A method for preparing a conductive aid based on electrospinning technology, a conductive aid and application

Abstract

The application belongs to the technical field of conductive additives, and particularly relates to a method for preparing a conductive additive based on electrostatic spinning technology, the conductive additive and application.The method for preparing the conductive additive based on electrostatic spinning technology comprises the following steps: (1) dissolving a carbon source in a solvent, adding a metal salt after complete dissolution, and obtaining a uniform electrostatic spinning precursor solution after heating and stirring; (2) spinning using a spinning device under an accelerating voltage to obtain spinning fibers containing metal ions; (3) pre-oxidizing in an air atmosphere to obtain stable nanofibers; and (4) high-temperature calcining in an inert atmosphere to obtain a metal-based / carbon nanofiber composite material, namely the conductive additive.The conductive additive is prepared through the electrostatic spinning process, and the dispersibility and conductive performance are significantly improved by combining with carbonization process adjustment, and the conductive additive is widely applicable to the fields of plastics, elastomers and rubbers such as PA, TPU and silicone rubber.

Description

Technical Field

[0001] This invention belongs to the field of conductive additives technology, and particularly relates to a method for preparing conductive additives based on electrospinning technology, the conductive additives, and their applications. Background Technology

[0002] The development of conductive plastics and conductive rubbers is of great significance for promoting the development of industries such as electronics, communications, automotive, and medical. However, while traditional conductive materials such as metals have excellent conductivity, they are subject to many limitations in terms of processability, weight, and cost. Therefore, the development of novel, efficient, economical, and easy-to-process conductive additives has become a current research hotspot.

[0003] Chinese patents CN 105694100 A and CN 115895129 B disclose conductive additives for plastics and rubber, respectively, which improve the conductivity of the matrix materials to a certain extent. The former uses a compound with a specific structure (1-isopropyl-N-(3-methoxy-4-(oxazol-5-yl)phenyl)piperidine-2-carboxamide) as a conductive additive, which can enhance the conductivity of plastics to a certain extent, increasing the surface resistivity to 8.9 × 10⁻⁶. 5 Ω. The latter rubber conductive additive includes conductive fillers, solid rubber, and liquid rubber, wherein the conductive fillers are dispersed in the solid rubber and liquid rubber. This rubber conductive additive can improve the dispersibility of the conductive fillers in the rubber matrix, reduce the amount of conductive fillers while ensuring conductivity, and take into account the hardness, strength, and permanent deformation of the vulcanized rubber, reducing its impact on the processing performance of the rubber compound. This is beneficial for obtaining conductive rubber with better overall performance. By optimizing the dispersibility of the conductive fillers in the solid rubber and liquid rubber, a good balance between conductivity and the mechanical properties of the vulcanized rubber is achieved.

[0004] However, although these conductive additives have solved the conductivity problem to some extent, the dispersibility of conductive fillers such as conductive carbon black, graphite, carbon fiber, and carbon nanotubes in matrices such as plastics, elastomers, and rubber remains a major challenge. Due to their unique physical structures (such as high specific surface area and aspect ratio) and poor wettability with the matrix material, these fillers are prone to agglomeration during processing, affecting the continuity of the conductive network and its conductivity.

[0005] Therefore, developing a conductive additive that has both good dispersibility and significantly improved conductivity, and can be used in plastics, elastomers, and rubber products, is of great significance for broadening the application fields of conductive plastics and conductive rubber and improving the overall performance of products. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing conductive additives based on electrospinning technology, the conductive additives, and their applications.

[0007] To achieve the above objectives, the technical solution adopted is:

[0008] One objective of this invention is to provide a method for preparing conductive additives based on electrospinning technology, comprising the following steps:

[0009] (1) Dissolve the carbon source in a solvent, add a metal salt after complete dissolution, heat and stir to obtain a uniform electrospinning precursor solution;

[0010] (2) Extract the electrospinning precursor solution obtained in step (1), and spin it using a spinning device under an accelerating voltage to obtain spun fibers containing metal ions.

[0011] (3) The spun fibers obtained in step (2) are pre-oxidized in an air atmosphere to obtain stable nanofibers;

[0012] (4) The nanofibers obtained in step (3) are calcined at high temperature in an inert atmosphere to obtain a metal-based / carbon nanofiber composite material, which is a conductive additive.

[0013] Further, the carbon source in step (1) is at least one of polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polycarbonate (PC), polycaprolactone (PCL), vinylidene fluoride (PVDF), lignin, and phenolic resin.

[0014] Furthermore, the solvent in step (1) is an amide or sulfoxide, preferably at least one of dimethylacetamide, dimethylformamide and dimethyl sulfoxide.

[0015] Further, the metal salt mentioned in step (1) is at least one of the following: iron triacetylacetonate, indium nitrate, cobalt nitrate tetrahydrate, stannous chloride dihydrate, sodium tungstate, ammonium molybdate tetrahydrate, zirconium chloride, manganese acetylacetonate, chromium nitrate nonahydrate, cerium ammonium nitrate, manganese acetate, tetrabutyl titanate, vanadium triisopropoxy, copper nitrate trihydrate, ruthenium trichloride, nickel acetate tetrahydrate, zinc nitrate, iridium chloroacetic acid, chloroplatinic acid, bismuth nitrate, and silver nitrate.

[0016] Furthermore, the weight ratio of the carbon source, solvent, and metal salt in step (1) is 1:(5-15):(0.01-0.16).

[0017] Furthermore, in step (1), the heating temperature is 70-90℃ and the stirring time is 2-6h.

[0018] Furthermore, in step (2), the spinning voltage is 10-14kV, the spinning temperature is 20-40℃, and the humidity is 20-50%. The electrospinning precursor solution obtained in step (1) is extracted with a syringe. The syringe needle type is 19-22G, and the needle tip of the syringe is kept 11-15cm away from the roller receiver of the spinning equipment.

[0019] Furthermore, the pre-oxidation temperature in step (3) is 260-280℃, the pre-oxidation reaction time is 0.5-1h, and the heating rate is 5-10℃ / min.

[0020] Furthermore, in step (4), the high-temperature calcination temperature is 600-1000℃, the reaction time is 1-6h, the heating rate is 5-10℃ / min, and the inert gas is nitrogen or argon.

[0021] A second objective of this invention is to provide a conductive additive, which is prepared according to the preparation method of the conductive additive based on electrospinning technology.

[0022] A third objective of this invention is to provide an application of the aforementioned conductive additive in the fields of plastics, elastomers, and rubber.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The present invention provides a method for preparing conductive additives based on electrospinning technology, which not only improves the utilization rate of conductive materials but also enhances conductivity stability. By loading metal-based materials in a one-step process, metal-based particles are grown in situ on the surface of carbon fibers, strengthening the bonding force between the metal nanoparticles and the carrier. Furthermore, the metal-based particles are uniformly dispersed and less prone to detachment, improving the stability of the conductive additive in the matrix, thereby enhancing conductivity stability. In addition, the carbon nanofiber structure readily forms a conductive network in the matrix, increasing the charge transfer rate. The oxygen functional groups of metal oxides can improve the dispersibility of carbon nanofibers in the matrix. This invention prepares conductive additives through electrospinning, combined with adjustments to the carbonization process, resulting in significantly improved dispersibility and conductivity. It is widely applicable to the fields of plastics, elastomers, and rubbers such as PA, TPU, and silicone rubber. Detailed Implementation

[0025] The present invention will be described below with reference to examples. These examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0026] Preparation Example 1

[0027] This preparation example provides a conductive additive prepared based on electrospinning technology, wherein the conductive additive is obtained by the following preparation method:

[0028] (1) Preparation of electrospinning precursor solution: Dissolve 1g of polyacrylonitrile (PAN) in 10mL of N,N-dimethylformamide (DMF) solution, then add 0.132g of tetrabutyl titanate, and stir magnetically at 70℃ for 5h to obtain a uniform electrospinning precursor solution.

[0029] (2) Electrospinning: The electrospinning precursor solution obtained in step (1) is injected into a 2mL syringe with a 21G stainless steel needle for spinning. The spinning parameters are: positive pressure 13.5kV, negative pressure 2kV; receiving distance 15cm; and pushing speed 1mL / h to obtain precursor fibers.

[0030] (3) Pre-oxidation: The precursor fibers obtained in step (2) are placed in a muffle furnace and heated to 270°C at a heating rate of 5°C / min. After holding at the temperature for 1 hour, the temperature is lowered to room temperature to obtain stable nanofibers.

[0031] (4) Carbonization: The pre-oxidized nanofibers from step (3) are placed in a tube furnace and calcined at high temperature. Under nitrogen protection, the temperature is increased to 900°C at a heating rate of 5°C / min. After holding at this temperature for 4 hours, the temperature is reduced to room temperature to obtain a titanium dioxide / carbon nanofiber composite material with a diameter of 160 nm, which is the conductive additive.

[0032] Preparation Example 2

[0033] This preparation example provides a conductive additive prepared based on electrospinning technology. The only difference from preparation example 1 is that the high-temperature calcination temperature in step (4) is changed to 700°C. The other preparation methods are the same as in preparation example 1.

[0034] Preparation Example 3

[0035] This preparation example provides a conductive additive prepared based on electrospinning technology. The only difference from Preparation Example 1 is that the high-temperature calcination temperature is changed to 800℃, while the other preparation methods are the same as those in Preparation Example 1.

[0036] Preparation Example 4

[0037] This preparation example provides a conductive additive prepared based on electrospinning technology. The only difference from Preparation Example 1 is that the high-temperature calcination holding time is changed to 2 hours. The other preparation methods are the same as those in Preparation Example 1.

[0038] Preparation Example 5

[0039] This preparation example provides a conductive additive prepared based on electrospinning technology. The only difference from Preparation Example 1 is that the high-temperature calcination holding time is changed to 6 hours. The other preparation methods are the same as those in Preparation Example 1.

[0040] Preparation Example 6

[0041] This preparation example provides a method for preparing a conductive additive using electrospinning technology. The only difference from Preparation Example 1 is that the 21G stainless steel needle is replaced with a 19G needle; the other preparation methods are the same as in Preparation Example 1. The final product is a titanium dioxide / carbon nanofiber composite material with a diameter of 220 nm.

[0042] Example 1

[0043] This embodiment provides an application of preparing conductive additives based on electrospinning technology, comprising the following components by weight percentage:

[0044] 53% thermoplastic polyurethane elastomer (TPU) particles

[0045] 10% antioxidant

[0046] 10% compatibilizer

[0047] 10% dispersant

[0048] 7% mold release agent

[0049] 10% conductive additive

[0050] The antioxidant is 4,4'-thiobis(6-tert-butyl-3-methylphenol), the compatibilizer is styrene-acrylonitrile-glycidyl methacrylate, the dispersant is polyethylene wax, the release agent is dimethyl silicone oil, and the conductive additive is the titanium dioxide / carbon nanofiber composite material obtained in Preparation Example 1. The above materials were stirred at 500 rpm for 20 minutes in a high-speed mixer, and then discharged into a twin-screw extruder at 120°C. The extrudate discharged from the die was cut into elliptical pellets by underwater pelletizing, and then dried at 40°C for 30 minutes to obtain the final product.

[0051] Example 2

[0052] This embodiment provides an application of preparing conductive additives based on electrospinning technology, comprising the following components by weight percentage:

[0053] 53% silicone rubber particles

[0054] 10% antioxidant

[0055] 10% compatibilizer

[0056] 10% dispersant

[0057] 7% mold release agent

[0058] 10% conductive additive

[0059] The only difference from Example 1 is that TPU particles are replaced with silicone rubber particles, while the content of other components and the preparation method are the same as in Example 1.

[0060] Example 3

[0061] This embodiment provides an application of preparing conductive additives based on electrospinning technology, comprising the following components by weight percentage:

[0062] 53% polyamide (PA) particles

[0063] 10% antioxidant

[0064] 10% compatibilizer

[0065] 10% dispersant

[0066] 7% mold release agent

[0067] 10% conductive additive

[0068] The only difference from Example 1 is that TPU particles are replaced with PA particles, while the content of other components and the preparation method are the same as in Example 1.

[0069] Example 4

[0070] This embodiment provides an application of a conductive additive, which differs from Example 1 only in that the conductive additive obtained in Preparation Example 1 is replaced with the conductive additive obtained in Preparation Example 2.

[0071] Example 5

[0072] This embodiment provides an application of a conductive additive, which differs from Example 1 only in that the conductive additive obtained in Preparation Example 1 is replaced with the conductive additive obtained in Preparation Example 3.

[0073] Example 6

[0074] This embodiment provides an application of a conductive additive, which differs from Example 1 only in that the conductive additive obtained in Preparation Example 1 is replaced with the conductive additive obtained in Preparation Example 4.

[0075] Example 7

[0076] This embodiment provides an application of a conductive additive, which differs from Example 1 only in that the conductive additive obtained in Preparation Example 1 is replaced with the conductive additive obtained in Preparation Example 5.

[0077] Example 8

[0078] This embodiment provides an application of a conductive additive, which differs from Example 1 only in that the conductive additive obtained in Preparation Example 1 is replaced with the conductive additive obtained in Preparation Example 6.

[0079] Comparative Example 1

[0080] This comparative example provides an application of a conductive additive, comprising the following components by weight percentage:

[0081] 53% thermoplastic polyurethane elastomer (TPU) particles

[0082] 10% antioxidant

[0083] 10% compatibilizer

[0084] 10% dispersant

[0085] 7% mold release agent

[0086] 10% conductive additive

[0087] The antioxidant is 4,4'-thiobis(6-tert-butyl-3-methylphenol), the compatibilizer is styrene-acrylonitrile-glycidyl methacrylate, the dispersing lubricant is polyethylene wax, the release agent is dimethyl silicone oil, and the conductive additive is conductive carbon black. The above substances are stirred in a high-speed mixer at 500 rpm for 20 minutes, then discharged into a twin-screw extruder at 120°C. The extrudate discharged from the die is cut into elliptical pellets by underwater pelletizing, and then dried at 40°C for 30 minutes to obtain the final product.

[0088] Comparative Example 2

[0089] This comparative example provides an application of a conductive additive, comprising the following components by weight percentage:

[0090] 53% silicone rubber particles

[0091] 10% antioxidant

[0092] 10% compatibilizer

[0093] 10% dispersant

[0094] 7% mold release agent

[0095] 10% conductive additive

[0096] The antioxidant is 4,4'-thiobis(6-tert-butyl-3-methylphenol), the compatibilizer is styrene-acrylonitrile-glycidyl methacrylate, the dispersing lubricant is polyethylene wax, the release agent is dimethyl silicone oil, and the conductive additive is single-walled carbon nanotubes. The above substances are stirred in a high-speed mixer at 500 rpm for 20 minutes, then discharged into a twin-screw extruder at 120°C. The extrudate discharged from the die is cut into elliptical pellets by underwater pelletizing, and then dried at 40°C for 30 minutes to obtain the final product.

[0097] Comparative Example 3

[0098] This comparative example provides an application of a conductive additive. The only difference from Example 3 is that the conductive additive, titanium dioxide / carbon nanofiber composite material, is replaced with an equal mass of conductive carbon black. The content of other components and the preparation method are the same as in Example 3.

[0099] Table 1. Main raw material composition of Examples 1-3 and Comparative Examples 1-3 (unit: mass percentage)

[0100]

[0101]

[0102] Table 2. Process Comparison of Examples 4-8

[0103]

[0104] The products obtained from Examples 1-8 and Comparative Examples 1-3 were subjected to the following tests, and the results are shown in Table 3.

[0105] Table 3. Test results for each embodiment and comparative example

[0106]

[0107]

[0108] A comparison of Examples 1 and 4-5 shows that as the carbonization temperature increases, the graphitization degree of the carbon nanofibers increases, thereby reducing their resistivity. A comparison of Examples 1 and 6-7 shows that if the carbonization time is too short, the material cannot achieve the expected degree of graphitization; if the carbonization time is too long, the voids in the carbon fibers begin to collapse, reducing the specific surface area of ​​the material and hindering charge transfer. A comparison of Examples 1 and 8 shows that the diameter of the carbon fibers affects the specific surface area of ​​the material, thus affecting charge transfer.

[0109] As can be seen from the data in Table 3, the conductive additives prepared based on electrospinning technology can significantly reduce surface resistance when applied to plastics, elastomers, and rubber products, thus meeting the conductivity requirements of downstream customers.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing conductive additives based on electrospinning technology, characterized in that, Includes the following steps: (1) Dissolve the carbon source in a solvent, add a metal salt after complete dissolution, heat and stir to obtain a uniform spinning precursor solution; (2) Extract the electrospinning precursor solution obtained in step (1), and spin it using a spinning device under an accelerating voltage to obtain spun fibers containing metal ions. (3) The spun fibers obtained in step (2) are pre-oxidized in an air atmosphere to obtain stable nanofibers; (4) The nanofibers obtained in step (3) are calcined at high temperature in an inert atmosphere to obtain a metal-based / carbon nanofiber composite material, which is a conductive additive. The weight ratio of carbon source, solvent, and metal salt in step (1) is 1:(5-15):(0.01-0.16); The temperature of the high-temperature calcination in step (4) is 900℃, and the reaction time of the high-temperature calcination is 4h. In step (2), the spinning voltage is 10-14 kV, the spinning temperature is 20-40℃, and the spinning humidity is 20-50%. The electrospinning precursor solution obtained in step (1) is extracted with a syringe. The syringe needle type is 19-22 G, and the syringe needle tip is kept 11-15 cm away from the roller receiver of the spinning equipment. The pre-oxidation temperature in step (3) is 260-280℃, the pre-oxidation reaction time is 0.5-1 h, and the pre-oxidation heating rate is 5-10℃ / min.

2. The method for preparing conductive additives based on electrospinning technology according to claim 1, characterized in that, The carbon source in step (1) is at least one of polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polycarbonate (PC), polycaprolactone (PCL), vinylidene fluoride (PVDF), lignin, and phenolic resin.

3. The method for preparing conductive additives based on electrospinning technology according to claim 1, characterized in that, The solvent in step (1) is an amide or sulfoxide.

4. The method for preparing conductive additives based on electrospinning technology according to claim 1, characterized in that, The metal salt mentioned in step (1) is at least one of the following: iron triacetylacetonate, indium nitrate, cobalt nitrate tetrahydrate, stannous chloride dihydrate, sodium tungstate, ammonium molybdate tetrahydrate, zirconium chloride, manganese acetylacetonate, chromium nitrate nonahydrate, cerium ammonium nitrate, manganese acetate, tetrabutyl titanate, vanadium triisopropoxy, copper nitrate trihydrate, ruthenium trichloride, nickel acetate tetrahydrate, zinc nitrate, iridium chloroacetic acid, chloroplatinic acid, bismuth nitrate, and silver nitrate.

5. The method for preparing conductive additives based on electrospinning technology according to claim 1, characterized in that, The heating rate of the high-temperature calcination in step (4) is 5-10℃ / min, and the inert gas is nitrogen or argon.

6. A conductive additive, characterized in that, The conductive additive is prepared according to any one of claims 1 to 5 using the method for preparing conductive additives based on electrospinning technology.

7. The application of the conductive additive as described in claim 6 in the fields of plastics, elastomers, and rubber.

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