3D printing high polymer material with microwave-assisted rapid repairing and self-healing functions and application of 3D printing high polymer material

Abstract

The invention discloses a 3D printing high polymer material with microwave-assisted repairing and self-healing functions and application of the 3D printing high polymer material. The preparation method comprises the following steps: organically modifying a spiral carbon nanotube material, compounding with a thermoplastic high polymer material, and carrying out melt extrusion to obtain the 3D printing high polymer material. The material is subjected to fused deposition modeling and then subjected to microwave irradiation treatment, and an FDM 3D printing product with excellent interlayer performance is obtained. According to the invention, the helical carbon nanotube material not only improves the interfacial interaction with the thermoplastic polymer through organic modification and a helical structure, and improves the strength and modulus of the thermoplastic polymer material, but also has chiral parameters and the capability of generating cross polarization through structural chirality; through microwave irradiation treatment, the spiral carbon nanotube material absorbs microwaves to generate instant heat, so that the thermoplastic high polymer material is softened, interlayer defects caused by FDM printing are repaired, and the performance of a thermoplastic high polymer FDM 3D printing product is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of 3D printing materials, and particularly relates to a 3D printing polymer material with microwave-assisted rapid repair and self-healing and application thereof. BACKGROUND

[0002] Fused deposition modeling (FDM) has become a mainstream 3D printing technology due to its low cost and high material adaptability, and plays an important role in the field of industrial manufacturing. However, the interlayer performance defects of FDM products have always been the core problem restricting its development. Due to the difference in interlayer cooling rate and the insufficient compatibility of material interface, the interlayer shear strength of the printed part is usually only 40%-60% of that of homogeneous injection molded parts, which limits its application in high-precision and high-load scenarios.

[0003] At present, there are many methods for improving the interlayer performance of FDM formed products. For example, patent CN 112480450B adds functional monomers to 3D printing, and activates these functional monomers to improve the interlayer performance of 3D printed products. Patent application CN 115008738 A discloses a method of printing a thin tough adhesive film between layers, which forms a multi-phase reinforced interface through thermal fusion and interfacial solidification with the upper and lower layers, thereby improving the interlayer performance of 3D printed products. Patent CN 114834034B improves the 3D printing equipment, realizes the controllable distribution of functional reinforcing materials such as fibers in the direction of 3D printed composite materials while printing layer by layer, and thereby improves the technical essential defects of weak interlayer bonding of 3D printing.

[0004] Although existing methods such as printing material formulation optimization, printing process and equipment improvement optimization can partially alleviate this problem, these methods have some shortcomings. Although printing material formulation optimization is simple to operate, the additional components in the formulation may affect other properties. Although printing process and equipment improvement optimization can maintain the original material performance, it has high parameter sensitivity, requires additional equipment and energy consumption, and has poor economic efficiency. These methods still have limitations. In the previous patent CN 112175224 B, the research and development team disclosed a method of adding TPU with ferroelectric fillers or conductive fillers, and improving the movement activity of high molecular chains in a short time through the introduction of microwave irradiation, thereby effectively promoting the interlayer force of 3D printed TPU shoe materials. However, the energy conversion efficiency of ferroelectric fillers or conductive fillers is still low, and the product still needs to be treated for 20s-60min, and the production efficiency is still low. At the same time, the long treatment time may cause structural deformation of the overall 3D printed product due to heating, thereby reducing the dimensional stability of the 3D printed product. SUMMARY

[0005] The application aims to provide a 3D printing polymer material with microwave-assisted rapid repair self-healing and application thereof.

[0006] The technical idea of the application is as follows: the helical carbon nanomaterials such as helical carbon nanotubes and helical carbon nanofibers have unique chiral parameters and the ability to cross-polarize through structural chirality, so they have excellent microwave absorption capacity and can convert microwave energy into heat in a short time to rapidly increase the temperature (Li, Y, et al. Carbon, 2025, 233, 119923.). Therefore, the helical carbon nanomaterials are compounded with thermoplastic polymer materials to prepare a 3D printing polymer material, which can improve the physical interaction with the polymer material and the stress load transmission efficiency through the helical structure, thereby improving the strength of the composite material. On the other hand, through microwave treatment, the helical carbon nanotube material absorbs microwave to generate instantaneous heat, which softens the thermoplastic polymer material, repairs the interlayer defects caused by FDM printing, and improves the mutual adhesion force between the printing layers, thereby improving the performance of the thermoplastic polymer FDM 3D printing product.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the application is:

[0008] A 3D printing polymer material with microwave-assisted repair self-healing, prepared from the following raw materials in mass fraction: 100 parts of thermoplastic polymer material, 0.5-15 parts of organic modified helical carbon nanotube material, 2-20 parts of filler, 0.1-10 parts of toughening agent, and 0.01-1 part of antioxidant.

[0009] The thermoplastic polymer material is one or a combination of several of thermoplastic polyurethane (TPU), thermoplastic polyester elastomer (TPEE), polylactic acid (PLA), nylon (PA), polyvinyl alcohol (PVA), polypropylene (PP), styrene-butadiene-acrylonitrile copolymer (ABS), and polycarbonate (PC).

[0010] The helical carbon nanotube material is one or both of helical carbon nanotubes and helical carbon nanofibers. The helical carbon nanotube material has a diameter of 10-5000 nm.

[0011] The organic modified helical carbon nanotube material is amino-modified helical carbon nanotube material, alkyl-modified helical carbon nanotube material, or carboxyl-modified helical carbon nanotube material.

[0012] The organic modification method of the organic modified helical carbon nanotubular material is as follows: helical carbon nanotubular material is added into a mixed solution of concentrated sulfuric acid (96wt%) and concentrated nitric acid (37wt%) with a volume ratio of 3:1, after stirring and reaction, suction filtration, drying at 95-105℃, obtaining oxidized helical carbon nanotubular material, then dispersing in an organic solvent, and adding an organic silicon coupling agent containing amino, alkyl or carboxyl, refluxing at 40-80℃ under stirring, filtering, drying, obtaining amino-modified helical carbon nanotubular material, alkyl-modified helical carbon nanotubular material or carboxyl-modified helical carbon nanotubular material.

[0013] Further, the use amount ratio of the helical carbon nanotubular material and the mixed solution of concentrated sulfuric acid and concentrated nitric acid is 3g:350-450mL, and the use amount ratio of the oxidized helical carbon nanotubular material, the organic silicon coupling agent containing amino, alkyl or carboxyl, and the organic solvent is 3g:0.45-0.55g:350-450mL.

[0014] The filler is one or a combination of several of talc, silica, chopped carbon fiber, alumina, calcium carbonate and silicon carbide.

[0015] The toughening agent is one or a combination of several of core-shell toughening particles, polyolefin elastomer, styrene-butadiene rubber, maleic anhydride grafted polymer, nitrile rubber, silicone rubber, phthalic acid ester and epoxy soybean oil.

[0016] The antioxidant is one or a combination of several of 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) s-triazine-2,4,6-(1H,3H,5H) trione or isocyanuric acid, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite and pentaerythritol diphosphite dioctadecyl ester.

[0017] The preparation method of the 3D printing high polymer material with microwave-assisted rapid repair and self-healing comprises the following steps: mixing a thermoplastic high polymer material, an organic modified helical carbon nanotubular material, a filler, a toughening agent and an antioxidant, and then performing extrusion and drawing in sequence to obtain the 3D printing high polymer material.

[0018] The extrusion is performed by using a double-screw extruder, the rotation speed of the double-screw extruder is 8-12rpm, and the three-stage temperature zones of the double-screw extruder are 160-220℃ (first zone and second zone), 170-240℃ (third zone, fourth zone and fifth zone) and 160-230℃ (sixth zone) in sequence.

[0019] The application discloses a preparation method of a 3D printing product with microwave-assisted self-repairing and self-healing, which comprises the following steps: forming a 3D printing polymer material into a printing sample through FDM printing, and performing microwave irradiation treatment on the printing sample to obtain a 3D printing product with high interlayer performance.

[0020] The microwave irradiation has a power of 23-2.6 GHz and an irradiation time of 3-20 s.

[0021] The method comprises the following steps: compounding the helical carbon nanotube material after organic treatment with a thermoplastic polymer material, preparing a polymer material, performing FDM printing forming on the polymer material, and performing microwave irradiation treatment to obtain a thermoplastic polymer FDM printing forming product with high strength and interlayer performance.

[0022] Compared with the prior art, the application has the following advantages:

[0023] 1. The helical carbon nanotube material is subjected to surface organic treatment, and the process is simple and mature, the production efficiency is high, the production can be scaled up, and the process is environmentally friendly. The compounding of the helical carbon nanotube material with the thermoplastic polymer material adopts a direct screw melting and blending method, and the operation is simple and the industrial production efficiency is high.

[0024] 2. The helical carbon nanotube material significantly reduces the shrinkage of the thermoplastic polymer material in the FDM forming process, improves the precision of the FDM forming, and improves the stress load transmission efficiency through chemical bonds and physical effects, thereby improving the strength of the thermoplastic polymer FDM forming product.

[0025] 3. The helical carbon nanotube material not only improves the interfacial interaction with the thermoplastic polymer through organic modification and helical structure, improves the stress load transmission efficiency, and thereby improves the strength and modulus of the thermoplastic polymer material, but also has a chiral parameter and a cross-polarization ability generated by structural chirality, so that the helical carbon nanotube material has excellent microwave absorption capacity. Therefore, through microwave irradiation treatment, the helical carbon nanotube material absorbs microwave to generate instantaneous heat, the thermoplastic polymer material is softened, the interlayer defects caused by FDM forming are repaired, and the mutual adhesion force between the printing layers is improved, so that the thermoplastic polymer FDM 3D printing product has good interlayer performance.

[0026] The scheme of the application not only retains the original characteristics of the FDM process, but also activates the self-healing ability of the material through external field energy, thereby providing a new idea for breaking through the interlayer performance bottleneck. Compared with the traditional method, the technology has high efficiency, economy and universality, and is expected to promote the further popularization of the FDM technology in the high-end manufacturing field. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1Microstructure images of helical carbon nanotubes (a) and aminated helical carbon nanotubes (b).

[0028] Figure 2 Infrared spectrograms of helical carbon nanotubes and aminated helical carbon nanotubes.

[0029] Figure 3 Cross-sectional SEM images of FDM printed samples of Example 2 before (a) and after (b) microwave irradiation.

[0030] Figure 4 is a comparison of the repair self-healing ability of the FDM printed products in Examples 1, 2 and Comparative Examples 1, 2 after being made scratches at different microwave irradiation times (0-20 s).

[0031] Figure 5 are the tensile property test results of the FDM printed products in Examples 1, 2, 3 and Comparative Examples 1, 2 before and after microwave irradiation. DETAILED DESCRIPTION

[0032] Example 1

[0033] 3 g of helical carbon nanotubes were added to 400 ml of a mixed solution of concentrated sulfuric acid (96 wt%) / concentrated nitric acid (37 wt%) with a volume ratio of 3:1, stirred for 6 h, then suction filtered, and dried at 100°C to obtain oxidized helical carbon nanotubes. 3 g of the oxidized helical carbon nanotubes were dispersed in 400 ml of a mixed solution of water-anhydrous ethanol with a volume ratio of 9:1, 0.5 g of γ-aminopropyltriethoxysilane was added dropwise, and after stirring for 6 h at 60°C, the mixture was filtered and dried to obtain aminated helical carbon nanotubes.

[0034] The TPU 100 parts, aminated helical carbon nanotubes 2 parts, calcium carbonate 5 parts, core-shell toughening particles MBS 3 parts, and tris(2,4-di-tert-butylphenyl) phosphite 0.2 parts were premixed in a high-speed mixer for 3 min. The premixed material was then fed into a co-rotating parallel twin-screw extruder from a feeder, melt-extruded at a screw speed of 15 r / min, and the temperature of each section of the extruder was 160-180°C, with the first and second sections at 160°C and the third, fourth, fifth and sixth sections at 180°C. The resulting filamentous 3D printing polymer material was wound into a bundle (partly cut into granules) and placed in a vacuum oven for drying for 8 h. The TPU composite material was formed by FDM 3D printing.

[0035] The FDM formed TPU composite material product was subjected to microwave irradiation under microwave conditions (2.45 GHz, irradiation time 15 s) to obtain a high-performance TPU FDM 3D printed product.

[0036] Example 2

[0037] Amino-functionalized helical carbon nanotubes were prepared by the method of Example 1.

[0038] TPU 100 parts, amino-functionalized helical carbon nanotubes 3 parts, calcium carbonate 5 parts, core-shell toughening particles MBS 3 parts, tris(2,4-di-tert-butylphenyl) phosphite 0.2 parts were premixed in a high-speed mixer for 3 min. Then the premixed material was added from a feeder into a co-rotating parallel twin-screw extruder, melt-extruded, with a screw speed of 15 r / min, and the temperature of each section of the extruder was 160-180°C, among which the first zone and the second zone were 160°C, the third zone, the fourth zone, and the fifth zone were 180°C, and the sixth zone was 160°C. A filamentous 3D printing polymer material was prepared, and after being wound into a bundle (partly cut into granules), it was placed in a vacuum oven for drying for 8 h. A TPU composite material was obtained by FDM 3D printing.

[0039] The FDM molded TPU composite material product was subjected to microwave irradiation under microwave conditions (2.45 GHz, irradiation time 15 s) to prepare a high-performance TPU FDM 3D printed product.

[0040] Example 3

[0041] Amino-functionalized helical carbon nanotubes were prepared by the method of Example 1.

[0042] PA6 100 parts, amino-functionalized helical carbon nanotubes 3 parts, calcium carbonate 5 parts, core-shell toughening particles MBS 3 parts, tris(2,4-di-tert-butylphenyl) phosphite 0.2 parts were premixed in a high-speed mixer for 3 min. Then the premixed material was added from a feeder into a co-rotating parallel twin-screw extruder, melt-extruded, with a screw speed of 15 r / min, and the temperature of each section of the extruder was 200-220°C, among which the first zone and the second zone were 210°C, the third zone, the fourth zone, and the fifth zone were 220°C, and the sixth zone was 200°C. A filamentous 3D printing polymer material was prepared, and after being wound into a bundle (partly cut into granules), it was placed in a vacuum oven for drying for 8 h. A PA6 composite material was obtained by FDM 3D printing.

[0043] The FDM molded PA6 composite material product was subjected to microwave irradiation under microwave conditions (2.45 GHz, irradiation time 15 s) to prepare a high-performance FDM 3D printed product.

[0044] Example 4

[0045] 3g of helical carbon nanotubes were added to 400ml of a 3:1 mixture of concentrated sulfuric acid (96wt%) and concentrated nitric acid (37wt%), and the mixture was stirred for 6 hours. The mixture was then filtered and dried at 100℃ to obtain oxidized helical carbon nanotubes. 3g of oxidized helical carbon nanotubes were dispersed in 400ml of a 9:1 mixture of water and anhydrous ethanol, and 0.5g of hexadecyltrimethoxysilane was added dropwise. After stirring at room temperature for 6 hours, the mixture was filtered, dried, and alkylated helical carbon nanotubes were prepared.

[0046] By weight, 100 parts of ABS, 3 parts of alkylated helical carbon nanotubes, 5 parts of calcium carbonate, 3 parts of nitrile rubber, and 0.2 parts of tris(2,4-di-tert-butylphenyl) phosphite were premixed in a high-speed mixer for 3 minutes. The premixed material was then fed into a co-rotating parallel twin-screw extruder for melt extrusion at a screw speed of 15 r / min. The extruder temperatures were maintained at 200–220 °C in each section, with zones 1 and 2 at 200 °C, zones 3, 4, and 5 at 210 °C, and zone 6 at 200 °C, to obtain filamentous 3D printing polymer material. This material was then wound into bundles (partially granulated) and dried in a vacuum oven for 8 hours. The resulting ABS composite material was then printed using an FDM 3D printer.

[0047] The ABS composite material products formed by FDM were subjected to microwave irradiation under microwave conditions (2.45 GHz, irradiation time of 15 s) to prepare high-performance ABS FDM 3D printed products.

[0048] Comparative Example 1

[0049] This comparative example provides a polymer material for TPU FDM printing and its 3D printed products. Except for the absence of aminated helical carbon nanotubes, the other components and conditions are the same as in Example 1.

[0050] Comparative Example 2

[0051] This comparative example provides a polymer material for TPU FDM printing and its 3D printed products, in which aminated carbon nanotubes are used instead of the aminated helical carbon nanotubes in Example 2, and the remaining components and conditions are the same as in Example 2.

[0052] Comparative Example 3

[0053] This comparative example provides PA6 FDM printing polymer material and its 3D printed products. Except for the absence of aminated helical carbon nanotubes, the other components and conditions are the same as in Example 3.

[0054] Figure 1 The images show the microstructures of helical carbon nanotubes (a) and aminated helical carbon nanotubes (b). It can be seen that the amination modification did not destroy the structure of the helical carbon nanotubes.

[0055] Figure 2 The infrared spectra of helical carbon nanotubes and aminated helical carbon nanotubes show that, after amination, nitrogen-containing groups such as carbonyl (-C=O) and amino (-NH2) are introduced onto the surface of the helical carbon nanotubes through chemical modification, resulting in new characteristic peaks in the infrared spectrum: 3300-3500 cm⁻¹. -1 A double peak of symmetric and asymmetric stretching vibrations of the NH bond appeared at 1630-1550 cm⁻¹. -1 An in-plane bending vibration peak of NH appeared at 1250-1020 cm⁻¹. -1 The presence of weak stretching vibration peaks of CN bonds indicates the effectiveness of the amination treatment.

[0056] Figure 3 The cross-sectional SEM images of the FDM-printed samples before (a) and after (b) microwave irradiation in Example 2 show that the internal defects of the FDM-molded TPU products were significantly reduced after microwave irradiation, demonstrating the self-healing ability of microwave irradiation-assisted repair.

[0057] The FDM printed articles in Examples 1 and 2 and Comparative Examples 1 and 2 were scratched with a scalpel to create scratches, and their self-healing ability was observed under different microwave irradiation times (0-20s). Figure 4 As shown, it can be observed that after 20 seconds of microwave irradiation, the scratches in Comparative Example 1 did not show significant change, indicating that the FDM printed product in Comparative Example 1 did not have self-healing ability under 20 seconds of irradiation. Comparative Example 2 added aminated carbon nanotubes, but after 20 seconds of microwave irradiation, the scratches showed some change, with localized self-healing, but the overall scratches remained, indicating that 20 seconds of irradiation was insufficient to achieve significant self-healing in the FDM printed product of Comparative Example 2. In Examples 1 and 2, it is evident that the scratches gradually healed with prolonged microwave irradiation time. The lower content of helical carbon nanotubes in Example 1 resulted in localized healing of the scratches, while the higher content in Example 2 led to near-complete healing of the scratches. Therefore, the above comparison confirms that helical carbon nanotubes have a more significant and effective self-healing effect on FDM printed products than ordinary carbon nanotubes.

[0058] The tensile properties of the FDM printed articles in Examples 1, 2, and 3 and Comparative Examples 1 and 2 before and after microwave irradiation were tested (according to GB / T 1040.2-2006 standard). Figure 5 As shown, it can be observed that the tensile strength and elongation at break of the printed products in Examples 1, 2, and 3 were significantly higher after microwave irradiation than before irradiation, indicating the effectiveness of microwave irradiation in repairing structural defects in FDM printed products.

[0059] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A 3D-printed polymer material with microwave-assisted self-healing properties, characterized in that, The raw materials for its preparation, by mass parts, include: 100 parts of thermoplastic polymer material, 0.5-15 parts of organic modified spiral carbon nanotube material, 2-20 parts of filler, 0.1-10 parts of toughening agent, and 0.01-1 parts of antioxidant. The organically modified spiral carbon nanotube material is an aminated, alkylated, or carboxylated spiral carbon nanotube material.

2. The 3D-printed polymer material with microwave-assisted self-healing properties according to claim 1, characterized in that, The organic modification method of the organic modified helical carbon nanotube material is as follows: The helical carbon nanotube material is added to a concentrated sulfuric acid / concentrated nitric acid mixed solution with a volume ratio of 3:

1. After stirring and reacting, the mixture is filtered and dried at 95~105°C to obtain oxidized helical carbon nanotube material. Then, it is dispersed in an organic solvent, and an organosilicon coupling agent containing amino, alkyl or carboxyl groups is added. The mixture is refluxed at 40~80°C with stirring, filtered, and dried to obtain aminated modified helical carbon nanotube material, alkylated modified helical carbon nanotube material or carboxylated modified helical carbon nanotube material.

3. A 3D-printed polymer material with microwave-assisted self-healing properties according to claim 2, characterized in that, The spiral carbon nanotube material is one or both of spiral carbon nanotubes and spiral carbon nanofibers, and the diameter of the spiral carbon nanotube material is 10 nm to 5000 nm.

4. A 3D-printed polymer material with microwave-assisted self-healing properties according to claim 2, characterized in that, The ratio of the spiral carbon nanotube material to the concentrated sulfuric acid / concentrated nitric acid mixed solution is 3g:350~450mL, and the ratio of the oxidized spiral carbon nanotube material, the organosilicon coupling agent containing amino, alkyl or carboxyl groups, and the organic solvent is 3g:0.45~0.55g:350~450mL.

5. The 3D-printed polymer material with microwave-assisted self-healing properties according to claim 1, characterized in that, The thermoplastic polymer material is one or a combination of several of the following: thermoplastic polyurethane, thermoplastic polyester elastomer, polylactic acid, nylon, polyvinyl alcohol, polypropylene, styrene-butadiene-acrylonitrile copolymer, and polycarbonate.

6. The 3D-printed polymer material with microwave-assisted self-healing repair according to claim 1, characterized in that, The filler is one or a combination of several of the following: talc, silica, chopped carbon fibers, alumina, calcium carbonate, and silicon carbide. The toughening agent is one or a combination of core-shell toughening particles, polyolefin elastomer, styrene-butadiene rubber, maleic anhydride graft polymer, nitrile rubber, silicone rubber, phthalate, and epoxidized soybean oil. The antioxidant is one or a combination of several of the following: 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)triazine-2,4,6-(1H,3H,5H)trione or isocyanuric acid, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)trione, tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, and pentaerythritol diphosphite bisoctadecyl ester.

7. A method for preparing a 3D-printed polymer material with microwave-assisted self-healing properties according to any one of claims 1 to 6, characterized in that, Thermoplastic polymer material, organic modified spiral carbon nanotube material, filler, toughening agent and antioxidant are mixed and then extruded and drawn into fibers in sequence to obtain 3D printing polymer material.

8. The method for preparing a microwave-assisted self-healing 3D-printed polymer material according to claim 7, characterized in that, The extrusion is carried out using a twin-screw extruder with a rotation speed of 8~12 rpm and three temperature zones of the twin-screw extruder of 160~220℃, 170~240℃ and 160~230℃ respectively.

9. A method for preparing a 3D printed product with microwave-assisted self-healing repair, characterized in that, The 3D printing polymer material is FDM printed to obtain a printed sample. The printed sample is then subjected to microwave irradiation to obtain a 3D printed product with high interlayer properties. The 3D printing polymer material is the 3D printing polymer material according to any one of claims 1 to 6 or the 3D printing polymer material obtained by the preparation method according to claim 7.

10. A method for preparing a 3D printed article with microwave-assisted self-healing repair according to claim 9, characterized in that, The microwave irradiation power is 2.3~2.6 GHz, and the irradiation time is 3~20s.

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