Thermoplastic polyamide elastomer capable of being used for fused deposition 3D printing foam molding and preparation method of thermoplastic polyamide elastomer

Abstract

The invention discloses a thermoplastic polyamide elastomer capable of being used for fused deposition 3D printing foam molding and a preparation method of the thermoplastic polyamide elastomer. The method comprises the following steps: adding a polyamide hard segment monomer, a polyether or polyester soft segment, an end-capping reagent, water and an antioxidant into a polymerization kettle, and stirring and mixing; introducing inert gas to replace air in the system, and heating to promote hydrolysis and ring opening of the polyamide hard segment monomer; heating to a higher temperature, releasing the pressure in the kettle to normal pressure, and pumping out small molecules such as water by using a vacuum pump; adding a catalyst after normal pressure is recovered, increasing the vacuum degree in the kettle, observing the current change in the kettle, stopping the reaction when the current rises and tends to stop, and drying and cooling after discharging to obtain the polymer. The thermoplastic polyamide elastomer disclosed by the invention is high in molecular weight and viscosity, good in interlayer cohesiveness and stable and smooth in extrusion when being used for FDM printing, and a finished product has good stability; and a foam sample obtained by supercritical CO2 foaming has the advantages of large cell density, uniform cell size and high foaming ratio.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, and specifically relates to a thermoplastic polyamide elastomer that can be used for fused deposition modeling (FDM) foaming and its preparation method. Background Technology

[0002] 3D printing, also known as additive manufacturing, is a revolutionary manufacturing technology that enables the rapid and flexible production of complex three-dimensional objects. Compared to traditional manufacturing processes, 3D printing offers disruptive advantages, achieving complex geometries that are difficult to manufacture using traditional methods. It demonstrates superior efficiency and flexibility, particularly in customized production and small-batch manufacturing, allowing for rapid response to market demands and flexible adjustments to product designs.

[0003] Depending on the forming method, 3D printing technology can be divided into three types: stereolithography (SLA), fused deposition modeling (FDM), and selective laser sintering (SLS). Among them, FDM has become the most common and widely used 3D printing technology due to its high cost-effectiveness and ease of operation. The FDM forming mechanism involves feeding thermoplastic material into the printer nozzle, heating the material to a molten state, and then precisely extruding it through the nozzle. The extruded molten material is deposited layer by layer on a heated bed or the previous layer of material along a preset path, forming a solid structure. After cooling, the final three-dimensional product is formed. The FDM forming mechanism dictates very high performance requirements for the printing material, requiring excellent mechanical properties, thermal properties, and melt strength to ensure stable melting, extrusion, and deposition during the forming process. Therefore, the types of materials that can be used in FDM are currently relatively limited, mainly consisting of several common thermoplastic materials such as PLA, ABS, and TPU. Thus, the printing material directly affects the mechanical properties, surface quality, and durability of the finished product.

[0004] Foamed materials, due to their unique porous structure, have become an ideal choice for lightweight, high-strength materials. By introducing gas into the material through physical methods or using chemical foaming agents, the gas forms bubbles within the material. These bubbles are distributed throughout the matrix, and as temperature and pressure increase, they expand, causing the material to expand and form a porous structure. This significantly reduces the material's density and usage while maintaining its mechanical properties. Foamed materials possess excellent toughness, thermal stability, energy absorption, and insulation properties, showing broad application prospects in automotive manufacturing, home appliances, electronics, and construction. However, producing foamed materials or components with complex geometries requires customized molds, which typically require high-precision machining and manufacturing, leading to increased costs. Therefore, combining FDM printing technology with traditional foaming technology holds great potential. This combination can significantly shorten product development cycles, rapidly manufacture complex structures, reduce reliance on expensive molds, and lower production costs.

[0005] Against this backdrop, thermoplastic polyamide elastomer (TPAE), as a novel thermoplastic elastomer (TPE) material, has shown broad application prospects. Although research on TPAE in the FDM field is relatively limited, its unique material properties demonstrate its potential in multiple areas. TPAE is composed of polyamide hard segments and polyester or polyether soft segments through block copolymerization. The polyamide hard segments, due to their high melting point or glass transition temperature, act as physical cross-linkers at room temperature, thus maintaining the material's solid-state properties; the polyester or polyether soft segments endow the material with excellent elasticity and toughness, giving TPAE superior mechanical properties, chemical resistance, abrasion resistance, low moisture absorption, and sound absorption. This unique molecular structure makes TPAE suitable for a wide range of potential applications in fields including medical devices, automotive manufacturing, sports equipment, and microelectronic devices. Therefore, researchers are dedicated to combining TPAE materials with FDM printing technology to explore its application prospects in these fields and promote the development of this new material in more practical applications.

[0006] The main synthesis methods for TPAE include the diacid method, the isocyanate method, and the anionic polymerization method. The diacid method is the most mature industrial production method due to its stable process, readily available raw materials, and ease of large-scale production. The diacid method is further divided into "one-step" and "two-step" methods. The "two-step" method typically divides the polymerization process into two stages: the first stage synthesizes a polyamide prepolymer, and the second stage involves esterification of the prepolymer with polyether or polyester to synthesize TPAE. However, the low compatibility between the polyamide prepolymer and polyether or polyester results in TPAE with low molecular weight and low viscosity. During FDM printing, this leads to problems such as unstable extrusion diameter, poor interlayer adhesion, and poor extrusion, severely affecting the performance and quality of the finished product and limiting its further development in the FDM field.

[0007] Furthermore, the melt strength of TPAE plays a crucial role in the preparation of foam materials. Higher melt strength allows for thorough mixing of the gas generated by the blowing agent with the polymer melt, promoting uniform foam formation. However, TPAE materials prepared using the "two-step method" have lower melt strength, resulting in insufficient support from the cell walls during foaming. This leads to cell rupture or collapse, reducing the foaming ratio and severely impacting cell uniformity and quality, ultimately resulting in poor-quality foam products. Therefore, increasing the molecular weight of TPAE and enhancing its viscosity and melt strength are key factors in improving its performance in FDM printing foam materials applications. This will help expand the application opportunities of TPAE in a wider range of fields and promote the integration of FDM and foaming technologies, opening up more opportunities for future industrial manufacturing and technological innovation. Summary of the Invention

[0008] The purpose of this invention is to provide a thermoplastic polyamide elastomer (TPAE) suitable for fused deposition modeling (FDM) 3D printing and its preparation method. This method is applicable to the preparation of TPAE using FDM and supercritical foaming, aiming to overcome the shortcomings of TPAE prepared by the "two-step method," such as low molecular weight, low viscosity, and low melt strength.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing thermoplastic polyamide elastomers that can be used for fused deposition modeling (FDM) foaming includes the following steps: (1) Add polyamide hard segment monomer, polyether or polyester soft segment, end capping agent, deionized water and antioxidant to the polymerization reactor in sequence, and start mechanical stirring; (2) Inert gas is introduced for 5-15 min to replace the air in the system, and the temperature is slowly heated to 140-180 °C and maintained for 10-60 min to promote the ring opening of the polyamide hard segment monomer; (3) Slowly heat to 230~260 ℃ and maintain this temperature for 1~4 hours; release the pressure inside the vessel to atmospheric pressure, use a vacuum pump to extract small molecules such as water, maintain the vacuum inside the vessel at 3~6 KPa, and maintain for 1~2 hours; (4) After restoring normal pressure, add catalyst and gradually increase the vacuum in the reactor to 0.5~2 KPa to remove small molecules in the reactor to promote the forward reaction. Observe the change of current in the reactor until the current rise tends to stop and stop the reaction. After discharge, dry and cool to obtain thermoplastic polyamide elastomer.

[0010] In step (1), the polyamide hard segment monomer is at least one of caprolactam, undecanolactam, dodecanolactam, hexamethylenediamine / adipate nylon salt, hexamethylenediamine / decanoic acid nylon salt, hexamethylenediamine / undecanoic acid nylon salt, hexamethylenediamine / dodecanoic acid nylon salt, decanediamine / decanoic acid nylon salt, decanediamine / undecanoic acid nylon salt, decanediamine / dodecanoic acid nylon salt, undecanodiamine / undecanoic acid nylon salt, undecanodiamine / dodecanoic acid nylon salt, and dodecanodiamine / dodecanoic acid nylon salt.

[0011] In step (1), the polyether or polyester soft segment is at least one of polytetrahydrofuran, polyethylene glycol, polypropylene glycol, polybutylene glycol, polycaprolactone diol, polyadipate diol, polycarbonate diol, and polycaprolactone polyether diol, with a molecular weight range of 600 to 2000.

[0012] Furthermore, the polyamide hard segment monomer accounts for 40-53% of the mass fraction of the thermoplastic polyamide elastomer, and the polyether or polyester soft segment accounts for 46-59% of the mass fraction of the thermoplastic polyamide elastomer.

[0013] In step (1), the capping agent is at least one of adipic acid, glutaric acid, azelaic acid, sebacic acid, undecanoic acid, and dodecanoic acid.

[0014] Furthermore, the molar ratio of the end-capping agent to the polyether or polyester soft segment is 1:1.

[0015] In step (1), the antioxidant is at least one of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 300.

[0016] Furthermore, the antioxidant accounts for 0.5-1% of the mass fraction of the thermoplastic polyamide elastomer.

[0017] In step (2), the inert gas is one of nitrogen, argon, or other gases.

[0018] In step (4), the catalyst is at least one of tetrabutyl titanate, tetraethyl titanate, diisobutyl titanate, dibutyl titanate, antimony acetate, and sodium antimonate.

[0019] Furthermore, the catalyst accounts for 0.05~0.5% of the mass fraction of the thermoplastic polyamide elastomer.

[0020] This invention employs a one-step method for the efficient synthesis of thermoplastic polyamide elastomers. By studying the effect of soft segment content on the structure and properties of TPA6Es, it adapts to foaming requirements. The prepared thermoplastic polyamide elastomer possesses significant advantages: (1) The molecular weight of TPAE is significantly increased, while maintaining excellent tensile strength and elongation at break, resulting in balanced mechanical properties.

[0021] (2) The viscosity of TPAE is greatly enhanced, which is suitable for the requirements of 3D printing (FDM) process. It has good extrusion stability and tight interlayer bonding during printing, and the final 3D printed product has a regular structure and stable dimensions.

[0022] (3) TPAE melt has high strength. When combined with supercritical CO2 foaming technology, it can effectively support the formation of cells and avoid cell rupture or collapse. The prepared foam sample has uniform cell distribution, high cell density, and significantly improved foaming ratio, resulting in excellent overall foaming performance. Attached Figure Description

[0023] Figure 1 This is the FTIR image of the TPAE prepared in Example 1.

[0024] Figure 2 These are mechanical property diagrams of TPAE prepared in Examples 1, 2, and 3.

[0025] Figure 3 This is a SEM image of the foamed TPAE sample prepared in Example 2.

[0026] Figure 4 This is a printed sample image of the TPAE prepared in Example 2 for FDM.

[0027] Figure 5 This is a sample obtained by foaming the TPAE prepared in Example 2 after FDM printing. Detailed Implementation

[0028] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0029] The chemical reagents used in the following examples or comparative examples, such as caprolactam, adipic acid, polytetrahydrofuran (molecular weight 1000), antioxidant 1010, and tetrabutyl titanate, were purchased from Shanghai Maclean Biotechnology Co., Ltd. Example 1

[0030] A method for preparing thermoplastic polyamide elastomers for fused deposition modeling (FDM) foaming. Add 50 g of caprolactam, 7.4 g of adipic acid, 50 g of polytetrahydrofuran (molecular weight 1000), 3 g of deionized water, and 0.5 g of antioxidant 1010 to a polymerization reactor. Purge with nitrogen for 10 min to replace the air in the system. Slowly raise the temperature to 160 ℃ and hold for 30 min. Gradually raise the temperature to 245 ℃ and hold for 2 h. Slowly release the pressure inside the reactor to atmospheric pressure, then use a vacuum pump to increase the vacuum inside the reactor, extract small molecules such as water, and maintain the vacuum inside the reactor at about 5 kPa for one hour. After restoring atmospheric pressure, add 0.05 g of tetrabutyl titanate and gradually reduce the pressure inside the reactor to 1 kPa, observing the change in current. After the current rise basically stops, restore atmospheric pressure and stop the reaction. After discharging, cool and dry to obtain a thermoplastic polyamide elastomer polymer.

[0031] Comparative Example 1 Add 50 g of caprolactam, 7.4 g of adipic acid, 3 g of deionized water, and 0.5 g of antioxidant 1010 to the polymerization reactor. Purge with nitrogen to replace the air in the system. Slowly raise the temperature to 160 °C and hold for 30 minutes. Gradually raise the temperature to 245 °C and hold for 2 hours. Slowly release the pressure inside the reactor to atmospheric pressure, then use a vacuum pump to increase the vacuum inside the reactor, extract small molecules such as water, and maintain the vacuum inside the reactor at about 5 kPa. Observe the change in current. After the current rise basically stops, restore atmospheric pressure and stop the reaction. After discharge, cool and dry to obtain the polymer. Example 2

[0032] A method for preparing thermoplastic polyamide elastomers for fused deposition modeling (FDM) foaming. Add 75 g of caprolactam, 15.5 g of adipic acid, 105 g of polytetrahydrofuran (molecular weight 1000), 3.5 g of deionized water, and 0.8 g of antioxidant 1010 to a polymerization reactor. Purge with nitrogen to replace the air in the system. Slowly raise the temperature to 160 °C and maintain it for one hour. Gradually raise the temperature to 245 °C and maintain it for 3 hours. Slowly release the pressure inside the reactor to atmospheric pressure, then use a vacuum pump to increase the vacuum inside the reactor, extract small molecules such as water, and maintain the vacuum inside the reactor at about 3 kPa for one hour. After restoring atmospheric pressure, add 0.1 g of tetrabutyl titanate and gradually reduce the pressure inside the reactor to 0.8 kPa, observing the change in current. After the current rise basically stops, restore atmospheric pressure and stop the reaction. After discharging, cool and dry to obtain a thermoplastic polyamide elastomer polymer. Example 3

[0033] A method for preparing thermoplastic polyamide elastomers for fused deposition modeling (FDM) foaming. Add 101 g of caprolactam, 26.7 g of adipic acid, 180 g of polytetrahydrofuran (molecular weight 1000), 3.5 g of deionized water, and 1 g of antioxidant 1010 to a polymerization reactor. Purge with nitrogen to replace the air in the system. Slowly raise the temperature to 160 °C and maintain it for one hour. Gradually raise the temperature to 245 °C and maintain it for 3 hours. Slowly release the pressure inside the reactor to atmospheric pressure, then use a vacuum pump to increase the vacuum inside the reactor, extract small molecules such as water, and maintain the vacuum inside the reactor at about 4 kPa for one hour. After restoring atmospheric pressure, add 0.2 g of tetrabutyl titanate and gradually reduce the pressure inside the reactor to 0.5 kPa, observing the change in current. After the current rise basically stops, restore atmospheric pressure and stop the reaction. After discharging, cool and dry to obtain a thermoplastic polyamide elastomer polymer. Example 4

[0034] A method for preparing thermoplastic polyamide elastomers for fused deposition modeling (FDM) foaming. Add 101 g of caprolactam, 6.6 g of adipic acid, 45.3 g of polytetrahydrofuran (molecular weight 1000), 3.5 g of deionized water, and 0.6 g of antioxidant 1010 to a polymerization reactor. Purge with nitrogen to replace the air in the system. Slowly raise the temperature to 160 °C and maintain it for one hour. Gradually raise the temperature to 245 °C and maintain it for 3 hours. Slowly release the pressure inside the reactor to atmospheric pressure, then use a vacuum pump to increase the vacuum level inside the reactor, extract small molecules such as water, and maintain the vacuum level inside the reactor at about 4 kPa for one hour. After restoring atmospheric pressure, add 0.45 g of tetrabutyl titanate and gradually reduce the pressure inside the reactor to 0.5 kPa, observing the change in current. After the current rise basically stops, restore atmospheric pressure and stop the reaction. After discharging, cool and dry to obtain a thermoplastic polyamide elastomer polymer. Example 5

[0035] A method for preparing thermoplastic polyamide elastomers for fused deposition modeling (FDM) foaming. Add 50.5 g of caprolactam, 20.6 g of adipic acid, 140 g of polytetrahydrofuran (molecular weight 1000), 3.5 g of deionized water, and 0.8 g of antioxidant 1010 to a polymerization reactor. Purge with nitrogen to replace the air in the system. Slowly raise the temperature to 170 °C and maintain it for one hour. Gradually raise the temperature to 245 °C and maintain it for 3 hours. Slowly release the pressure inside the reactor to atmospheric pressure, then use a vacuum pump to increase the vacuum inside the reactor, extract small molecules such as water, and maintain the vacuum inside the reactor at about 4 kPa for one hour. After restoring atmospheric pressure, add 1.0 g of tetrabutyl titanate and gradually reduce the pressure inside the reactor to 0.5 kPa, observing the change in current. After the current rise basically stops, restore atmospheric pressure and stop the reaction. After discharging, cool and dry to obtain a thermoplastic polyamide elastomer polymer. Example 6

[0036] A method for preparing thermoplastic polyamide elastomers for fused deposition modeling (FDM) foaming. Add 50.5 g of caprolactam, 14.7 g of adipic acid, 100 g of polytetrahydrofuran (molecular weight 1000), 3.5 g of deionized water, and 0.4 g of antioxidant 1010 to a polymerization reactor. Purge with nitrogen to replace the air in the system. Slowly raise the temperature to 170 °C and maintain it for one hour. Gradually raise the temperature to 245 °C and maintain it for 3 hours. Slowly release the pressure inside the reactor to atmospheric pressure, then use a vacuum pump to increase the vacuum inside the reactor, extract small molecules such as water, and maintain the vacuum inside the reactor at about 4 kPa for one hour. After restoring atmospheric pressure, add 0.05 g of tetrabutyl titanate and gradually reduce the pressure inside the reactor to 0.5 kPa, observing the change in current. After the current rise basically stops, restore atmospheric pressure and stop the reaction. After discharging, cool and dry to obtain a thermoplastic polyamide elastomer polymer.

[0037] Figure 1 These are the FTIR spectra of the TPAE prepared in Example 1 and the polyamide prepared in Comparative Example 1. It can be seen from the figures that at 3302 cm⁻¹... -1 The characteristic peak at 1642 cm⁻¹ is produced by the NH stretching vibration; while at 1642 cm⁻¹... -1 and 1541 cm -1 The characteristic peaks at the amide I and β bands indicate the presence of amide bonds in the block copolymer, and these peaks indicate the presence of polyamide hard segments in the polymer; at 1742 cm⁻¹ -1 An additional sharp peak appeared, which is the stretching vibration peak of the ester carbonyl group, indicating the formation of ester bonds and the occurrence of a polyesterification reaction during polymerization. This suggests that the polyether and polyamide in the system are not simply blended, but rather a chemical reaction has occurred to form a new polymer; at 1118 cm⁻¹ -1The vibrations are caused by the symmetrical stretching vibrations of the ether bonds in COC, indicating that the block copolymer possesses polyether soft segments. In conclusion, a polyamide thermoplastic elastomer has been successfully produced.

[0038] like Figure 2 As shown, the tensile strengths of the tapes prepared in Examples 1, 2, and 3 were (31.84 ± 0.67) MPa, (27.82 ± 0.59) MPa, and (23.04 ± 1.75) MPa, respectively, and the elongations at break were (775.4 ± 14.50)%, (864.14 ± 17.44)%, and (961.79 ± 35.96)%, respectively. Therefore, it can be inferred that the tensile elongation at break of TPAE increases with the increase of the soft segment content, while the tensile strength shows the opposite trend. This is because the soft segment polytetrahydrofuran (PTMG) molecular chain contains a large number of ether bonds, which makes the molecular chain easy to rotate. Therefore, the addition of PTMG enhances the mobility of the molecular chain, giving TPAE good flexibility, leading to a decrease in tensile strength and an increase in elongation at break.

[0039] Figure 3 The results show that the foamed pore morphology of the TAPE sample prepared in Example 2 is significantly improved. Under the same conditions, due to the lower content of hard segments in Example 2, the melting of hard segment crystals is beneficial to the dissolution of CO2 and the growth of pores. Therefore, more areas have the ability to form pores, resulting in larger and more uniform average pore size and thinner pore walls. In addition, the remaining unmelted crystals provide a certain strength to the pore walls to support the gas and prevent the foam from shrinking or collapsing.

[0040] Figure 4 and Figure 5 These are before-and-after comparison images of the TPAE sample prepared in Example 2. The unfoamed honeycomb structure has higher compressive strength and is suitable for applications requiring high strength, while the foamed structure is suitable for applications where the stress range that the object to be protected can withstand is relatively low. The foamed honeycomb structure exhibits higher energy absorption and efficiency under low stress, demonstrating better elasticity and fatigue resistance.

[0041] These results demonstrate that combining FDM printing with supercritical CO2 foaming technology can produce complex-structured foam materials with excellent properties. This invention, through systematic research and experimentation, successfully combines TPAE materials with 3D printing and microporous foaming technology. In the future, with the continuous development of 3D printing and supercritical CO2 foaming technologies, TPAE materials are expected to be widely used in more fields.

Claims

1. A method for preparing thermoplastic polyamide elastomers that can be used for fused deposition modeling (FDM) foaming, characterized in that, Includes the following steps: (1) Add polyamide hard segment monomer, polyether or polyester soft segment, end capping agent, water and antioxidant to the polymerization reactor in sequence, and stir to mix evenly; (2) Inert gas is introduced to replace the air in the system, and the temperature is heated to 140~180 ℃ and maintained for 10~60 min to promote the ring opening of polyamide hard segment monomers; (3) Heat to 230~260 ℃ and maintain the reaction at this temperature for 1~4 hours; release the pressure inside the vessel to atmospheric pressure, use a vacuum pump to extract small molecules, maintain the vacuum degree inside the vessel at 3~6 KPa, and maintain for 1~2 hours; (4) After restoring normal pressure, add catalyst and increase the vacuum in the reactor to 0.5~2 KPa to remove small molecules in the reactor to promote the forward reaction. Observe the change of current in the reactor until the current rise tends to stop and stop the reaction. After discharge, dry and cool to obtain thermoplastic polyamide elastomer.

2. The method for preparing a thermoplastic polyamide elastomer that can be used for fused deposition modeling (FDM) foaming according to claim 1, characterized in that, In step (1), the polyamide hard segment monomer is at least one of caprolactam, undecanolactam, dodecanolactam, hexamethylenediamine / adipate nylon salt, hexamethylenediamine / decanoic acid nylon salt, hexamethylenediamine / undecanoic acid nylon salt, hexamethylenediamine / dodecanoic acid nylon salt, decanediamine / decanoic acid nylon salt, decanediamine / undecanoic acid nylon salt, decanediamine / dodecanoic acid nylon salt, undecanodiamine / undecanoic acid nylon salt, undecanodiamine / dodecanoic acid nylon salt, and dodecanodiamine / dodecanoic acid nylon salt.

3. The method for preparing a thermoplastic polyamide elastomer that can be used for fused deposition modeling (FDM) foaming according to claim 1, characterized in that, In step (1), the polyether or polyester soft segment is at least one of polytetrahydrofuran, polyethylene glycol, polypropylene glycol, polybutylene glycol, polycaprolactone diol, polyadipate diol, polycarbonate diol, and polycaprolactone polyether diol.

4. The method for preparing a thermoplastic polyamide elastomer that can be used for fused deposition modeling (FDM) foaming according to claim 1, characterized in that, In step (1), the capping agent is at least one of adipic acid, glutaric acid, azelaic acid, sebacic acid, undecanoic acid, and dodecanoic acid.

5. The method for preparing a thermoplastic polyamide elastomer that can be used for fused deposition modeling (FDM) foaming according to claim 1, characterized in that, In step (1), the antioxidant is at least one of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 300.

6. The method for preparing a thermoplastic polyamide elastomer for fused deposition modeling (FDM) foaming according to claim 1, characterized in that, In step (2), the inert gas is nitrogen or argon, and the inert gas is introduced for 5 to 15 minutes.

7. The method for preparing a thermoplastic polyamide elastomer that can be used for fused deposition modeling (FDM) foaming according to claim 1, characterized in that, In step (4), the catalyst is at least one of tetrabutyl titanate, tetraethyl titanate, diisobutyl titanate, dibutyl titanate, antimony acetate, and sodium antimonate.

8. The method for preparing a thermoplastic polyamide elastomer that can be used for fused deposition modeling (FDM) foaming according to claim 1, characterized in that, The polyamide hard segment monomer accounts for 40-53% of the mass fraction of the thermoplastic polyamide elastomer, the polyether or polyester soft segment accounts for 46-59% of the mass fraction of the thermoplastic polyamide elastomer, the antioxidant accounts for 0.5-1% of the mass fraction of the thermoplastic polyamide elastomer, the catalyst accounts for 0.05-0.5% of the mass fraction of the thermoplastic polyamide elastomer, and the molar ratio of the end-capping agent to the polyether or polyester soft segment is 1:

1.

9. The thermoplastic polyamide elastomer prepared by the preparation method according to any one of claims 1-8.

10. The application of the thermoplastic polyamide elastomer as described in claim 9 in FDM and supercritical CO2 foaming.

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