Antistatic aerogel for 3D printing and preparation method and application thereof

Abstract

This invention belongs to the field of aerogel materials technology, specifically relating to an antistatic aerogel for 3D printing, its preparation method, and its application. The preparation method includes the following steps: (1) dispersing inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomers in an acidic solvent to obtain a monomer mixed solution; (2) dissolving polyamide in the monomer mixed solution by stirring; (3) obtaining a polyaniline-modified polyamide solution after initiating the reaction; and (4) freeze-drying to obtain the antistatic aerogel for 3D printing. By controlling the synthesis conditions, a core-shell structure of acid-doped polyaniline-coated inorganic nanoparticles is formed, creating a good conductive pathway in the polyamide with a relatively small amount of polyaniline added. This antistatic aerogel for 3D printing can be used in 3D printing technologies such as photopolymerization and fused deposition modeling of polyurethane resin to improve the antistatic and mechanical properties of 3D printed products.

Description

Technical Field

[0001] This invention belongs to the field of aerogel materials technology, specifically relating to an antistatic aerogel for 3D printing, its preparation method, and its application. Background Technology

[0002] 3D printing technology is one of the advanced additive manufacturing (AM) technologies. It is a process of adding and connecting materials layer by layer to form a part. AM is the opposite of subtractive manufacturing (SM), which removes material from a bulk material (i.e., machining) to form the desired product. A major advantage of AM over SM is its ability to accurately create more complex shapes. Due to its high manufacturing efficiency, scalability, and low cost, it has attracted widespread attention in the development of advanced manufacturing materials.

[0003] With the rapid development of 3D printing technology in recent years, it has been widely used and made great progress in many fields. First, 3D printing technology is an ideal choice for aerospace components because they have complex geometries and require consideration of structural, heat dissipation, and airflow effects. Custom production through 3D printing can reduce waste and provide complex shapes. The aerospace industry is characterized by the production of small batches of parts, and 3D printing technology is relatively convenient and, compared to traditional technologies, does not require expensive equipment such as molds for small-batch production.

[0004] Secondly, 3D printing technology also has wide applications in the biomedical field. 3D printing technology can 3D print biocompatible materials, cells, and supporting components into complex 3D functional living tissues. 3D bioprinting is being applied to regenerative medicine to address the need for transplantable tissues and organs. 3D bioprinting has been used for the generation and transplantation of various tissues, including skin, bone, vascular grafts, tracheal splints, heart tissue, and cartilage structures.

[0005] 3D printing technology also has applications in automated construction. Due to its advantages such as high precision, strong drilling capabilities, and various design possibilities, 3D printing offers a certain degree of reliability in the construction industry, particularly in handling geometrically complex and hollow structures.

[0006] Furthermore, 3D printing technology, as a common production method, is currently being applied in numerous manufacturing fields, including clothing, electronics, automobiles, robotics, military, and oceanography. Among these 3D printing technologies, the most widely used printing materials are resin materials such as polyurethane. Polyurethane is widely used in 3D printing technology due to its good mechanical strength and toughness, as well as excellent processing performance. However, as a resin material, it has poor antistatic properties, which can lead to high-voltage discharge due to charge accumulation during use, interfering with the normal operation of the equipment. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art and provide an antistatic aerogel for 3D printing. This antistatic material has a porous gel structure, which is conducive to the full wetting of the resin material during the printing process, improves its compatibility with materials such as polyurethane resin, and further improves its antistatic performance on the basis of improving the mechanical properties of the printing material.

[0008] To improve the antistatic properties of resins, conductive fillers are typically added. From the perspective of how the conductive filler is added, the preparation methods of polymer conductive composites can be divided into two main categories: one is in-situ polymerization and solution blending, where the conductive filler and polymer are physically dispersed before or after polymerization to prepare nanocomposites; the other is prefabricating a conductive three-dimensional structure followed by polymer infiltration polymerization to prepare polymer nanocomposites. In previous work, the inventors have prepared aerogel powders with certain conductive properties using in-situ polymerization (CN118667223A) and post-infiltration processes (CN118702962A, CN118812911A, CN118834412A, etc.). In-situ polymerization requires the polymerization of multiple raw materials, making the preparation process complex; while post-infiltration processes take even longer, requiring not only the preconstruction of a three-dimensional conductive matrix but also a cumbersome infiltration process. During this process, the infiltrated components are prone to uneven dispersion, producing micron-sized aggregates, thereby reducing the performance of the composite material. To address the aforementioned issues, this invention uses polyamide as the aerogel matrix to directly prepare acid-doped polyaniline conductive particles in a polyamide solution.

[0009] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0010] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0011] (1) Disperse inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in acidic solvent and let stand for a period of time to obtain monomer mixed solution; specifically, let stand for 1-2 hours to promote the formation of hydrogen bonds between aniline monomer and epoxy group silane coupling agent.

[0012] (2) Dissolve the polyamide in the monomer mixture solution by stirring to obtain a polyamide mixture solution;

[0013] (3) Add the initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain a polyaniline modified polyamide solution;

[0014] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain an antistatic aerogel for 3D printing. Freeze-drying is a simple, economical, and environmentally friendly drying method. It utilizes the principle of ice crystal sublimation, lowering the solvent temperature below the freezing point to convert water into ice. Then, under a high vacuum, the ice is directly sublimated into vapor, eliminating the gas-liquid interface, preventing the formation of curved liquid surfaces within the pores, thereby reducing drying stress and obtaining an aerogel with a complete skeleton. In particular, after the reaction is complete, appropriate heating can be performed to promote the dispersion of components before freeze-drying.

[0015] The reason polyamide was chosen as the matrix resin for the antistatic aerogel used in 3D printing is that the structural differences between polymers directly reflect their compatibility. Polyurethane is a block polymer with urethane bonds as repeating units, while the characteristic group in polyamide is the amide bond. Urethane and amide bonds have similar structures and can act as hydrogen bond donors and acceptors for each other. Therefore, structurally, polyurethane and polyamide have good compatibility. Polyurethane and polyamide also have their own performance advantages. Due to the presence of microphase separation, polyurethane possesses unique properties such as high tensile strength, high elongation at break, good wear resistance, and low-temperature elasticity. Polyamide has good mechanical, electrical, and thermal properties and exhibits high temperature resistance. Both polyurethane and polyamide can be used as a second component to improve each other's properties. Furthermore, polyamide typically has a high melting point (generally above 240°C) and high tensile strength. Using polyamide as the matrix structure of the aerogel can improve the mechanical properties of the aerogel, thereby increasing the mechanical strength of the polyurethane composite material. More importantly, compared to thermoplastic resins such as polyimide and polyurethane, polyamide is readily soluble in acidic solvents. Intrinsic polyaniline and its derivatives are electrical insulators with low conductivity; however, after protonic acid doping, their conductivity can increase by ten orders of magnitude. The doping process of polyaniline is reversible. When polyaniline is doped with protonic acid, only a positive charge is introduced; the number of electrons in its main chain is not changed, meaning only proton transfer occurs. Essentially, it is an intramolecular redox reaction, and the electronic structure undergoes significant changes. During doping, the imine groups on the molecular chain form hemiketone radical cations with the protonic acid, and simultaneously, through electron transfer from nitrogen atoms, a conductive bipolar sublattice is formed, giving polyaniline conductivity. This invention polymerizes polyaniline in situ in an acidic polyamide solution, cleverly utilizing the acidic solvent in the polyamide solution directly to dope polyaniline. This not only simplifies the production process but also ensures that the acid-doped polyaniline is uniformly dispersed in the polyamide matrix.

[0016] However, polyaniline synthesized by directly adding aniline monomer to a polyamic acid solution exhibits poor dispersibility and struggles to form conductive pathways. To ensure uniform dispersion of polyaniline within the polyamide aerogel network, this invention introduces inorganic nanoparticles modified with epoxy-group silane coupling agents as nucleating agents for polyaniline. Furthermore, as rigid particles, these epoxy-group silane coupling agents-modified inorganic nanoparticles can provide reinforcement, improving the mechanical properties of the polyamide-based aerogel powder. The epoxy groups on the surface of the epoxy-group silane coupling agent-modified inorganic nanoparticles readily form hydrogen bonds with the amino groups on the aniline monomer. Upon the addition of an initiator, the aniline monomer uses these epoxy-group silane coupling agent-modified inorganic nanoparticles as nuclei to form polyaniline-coated inorganic nanoparticles. These polyaniline-modified inorganic nanoparticles, formed by in-situ polymerization in a polyamic acid solution, combine the effects of doping, reinforcement, and conductivity: First, the polyamide dissolved in the acid solution acts as the matrix resin of the aerogel, serving as a framework; second, the acid in the polyamide solution not only dissolves the polyamide but also dopes the polyaniline, improving its conductivity; and third, the inorganic nanoparticles modified with epoxy-containing silane coupling agents not only provide rigid particle reinforcement but, more importantly, act as nucleating agents for aniline monomers, forming core-shell structured polyaniline nanoparticles in situ in the polyamide solution. This improves the dispersion properties of polyaniline, promotes the formation of conductive pathways, and significantly increases the conductivity of the aerogel with relatively little conductive filler. Conversely, polyaniline on the surface of inorganic particles not only enhances conductivity, but also has good compatibility with polyurethane and polyamide, which are all nitrogen-containing organic compounds. Coating inorganic nanoparticles with polyaniline can improve the compatibility between inorganic nanoparticles and resins such as polyamide and polyurethane, thereby improving dispersion and mechanical properties.

[0017] It is important to note the order of adding the epoxy-group silane coupling agent-modified inorganic nanoparticles and aniline monomers. Specifically, an acidic solution of the epoxy-group silane coupling agent-modified inorganic nanoparticles and aniline monomers should be prepared first, followed by the addition of polyamide to the acidic solution, allowing the polyamide to gradually dissolve. If the epoxy-group silane coupling agent-modified inorganic nanoparticles and aniline monomers are directly added to the acidic polyamide solution, the presence of nitrogen-containing groups in the polyamide will affect the nucleation of the epoxy-group silane coupling agent-modified inorganic nanoparticles, hindering the formation of an organic-inorganic core-shell structure.

[0018] In one embodiment, the epoxy-containing silane coupling agent in step (1) is at least one of γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropyltriethoxysilane, γ-glycidyl etheroxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Compared to amino-containing silane coupling agents, the epoxy group contains a highly active oxygen-containing ether bond, which can form hydrogen bonds with the amino group on the aniline monomer, forming a stronger bonding effect, enabling the inorganic nanoparticles to play a nucleation role, unaffected by the nitrogen-containing polymer polyamide in the formic acid solution. In contrast, the amino group on the silane coupling agent lacks an oxygen-containing active functional group, making it difficult to form hydrogen bonds or other bonding effects with the aniline monomer, which also contains an amino group. Furthermore, it is easily affected by polyamide in solution, and can only improve the compatibility between the inorganic nanoparticles and the matrix resin, without playing a nucleation role.

[0019] In one embodiment, the inorganic nanoparticles in step (1) are at least one of nano-silica, nano-zirconium dioxide, nano-silicon carbide, nano-silicon nitride, and nano-boron carbide.

[0020] In one embodiment, the inorganic nanoparticles have a particle size of 10-100 nm. Specifically, they can be any value of 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm. Inorganic nanoparticles with suitable particle size can simultaneously perform nucleation, dispersion, and reinforcement functions, thereby improving the mechanical properties of 3D printed antistatic materials.

[0021] In one embodiment, the acidic solvent is a formic acid solution. Specifically, an 88 wt% aqueous formic acid solution can be used.

[0022] In one embodiment, the mass ratio of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent to the aniline monomer in step (1) is (0.05-0.5):1. The modified inorganic nanoparticles are rich in epoxy groups on their surface, which readily form hydrogen bonds with the amino groups on the aniline monomer, thus enhancing the nucleation effect of the inorganic nanoparticles. Specifically, the mass ratio of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent to the aniline monomer is (0.05-0.4):1; further, (0.1-0.35):1; and even further, (0.1-0.3):1. An appropriate amount of inorganic nanoparticles can both provide rigid particle reinforcement and nucleation, while avoiding the problems of excessive particle aggregation and incomplete coating of polyaniline. This promotes the formation of the polyaniline core-shell structure and improves the compatibility between the inorganic nanoparticles and the polyamide resin.

[0023] In one embodiment, the specific preparation process of the inorganic nanoparticles modified with epoxy group silane coupling agent in step (1) is as follows: the epoxy group silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 40-60℃ for 1-2 hours, filtered, washed and dried to obtain the inorganic nanoparticles modified with epoxy group silane coupling agent.

[0024] In one embodiment, the mass ratio of the epoxy group-containing silane coupling agent and the inorganic nanoparticles in step (1) is (0.5-1):1.

[0025] In one embodiment, the polyamide in step (2) is at least one of polyamide 6, polyamide 66, polyamide 46, polyamide 56, polyamide 610, polyamide 1010, and polyamide 12.

[0026] In one embodiment, the polyamide concentration in the polyamide mixed solution in step (2), i.e., the ratio of polyamide mass to solvent mass, is 1-10 wt%.

[0027] In one embodiment, the mass ratio of aniline monomer to polyamide in step (2) is (0.2-0.8):1. Specifically, it can be any value among 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, or 0.8:1. Insufficient polyaniline monomer content hinders the formation of conductive pathways and results in poor antistatic properties; excessive content can negatively impact the aerogel structure and impede the improvement of the mechanical properties of the 3D printed product.

[0028] In one embodiment, the initiator in step (3) is at least one of ammonium persulfate and potassium persulfate; specifically, the initiator is added dropwise in the form of an aqueous solution.

[0029] In one embodiment, the molar ratio of the initiator to the aniline monomer in step (3) is (0.1-1):1.

[0030] In one embodiment, the reaction temperature in step (3) is 0-5°C and the reaction time is 10-20h.

[0031] On the other hand, the present invention also provides an antistatic aerogel for 3D printing prepared by the above method. This material is an aerogel material with a three-dimensional porous structure. Using this aerogel material as a reinforcement and antistatic filler for 3D printing resin materials such as polyurethane can improve the mechanical properties and antistatic ability of printed products.

[0032] Furthermore, this invention also provides an application of the aforementioned antistatic aerogel for 3D printing and a 3D printing polyurethane material prepared from it. The antistatic aerogel for 3D printing can be used in photopolymerization, selective laser sintering, fused deposition modeling (FDM), or layered solid fabrication technologies in 3D printing. Specifically, the 3D printing polyurethane material comprises polyurethane resin material and the antistatic aerogel for 3D printing. Further, photopolymerization or FDM can be employed. In particular, FDM is used to prepare the polyurethane material. The printing temperature in FDM is not particularly limited, generally between 190-220°C, and can be adjusted according to the production process.

[0033] The synthesis of the antistatic aerogel for 3D printing in this invention first involves effective control of the geometric parameters (particle size and particle size distribution), spatial distribution parameters (uniformity), and volume fraction (content) of the polyaniline nanoparticles in the composite system. In particular, by controlling the synthesis conditions, it is ensured that the polyaniline particles in the system are at least in the nanoscale range in one dimension (i.e., controlling the primary structure of the nanoparticles). Secondly, it involves the control of the secondary structure of the nanoparticle aggregates, which includes the control of the aggregation of modified polyaniline nanoparticles and the distribution of nanoparticles in the polyamide matrix resin material. This allows for the formation of good conductive pathways with a small amount of polyaniline added, thereby improving the antistatic properties of the antistatic aerogel for 3D printing.

[0034] Beneficial effects:

[0035] This invention involves the in-situ polymerization of polyaniline in an acidic polyamide solution. It cleverly utilizes the acidic solvent in the polyamide solution to directly dope the polyaniline, simplifying the production process and ensuring uniform dispersion of the acid-doped polyaniline within the polyamide matrix. This invention introduces inorganic nanoparticles modified with epoxy-containing silane coupling agents as nucleating agents for polyaniline and as rigid particle reinforcing agents for polyamide-based aerogel powders. These epoxy-containing silane coupling agent-modified inorganic nanoparticles act as nucleating agents for aniline monomers, forming core-shell structured polyaniline nanoparticles in situ within the polyamide solution. This improves the dispersion properties of polyaniline, promotes the formation of conductive pathways, and significantly enhances the conductivity of the aerogel with a smaller amount of conductive filler. By controlling the aggregation of modified polyaniline nanoparticles and the distribution of nanoparticles in the polyamide matrix resin material, good conductive pathways are formed with a smaller amount of polyaniline added, improving the antistatic properties of antistatic aerogels for 3D printing. Attached Figure Description

[0036] Figure 1 A scanning electron microscope image of the antistatic aerogel for 3D printing prepared in Example 10;

[0037] Figure 2Transmission electron microscope image of particles obtained by acid dissolution of the antistatic aerogel for 3D printing prepared in Example 10;

[0038] Figure 3 Transmission electron microscopy (TEM) image of particles obtained by acid dissolution of the antistatic aerogel prepared for 3D printing as Comparative Example 1.

[0039] in, Figure 2 and Figure 3 The specific preparation method of the particles described in the article is as follows: the antistatic aerogel for 3D printing prepared in Example 10 and Comparative Example 1 is re-dissolved by ultrasonication and dispersed in formic acid solution, and the precipitate is obtained after filtration; then it is washed with a large amount of deionized water to obtain an aqueous dispersion of the precipitate; the precipitate is separated by centrifugation, and since silica has a high density, it settles at the bottom; the bottom precipitate is dried to obtain the particles. Detailed Implementation

[0040] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0041] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0042] Example 1

[0043] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0044] (1) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain monomer mixed solution; the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is 0.1:1;

[0045] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 40°C for 2 hours, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 0.5:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 50 nm.

[0046] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.2:1;

[0047] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.6:1; the reaction temperature is 0℃ and the reaction time is 13h.

[0048] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0049] Example 2

[0050] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0051] (1) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain monomer mixed solution; the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is 0.35:1;

[0052] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 60°C for 1 hour, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 1:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltriethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 50 nm.

[0053] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.62:1;

[0054] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.9:1; the reaction temperature is 0℃ and the reaction time is 20h.

[0055] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0056] Example 3

[0057] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0058] (1) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain monomer mixed solution; the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is 0.05:1;

[0059] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 50°C for 1.6 h, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 0.8:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 40 nm.

[0060] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.48:1;

[0061] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.8:1; the reaction temperature is 0℃ and the reaction time is 17h.

[0062] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0063] Example 4

[0064] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0065] (1) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain monomer mixed solution; the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is 0.12:1;

[0066] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 48°C for 1.6 h, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 1:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltriethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 35 nm.

[0067] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.58:1;

[0068] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.9:1; the reaction temperature is 0℃ and the reaction time is 10h.

[0069] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0070] Example 5

[0071] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0072] (1) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain monomer mixed solution; the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is 0.5:1;

[0073] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 50°C for 1.6 h, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 0.8:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 40 nm.

[0074] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.48:1;

[0075] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.8:1; the reaction temperature is 0℃ and the reaction time is 17h.

[0076] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0077] Example 6

[0078] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0079] (1) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain monomer mixed solution; the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is 0.17:1;

[0080] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 45°C for 1.7 h, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 0.6:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltriethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 40 nm.

[0081] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.4:1;

[0082] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.7:1; the reaction temperature is 0℃ and the reaction time is 15h.

[0083] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0084] Example 7

[0085] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0086] (1) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain monomer mixed solution; the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is 0.2:1;

[0087] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 50°C for 1.6 h, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 0.8:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 40 nm.

[0088] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.8:1;

[0089] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.8:1; the reaction temperature is 0℃ and the reaction time is 17h.

[0090] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0091] Example 8

[0092] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0093] (1) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain monomer mixed solution; the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is 0.25:1;

[0094] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 55°C for 1.3 h, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 0.8:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 50 nm.

[0095] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.55:1;

[0096] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.7:1; the reaction temperature is 0℃ and the reaction time is 17h.

[0097] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0098] Example 9

[0099] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0100] (1) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain monomer mixed solution; the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is 0.3:1;

[0101] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 47°C for 1.4 h, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 0.7:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltriethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 60 nm.

[0102] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.43:1;

[0103] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.7:1; the reaction temperature is 0℃ and the reaction time is 19h.

[0104] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0105] Example 10

[0106] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0107] (1) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain monomer mixed solution; the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is 0.2:1;

[0108] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 50°C for 1.6 h, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 0.8:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 40 nm.

[0109] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.48:1;

[0110] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.8:1; the reaction temperature is 0℃ and the reaction time is 17h.

[0111] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0112] Comparative Example 1

[0113] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0114] (1) After stirring and dispersing the inorganic nanoparticles modified with amino-group silane coupling agent and aniline monomer in formic acid solvent, let stand for 1.5 h to obtain a monomer mixed solution; the mass ratio of the inorganic nanoparticles modified with amino-group silane coupling agent to aniline monomer is 0.2:1;

[0115] The specific preparation process of the inorganic nanoparticles modified with the amino-group silane coupling agent is as follows: the amino-group silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 50°C for 1.6 h, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the amino-group silane coupling agent; the mass ratio of the amino-group silane coupling agent to the inorganic nanoparticles is 0.8:1; the amino-group silane coupling agent is γ-aminopropyltriethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 40 nm.

[0116] (2) The polyamide was stirred and dissolved in the monomer mixture solution to obtain a polyamide mixture solution; the polyamide was polyamide 66; the polyamide concentration in the polyamide mixture solution was 3.5 wt%; the mass ratio of aniline monomer to polyamide was 0.48:1;

[0117] (3) Add ammonium persulfate initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.8:1; the reaction temperature is 0℃ and the reaction time is 17h.

[0118] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0119] Comparative Example 2

[0120] A method for preparing antistatic aerogel for 3D printing includes the following steps:

[0121] (1) The polyamide was dissolved in formic acid solvent by stirring to obtain a polyamide mixed solution; the polyamide was polyamide 66; the concentration of polyamide in the polyamide mixed solution was 3.5 wt%;

[0122] (2) After stirring and dispersing the inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer in a polyamide mixed solution, the mixture was allowed to stand for 1.5 h to obtain a monomer mixed solution; the mass ratio of the inorganic nanoparticles modified with epoxy group silane coupling agent to the aniline monomer was 0.2:1; the mass ratio of the aniline monomer to the polyamide was 0.48:1;

[0123] The specific preparation process of the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent is as follows: the epoxy group-containing silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 50°C for 1.6 h, filtered, washed, and dried to obtain the inorganic nanoparticles modified with the epoxy group-containing silane coupling agent; the mass ratio of the epoxy group-containing silane coupling agent to the inorganic nanoparticles is 0.8:1; the epoxy group-containing silane coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane; the inorganic nanoparticles are nano-silica; the volume average particle size D50 of the inorganic nanoparticles is 40 nm.

[0124] (3) Add the ammonium persulfate initiator dropwise to the monomer mixture solution and stir for a certain time to obtain a polyaniline modified polyamide solution; the molar ratio of initiator to aniline monomer is 0.8:1; the reaction temperature is 0℃ and the reaction time is 17h.

[0125] (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing.

[0126] The performance testing method for the aerogel materials prepared in the above embodiments and comparative examples is as follows: under the same conditions, the effect of the antistatic aerogels for 3D printing prepared in Examples 1-10 and Comparative Examples 1-2 on the performance of 3D printed polyurethane products is tested.

[0127] Specifically, the 3D printing polyurethane material comprises 100 parts thermoplastic polyurethane, 15 parts antistatic aerogel for 3D printing, and 3 parts zinc stearate. The 3D printing polyurethane material was printed into specimens, and the tensile strength of the specimens was tested according to GB / T528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". The conductivity was tested using a conductivity meter. The results are shown in Table 1.

[0128] Table 1. Performance of 3D printed polyurethane products corresponding to Examples 1-10 and Comparative Examples 1-2.

[0129]

[0130] Continued from Table 1

[0131]

[0132] Figure 1 The image shows a scanning electron microscope (SEM) image of the antistatic aerogel for 3D printing prepared in Example 10. As can be seen from the image, the aerogel has a rich porous structure with relatively uniform pore size, which is beneficial for the melting and impregnation of thermoplastic resins such as polyurethane, and improves the compatibility and interfacial interaction between the aerogel and the 3D printing matrix resin.

[0133] Figure 2The image shows a transmission electron microscope (TEM) image of the particles obtained by acid dissolution of the antistatic aerogel for 3D printing prepared in Example 10. As can be seen from the image, polyaniline is uniformly coated on the surface of the dense silica particles, which not only provides conductivity but also acts as a surface modifier for the inorganic nanoparticles, improving the compatibility between the inorganic nanoparticles and the organic polyamide resin, enhancing the stability of the aerogel, and improving the mechanical properties of the 3D printing material.

[0134] Figure 3 Transmission electron microscopy (TEM) images of particles obtained by acid dissolution of the antistatic aerogel prepared for 3D printing as Comparative Example 1. Figure 3 It can be seen that the surface of the inorganic nanoparticles is relatively smooth and there is no obvious coating layer, indicating that polyaniline did not undergo a polymerization reaction on the surface of the inorganic nanoparticles and did not form a core-shell structure.

[0135] Furthermore, as shown in Table 1, this invention ingeniously utilizes the acidic solvent in the polyamide solution to directly dope polyaniline, simplifying the production process and ensuring uniform dispersion of acid-doped polyaniline within the polyamide matrix. This invention introduces inorganic nanoparticles modified with epoxy-containing silane coupling agents as nucleating agents for polyaniline and as rigid particle reinforcing agents for polyamide-based aerogel powders. These epoxy-containing silane coupling agents, acting as nucleating agents for aniline monomers, form core-shell structured polyaniline nanoparticles in situ within the polyamide solution, improving the dispersion properties of polyaniline and promoting the formation of conductive pathways. This significantly enhances the conductivity of the aerogel with a smaller amount of conductive filler. By controlling the aggregation of modified polyaniline nanoparticles and the distribution of nanoparticles in the polyamide matrix resin material, a good conductive pathway is formed with a smaller amount of polyaniline added, improving the antistatic properties of the antistatic aerogel for 3D printing.

[0136] Specifically, compared to Example 10, Comparative Example 1 used an amino-containing silane coupling agent to modify nano-silica. In formic acid solution, the amino groups on the silane coupling agent cannot form strong bonds with aniline monomers, and the inorganic nanoparticles cannot act as nucleating agents; they can only act as inorganic fillers. Polyaniline also simply acts as a conductive filler, and cannot enable polyaniline and inorganic nanoparticles to exert synergistic reinforcement and antistatic effects.

[0137] Compared to Example 10, in Comparative Example 2, polyamide was dissolved in an acidic solvent beforehand, and then inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomer were added to the acidic solution of polyamide. Due to the nitrogen-containing groups in polyamide and the high viscosity of the polymer, the inorganic nanoparticles modified with epoxy group silane coupling agent were not conducive to nucleation, resulting in poor dispersion of inorganic nanoparticles. As a result, polyaniline could not form a stable conductive network, leading to a reduction in the conductivity and mechanical properties of the 3D printed product.

[0138] The above description is merely a preferred embodiment of the invention and is not intended to limit the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should be considered within the technical scope of this invention.

Claims

1. A method for preparing antistatic aerogel for 3D printing, characterized in that, Includes the following steps: (1) Inorganic nanoparticles modified with epoxy group silane coupling agent and aniline monomers are dispersed in acidic solvent and allowed to stand for a period of time to obtain monomer mixed solution; (2) Dissolve the polyamide in the monomer mixture solution by stirring to obtain a polyamide mixture solution; (3) Add the initiator dropwise to the polyamide mixed solution and stir for a certain time to obtain a polyaniline modified polyamide solution; (4) Freeze-dry the polyaniline-modified polyamide solution to obtain the antistatic aerogel for 3D printing; In step (1), the mass ratio of inorganic nanoparticles modified with epoxy group silane coupling agent to aniline monomer is (0.05-0.5):1; In step (2), the mass ratio of aniline monomer to polyamide is (0.2-0.8):

1.

2. The method for preparing an antistatic aerogel for 3D printing as described in claim 1, characterized in that, The epoxy group-containing silane coupling agent in step (1) is at least one of γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropyltriethoxysilane, γ-glycidyl etheroxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

3. The method for preparing an antistatic aerogel for 3D printing as described in claim 1, characterized in that, In step (1), the inorganic nanoparticles are at least one of nano-silica, nano-zirconium dioxide, nano-silicon carbide, nano-silicon nitride, and nano-boron carbide; the particle size of the inorganic nanoparticles is 10-100 nm.

4. The method for preparing an antistatic aerogel for 3D printing as described in claim 1, characterized in that, The specific preparation process of the inorganic nanoparticles modified with epoxy group silane coupling agent in step (1) is as follows: the epoxy group silane coupling agent and inorganic nanoparticles are uniformly dispersed in a mixed solvent of ethanol and deionized water, stirred at 40-60℃ for 1-2 hours, filtered, washed and dried to obtain the inorganic nanoparticles modified with epoxy group silane coupling agent.

5. The method for preparing an antistatic aerogel for 3D printing as described in claim 1, characterized in that, In step (3), the initiator is at least one of ammonium persulfate and potassium persulfate.

6. An antistatic aerogel for 3D printing, characterized in that, It is prepared by the method of any one of claims 1-5 for preparing an antistatic aerogel for 3D printing.

7. An application of the antistatic aerogel for 3D printing as described in claim 6, characterized in that, The antistatic aerogel for 3D printing is used in photopolymerization, selective laser sintering, fused deposition modeling, or layered solid manufacturing technologies in 3D printing.

8. A 3D printing polyurethane material, characterized in that, It comprises a polyurethane resin material and an antistatic aerogel for 3D printing; the antistatic aerogel for 3D printing is the antistatic aerogel for 3D printing as described in claim 6.

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