A polydopamine modified polypropylene antistatic fiber and a preparation method thereof

Abstract

This invention relates to the field of fiber materials technology, specifically to a polydopamine-modified polypropylene antistatic fiber and its preparation method. This invention overcomes the problems of poor antistatic effect and mechanical properties of polypropylene fibers. The invention involves the stepwise mixing, melt extrusion, spinning, drawing, and heat setting of raw materials such as polypropylene chips, polydopamine-modified polypropylene, carbon nanotubes, modified titanium dioxide, and modified graphene to obtain 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. The various materials and processes synergistically construct an antistatic system on the fiber surface and inside, while simultaneously improving mechanical properties. The fibers obtained by this method exhibit excellent antistatic effect and mechanical properties, and have promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of fiber materials technology, specifically to a polydopamine-modified polypropylene antistatic fiber and its preparation method. Background Technology

[0002] Polypropylene fiber, also known as polypropylene fiber, has emerged in many fields such as textiles since its industrial production, thanks to its unique advantages. Polypropylene fiber is polymerized from propylene monomers and has properties such as light weight, high strength, low moisture regain, low water absorption, as well as good wicking properties, abrasion resistance, and resilience. It is widely used in the manufacture of many products such as decorative fabrics, industrial filter cloths, and non-woven fabrics.

[0003] Despite its numerous advantages, polypropylene fiber's inherent technical limitations restrict its further development. From an antistatic perspective, polypropylene fiber is a nonpolar molecule with weak intermolecular attraction, making it difficult for its surface to attract airborne charges. Furthermore, its poor electrical conductivity means that frequent friction between fibers and between fibers and equipment during spinning and other processing easily generates static electricity, rendering the resulting polypropylene fiber unsuitable for antistatic applications. In terms of mechanical properties, polypropylene fiber exhibits poor light and heat stability and a low softening point. In practical applications, exposure to light or high temperatures significantly reduces fiber strength, increases elongation, and decreases modulus, severely limiting its use in fields requiring high strength and stability.

[0004] To this end, a polydopamine-modified polypropylene antistatic fiber and its preparation method are proposed. Summary of the Invention

[0005] The purpose of this invention is to design a polydopamine-modified polypropylene antistatic fiber and its preparation method. This invention involves the stepwise mixing, melt extrusion, spinning, stretching, and heat setting of raw materials such as polypropylene chips, polydopamine-modified polypropylene, carbon nanotubes, modified titanium dioxide, and modified graphene to obtain 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. The synergistic effect of multiple substances such as polydopamine-modified polypropylene, carbon nanotubes, modified titanium dioxide, and modified graphene constructs an antistatic system on the fiber surface and inside, while simultaneously improving mechanical properties. The antistatic fiber prepared by this method exhibits excellent antistatic and mechanical properties and has promising application prospects.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing polydopamine-modified polypropylene antistatic fibers, comprising the following steps: Polypropylene chips, polydopamine-modified polypropylene, carbon nanotubes, modified titanium dioxide, modified graphene, antioxidants, compatibilizers, and dispersants are added to a high-speed mixer and mixed evenly to obtain a mixture. The mixture is added to a twin-screw extruder and melt-extruded to obtain a spinning melt; the spinning melt is spun to form nascent fibers; the nascent fibers are then stretched and heat-set to finally obtain antistatic fibers. Polydopamine-modified polypropylene is obtained by modifying polypropylene with dopamine hydrochloride; modified titanium dioxide is obtained by modifying nano-titanium dioxide with 3-aminopropyltriethoxysilane; modified graphene is obtained by sulfonating graphene oxide and adding octadecylamine for modification.

[0007] Preferably, the specific preparation method of the mixture by weight is as follows: 85 parts of polypropylene chips, 5-10 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, 1-5 parts of carbon nanotubes, 0.1-2 parts of modified graphene and 0.1-2 parts of calcium stearate are added and stirred for another 10 min. Finally, 1-3 parts of modified titanium dioxide and 0.5-1 parts of antioxidant 1010 are added and mixed for 20-30 min. The mixing temperature is 90℃ and the stirring speed is 300 r / min to obtain the mixture.

[0008] Preferably, the preparation method of polydopamine-modified polypropylene by weight is as follows: 90-110 parts of polypropylene particles are dissolved in 300 parts of xylene, and spray granulation is performed to obtain polypropylene microspheres; 0.5-2 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 hours, washed 5 times with deionized water, and vacuum dried at 60°C for 12 hours to obtain polydopamine-modified polypropylene.

[0009] Preferably, the modified titanium dioxide is prepared by means of the following method: 90-110 parts of nano-titanium dioxide (average particle size 50 nm) are vacuum dried at 110 °C for 3 h to obtain pretreated titanium dioxide; 2-5 parts of 3-aminopropyltriethoxysilane are added to 400 parts of anhydrous ethanol, stirred for 15 min, and then 40 parts of deionized water are added and stirred for 30 min to obtain a hydrolysate; the pretreated titanium dioxide is added to the hydrolysate and stirred at 70 °C for 2 h-4 h. After the reaction is completed, the modified titanium dioxide is obtained by centrifugation, washing with deionized water 3 times, and vacuum drying at 60 °C for 12 h.

[0010] Preferably, the modified graphene is prepared by the following method by weight: 10-30 parts of graphene oxide (monolayer content ≥90%) 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 4 hours. After the reaction is completed, the system is cooled to 0℃, and isopropanol at -20℃ is slowly added until the pH is 5-6. Then, the system is washed, centrifuged, and vacuum dried for 12 hours to obtain sulfonated graphene. 2-6 parts of octadecylamine are added to 100 parts of NMP and heated to 80℃ to dissolve, to obtain a solution. Sulfonated graphene and 0.1 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride are added to 100 parts of NMP and sonicated for 30 minutes to obtain a dispersion. The solution is added dropwise to the dispersion and refluxed at 85℃ for 8-12 hours. After the reaction solution is cooled, it is centrifuged, washed, and vacuum dried for 24 hours to obtain modified graphene.

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

[0012] Preferably, the specific processes of spinning, drawing, and heat setting are as follows: the spinning melt is conveyed to the spinning assembly and extruded through a spinneret with an average spinneret diameter of 0.1mm-0.3mm. It is then cooled and shaped under side-blowing conditions with a wind speed of 0.3m / s and a wind temperature of 25℃-30℃ to form nascent fibers. The nascent fibers are then drawn with a drawing ratio of 3-5 times and a drawing temperature of 90℃. After drawing, they are heat-set at a temperature of 150℃ for 1-5 minutes to finally obtain antistatic fibers.

[0013] Another aspect of the present invention provides a polydopamine-modified polypropylene antistatic fiber, which is prepared according to the above preparation method. The raw materials for preparing 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 beneficial effects of the present invention are as follows: 1. Polydopamine in polypropylene-modified polypropylene (PPM) exhibits strong adhesion, enabling it to adhere tightly to the surface of polypropylene fibers, forming a thin film rich in hydrophilic groups. These hydrophilic groups can absorb moisture from the air, reducing the surface resistance of the fiber and thus achieving antistatic properties. Carbon nanotubes, with their excellent conductivity and high strength, are added to polypropylene-modified polypropylene. The carbon nanotubes interconnect within the fiber, constructing a highly efficient conductive network. Regarding antistatic performance, the hydrophilic film formed by polydopamine reduces surface resistance, while the conductive network of carbon nanotubes provides electron transport channels from within. The combined effect of these two components significantly enhances the antistatic performance of the fiber.

[0015] 2. Carbon nanotubes, with their high conductivity and aspect ratio, create one-dimensional conductive channels within the fiber, serving as high-speed pathways for charge transport. Modified graphene, after sulfonation and octadecylamine modification, forms a planar conductive network through its two-dimensional sheet structure, enhancing antistatic properties. Modified titanium dioxide, through silane coupling agent modification, forms hydrogen bonds or electrostatic interactions with carbon nanotubes and graphene via surface polar groups, constructing a three-dimensional interconnected conductive network. In terms of mechanical properties, modified titanium dioxide strengthens interfacial bonding, acting as a stress buffer to inhibit crack propagation; the high strength of carbon nanotubes bears the load; and the slippage energy dissipation characteristics of graphene sheets complement this effect. All three synergistically enhance the mechanical properties of the fiber.

[0016] 3. The anhydride groups of maleic anhydride-grafted polypropylene form covalent bonds with the amino groups on the modified titanium dioxide surface, and simultaneously entangle with the polypropylene matrix molecular chains, enhancing the interfacial bonding force between the inorganic filler and the matrix. Calcium stearate, by reducing the surface energy of fillers such as carbon nanotubes and modified graphene, ensures uniform dispersion under the strong shearing action of a twin-screw extruder, avoiding stress concentration caused by agglomeration. Antioxidant 1010 captures free radicals during melt extrusion, inhibiting high-temperature oxidative degradation of the polypropylene matrix and maintaining the integrity of the molecular chains. The drawing process after spinning allows the oriented molecular chains to form a rigid framework with the uniformly dispersed fillers, and heat setting eliminates internal stress, promoting a more stable physical entanglement structure at the filler-matrix interface. These four factors work synergistically to improve the mechanical properties of the fiber. Attached Figure Description

[0017] Figure 1 The diagram shows the fracture strength and elongation at break of Example 1 and Comparative Examples 9-13 in this invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] For details, please refer to [link / reference]. Figure 1 This invention provides a polydopamine-modified polypropylene antistatic fiber and its preparation method, the technical solution of which is as follows: Example 1 100 parts of polypropylene particles were dissolved in 300 parts of xylene and spray-granulated to obtain polypropylene microspheres; 1.5 parts of dopamine hydrochloride were dissolved in 200 parts of Tris buffer solution to obtain a dopamine solution; the polypropylene microspheres were added to the dopamine solution, stirred for 24 h, washed 5 times with deionized water, and dried under vacuum at 60 °C for 12 h to obtain polydopamine modified polypropylene.

[0020] 100 parts of nano-titanium dioxide were vacuum dried at 110℃ for 3 h to obtain pretreated titanium dioxide; 4 parts of 3-aminopropyltriethoxysilane were added to 400 parts of anhydrous ethanol, stirred for 15 min, and then 40 parts of deionized water were added and stirred for 30 min to obtain hydrolysate; the pretreated titanium dioxide was added to the hydrolysate and stirred at 70℃ for 3 h. After the reaction was completed, the mixture was centrifuged, washed three times with deionized water, and vacuum dried at 60℃ for 12 h to obtain modified titanium dioxide.

[0021] 20 parts of graphene oxide were dispersed in 300 parts of anhydrous chloroform. 8 parts of chlorosulfonic acid were added under nitrogen protection, and the mixture was heated to 45°C and reacted for 4 hours. After the reaction, the system was cooled to 0°C, and isopropanol at -20°C was slowly added. The mixture was then washed, centrifuged, and vacuum dried for 12 hours to obtain sulfonated graphene. 4 parts of octadecylamine were added to 100 parts of NMP and heated to 80°C to dissolve, obtaining a solution. Sulfonated graphene and 0.1 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were added to 100 parts of NMP and sonicated for 30 minutes to obtain a dispersion. The solution was added dropwise to the dispersion, and the mixture was refluxed at 85°C for 10 hours. After cooling, the reaction solution was centrifuged, washed, and vacuum dried for 24 hours 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 were 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 were added and stirred for another 10 min. Finally, 2 parts of modified titanium dioxide and 0.8 parts of antioxidant 1010 were added and mixed for 25 min. The mixing temperature was 90℃ and the stirring speed was 300 r / min to obtain the mixture. The mixture is added to a twin-screw extruder, and the temperatures of each section are set as follows: Zone 1 195℃, Zone 2 200℃, Zone 3 205℃, Zone 4 210℃, Zone 5 215℃, the die head temperature is 220℃, and the screw speed is controlled at 250 r / min to obtain the spinning melt. The spinning melt is conveyed to the spinning assembly, extruded through a spinneret, and cooled and shaped under side-blowing conditions at a wind speed of 0.3 m / s and a wind temperature of 28°C to form nascent fibers. The nascent fibers are then stretched at a stretch ratio of 4 times and a stretching temperature of 90°C. After stretching, they are heat-set at a temperature of 150°C for 3 minutes to finally obtain antistatic fibers.

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

[0024] Table 1 Parameters and Conditions for Examples 1-5 Comparative Example 1 follows the same parameters and conditions as in Example 1, except that the polypropylene is not modified.

[0025] Comparative Example 2 follows the same parameters and conditions as in Example 1, except that polydopamine-modified polypropylene is not added.

[0026] Comparative Example 3 follows the same parameters and conditions as in Example 1, except that carbon nanotubes are not added.

[0027] Experiment Example 1: Antistatic Effect Test The surface resistance of Examples 1-5 and Comparative Examples 1-3 was tested according to AATCC 76-2019 "Textiles - Test Method for Surface Resistance". The results are shown in Table 2.

[0028] Table 2 Antistatic effects of Examples 1-5 and Comparative Examples 1-3 Table 2 shows that in Comparative Example 1, due to the lack of polydopamine modification of polypropylene, the fiber surface lacks a hydrophilic conductive film formed by polydopamine, making it unable to reduce surface resistance by adsorbing moisture. Furthermore, the non-polar structure of polypropylene itself makes charge dissipation difficult, resulting in extremely high surface resistance. In Comparative Example 2, lacking polydopamine modification, the fiber surface cannot form a hydrophilic antistatic layer constructed by polydopamine. It relies solely on conductive fillers such as carbon nanotubes to build a network internally, but the lack of surface charge dissipation pathways leads to a significant increase in surface resistance and a substantial decrease in antistatic performance. In Comparative Example 3, the absence of carbon nanotubes prevents the formation of a continuous conductive network within the fiber. Relying solely on the antistatic effect of polydopamine-modified polypropylene on the surface, it is difficult to quickly conduct charge, resulting in a significant increase in surface resistance. The antistatic effect is significantly weakened due to the lack of internal conductive pathways.

[0029] In summary, polydopamine-modified polypropylene and carbon nanotubes achieve a synergistic effect on antistatic properties from the surface to the interior: polydopamine reduces surface resistance through a hydrophilic film, while carbon nanotubes construct an internal conductive network with high conductivity. The combined effect of the two allows charges to be dissipated on the surface and conducted internally, significantly reducing surface resistance and ultimately improving the antistatic properties of the fiber.

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

[0031] Table 3 Parameters and conditions for Examples 1 and 6-9 Comparative Example 3 follows the same parameters and conditions as in Example 1, except that carbon nanotubes are not added.

[0032] Comparative Example 4 follows the same parameters and conditions as in Example 1, except that the nano-titanium dioxide is not modified.

[0033] Comparative Example 5 follows the same parameters and conditions as in Example 1, except that modified titanium dioxide is not added.

[0034] Comparative Example 6 follows the same parameters and conditions as in Example 1, except that the graphene oxide is not sulfonated.

[0035] Comparative Example 7 follows the same parameters and conditions as in Example 1, except that the sulfonated graphene is not modified.

[0036] Comparative Example 8 follows the same parameters and conditions as in Example 1, except that no modified graphene is added.

[0037] Experiment Example 2: Antistatic Effect and Mechanical Property Testing The surface resistivity of Examples 1, 6-9 and Comparative Examples 3-8 was tested according to Experimental Example 1; the breaking strength and elongation at break of Examples 1, 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 effects and mechanical properties of Examples 1, 6-9 and Comparative Examples 3-8 Table 4 shows that in Comparative Example 3, the absence of carbon nanotubes prevents the formation of a highly efficient conductive network within the fiber. Relying solely on surface-modified materials makes it difficult to quickly conduct charges, leading to significant static electricity buildup. Simultaneously, the lack of carbon nanotubes as a high-strength reinforcing phase deprives the fiber of an effective stress transfer path when subjected to external forces, resulting in a significant decrease in mechanical properties. In Comparative Example 4, the unmodified nano-titanium dioxide exhibits poor compatibility with the matrix, easily agglomerating to form stress concentration points and weakening the fiber's mechanical properties. Furthermore, its surface lacks active groups, preventing it from collaboratively constructing a continuous conductive network with other conductive fillers, thus reducing charge conduction efficiency and limiting antistatic effects. In Comparative Example 5, the absence of modified titanium dioxide causes the fiber to lose crucial three-dimensional conductive connection points and interfacial reinforcing phases. This not only disrupts the integrity of the conductive network formed by carbon nanotubes and graphene but also results in insufficient interfacial bonding between the filler and the matrix, leading to a significant decline in both antistatic and mechanical properties. In Comparative Example 6, the unsulfonated graphene oxide lacks polar groups on its surface, resulting in weak interaction with materials such as carbon nanotubes. This prevents it from effectively filling the gaps in the conductive network, leading to a decrease in charge conduction efficiency. Simultaneously, its poor dispersion in the matrix prevents it from playing a reinforcing role, further reducing the fiber's mechanical properties. In Comparative Example 7, the unmodified sulfonated graphene has insufficient surface activity and poor compatibility with the matrix and other fillers, easily leading to agglomeration. This hinders the construction of the conductive network and stress transfer, causing impaired charge conduction within the fiber and making it prone to defects under stress, resulting in a simultaneous deterioration of antistatic and mechanical properties. In Comparative Example 8, the absence of modified graphene results in the fiber lacking a crucial two-dimensional conductive reinforcement structure, preventing it from complementing the carbon nanotubes and leading to an incomplete conductive network. Furthermore, the loss of graphene's high-modulus reinforcement makes it difficult for the fiber to disperse stress under stress, significantly reducing its mechanical properties.

[0039] In summary, carbon nanotubes, modified titanium dioxide, and modified graphene enhance fiber performance through structural complementarity and functional synergy: carbon nanotubes construct a one-dimensional conductive framework and mechanically reinforcing axes; modified titanium dioxide acts as a connecting point to strengthen network stability and interfacial bonding; and modified graphene fills gaps with two-dimensional sheets, enhancing charge conduction efficiency and improving dispersibility through surface polar groups. The three components work together to not only form a highly efficient conductive network within the fiber and reduce surface resistance, but also significantly improve breaking strength and elongation at break by enhancing interfacial compatibility and stress transfer capabilities, achieving dual optimization of antistatic and mechanical properties.

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

[0041] Table 5. Parameters and conditions for Examples 1 and 10-13 Comparative Example 9 follows the same parameters and conditions as in Example 1, except that calcium stearate is not added.

[0042] Comparative Example 10 follows the same parameters and conditions as in Example 1, except that no antioxidant is added.

[0043] Comparative Example 11 follows the same parameters and conditions as in Example 1, except that the compatibilizer maleic anhydride-grafted polypropylene is not added.

[0044] Comparative Example 12 follows the same parameters and conditions as in Example 1, except that the mixture is not mixed in steps during preparation.

[0045] Comparative Example 13 follows the same parameters and conditions as in Example 1, except that no heat setting treatment is performed.

[0046] Experiment Example 3 Mechanical Property Testing The fracture strength and elongation at break of Examples 1, 10-13, and Comparative Examples 9-13 were tested according to Experimental Example 2; the results are shown in Table 6. The fracture strength and elongation at break of Examples 1 and Comparative Examples 9-13 are as follows: Figure 1 As shown.

[0047] Table 6 Mechanical properties of Examples 1, 10-13 and Comparative Examples 9-13 From Table 6 and Figure 1It can be observed that in Comparative Example 9, calcium stearate, acting as a dispersant, can reduce the surface energy of fillers such as carbon nanotubes and modified graphene, promoting their uniform dispersion in the polypropylene matrix. Without calcium stearate, the fillers are prone to agglomeration, forming stress concentration points, making the fibers more susceptible to defects under stress, and significantly reducing mechanical properties. In Comparative Example 10, the antioxidant can effectively capture free radicals during high-temperature melt extrusion, inhibiting the oxidative degradation of the polypropylene matrix. Without the addition of antioxidants, the high-temperature environment accelerates the breakage of polypropylene molecular chains, reducing the molecular chain length and molecular weight, leading to a weakening of the overall fiber strength and toughness, and a decline in mechanical properties. In Comparative Example 11, maleic anhydride-grafted polypropylene enhances the interfacial bonding force between the inorganic filler and the matrix through the reaction of its anhydride groups with the amino groups on the surface of modified titanium dioxide and the entanglement with the molecular chains of the polypropylene matrix. Without a compatibilizer, the interfacial compatibility between the filler and the matrix is ​​poor, easily leading to interfacial debonding under stress, failing to effectively transfer stress, and significantly weakening the fiber's mechanical properties. In Comparative Example 12, the stepwise mixing process ensures sufficient contact and dispersion of each component in the high-speed mixer by gradually adding raw materials. Without stepwise mixing, key components such as carbon nanotubes and modified graphene are unevenly dispersed, affecting the uniformity of the internal reinforcement structure of the fiber and thus reducing mechanical properties. In Comparative Example 13, heat setting eliminates the internal stress generated by stretching within the fiber, promotes the rearrangement of molecular chains, and strengthens the bond between the filler and the matrix. Without heat setting, residual internal stress in the fiber leads to structural instability, making it prone to molecular chain slippage or breakage under stress, while also weakening the reinforcement effect of the filler, ultimately reducing the fiber's breaking strength and elongation.

[0048] In summary, calcium stearate, antioxidants, compatibilizers, stepwise mixing processes, and heat setting treatment synergistically enhance fiber mechanical properties from multiple dimensions: dispersants ensure uniform filler dispersion, antioxidants maintain matrix molecular chain stability, compatibilizers strengthen interfacial bonding, stepwise mixing optimizes raw material dispersion, and heat setting eliminates internal stress and stabilizes the structure. These elements work together to form a complete system from raw material dispersion and matrix protection to interfacial strengthening and structural optimization, effectively avoiding problems such as stress concentration, molecular chain degradation, and interfacial debonding. Ultimately, this significantly improves the fiber's breaking strength and elongation at break, achieving a comprehensive improvement in mechanical properties.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which 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 includes the following steps: Polypropylene chips, polydopamine-modified polypropylene, carbon nanotubes, modified titanium dioxide, modified graphene, antioxidants, compatibilizers, and dispersants are added to a high-speed mixer and mixed evenly to obtain a mixture. The mixture is added to a twin-screw extruder and melt-extruded to obtain a spinning melt; the spinning melt is spun to form nascent fibers; the nascent fibers are drawn and heat-set to finally 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; the modified graphene is obtained by sulfonating graphene oxide and adding octadecylamine for modification.

2. The method for preparing polydopamine-modified polypropylene antistatic fiber according to claim 1, characterized in that: The specific preparation method of the mixture is as follows: the polypropylene chips, the polydopamine-modified polypropylene and the compatibilizer maleic anhydride-grafted polypropylene are added to the high-speed mixer and mixed. Then, the carbon nanotubes, the modified graphene and the dispersant calcium stearate are added and stirred. Finally, the modified titanium dioxide and antioxidant 1010 are added and mixed. The mixing temperature and stirring speed are controlled to obtain the mixture.

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

4. The method for preparing polydopamine-modified polypropylene antistatic fiber according to claim 2, characterized in that: The modified titanium dioxide is prepared by: vacuum drying the nano-titanium dioxide to obtain pretreated titanium dioxide; adding 3-aminopropyltriethoxysilane to anhydrous ethanol, stirring, then adding deionized water, stirring again to obtain a hydrolysate; adding the pretreated titanium dioxide to the hydrolysate, stirring to react, and after the reaction is completed, obtaining the modified titanium dioxide by centrifugation, washing with deionized water, and vacuum drying.

5. The method for preparing polydopamine-modified polypropylene antistatic fiber according to claim 2, characterized in that: The method for preparing the modified graphene is as follows: 10-30 parts of the graphene oxide are dispersed in anhydrous chloroform, chlorosulfonic acid is added under nitrogen protection, the temperature is raised and the reaction is carried out. After the reaction is completed, the system is cooled down, isopropanol is slowly added until the pH is weakly acidic, then washed, centrifuged, and vacuum dried to obtain sulfonated graphene. The octadecylamine was added to NMP and heated to dissolve, yielding a solution. The sulfonated graphene and the catalyst were added to NMP and sonicated to obtain a dispersion. The solution was added dropwise to the dispersion, and the mixture was refluxed. After cooling, the reaction solution was centrifuged, washed, and vacuum dried to obtain the modified graphene.

6. The method for preparing polydopamine-modified polypropylene antistatic fiber according to claim 1, characterized in that: The specific process of melt extrusion is as follows: the mixture is added to a twin-screw extruder, the temperature of each stage is set, the screw speed is controlled, and the spinning melt is obtained.

7. The method for preparing polydopamine-modified polypropylene antistatic fiber according to claim 1, characterized in that: The specific processes of the spinning treatment, the drawing treatment, and the heat setting treatment are as follows: the spinning melt is conveyed to the spinning assembly, extruded through the spinneret, and cooled and shaped under side blowing conditions to form the nascent fiber; the nascent fiber is drawn, the drawing ratio and drawing temperature are controlled, and after drawing, heat setting is performed, the heat setting temperature and time are controlled, and finally the antistatic fiber is obtained.

8. A polydopamine-modified polypropylene antistatic fiber, characterized in that: The raw materials for synthesizing 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 1-7.

Images