Polydopamine modified polypropylene antistatic fiber and preparation method thereof

Abstract

The invention relates to the technical field of fiber materials, in particular to a polydopamine modified polypropylene antistatic fiber and a preparation method thereof. The antistatic polypropylene fiber overcomes the problems of poor antistatic effect and mechanical property of the polypropylene fiber. The preparation method comprises the following steps: carrying out step-by-step mixing, melt extrusion, spinning, drafting and heat setting on raw materials such as polypropylene slices, polydopamine modified polypropylene, carbon nanotubes, modified titanium dioxide, modified graphene and the like to obtain the antistatic fiber. The polydopamine modified polypropylene is obtained by modifying polypropylene with dopamine hydrochloride; the modified titanium dioxide is obtained by modifying nano titanium dioxide by using 3-aminopropyltriethoxysilane; the modified graphene is obtained by sulfonating graphene oxide and adding octadecylamine for modification. All the materials and the process cooperate with each other, an antistatic system is constructed on the surface and in the fiber, and meanwhile the mechanical property is improved. The fiber prepared by the method is excellent in antistatic effect and mechanical property, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fiber materials, in particular to a kind of polydopamine modified polypropylene antistatic fiber and preparation method thereof. BACKGROUND

[0002] Polypropylene fiber, also known as polypropylene fiber, since industrial production, with its unique advantages in many fields such as textiles. Polypropylene fiber is polymerized with propylene as monomer, has the characteristics of light specific gravity, high strength, low moisture regain, small water absorption, good wicking, wear resistance and resilience, etc., is widely used in decorative fabric, industrial filter cloth, non-woven fabric and many other product manufacturing.

[0003] Although polypropylene fiber has many advantages, but its own technical problems also limit its further development. From the antistatic effect, polypropylene fiber belongs to non-polar molecules, the molecular chains lack strong attraction, so that its surface is not easy to adsorb the charge in the air, and itself poor conductivity, in the spinning process, frequent friction between fibers and between fibers and equipment, easy to produce static effect, the polypropylene fiber obtained cannot be applied to antistatic scene. In terms of mechanical properties, polypropylene fiber has poor light and thermal stability, low softening point, in actual use scene, such as light or in a higher temperature environment, the fiber strength decreases significantly, the elongation increases, the modulus decreases, which greatly limits the application of polypropylene fiber in the field with high strength and stability requirements.

[0004] Therefore, a kind of polydopamine modified polypropylene antistatic fiber and preparation method thereof are provided. SUMMARY

[0005] The present application aims to design a kind of polydopamine modified polypropylene antistatic fiber and preparation method thereof. The present application is prepared by step-by-step mixing, melt extrusion, spinning, drawing and heat setting of polypropylene chip, polydopamine modified polypropylene, carbon nanotube, modified titanium dioxide, modified graphene and other raw materials to obtain antistatic fiber;Among them, the polydopamine modified polypropylene is obtained by modifying polypropylene with dopamine hydrochloride;The modified titanium dioxide is obtained by modifying nano-titanium dioxide with 3-aminopropyl triethoxysilane;The modified graphene is obtained by sulfonating graphene oxide and adding octadecylamine modification. Polydopamine modified polypropylene, carbon nanotube, modified titanium dioxide and modified graphene and other substances synergize to build an antistatic system on the surface and inside of the fiber, and improve the mechanical properties. The antistatic fiber prepared by the method has excellent antistatic and mechanical properties, and has good application prospect.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: The present application provides a kind of polydopamine modified polypropylene antistatic fiber and preparation method thereof, comprising the following steps: The polypropylene chips, the polydopamine modified polypropylene, the carbon nanotubes, the modified titanium dioxide, the modified graphene, the antioxidant, the compatibilizer and the dispersant are added into a high-speed mixer to be mixed uniformly to obtain a mixture; The mixture is added into a double-screw extruder to be melt-extruded to obtain a spinning melt; the spinning melt is subjected to spinning treatment to form a primary fiber; the primary fiber is subjected to drawing treatment and heat setting treatment to finally obtain the antistatic fiber. The polydopamine modified polypropylene is obtained by modifying polypropylene with dopamine hydrochloride; the modified titanium dioxide is obtained by modifying nano-titanium dioxide with 3-aminopropyl triethoxysilane; and the modified graphene is obtained by sulfonating graphene oxide and adding octadecylamine for modification.

[0007] Preferably, the specific preparation method of the mixture is as follows: 85 parts of the polypropylene chips, 5-10 parts of the polydopamine modified polypropylene and 1.5 parts of the maleic anhydride grafted polypropylene are added into a high-speed mixer to be mixed for 10 min, then 1-5 parts of the carbon nanotubes, 0.1-2 parts of the modified graphene and 0.1-2 parts of calcium stearate are added to continue stirring for 10 min, finally 1-3 parts of the modified titanium dioxide and 0.5-1 part of antioxidant 1010 are added to be mixed for 20-30 min, the mixing temperature is 90°C, and the stirring speed is 300 r / min, to obtain the mixture.

[0008] Preferably, the preparation method of the polydopamine modified polypropylene is as follows: 90-110 parts of polypropylene particles are dissolved in 300 parts of dimethylbenzene to be spray granulated to obtain polypropylene microspheres; 0.5-2 parts of dopamine hydrochloride is dissolved in 200 parts of Tris buffer solution to obtain a dopamine solution; the polypropylene microspheres are added into the dopamine solution, stirred for 24 h, washed with deionized water for 5 times, and vacuum dried at 60°C for 12 h to obtain the polydopamine modified polypropylene.

[0009] Preferably, the preparation method of the modified titanium dioxide is as follows: 90-110 parts of nano-titanium dioxide (average particle size 50 nm) is vacuum dried at 110°C for 3 h to obtain pretreated titanium dioxide; 2-5 parts of 3-aminopropyl triethoxysilane is added into 400 parts of anhydrous ethanol, stirred for 15 min, then 40 parts of deionized water is added, stirred for 30 min to obtain a hydrolysis solution; the pretreated titanium dioxide is added into the hydrolysis solution, stirred at 70°C for 2-4 h, after the reaction is completed, centrifugal separation, washing with deionized water for 3 times, and vacuum drying at 60°C for 12 h are performed to obtain the modified titanium dioxide.

[0010] Preferably, the preparation method of the modified graphene is as follows: 10-30 parts of graphene oxide (single layer content ≥ 90%) is dispersed in 300 parts of anhydrous chloroform, 8 parts of chlorosulfonic acid is added under nitrogen protection, the temperature is raised to 45 DEG C and reacted for 4 hours, after the reaction, the system is cooled to 0 DEG C, isopropanol at -20 DEG C is slowly added until pH = 5-6, then centrifugal washing and vacuum drying for 12 hours to obtain sulfonated graphene; 2-6 parts of octadecylamine is added to 100 parts of NMP and dissolved at 80 DEG C to obtain a dissolving solution; the sulfonated graphene and 0.1 parts of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride are added to 100 parts of NMP and ultrasonic for 30 minutes to obtain a dispersion solution; the dissolving solution is added dropwise into the dispersion solution, and refluxed at 85 DEG C for 8-12 hours, after the reaction liquid is cooled, centrifugal washing and vacuum drying for 24 hours to obtain the modified graphene.

[0011] Preferably, the specific process of melt extrusion is as follows: the mixture is added into a double screw extruder, the temperature of each section is set as follows: zone 1 195 DEG C, zone 2 200 DEG C, zone 3 205 DEG C, zone 4 210 DEG C, zone 5 215 DEG C, the temperature of the die head is 210 DEG C-230 DEG C, and the screw rotation speed is controlled at 250 r / min to obtain a spinning melt.

[0012] Preferably, the specific process of spinning treatment, drawing treatment and heat setting treatment is as follows: the spinning melt is transported to a spinning assembly and extruded through a spinneret, the average diameter of the spinneret hole is 0.1 mm-0.3 mm, the nascent fiber is formed by cooling and molding under the condition of side blowing, the wind speed is 0.3 m / s, the wind temperature is 25 DEG C-30 DEG C, the nascent fiber is drawn, the draw ratio is 3-5 times, the drawing temperature is 90 DEG C, and the drawn fiber is heat set at 150 DEG C for 1-5 minutes to obtain the antistatic fiber finally.

[0013] Another aspect of the present application provides a polydopamine modified polypropylene antistatic fiber, which is prepared by the above preparation method, and the preparation raw materials of the antistatic fiber include polypropylene chips, polydopamine modified polypropylene, carbon nanotubes, modified titanium dioxide, modified graphene, antioxidants, compatibilizers and dispersants.

[0014] Compared with the prior art, the present application has the following beneficial effects: 1、Polydopamine modified polypropylene has strong adhesion, which can tightly adhere to the surface of polypropylene fiber to form a thin film rich in hydrophilic groups. These hydrophilic groups can adsorb moisture in the air, reduce the surface resistance of the fiber, and thus realize the antistatic function. Carbon nanotubes have excellent conductivity and high strength characteristics. When they are added to polypropylene fiber together with polydopamine modified polypropylene, carbon nanotubes can be connected to each other inside the fiber to build a high-efficiency conductive network. In terms of antistatic performance, the hydrophilic film formed by polydopamine reduces the resistance from the surface, and the conductive network of carbon nanotubes provides an electron transmission channel from the inside. The combination of the two greatly improves the antistatic effect of the fiber.

[0015] 2、Carbon nanotubes build a one-dimensional conductive channel inside the fiber as a high-speed path for charge transmission due to their high conductivity and aspect ratio. Modified graphene forms a two-dimensional conductive network through the formation of a sheet-like conductive network after sulfonation and modification with octadecylamine. Modified titanium dioxide is modified by silane coupling agent, and forms hydrogen bonds or electrostatic interactions with carbon nanotubes and graphene through surface polar groups to build a three-dimensional conductive network. In terms of mechanical properties, modified titanium dioxide enhances the interface bonding and acts as a stress buffer point to inhibit crack propagation. Carbon nanotubes have high strength to bear the load, and the slip energy dissipation characteristics of graphene sheets complement each other, thus synergistically improving the mechanical properties of the fiber.

[0016] 3、The anhydride groups of maleic anhydride grafted polypropylene form covalent bonds with the surface amino groups of modified titanium dioxide, and at the same time entangle with the molecular chains of the polypropylene matrix, enhancing the interfacial bonding force between the inorganic filler and the matrix. Calcium stearate reduces the surface energy of fillers such as carbon nanotubes and modified graphene, allowing them to be uniformly dispersed under the strong shearing action of a twin-screw extruder, avoiding stress concentration caused by agglomeration. Antioxidant 1010 captures free radicals during melt extrusion, inhibits the high-temperature oxidative degradation of the polypropylene matrix, and maintains the integrity of the molecular chains. The drawing process after spinning forms a rigid skeleton with oriented molecular chains and uniformly dispersed fillers, and the heat setting process eliminates internal stress, promoting the formation of a more stable physical entanglement structure between the filler and the matrix. The four work together to improve the mechanical properties of the fiber. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The figure shows the breaking strength and elongation at break of Example 1 and Comparative Examples 9-13 in the present invention. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0019] Specifically referring to Figure 1 The present application provides a kind of polydopamine modified polypropylene antistatic fiber and preparation method thereof, technical scheme as follows: Example 1 100 parts of polypropylene particles are dissolved in 300 parts of dimethylbenzene to obtain polypropylene microspheres by spray granulation; 1.5 parts of dopamine hydrochloride are dissolved in 200 parts of Tris buffer solution to obtain a dopamine solution; the polypropylene microspheres are added to the dopamine solution, stirred for 24 h, washed with deionized water for 5 times, and vacuum dried at 60℃ for 12 h to obtain polydopamine modified polypropylene.

[0020] 100 parts of nano-titanium dioxide are vacuum dried at 110℃ for 3h to obtain pretreated titanium dioxide; 4 parts of 3-aminopropyl triethoxysilane are added to 400 parts of anhydrous ethanol, stirred for 15 min, then 40 parts of deionized water are added, and stirred for 30 min to obtain a hydrolysis solution; the pretreated titanium dioxide is added to the hydrolysis solution, stirred at 70℃ for 3h, after the reaction is completed, centrifugal separation, deionized water washing for 3 times, and vacuum drying at 60℃ for 12h are carried out to obtain modified titanium dioxide.

[0021] 20 parts of graphene oxide are dispersed in 300 parts of anhydrous chloroform, 8 parts of chlorosulfonic acid are added under nitrogen protection, the temperature is raised to 45℃, and the reaction is carried out for 4h; after the reaction is completed, the system is cooled to 0℃, isopropanol at-20℃ is slowly added, then washing and centrifugation are carried out, and vacuum drying is carried out for 12h to obtain sulfonated graphene; 4 parts of octadecylamine are added to 100 parts of NMP, heated to dissolve at 80℃ to obtain a dissolution solution; the sulfonated graphene and 0.1 parts of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride are added to 100 parts of NMP, ultrasonic is carried out for 30 min to obtain a dispersion solution; the dissolution solution is added dropwise into the dispersion solution, reflux reaction is carried out at 85℃ for 10h, after the reaction solution is cooled, centrifugal washing is carried out, and vacuum drying is carried out for 24h to obtain modified graphene.

[0022] 85 parts of polypropylene chips, 8 parts of polydopamine modified polypropylene, and 1.5 parts of maleic anhydride grafted polypropylene are added to a high-speed mixer and mixed for 10 min, then 3 parts of carbon nanotubes, 1 part of modified graphene, and 1 part of calcium stearate are added and continue to stir for 10 min, finally 2 parts of modified titanium dioxide and 0.8 parts of antioxidant 1010 are added and mixed for 25 min, the mixing temperature is 90℃, and the stirring speed is 300r / min to obtain a mixture; The mixture is added into a twin-screw extruder, and the temperature of each section is set as follows: 195℃ for the first section, 200℃ for the second section, 205℃ for the third section, 210℃ for the fourth section, and 215℃ for the fifth section, the head temperature is 220℃, and the screw rotation speed is controlled at 250r / min, to obtain a spinning melt; The spinning melt is transported to a spinning assembly, extruded through a spinneret, and cooled and formed under side-blowing conditions, with a wind speed of 0.3m / s and a wind temperature of 28℃, to form a primary fiber; the primary fiber is subjected to a drawing treatment, with a draw ratio of 4 times and a drawing temperature of 90℃, and is then subjected to a heat setting treatment, with a heat setting temperature of 150℃ and a time of 3min, to finally obtain an antistatic fiber.

[0023] Examples 2-5 refer to the parameter conditions in Example 1, with specific differences as shown in Table 1.

[0024] Table 1 Parameter conditions of Examples 1-5 Comparative Example 1 refers to the parameter conditions in Example 1, with the difference being that the polypropylene is not subjected to a modification treatment.

[0025] Comparative Example 2 refers to the parameter conditions in Example 1, with the difference being that the polydopamine modified polypropylene is not added.

[0026] Comparative Example 3 refers to the parameter conditions in Example 1, with the difference being that the carbon nanotubes are not added.

[0027] Experimental Example 1 Antistatic effect test The surface resistance of Examples 1-5 and Comparative Examples 1-3 is tested according to AATCC 76-2019 "Textile Surface Resistance Test Method", and the results are shown in Table 2.

[0028] Table 2 Antistatic effect of Examples 1-5 and Comparative Examples 1-3 As can be seen from Table 2, Comparative Example 1 lacks a hydrophilic conductive film formed by polydopamine on the surface of the fiber due to the absence of polydopamine modification of the polypropylene, and cannot reduce the surface resistance by adsorbing moisture, and the non-polar structure of the polypropylene itself makes it difficult to dissipate charges, so the surface resistance is extremely high. After the polydopamine modified polypropylene is absent in Comparative Example 2, the fiber surface cannot form a hydrophilic antistatic layer constructed by polydopamine, and only relies on the internal network constructed by conductive fillers such as carbon nanotubes, but lacks a surface charge dissipation path, resulting in a significant increase in surface resistance and a significant decrease in antistatic performance. The absence of carbon nanotubes in Comparative Example 3 makes it impossible to form a continuous conductive network inside the fiber, and only relies on the antistatic effect of the polydopamine modified polypropylene on the surface, which makes it difficult to quickly conduct charges, resulting in a significant increase in surface resistance and a significant weakening of the antistatic effect due to the absence of internal conductive paths.

[0029] In summary, the polydopamine modified polypropylene and carbon nanotubes form a synergy from the surface to the inside in terms of antistatic performance: the polydopamine reduces the surface resistance through the hydrophilic film, and the carbon nanotubes construct an internal conductive network with high conductivity, and the two work together to make the charge dissipate on the surface and conduct in the interior, greatly reducing the surface resistance, and ultimately achieving the improvement of the antistatic performance of the fiber.

[0030] Example 6-9 refer to the parameter conditions in Example 1, the specific differences are shown in Table 3.

[0031] Table 3 Parameter conditions of Example 1 and Example 6-9 Comparative Example 3 refers to the parameter conditions in Example 1, the difference is that no carbon nanotubes are added.

[0032] Comparative Example 4 refers to the parameter conditions in Example 1, the difference is that the nano-titanium dioxide is not modified.

[0033] Comparative Example 5 refers to the parameter conditions in Example 1, the difference is that no modified titanium dioxide is added.

[0034] Comparative Example 6 refers to the parameter conditions in Example 1, the difference is that the graphene oxide is not sulfonated.

[0035] Comparative Example 7 refers to the parameter conditions in Example 1, the difference is that the sulfonated graphene is not modified.

[0036] Comparative Example 8 refers to the parameter conditions in Example 1, the difference is that no modified graphene is added.

[0037] Experimental Example 2 Antistatic effect and mechanical property test The surface resistance of Example 1, Example 6-9 and Comparative Examples 3-8 was tested according to Experimental Example 1; the breaking strength and elongation at break of Example 1, Example 6-9 and Comparative Examples 3-8 were tested according to GB / T14337-2022; the results are shown in Table 4.

[0038] Table 4 Antistatic effect and mechanical property of Example 1, Example 6-9 and Comparative Examples 3-8 It can be found from Table 4 that the comparative example 3 cannot form a high-efficiency conductive network inside the fiber due to the absence of carbon nanotubes, and it is difficult to quickly conduct electricity by relying on the surface modification material alone, resulting in obvious static accumulation; at the same time, the absence of carbon nanotubes as a high-strength reinforcing phase makes the fiber lack an effective stress transmission path when subjected to external force, and the mechanical properties are significantly reduced. In the comparative example 4, the unmodified nano-titanium dioxide has poor compatibility with the matrix and is easy to agglomerate to form stress concentration points, weakening the mechanical properties of the fiber; at the same time, its surface lacks active groups and cannot cooperatively build a continuous conductive network with other conductive fillers, resulting in reduced charge conduction efficiency and limited antistatic effect. The absence of modified titanium dioxide in the comparative example 5 makes the fiber lose the key three-dimensional conductive connection points and interface reinforcing phase, not only destroying the integrity of the conductive network formed by carbon nanotubes and graphene, but also leading to insufficient interfacial bonding force between the filler and the matrix, resulting in obvious decline in both antistatic performance and mechanical properties. In the comparative example 6, the un-sulfonated graphene oxide lacks polar groups on its surface, has weak interaction with materials such as carbon nanotubes, and cannot effectively fill the gaps in the conductive network, resulting in reduced charge conduction efficiency; at the same time, it has poor dispersibility in the matrix and cannot play a reinforcing role, further reducing the mechanical properties of the fiber. In the comparative example 7, the sulfonated graphene is not modified, and the surface activity is insufficient, which has poor compatibility with the matrix and other fillers, is easy to agglomerate, hinders the construction of the conductive network and stress transmission, causes the internal charge conduction of the fiber to be blocked, and is prone to defects when stressed, resulting in simultaneous deterioration of antistatic and mechanical properties. In the comparative example 8, the absence of modified graphene makes the fiber lack the key two-dimensional conductive reinforcing structure and cannot form a complement with carbon nanotubes, resulting in an incomplete conductive network; at the same time, the absence of the high-modulus reinforcing effect of graphene makes it difficult for the fiber to disperse stress when stressed, and the mechanical properties are significantly reduced.

[0039] In summary, carbon nanotubes, modified titanium dioxide, and modified graphene improve the performance of the fiber through structural complementation and functional synergy: carbon nanotubes construct one-dimensional conductive skeletons and mechanical reinforcing axes; modified titanium dioxide strengthens the network stability and interfacial bonding as connection points; and modified graphene fills the gaps and enhances the charge conduction efficiency in the form of two-dimensional sheets, and improves the dispersibility through surface polar groups. The three work together not only to form a high-efficiency conductive network inside the fiber, reducing the surface resistance, but also to significantly improve the breaking strength and elongation at break by enhancing the interfacial compatibility and stress transmission ability, achieving dual optimization of antistatic and mechanical properties.

[0040] Examples 10-13 refer to the parameter conditions in Example 1, with specific differences as shown in Table 5.

[0041] Table 5 Parameter conditions of Example 1 and Examples 10-13 Comparative Example 9 refers to the parameter conditions in Example 1, with the difference being that no calcium stearate is added.

[0042] Comparative Example 10 refers to the conditions of the parameters in Example 1, except that no antioxidant was added.

[0043] Comparative Example 11 refers to the conditions of the parameters in Example 1, except that no compatibilizer maleic anhydride grafted polypropylene was added.

[0044] Comparative Example 12 refers to the conditions of the parameters in Example 1, except that the mixture was not prepared in steps.

[0045] Comparative Example 13 refers to the conditions of the parameters in Example 1, except that no heat setting was performed.

[0046] Experimental Example 3 - Mechanical Properties Test The breaking strength and elongation at break of Example 1, Examples 10-13 and Comparative Examples 9-13 were tested according to Experimental Example 2; the results are shown in Table 6, and the breaking strength and elongation at break of Example 1 and Comparative Examples 9-13 are shown in Figure 1

[0047] Table 6 - Mechanical Properties of Example 1, Examples 10-13 and Comparative Examples 9-13 From Table 6 and Figure 1 ​It can be found that the calcium stearate in Comparative Example 9 can reduce the surface energy of the fillers such as carbon nanotubes and modified graphene, and promote the uniform dispersion of the fillers in the polypropylene matrix; after the absence of calcium stearate, the fillers are prone to agglomeration, forming stress concentration points, resulting in more defects in the fiber under stress, and the mechanical properties decrease significantly. In Comparative Example 10, the antioxidant can effectively capture free radicals during high-temperature melt extrusion, and inhibit the oxidative degradation of the polypropylene matrix; without the addition of the antioxidant, the high-temperature environment can accelerate the breakage of the polypropylene molecular chain, reduce the molecular chain length and molecular weight, and weaken the overall strength and toughness of the fiber, resulting in the degradation of the mechanical properties. In Comparative Example 11, the maleic anhydride grafted polypropylene enhances the interfacial bonding force between the inorganic fillers and the matrix by the reaction of the anhydride groups with the amino groups on the surface of the modified titanium dioxide and the entanglement with the molecular chains of the polypropylene matrix; without the compatibilizer, the interfacial compatibility between the fillers and the matrix is poor, and the interfacial debonding occurs easily under stress, which cannot effectively transfer stress and significantly weaken the mechanical properties of the fiber. In Comparative Example 12, the step-by-step mixing process can ensure the full contact and dispersion of the components in the high-speed mixer by gradually adding the raw materials; without the step-by-step mixing, the key ingredients such as carbon nanotubes and modified graphene are not uniformly dispersed, which affects the uniformity of the internal reinforcing structure of the fiber, and further reduces the mechanical properties. In Comparative Example 13, the heat setting treatment can eliminate the internal stress in the fiber caused by drawing, promote the reordering of the molecular chains, and strengthen the bonding between the fillers and the matrix; without the heat setting, the residual internal stress in the fiber can cause unstable structure, and the molecular chain is prone to slip or break under stress, which weakens the reinforcing effect of the fillers, and finally reduces the breaking strength and elongation of the fiber.

[0048] In summary, the calcium stearate, antioxidant, compatibilizer, step-by-step mixing process and heat setting treatment can synergistically improve the mechanical properties of the fiber in multiple dimensions: the dispersant ensures uniform dispersion of the fillers, the antioxidant maintains the stability of the molecular chains of the matrix, the compatibilizer enhances the interfacial bonding, the step-by-step mixing process optimizes the dispersion effect of the raw materials, and the heat setting treatment eliminates the internal stress and stabilizes the structure. The elements cooperate with each other to form a complete system from raw material dispersion, matrix protection, interface strengthening to structure optimization, effectively avoiding problems such as stress concentration, molecular chain degradation and interfacial debonding, and finally significantly improving the breaking strength and elongation at break of the fiber, and achieving the overall improvement of the mechanical properties.

[0049] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing polydopamine-modified polypropylene antistatic fiber, characterized in that: The preparation method comprises the following steps: Adding polypropylene chips, polydopamine-modified polypropylene, carbon nanotubes, modified titanium dioxide, modified graphene, antioxidant, compatibilizer and dispersant into a high-speed mixer and mixing them uniformly to obtain a mixed material; The mixed material is added to a twin-screw extruder and melt-extruded to obtain a spinning melt; the spinning melt is spun to form spun fibers; the spun fibers are stretched and heat-set to obtain the antistatic fibers; The polydopamine-modified polypropylene is obtained by modifying polypropylene with dopamine hydrochloride; the modified titanium dioxide is obtained by modifying nano-titanium dioxide with 3-aminopropyltriethoxysilane; and the modified graphene is obtained by sulfonating graphene oxide and adding octadecylamine for modification.

2. The method for preparing a polydopamine-modified polypropylene antistatic fiber according to claim 1, characterized in that: The specific preparation method of the mixed material is: adding the polypropylene chips, the polydopamine-modified polypropylene and the compatibilizer maleic anhydride-grafted polypropylene into the high-speed mixer and mixing, then adding the carbon nanotubes, the modified graphene and the dispersant calcium stearate and continuing to stir, and finally adding the modified titanium dioxide and antioxidant 1010 and mixing, controlling the mixing temperature and stirring speed to obtain the mixed material.

3. The method for preparing a polydopamine-modified polypropylene antistatic fiber according to claim 2, characterized in that: The preparation method of the polydopamine-modified polypropylene comprises: dissolving polypropylene particles in xylene, spraying and granulating to obtain polypropylene microspheres; dissolving the dopamine hydrochloride in a buffer solution to obtain a dopamine solution; The polypropylene microspheres are added to the dopamine solution, stirred, washed with deionized water, and vacuum dried to obtain the polydopamine-modified polypropylene.

4. The method for preparing a polydopamine-modified polypropylene antistatic fiber according to claim 2, characterized in that: The preparation method of the modified titanium dioxide comprises: vacuum drying the nano titanium dioxide to obtain pretreated titanium dioxide; adding the 3-aminopropyltriethoxysilane to anhydrous ethanol, stirring, adding deionized water, and stirring to obtain a hydrolyzate; adding the pretreated titanium dioxide to the hydrolyzate, stirring for reaction, and after the reaction is completed, performing centrifugal separation, washing with deionized water, and vacuum drying to obtain the modified titanium dioxide.

5. The method for preparing a polydopamine-modified polypropylene antistatic fiber according to claim 2, characterized in that: The modified graphene preparation method comprises: dispersing 10-30 parts of the graphene oxide in anhydrous chloroform, adding chlorosulfonic acid under nitrogen protection, heating the system for reaction, cooling the system after the reaction, slowly adding isopropanol until the pH is weakly acidic, then washing, centrifuging, and vacuum drying to obtain sulfonated graphene; The octadecylamine is added to NMP and heated to dissolve to obtain a dissolving solution; the sulfonated graphene and the catalyst are added to NMP and ultrasonically obtained to obtain a dispersion solution; the dissolving solution is dropwise added to the dispersion solution, refluxed for reaction, and the reaction solution is cooled, centrifuged, washed, and vacuum dried to obtain the modified graphene.

6. The method for preparing a polydopamine-modified polypropylene antistatic fiber according to claim 1, characterized in that: The specific process of the melt extrusion is: adding the mixed material into a twin-screw extruder, setting the temperature of each stage, and controlling the screw speed to obtain the spinning melt.

7. The method for preparing a polydopamine-modified polypropylene antistatic fiber according to claim 1, characterized in that: The specific process of the spinning treatment, the drawing treatment and the heat setting treatment is: the spinning melt is transported to the spinning assembly, extruded through the spinneret, and cooled and formed under side blowing conditions to form the spun fiber; the spun fiber is drawn, the drawing multiple and the drawing temperature are controlled, and after drawing, heat setting is performed, and the heat setting temperature and time are controlled to finally obtain the antistatic fiber.

8. A polydopamine-modified polypropylene antistatic fiber, characterized by: The synthetic raw materials of the antistatic fiber include polypropylene chips, polydopamine-modified polypropylene, carbon nanotubes, modified titanium dioxide, modified graphene, antioxidants, compatibilizers and dispersants; the antistatic fiber is prepared by the preparation method according to any one of claims 1 to 7.

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