Self-healing long-carbon-chain polyamide elastomer as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of novel materials, and particularly relates to a self-healing long-carbon-chain polyamide elastomer as well as a preparation method and application thereof. The preparation method of the long-carbon-chain polyamide elastomer comprises the following steps: jointly adding long-carbon-chain diamine, binary acid, binary acid containing diselenide bonds, a polyether soft segment and a catalyst into a reaction kettle, carrying out melt mixing, and then carrying out programmed temperature control, reaction process adjustment and molecular structure optimization to obtain the long-carbon-chain polyamide elastomer. According to the invention, binary acid containing diselenide bonds is adopted to regulate and control the molecular structure of a polyamide hard segment, the long-carbon-chain polyamide elastomer is prepared through a melt polycondensation one-pot process, and the elastomer is endowed with a self-healing function by dynamically reversible diselenide bonds and hydrogen bonds between molecular chains; furthermore, the flexible electronic skin prepared from the graphene has good conductivity, low temperature resistance and self-healing capability, and has great application prospects in the fields of wearable equipment, artificial intelligence, medical instruments and the like used in extreme environments.

Description

Technical Field

[0001] This invention belongs to the field of novel materials technology, specifically relating to a self-healing long-chain polyamide elastomer, its preparation method, and its applications. Background Technology

[0002] Polyamide elastomers (TPAEs) are thermoplastic elastomers with polyamide as the hard segment and polyether or polyester as the soft segment. Due to their excellent processability, mechanical properties, and extremely wide hardness range, polyamide elastomers are widely used in various fields, such as sports equipment, medical tubing, chip packaging, high-elasticity fibers, and high-precision separation membranes. Among them, long-chain polyamide elastomers have advantages such as low hardness, high elastic recovery rate, and high low-temperature impact strength, offering even broader application possibilities. For example, the development of self-healing long-chain polyamide elastomers, enabling them to recover and regain their original mechanical properties and functions after cracking, is of great significance for the development of biomimetic skin in the field of flexible electronics.

[0003] Currently, the mainstream market commonly uses a two-step method to prepare long-chain polyamide elastomers. This involves first developing long-chain polyamide hard segments with terminal carboxyl groups, and then esterifying them with different soft segments. By adjusting the structure and ratio of the hard and soft segments, a series of high-performance polyamide elastomers are formed. This preparation method is cumbersome, with difficult-to-control reaction conditions, requiring mid-process feeding at high temperatures, and is complex and potentially dangerous. The complex synthesis process has many uncontrollable factors, resulting in low production efficiency, and these products command high market prices. These technological challenges limit the development of long-chain polyamide elastomers. Furthermore, there is a lack of research on endowing long-chain polyamide elastomers with self-healing capabilities, and few products offer high elasticity, low hardness, and low-temperature resistance suitable for emerging industries such as flexible electronics and intelligent robotics. Summary of the Invention

[0004] One objective of this invention is to provide a method for preparing self-healing long-chain polyamide elastomers. This invention utilizes a one-pot melt polycondensation process to prepare long-chain polyamide elastomers, which shortens the process flow, improves production efficiency, and provides new ideas for the modification and functionalization of long-chain polyamide elastomers.

[0005] A second objective of this invention is to provide a self-healing long-chain polyamide elastomer. This long-chain polyamide elastomer is a polymer material possessing excellent elasticity, strength, toughness, and self-healing capabilities. It primarily utilizes diacids containing diselenoses to regulate the hard segment molecular structure of the polyamide, thereby not only endowing the elastomer with excellent self-healing properties but also increasing the flexibility and elasticity of the polyamide molecular chains.

[0006] The third objective of this invention is to provide the application of self-healing long-chain polyamide elastomers in the preparation of flexible electronic skin; MXene / polyamide elastomer-based flexible electronic films exhibit good conductivity, low-temperature resistance and self-healing ability, and have great application prospects in wearable devices, artificial intelligence and medical devices used in extreme environments.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a self-healing long-chain polyamide elastomer includes the following steps: Long-chain diamine, long-chain dicarboxylic acid, dicarboxylic acid containing diselenyl bonds, polyether soft segments, and catalyst are melt-mixed and then polymerized. The reaction is terminated by vacuuming to obtain long-chain polyamide elastomer.

[0008] Furthermore, the dicarboxylic acid containing a diseleno bond is 3,3-diselenodipropionic acid or 4,4'-diselenodibutyric acid.

[0009] This invention utilizes 3,3-diselenodipropionic acid or 4,4'-diselenodibutyric acid, both containing diselenobonds. These two diselenobond-containing diacarboxylic acids have low preparation costs, high reactivity, and more stable molecular chain structures. Diselenobonds have the function of promoting cell and tissue repair. Polyamide elastomers based on diselenobonds are non-toxic, and the prepared self-healing elastomers can be used as medical materials. Flexible electronic skin prepared from these elastomers can be in direct contact with the body.

[0010] In the one-pot melt polycondensation process for preparing diselenylene-containing polyamide elastomers, the diselenylene-containing diacid reacts with long-chain diamines and the amino groups of polyetheramines, becoming attached to the polymer backbone through strong covalent amide bonds. This effectively controls the crystallinity of the nylon segments. The diselenylene-containing diacid, as a relatively short, flexible segment, further increases the flexibility of the molecular chain, endowing the material with excellent elasticity and toughness. The diselenylene bond in the diacid acts as a "sacrificial bond," preferentially breaking under external impact, dissipating a large amount of energy, thus greatly improving the material's toughness and preventing brittle fracture.

[0011] The synergistic effect of the amount of polyetheramine and the amount of diacid containing diselenide bonds in this invention precisely controls the ratio and compatibility of soft and hard segments, avoids macroscopic phase separation, ensures the formation of nanoscale microphase separation structure, and improves the stability of polyamide molecules.

[0012] Excessive use of polyetheramine can reduce the crystallinity of polyamide elastomers, thereby decreasing their Shore hardness. 3,3-diselenodipropionic acid or 4,4'-diselenodibutyric acid can adjust the degree of crystallinity and elasticity of the material. This invention, by controlling the ratio of polyetheramine to diselenodicarboxylic acids containing diseleno bonds, slightly reduces the hardness or maintains it within a more ideal elastic range, and significantly improves toughness and self-healing ability without excessively sacrificing hardness.

[0013] In addition, the diselenide bond has a low bond energy, and can undergo reversible homolytic cracking and recombination under stimuli such as heat and mechanical force, giving the material good self-healing function.

[0014] Further, the molar ratio of the long-chain diamine, the long-chain dicarboxylic acid, the dicarboxylic acid containing diselenyl bonds, the polyether soft segment, and the catalyst is (5-6):(7-8):(1-2):(3-4):(0.1-0.2).

[0015] Furthermore, the molar ratio of the long-chain diamine, the long-chain dicarboxylic acid, the dicarboxylic acid containing diselenyl bonds, the polyether soft segment, and the catalyst is (5.8-6):(7.7-8):(1.9-2):(3.8-4):0.1.

[0016] This invention allows for the preparation of elastomers with different self-healing effects by controlling the content of diselenyl bonds, and elastomers with good mechanical properties by controlling the proportion of soft segments (polyetheramines). Specifically, this invention strictly controls the ratios of the raw materials: the molar ratio of long-chain diamines to long-chain diacids is maintained at (5.8-6):(7.7-8), the molar ratio of long-chain diacids to diacids containing diselenyl bonds is maintained at (7.7-8):(1.9-2), the molar ratio of long-chain diamines to polyether soft segments (polyetheramines) is maintained at (5.8-6):(3.8-4), and the molar ratio of diacids containing diselenyl bonds to polyether soft segments (polyetheramines) is maintained at (1.9-2):(3.8-4). This ensures the preparation of elastomers with self-healing functions based on carboxyl-terminated polyamides. These ratios are to ensure that the prepared long-chain polyamide elastomers exhibit high elasticity at room temperature, and to prepare elastomers with different self-healing capabilities by controlling the content of diselenyl bonds.

[0017] Furthermore, the long-chain diamine is any one of decanediamine, undecyldiamine, dodecyldiamine, or tridecyldiamine; the long-chain dicarboxylic acid is any one of sebacic acid, undecyldic acid, dodecyldic acid, or tridecyldic acid.

[0018] Furthermore, the polyether soft segment is an amino-terminated polyetheramine with a molecular weight of 900-2000 Da. The terminal amino group of the polyetheramine readily undergoes an amidation reaction with the carboxyl group of a diacid containing a diselenyl bond, and the reaction conditions are mild.

[0019] The present invention utilizes a milder reaction temperature between the terminal carboxyl group of polyamide and the terminal amino group of polyetheramine. The lower reaction temperature can improve the preparation efficiency and reduce the preparation cost.

[0020] Furthermore, the catalyst is sodium hypophosphite or calcium hypophosphite.

[0021] Furthermore, the melting and mixing temperature is 150-160℃; the polymerization reaction temperature is 190-200℃, and the time is 2-4h; the vacuuming holding time is 2-3h.

[0022] This invention employs a one-step melt polycondensation method to prepare polyamide elastomers with self-healing capabilities, while controlling the reaction temperature within a relatively low range. This ensures efficient elastomer preparation, shortens the process flow, optimizes the preparation process, and reduces preparation costs.

[0023] A self-healing long-chain polyamide elastomer is prepared according to the preparation method described above.

[0024] This invention provides the application of the above-mentioned self-healing long-chain polyamide elastomer in the preparation of flexible electronic skin, comprising the following process: the long-chain polyamide elastomer is granulated and dried, then hot-pressed to obtain a film, conductive nanomaterials are sprayed onto the surface of the film, and the film is fixed by pressing, thus obtaining the final product.

[0025] Furthermore, the conductive nanomaterial is any one of carbon nanotubes, MXene, and graphene.

[0026] Compared with the prior art, the beneficial effects of this invention are as follows: 1. This invention utilizes a diacid containing diselenyl bonds to regulate the molecular structure of polyamide hard segments, and prepares a low-temperature resistant long-chain polyamide elastomer with self-healing capabilities via a one-pot melt polycondensation method. The long-chain polyamide elastomer consists of long-chain polyamide hard segments and polyether soft segments. By introducing dynamically reversible diselenyl bonds within the polyamide hard segments, combined with abundant hydrogen bonds, the two components can jointly endow the long-chain elastomer with excellent self-healing, high resilience, ultra-lightweight, and low-temperature resistance characteristics.

[0027] 2. This invention discloses a method for preparing self-healing long-chain polyamide elastomers. This synthesis method is simple and easy to scale up for production. Furthermore, this invention shortens the process flow and improves the preparation efficiency of long-chain polyamide elastomers by optimizing the synthesis formula and controlling the temperature process.

[0028] 3. This invention provides the application of self-healing long-chain polyamide elastomers in the preparation of flexible electronic skin. By combining hot pressing and spraying, long-chain polyamide elastomers are prepared into MXene / polyamide elastomer-based flexible electronic films, thereby obtaining low-temperature resistant, highly conductive, self-healing flexible electronic skin. It has great application prospects in wearable devices, artificial intelligence, and medical devices used in extreme environments. Attached Figure Description

[0029] Figure 1 The infrared spectrum of the self-healing polyamide elastomer prepared in Example 1 of this invention; Figure 2 This is a diagram showing the heat-induced self-healing process of the polyamide elastomer prepared in Example 1 of the present invention under a polarizing microscope. Figure 3 In this text, 'a' represents the stress-strain curve of the polyamide elastomer prepared in Example 1 of this invention. Figure 3 In Figure b, the recovery results of the polyamide elastomer prepared in Example 1 under different strains are shown. Figure 4 This is a scanning electron microscope image of the polyamide elastomer film prepared in Example 1 of the present invention; Figure 5 Image of the MXene / polyamide elastomer-based flexible electronic thin film sample prepared according to the present invention; Figure 6 The resistivity and bending stability of the MXene / polyamide elastomer-based flexible electronic thin film prepared by this invention at low temperatures. Detailed Implementation

[0030] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0031] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention.

[0032] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, 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 invention pertains.

[0033] In this embodiment of the invention, the long-chain diamine is decanediamine; the long-chain dicarboxylic acid is dodecyl diacid; the dicarboxylic acid containing diselenobonds is 3,3-diselenodipropionic acid or 4,4'-diselenodibutyric acid; the polyether soft segment is an amino-terminated polyether amine (number average molecular weight of 900-2000 Da); the catalyst is sodium hypophosphite; and the conductive nanomaterial is Mxene.

[0034] Example 1 This embodiment provides a method for preparing a long-chain polyamide elastomer with self-healing function, including the following steps: 0.058 mol of decanediamine, 0.077 mol of dodecyl diacid, 0.019 mol of 3,3-diselenodipropionic acid, 0.038 mol of polyetheramine (molecular weight 900), and 0.001 mol of sodium hypophosphite were added to a polymerization reactor. The reactor was sealed, and nitrogen gas was introduced into the reactor to replace the air inside. This process was repeated 5 times, maintaining a slight positive pressure inside the reactor. Heating was then started, and when the reactor temperature reached 150°C, stirring was initiated. After the mixture was homogeneous, heating was stopped, and the temperature was increased to 200°C. The reaction was allowed to proceed for 2 hours. Then, the vent valve was slowly opened to gradually release the pressure inside the reactor. Furthermore, a vacuum pump was used to create a vacuum, which was maintained for 2 hours before the reaction was stopped. Nitrogen gas was then introduced to restore atmospheric pressure, and the material was blown out using nitrogen gas to obtain the final product.

[0035] Example 2 This embodiment provides a method for preparing a long-chain polyamide elastomer with self-healing function, including the following steps: 0.058 mol of decanediamine, 0.077 mol of dodecyl diacid, 0.019 mol of 3,3-diselenodipropionic acid, 0.038 mol of polyetheramine (molecular weight 1000), and 0.001 mol of sodium hypophosphite were added to a polymerization reactor. The reactor was sealed, and nitrogen gas was introduced into the reactor to replace the air inside. This process was repeated 5 times, maintaining a slight positive pressure inside the reactor. Heating was then started, and when the reactor temperature reached 150°C, stirring was initiated. After the mixture was homogeneous, heating was stopped, and the temperature was increased to 195°C. The reaction was allowed to proceed for 2 hours. Then, the vent valve was slowly opened to gradually release the pressure inside the reactor. Furthermore, a vacuum pump was used to create a vacuum, which was maintained for 2 hours before the reaction was stopped. Nitrogen gas was then introduced to restore atmospheric pressure, and the material was blown out using nitrogen gas to obtain the final product.

[0036] Example 3 This embodiment provides a method for preparing a long-chain polyamide elastomer with self-healing function, including the following steps: 0.058 mol of decanediamine, 0.077 mol of dodecyl diacid, 0.019 mol of 3,3-diselenodipropionic acid, 0.038 mol of polyetheramine (molecular weight 2000), and 0.001 mol of sodium hypophosphite were added to a polymerization reactor. The reactor was sealed, and nitrogen gas was introduced into the reactor to replace the air inside. This process was repeated three times, maintaining a slight positive pressure inside the reactor. Heating was then started, and when the reactor temperature reached 150°C, stirring was initiated. After the mixture was homogeneous, heating was stopped, and the temperature was increased to 200°C. The reaction was allowed to proceed for 2 hours. Then, the vent valve was slowly opened to gradually release the pressure inside the reactor. Furthermore, a vacuum pump was used to create a vacuum, which was maintained for 2 hours before the reaction was terminated. Nitrogen gas was then introduced to restore atmospheric pressure, and the material was blown out using nitrogen gas to obtain the final product.

[0037] Example 4 This embodiment provides a method for preparing a long-chain polyamide elastomer with self-healing function, including the following steps: 0.058 mol of decanediamine, 0.077 mol of dodecyl diacid, 0.019 mol of 4,4'-diselenodibutyric acid, 0.038 mol of polyetheramine (molecular weight 900), and 0.001 mol of sodium hypophosphite were added to a polymerization reactor. The reactor was sealed, and nitrogen gas was introduced into the reactor to replace the air inside. This process was repeated 5 times, maintaining a slight positive pressure inside the reactor. Heating was then started, and when the reactor temperature reached 150°C, stirring was initiated. After the mixture was homogeneous, heating was stopped, and the temperature was increased to 190°C. The reaction was allowed to proceed for 2 hours. Then, the vent valve was slowly opened to gradually release the pressure inside the reactor. Furthermore, a vacuum pump was used to create a vacuum, which was maintained for 2 hours before the reaction was terminated. Nitrogen gas was then introduced to restore atmospheric pressure, and the material was blown out using nitrogen gas to obtain the final product.

[0038] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that 3,3-diselenodipropionic acid is not added, while the rest is the same as Example 1.

[0039] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the polyetheramine is replaced with polyether alcohol (polytetrahydrofuran, molecular weight 2000), while the rest is the same as in Example 1.

[0040] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that 3,3-diselenodipropionic acid is replaced with 5,5'-diselenodivalerate, while the rest remains the same as in Example 1.

[0041] 1. The polyamide elastomer obtained in Example 1 of the present invention was subjected to infrared spectroscopy testing. Figure 1 The image shows the FTIR spectrum of the polyamide elastomer prepared in Example 1 of this invention.

[0042] from Figure 1 It can be seen that 3303cm -1 The absorption peak at 1636 cm⁻¹ is the stretching vibration of the NH group in the amide bond. -1 The absorption peak is the stretching vibration of the carbonyl group (C=O) in the amide bond, at 1540 cm⁻¹. -1 The absorption peak at 1097 cm⁻¹ represents the bending vibration of the NH group in the amide bond. -1 The absorption peak is the stretching vibration of the ether bond (COC) on polyetheramine, at 610 cm⁻¹. -1 The absorption peaks are for diselenylene bonds, and the presence of these absorption peaks proves that the polyamide elastomer containing diselenylene bonds has been successfully synthesized.

[0043] 2. After the polyamide elastomer obtained in Example 1 of this invention is pressed into a film, cracks are cut into its surface and placed under a polarizing microscope. It is then heated using a hot stage at 150°C. The self-healing process of the polyamide elastomer prepared in Example 1 under heating under a polarizing microscope is observed and recorded. The results are as follows: Figure 2 As shown. Figure 2 In the diagram, (a) represents before heating, (b) represents after heating for 10 minutes, (c) represents after heating for 20 minutes, and (d) represents after heating for 30 minutes.

[0044] from Figure 2 As can be seen, under a polarizing microscope, the cracks in the polyamide elastomer prepared in Example 1 of this invention gradually heal, proving that the elastomer has a self-healing function.

[0045] 3. The properties of the polyamide elastomers obtained in Examples 1-4 and Comparative Examples 1-3 of this invention were tested: (1) Self-healing rate: The self-healing rate mentioned in each embodiment and comparative example refers to the ratio of the elongation at break of the polyamide elastomer sample after a scalpel cuts half the thickness of the sample in the middle of the tensile sample and repairs it for 30 minutes at 150°C to the elongation at break of the original sample. (2) Tensile strength and elongation at break: The mechanical properties of the specimens were tested using a universal testing machine with a tensile rate of 100 mm / min and a gauge length of 20 mm. (3) Shore hardness: The Shore hardness was measured using a desktop Shore hardness tester.

[0046] The experimental results are shown in Table 1. Among them, Figure 3 This is the stress-strain curve of the polyamide elastomer prepared in Example 1 of the present invention. From... Figure 3 As can be seen in (a), the tensile strength of this polyamide elastomer is 18 MPa and the elongation at break is 376%. Figure 3 (b) shows the recovery of the elastomer under different strains, indicating that the prepared elastomer has good elasticity.

[0047] Table 1 As shown in Table 1, the polyamide elastomer obtained in this invention exhibits good self-healing properties, with tensile strength and elongation at break both exceeding those of Comparative Example 3. The self-healing rate and mechanical properties of the polyamide elastomers obtained in Examples 1-4 show varying degrees of change. Specifically, as seen in Examples 1-3, with the increase of the molecular weight of the polyetheramine, the self-healing rate, tensile strength, and elongation at break of the polyamide elastomer all increase, while the hardness gradually decreases. This is because the diselenyl bonds are embedded in the polyamide molecule. The increase in the molecular weight of the polyetheramine effectively regulates the ratio of soft to hard segments in the polyamide elastomer, making the diselenyl bonds in the molecular chain easier to move, thereby promoting the healing of the fracture surface and facilitating the self-healing properties of the diselenyl bonds.

[0048] Meanwhile, the increased molecular weight of polyetheramine results in longer soft segments and more flexible chains, enabling them to undergo greater deformation without breaking. Furthermore, the longer soft segments can absorb more energy, dissipating stress through segment slippage and reorientation, thus delaying fracture and improving chain flowability and flexibility.

[0049] Compared to Example 1, Comparative Example 1 showed a significant decrease in self-healing rate. This is because the absence of dynamic reversible covalent bonds (diselement bonds) in the molecular chain reduces the self-repairing ability of the elastomer.

[0050] Compared to Example 1, Comparative Example 2 replaced polyetheramine with polytetrahydrofuran. The tensile strength and elongation at break of Comparative Example 2 were significantly lower than in Example 1. This is because the reaction between the terminal carboxyl groups of polyamide and the terminal hydroxyl groups of polytetrahydrofuran requires higher temperatures and stringent synthesis conditions. At lower temperatures (around 200°C), it is impossible to generate elastomers with high molecular weight and narrow molecular weight distribution through copolymerization, resulting in poor mechanical properties. In contrast, this invention uses polyetheramine, where the reaction between the terminal carboxyl and terminal amino groups occurs at a milder temperature, allowing for the efficient and low-cost preparation of self-healing elastomers at lower reaction temperatures.

[0051] On the other hand, in Comparative Example 2, the lack of polyetheramine significantly reduced the self-healing properties of the polyamide elastomer. This is because the diselenide bonds are fixed in the polyamide elastomer and cannot move effectively. However, when polyetheramine is present, the reaction between the polyetheramine and the diacid containing diselenide bonds can maintain the stability of the polyamide elastomer, and the diselenide bonds can move more easily, thus improving its self-healing properties.

[0052] In Comparative Example 3, 3,3-diselenodipropionic acid was replaced with 5,5'-diselenodivalerate. The excessively long flexible alkane chain damaged the hard segments of the polyamide elastomer, severely weakening the physical cross-linking network and leading to a decrease in elastomer strength. Furthermore, the excessively long chain segment of 5,5'-diselenodivalerate greatly reduced the mobility of the free radical ends after the diseleno bond broke, making the self-healing rate slow and hindering self-healing.

[0053] Application Example 1 The application of the self-healing long-chain polyamide elastomer containing diselenide bonds prepared in Example 1 in the preparation of flexible electronic skin includes the following steps: The elastomer obtained in Example 1 was cooled, granulated, and dried. Then, with the aid of a copper template having micro / nano patterns, a thin film with a specific pattern was prepared by hot pressing. The thin film obtained in Example 1 is as follows: Figure 4 As shown, an aqueous solution containing MXene (4 mg / mL) is then sprayed onto its surface, and a conductive network is further fixed by lamination to prepare a highly conductive flexible electronic skin with a fixed pattern, denoted as an MXene / polyamide elastomer-based flexible electronic film. Figure 5 As shown, the MXene / polyamide elastomer-based flexible electronic film was bent 500 times at a low temperature (-20℃), and the resistance change was observed. The results are as follows. Figure 6 As shown.

[0054] from Figure 4 It can be seen that the thin film surface has a specific pattern. The specific pattern can increase the contact area between the elastomer substrate and the conductive particles, promote the bonding between the two, enhance the conductivity of the thin film, and thus obtain a low-temperature resistant, highly conductive, self-healing flexible electronic skin.

[0055] The sheet resistance of this MXene / polyamide elastomer-based flexible electronic thin film was tested. It was found that the sheet resistance of this film was as low as 25 Ω / sq.

[0056] Figure 6 This shows the resistance change of an MXene / polyamide elastomer-based flexible electronic thin film after 500 bending cycles at low temperature (-20°C). From... Figure 6 It can be seen that the MXene / polyamide elastomer-based flexible electronic film obtained by this invention has good conductivity and low temperature resistance, and has great application prospects in wearable devices, artificial intelligence and medical devices used in extreme environments.

[0057] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a self-healing long-chain polyamide elastomer, characterized in that, Includes the following steps: Long-chain diamine, long-chain dicarboxylic acid, dicarboxylic acid containing diselenyl bonds, polyether soft segments, and catalyst are melt-mixed and then polymerized. The reaction is terminated by vacuuming to obtain long-chain polyamide elastomer.

2. The method for preparing the self-healing long-chain polyamide elastomer according to claim 1, characterized in that, The dicarboxylic acid containing a diseleno bond is 3,3-diselenodipropionic acid or 4,4'-diselenodibutyric acid.

3. The method for preparing the self-healing long-chain polyamide elastomer according to claim 1, characterized in that, The molar ratio of the long-chain diamine, the long-chain dicarboxylic acid, the dicarboxylic acid containing diselenobonds, the polyether soft segment, and the catalyst is (5-6):(7-8):(1-2):(3-4):(0.1-0.2).

4. The method for preparing the self-healing long-chain polyamide elastomer according to claim 1, characterized in that, The long-chain diamine is any one of decanediamine, undecyldiamine, dodecyldiamine, or tridecyldiamine; the long-chain dicarboxylic acid is any one of sebacalic acid, undecyldicic acid, dodecyldicic acid, or tridecyldicic acid.

5. The method for preparing the self-healing long-chain polyamide elastomer according to claim 1, characterized in that, The polyether soft segment is an amino-terminated polyetheramine with a molecular weight of 900-2000 Da.

6. The method for preparing the self-healing long-chain polyamide elastomer according to claim 1, characterized in that, The catalyst is sodium hypophosphite or calcium hypophosphite.

7. The method for preparing the self-healing long-chain polyamide elastomer according to claim 1, characterized in that, The melting and mixing temperature is 150-160℃; the polymerization reaction temperature is 190-200℃ and the time is 2-4h; the vacuum holding time is 2-3h.

8. A self-healing long-chain polyamide elastomer, characterized in that, Prepared by the preparation method according to any one of claims 1-7.

9. The application of the self-healing long-chain polyamide elastomer according to claim 8 in the preparation of flexible electronic skin, characterized in that, The process includes the following steps: granulating long-chain polyamide elastomer, drying it, hot-pressing it to form a film, spraying conductive nanomaterials onto the film surface, and then pressing it to fix the film.

10. The application of the self-healing long-chain polyamide elastomer according to claim 9 in the preparation of flexible electronic skin, characterized in that, The conductive nanomaterial is any one of carbon nanotubes, Mxene, and graphene.

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