquid crystal polyarylate fiber has already formed a multi-level microfiber structure of 5μm large fibrils and 1μm or so microfibrils inside. This unique structure makes the radial intermolecular force of the fiber weak, and when the fiber is subjected to mechanical action such as stretching and friction, or solvent swelling and temperature fluctuation, especially when it is subjected to axial compression or axial impact load, some crystal planes in the fiber structure are prone to slip, and then a deformation band structure is generated, which makes the wear resistance of the liquid crystal polyarylate fiber poor in many cases. Excessive fibrillation will further magnify this disadvantage, resulting in loose combination between the fibrils, and the fibrils are easy to fall off from the main body of the fiber and form small fiber debris when subjected to friction. These debris not only cannot resist friction, but also will generate new friction points on the surface of the fiber, aggravating the wear. At the same time, the stress concentration phenomenon is more obvious in the fiber with excessive fibrillation, making the fiber more prone to breakage and damage, which on the one hand leads to the difficulty in meeting the actual use requirements in some industrial application scenarios with extremely high wear resistance requirements, such as wear-resistant ropes and conveyor belts; on the other hand, it makes the fiber difficult to weave or the fiber is damaged too much during weaving, seriously affecting the performance of the fiber. SUMMARY

[0004] In order to solve the technical problem that the wear resistance of the liquid crystal polyarylate fiber in the prior art cannot meet the use requirement, the application provides a wear-resistant liquid crystal polyarylate fiber and a preparation method thereof.

[0005] To achieve the above object, the technical scheme adopted by the application is: In a first aspect, the application provides a preparation method of a wear-resistant liquid crystal polyarylate fiber, comprising the following steps: S1: dopamine deposition polymerization: hydrochloric acid dopamine and hydrogen peroxide are sequentially dissolved in a Tris buffer solution to obtain a mixed solution, and the liquid crystal polyarylate fiber is quickly immersed in the mixed solution, oscillated at an ambient temperature of 25 DEG C for 10-60 minutes to obtain a deposition fiber; S2: chain extension / crosslinking: after the deposition fiber is dried, it is immersed in a diethyl oxalate solution, oscillated at 25 DEG C for 5-30 minutes to obtain a wear-resistant liquid crystal polyarylate fiber.

[0006] Preferably, in the preparation method of the wear-resistant liquid crystal polyarylate fiber, the concentration of the hydrochloric acid dopamine and the hydrogen peroxide in the Tris buffer solution is 0.5-10 g / L and 5-100 mM respectively, and the pH of the Tris buffer solution is 8.5.

[0007] Preferably, in the preparation method of the wear-resistant liquid crystal polyarylate fiber, the oscillation time of the liquid crystal polyarylate fiber immersed in the mixed solution is 10-30 minutes.

[0008] Preferably, in the preparation method of the wear-resistant liquid crystal polyarylate fiber, the diethyl oxalate solution is an ethanol solution, and the concentration thereof is 5-100 mM.

[0009] Preferably, in the preparation method of the wear-resistant liquid crystal polyarylate fiber, the oscillation time of the deposition fiber in the diethyl oxalate ethanol solution is 5-10 minutes.

[0010] In a second aspect, the application provides a wear-resistant liquid crystal polyarylate fiber, and the maximum friction frequency Nf thereof is 2000-5000 times.

[0011] The above technical scheme has the following advantages or beneficial effects: the wear-resistant liquid crystal polyarylate fiber and the preparation method thereof provided by the application can quickly condense the amino group with the oxalate through the feature that the dopamine is chain-extended and crosslinked through the oxalate, thereby forming a thin, firm and smooth coating layer on the liquid crystal polyarylate fiber, and effectively improving the wear resistance of the liquid crystal polyarylate fiber. BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate embodiments consistent with the application and, together with the description, further serve to explain the principles of the application.

[0013] Figure 1 A flow chart of a preparation method of a wear-resistant liquid crystal polyarylate fiber provided by the application. DETAILED DESCRIPTION

[0014] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The description below refers to the accompanying drawings, which show by way of examples specific embodiments in which like numerals represent like elements and in which:

[0015] The fiber used in the application is Celanese LCP Vectra A950 liquid crystal polyarylate, which is prepared by melt spinning, and the linear density of the single filament is 10 dtex. Before wear-resistant modification, the liquid crystal polyarylate fiber is cleaned: after ultrasonic treatment in a mixed solution of anhydrous ethanol and acetone at a volume ratio of 1:1 for 30 min, the fiber is taken out, washed with deionized water three times to remove impurities on the surface of the fiber, and then dried in a vacuum oven at 80 DEG C overnight before use.

[0016] The reagents used in the application: dopamine hydrochloride (DA, analytical pure) and 30% hydrogen peroxide, purchased from Shanghai Maikelin Biotechnology Co., Ltd.; Tris purchased from Shanghai Bide Pharmaceutical Technology Co., Ltd.

[0017] The wear-resistant performance test of the wear-resistant liquid crystal polyarylate fiber provided by the application: the wear-resistant performance test refers to FZ / T 50025-2014, and the maximum friction times (Nf) of the liquid crystal polyarylate fiber until it is broken are used to quantitatively evaluate the modification effect by using a Martindale abrasion tester. When testing, the Ra 0.7-0.9 μm rubbing sub is selected, the fiber is fixed and a tension of 30 MPa is applied, and the number of times of breaking and rubbing is recorded. The rubbing sub is replaced each time, and the temperature is controlled at 25 DEG C and the humidity is controlled at 60% during testing.

[0018] Example 1: As Figure 1 shown, The preparation method of the wear-resistant liquid crystal polyarylate fiber provided by the application comprises the following steps: S1: Dopamine deposition polymerization: dissolve hydrochloric acid dopamine and hydrogen peroxide in Tris buffer solution in turn to obtain a mixed solution, quickly immerse the liquid crystal polyarylate fiber into the mixed solution, and shake at an ambient temperature of 25°C for 10-60 minutes to obtain a deposited fiber; S2: chain extension / crosslinking: after the deposited fiber is dried, immerse it into a diethyl oxalate solution, and shake at 25°C for 5-30 minutes to obtain a wear-resistant liquid crystal polyarylate fiber.

[0019] The specific operation of S1-S2 is as follows: 20 g of hydrochloric acid dopamine (concentration 2 g / L) is dissolved in 10 L of Tris buffer solution (pH 8.5, 50 mM); then 30% hydrogen peroxide 22.66 ml (concentration 20 mM) is added, and the mixed solution is obtained after stirring to dissolve thoroughly; then, the washed liquid crystal polyarylate fiber is quickly immersed, and shaken at 25°C for 30 minutes; after the deposited fiber is taken out and dried, it is immersed into a 20 mM diethyl oxalate ethanol solution, and shaken again at 25°C for 5 minutes; after being taken out again, it is washed with deionized water for 3 times, and dried in a vacuum oven at 60°C overnight to obtain a wear-resistant liquid crystal polyarylate fiber. After wear resistance test, the maximum friction times (Nf) is 3860 times (average value of 5 tests).

[0020] Example 2: The washed and dried liquid crystal polyarylate fiber is immersed in 10 L of Tris buffer solution (pH 8.5, 50 mM) and shaken at 25°C for 30 minutes, the fiber is taken out and washed with deionized water for 3 times, and dried in a vacuum oven at 60°C overnight; then, the wear resistance test is carried out, and the maximum friction times (Nf) is 1210 times (average value of 5 tests).

[0021] Example 3: 20 g of hydrochloric acid dopamine (concentration 2 g / L) is dissolved in 10 L of Tris buffer solution (pH 8.5, 50 mM); then 30% hydrogen peroxide 22.66 ml (concentration 20 mM) is added, and the mixed solution is obtained after stirring to dissolve thoroughly. Then, the washed and dried liquid crystal polyarylate fiber is quickly immersed in the above solution, shaken at 25°C for 30 minutes, the obtained fiber is taken out and washed with deionized water for 3 times, and dried in a vacuum oven at 60°C overnight to obtain a deposited liquid crystal polyarylate fiber. After wear resistance test, the maximum friction times (Nf) is 1650 times (average value of 5 tests).

[0022] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

[0023] It is to be understood that the application is not limited to the precise construction herein described and as shown in the attached drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is to be indicated by the appended claims, rather than the description.

Claims

1. A method for preparing wear-resistant liquid crystal polyarylate fiber, characterized in that, Includes the following steps, S1: Dopamine deposition polymerization: Dopamine hydrochloride and hydrogen peroxide are dissolved sequentially in Tris buffer solution to obtain a mixed solution. Liquid crystal polyarylate fiber is rapidly immersed in the mixed solution and shaken at an ambient temperature of 25°C for 10 to 60 minutes to obtain deposited fiber. S2: Chain extension / crosslinking: After drying the deposited fiber, immerse it in a diethyl oxalate solution and shake it at 25°C for 5-30 minutes to obtain wear-resistant liquid crystal polyarylate fiber.

2. The method for preparing wear-resistant liquid crystal polyarylate fiber according to claim 1, characterized in that, The concentrations of dopamine hydrochloride and hydrogen peroxide in Tris buffer solution were 0.5–10 g / L and 5–100 mM, respectively, and the pH of the Tris buffer solution was 8.

5.

3. The method for preparing wear-resistant liquid crystal polyarylate fiber according to claim 1, characterized in that, The liquid crystal polyarylate fiber is immersed in the mixed solution and shaken for 10 to 30 minutes.

4. The method for preparing wear-resistant liquid crystal polyarylate fiber according to claim 1, characterized in that, The diethyl oxalate solution is an ethanol solution with a concentration of 5–100 mM.

5. The method for preparing wear-resistant liquid crystal polyarylate fiber according to claim 1, characterized in that, The deposition fibers were shaken in an ethanol solution of diethyl oxalate for 5 to 10 minutes.

6. The wear-resistant liquid crystal polyarylate fiber prepared according to any one of claims 1 to 5, characterized in that, The maximum number of friction cycles (Nf) of the wear-resistant liquid crystal polyarylate fiber is 2000 to 5000.

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