Bio-based low-temperature-resistant super-tough polyamide elastomer and preparation method thereof

Abstract

The invention discloses a bio-based low-temperature-resistant super-tough polyamide elastomer and a preparation method thereof, and belongs to the technical field of high polymer materials. The elastomer has a specific molecular structure formed by polymerizing long-carbon-chain dibasic acid, dipolyamine and polyether; the preparation method comprises the following steps: under the protection of inert gas, adding reaction monomers into a reaction container in proportion, and carrying out pre-polycondensation in a specific temperature range to prepare an oligomer precursor; and adding a titanium catalyst, and carrying out condensation polymerization under a vacuum condition to obtain the bio-based low-temperature-resistant super-tough polyamide elastomer. The molecular weight, the mechanical property and the thermal property of the product can be effectively regulated and controlled by regulating and controlling the proportion of soft and hard segments; the one-pot melt polycondensation process does not need a solvent, equipment is simple, the catalyst cost is low, and the production safety and economic benefits are remarkably improved; the obtained long-carbon-chain polyamide elastomer has excellent flexibility and high rebound resilience, and is especially suitable for the fields of flexible wearable electronic equipment sensing layers, biocompatible medical instruments and environment-friendly packaging materials.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a bio-based low-temperature resistant ultra-tough polyamide elastomer and its preparation method. Background Technology

[0002] Polyamide elastomers (TPAEs) are widely used in sports shoe midsoles and gas separation membranes due to the mechanical strength of polyamide hard segments and the flexibility of polyether soft segments. However, traditional petroleum-based systems exhibit low-temperature brittleness because the high regularity of the hard segment molecular chains and the high density of hydrogen bonds hinder the movement of molecular chains at low temperatures. Furthermore, they are prone to rebound hysteresis and fatigue cracking in applications with high deformation recovery rates, severely limiting their performance in high-end applications.

[0003] To overcome the aforementioned bottlenecks, bio-based modification technologies have received widespread attention in recent years. Among these technologies, dimericamines, as derivatives of dimer acids, are derived from unsaturated fatty acids such as linoleic acid and oleic acid found in natural oils like soybean oil and tall oil. The unique long aliphatic chain branched structure of this monomer can theoretically improve chain mobility by reducing the crystal regularity and hydrogen bond density of the hard segments in polyamides, thereby synergistically optimizing the low-temperature toughness of the material. However, existing technologies have significant limitations in the application of dimericamines. Most studies only use them as modifiers, while exploration of their direct use as hard segment structural units to construct polyetheramide elastomers remains insufficient. For example, existing technology CN116056874B discloses aliphatic and semi-aromatic polyamides containing dimer acids and dimericamines. Although dimer acid / dimericamine modification of PA610 or PA612 salt solutions is used, the random insertion of dimer alkane during the high-temperature and high-pressure reaction may cause structural disorder in the hard segments.

[0004] Therefore, to address the aforementioned problems, this invention provides a bio-based low-temperature resistant ultra-tough polyamide elastomer and its preparation method. It develops a novel low-temperature resistant ultra-tough polyamide elastomer based on bio-based dimelamine as the hard segment structural unit. Through precise control of the microphase morphology via molecular structure design, this invention provides a pathway to solve the material performance bottlenecks in high-end sports equipment, medical catheters, wearable electronic devices, and other fields. The bio-based low-temperature resistant ultra-tough polyamide elastomer prepared by this invention has a designable molecular structure, controllable molecular weight, simple preparation process, and low equipment requirements, which obviously has significant research value. Summary of the Invention

[0005] The purpose of this invention is to provide a bio-based low-temperature resistant ultra-tough polyamide elastomer and its preparation method, so as to solve the technical defects of existing petroleum-based elastomers that have insufficient resilience and poor low-temperature toughness, as well as the complex synthesis process of bio-based elastomers.

[0006] The objective of this invention is achieved through the following technical solution: A bio-based, low-temperature resistant, ultra-tough polyamide elastomer, copolymerized from diamine, long-chain diacid, and polyether, has the following structure: ; Among them, R1 is selected from C 11 ~C 36 Straight-chain or branched alkylene groups; R2 is selected from C 24 ~C 44 A branched or alkene-bonded aliphatic carbon chain; R3 is selected from C2-C4 straight-chain or branched alkylene groups, m and n are the number of repeating units, where 1 <m<55,5<n<50。

[0007] Preferably, the diamine is selected from at least one natural oil selected from castor oil, erucic acid, or oleic acid, and has the general structural formula H2N-R2-NH2, wherein R2 is a C-type carbon containing a double or single bond. 24 ~C 44 Aliphatic long chains, or molecules containing at least one six-membered ring, including but not limited to benzene rings, piperidine rings, or naphthalene rings.

[0008] More preferably, the dimelamine includes, but is not limited to, one or more of Priamine 1071, Priamine 1074, or Versamine 551.

[0009] Preferably, the long-chain dicarboxylic acid includes those having C 11 ~C 36 A straight or branched carbon chain (C1-C2). 10 Dicarboxylic acid.

[0010] More preferably, the long-chain dicarboxylic acid includes a branched long-chain dicarboxylic acid with the general structural formula HOOC(CH2). x Linear dicarboxylic acids of COOH (where x≥10) and dimer acids.

[0011] Preferably, the polyether has a number-average molecular weight of 500-3000 g / mol, and the polyether is selected from at least one of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran.

[0012] Preferably, the number-average molecular weight of the bio-based low-temperature resistant ultra-tough polyamide elastomer is 1×10⁻⁶. 4 ~7×10 4 g / mol; The glass transition temperature of the bio-based low-temperature resistant ultra-tough polyamide elastomer is -80~10℃; The elongation at break of the bio-based low-temperature resistant ultra-tough polyamide elastomer is 1300%~3500%; The tensile strength of the bio-based low-temperature resistant ultra-tough polyamide elastomer is 1~50MPa.

[0013] This application also claims a method for preparing the above-mentioned bio-based low-temperature resistant ultra-tough polyamide elastomer, comprising the following steps: S1. Prepolymerization: Under inert gas protection, long-chain dicarboxylic acid, diamine and polyether are placed in a reactor in proportion, the reaction temperature is controlled at 160~240°C and the stirring speed is controlled, and the reaction is carried out for 1~4 hours to obtain oligomers. S2. Polycondensation: Add a catalyst to the oligomer obtained in step S1, and carry out a polycondensation reaction for 2-5 hours under vacuum of 80-250 Pa and reaction temperature of 200-280°C to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0014] Preferably, in step S1, the reaction temperature is controlled at 180~220°C and the stirring speed is controlled at 1.5~2h; the inert gas protection specifically involves: after purging nitrogen to replace the air three times, nitrogen is continuously purged at a uniform rate.

[0015] Preferably, in step S2, the polycondensation reaction is carried out for 3 to 4.5 hours under a vacuum of 100 to 180 Pa and a reaction temperature of 220 to 240°C.

[0016] Preferably, the catalyst is selected from at least one of tetrabutyl titanate, tetraisopropyl titanate, tetrabutyl zirconate, zinc acetate, germanium dioxide, and sodium hypophosphite.

[0017] Preferably, the molar ratio of the diamine to the long-chain dicarboxylic acid is 1.0:1.0~4.0; the mass ratio of the polyether is 10~70wt%; and the catalyst is 0.05~0.2wt% of the total feed mass.

[0018] More preferably, the molar ratio of the diamine to the long-chain dicarboxylic acid is 1.0:1.0~4.0; the mass ratio of the polyether is 20~60wt%; and the catalyst is 0.1~0.15wt% of the total feed mass.

[0019] This application also claims the use of the above-mentioned bio-based low-temperature resistant ultra-tough polyamide elastomer in wearable medical devices, medical instruments, polymer toughening materials or foam materials.

[0020] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. By adjusting the composition and ratio of diamine, long-chain dicarboxylic acid and polyether, this invention can precisely control the molecular structure and molecular weight of elastomer. The resulting elastomer has excellent low-temperature resistance, ultra-high toughness and moderate strength, meeting the needs of different application scenarios. 2. The main raw materials of this invention (such as dimelamine) can be derived from natural oils such as castor oil, erucic acid, and oleic acid, reducing dependence on petroleum-based raw materials and conforming to the concept of sustainable development; long-chain dicarboxylic acids and polyethers can be selected from bio-based or biodegradable materials to improve the environmental friendliness of the product. 3. This invention adopts a "one-pot" melt polycondensation process, which requires no solvent, has a high concentration of reactants, a simple process, and is easy to control. The reaction conditions are mild, the amount of catalyst used is low, and the cost is controllable. The resulting product is directly in a molten state, which is convenient for subsequent extrusion, injection molding and other processing, reducing energy consumption and improving production efficiency. 4. The elastomer prepared by this invention has excellent comprehensive performance and significant competitive advantages. Compared with traditional petroleum-based polyamide elastomers, the product of this invention performs better in terms of low temperature resistance, flexibility and biocompatibility. The preparation process is green and efficient, suitable for large-scale production, and has significant economic and social benefits. 5. This invention is applicable to wearable medical devices, medical instruments, polymer toughening materials, and foaming materials, with a wide range of applications and broad market prospects. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be made based on these drawings without creative effort.

[0022] Figure 1 This is the Fourier transform infrared (FTIR) curve of the bio-based low-temperature resistant ultra-tough polyamide elastomer in Example 5 of this invention. Figure 2 This is a differential scanning calorimetry (DSC) curve of the bio-based low-temperature resistant ultra-tough polyamide elastomer in Example 5 of the present invention; wherein, the left figure is the first cooling curve showing the hard segment crystallization temperature as 26.51℃; the right figure is the second heating curve showing the melting point as 75.68℃; Figure 3 This is an engineering stress-strain curve of the bio-based low-temperature resistant ultra-tough polyamide elastomer in Example 5 of the present invention; Figure 4 This is a dynamic mechanical-thermal analysis (DMTA) curve of the bio-based low-temperature resistant ultra-tough polyamide elastomer in Example 5 of this invention; Figure 5 This is the XRD curve of the bio-based low-temperature resistant ultra-tough polyamide elastomer in Example 5 of the present invention. Detailed Implementation

[0023] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific implementation schemes are now described in detail.

[0024] The present invention will be further described below with reference to embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0025] Example 1 This embodiment provides a method for preparing a bio-based, low-temperature resistant, ultra-tough polyamide elastomer, comprising the following steps: S1. Prepolymerization: Under inert gas protection, 0.06 mol of 1,12-dodecanoic acid, 0.05 mol of diamine Priamine 1071, and 0.01 mol of polytetrahydrofuran (molecular weight 2000 g / mol) were added to a three-necked flask connected to a mechanical stirrer, a nitrogen inlet, and a condenser. The reaction system was gradually heated to 180°C in an oil bath for 1 hour, and then heated to 210°C for another hour to obtain oligomers. S2, Polycondensation: Add 0.0004 mol of tetrabutyl titanate to the oligomer obtained in step S1, react at 220°C for 1.5 h under vacuum of 150 Pa, then raise the temperature to 240°C for 3 h, discharge the material and dry it under vacuum at 50°C for 12 h to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0026] In this embodiment (the mass ratio of polytetrahydrofuran is 33.0 wt%), the number average molecular weight of the final bio-based low-temperature resistant ultra-tough polyamide elastomer product is 3.78 × 10⁻⁶. 4 g / mol, glass transition temperature -72.72°C, hard segment crystallization temperature 14.5°C, melting point 79.11°C, tensile strength of the sample 18.5MPa, tensile modulus 37.4MPa, elongation at break 1792%.

[0027] Example 2 This embodiment provides a method for preparing a bio-based, low-temperature resistant, ultra-tough polyamide elastomer, comprising the following steps: S1. Prepolymerization: Under inert gas protection, 0.04 mol of 1,12-dodecanoic acid, 0.03 mol of diamine Priamine 1071, and 0.01 mol of polytetrahydrofuran (molecular weight 2000 g / mol) were added to a three-necked flask connected to a mechanical stirrer, a nitrogen inlet, and a condenser. The reaction system was gradually heated to 180°C in an oil bath for 1 hour, and then further heated to 210°C for 1 hour to obtain oligomers. S2, Polycondensation: Add 0.0004 mol of tetrabutyl titanate to the oligomer obtained in step S1, react at 220°C for 1.5 h under vacuum of 150 Pa, then raise the temperature to 240°C for 3 h, discharge the material and dry it under vacuum at 50°C for 12 h to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0028] In this embodiment (the mass ratio of polytetrahydrofuran is 44.2 wt%), the number average molecular weight of the final bio-based low-temperature resistant ultra-tough polyamide elastomer product is 3.97 × 10⁻⁶. 4 g / mol, glass transition temperature -73.37°C, hard segment crystallization temperature 16.08°C, melting point 78.02°C, tensile strength of the sample 26.4MPa, tensile modulus 6.5MPa, elongation at break 2070%.

[0029] Example 3 This embodiment provides a method for preparing a bio-based, low-temperature resistant, ultra-tough polyamide elastomer, comprising the following steps: S1. Prepolymerization: Under inert gas protection, 0.03 mol of 1,12-dodecanoic acid, 0.02 mol of diamine Priamine 1071, and 0.01 mol of polytetrahydrofuran (molecular weight 2000 g / mol) were added to a three-necked flask connected to a mechanical stirrer, a nitrogen inlet, and a condenser. The reaction system was gradually heated to 180°C in an oil bath for 1 hour, and then heated to 210°C for another hour to obtain oligomers. S2, Polycondensation: Add 0.0004 mol of tetrabutyl titanate to the oligomer obtained in step S1, react at 220°C for 1.5 h under vacuum of 150 Pa, then raise the temperature to 240°C for 3 h, discharge the material and dry it under vacuum at 50°C for 12 h to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0030] In this embodiment (the mass ratio of polytetrahydrofuran is 53.2 wt%), the number average molecular weight of the final bio-based low-temperature resistant ultra-tough polyamide elastomer product is 3.56 × 10⁻⁶. 4 g / mol, glass transition temperature is -73.63°C, hard segment crystallization temperature is 14.91°C, melting point is 77.62°C, tensile strength of the sample is 21.4 MPa, tensile modulus is 5.4 MPa, and elongation at break is 2320%.

[0031] Example 4 This embodiment provides a method for preparing a bio-based, low-temperature resistant, ultra-tough polyamide elastomer, comprising the following steps: S1. Prepolymerization: Under inert gas protection, 0.04 mol of 1,12-dodecanoic acid, 0.02 mol of diamine Priamine 1071, and 0.02 mol of polytetrahydrofuran (molecular weight 2000 g / mol) were added to a three-necked flask connected to a mechanical stirrer, a nitrogen inlet, and a condenser. The reaction system was gradually heated to 180°C in an oil bath for 1 hour, and then heated to 210°C for another hour to obtain oligomers. S2, Polycondensation: Add 0.0004 mol of tetrabutyl titanate to the oligomer obtained in step S1, react at 220°C for 1.5 h under vacuum of 150 Pa, then raise the temperature to 240°C for 3 h, discharge the material and dry it under vacuum at 50°C for 12 h to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0032] In this embodiment (the mass ratio of polytetrahydrofuran is 66.8 wt%), the number average molecular weight of the final bio-based low-temperature resistant ultra-tough polyamide elastomer product is 4.07 × 10⁻⁶. 4 g / mol, glass transition temperature -72.10°C, hard segment crystallization temperature 15.6°C, melting point 76.24°C, tensile strength of the sample 17.8MPa, tensile modulus 4.45MPa, elongation at break 2550%.

[0033] Example 5 See appendix Figure 1 ~Appendix Figure 5 This embodiment provides a method for preparing a bio-based low-temperature resistant, ultra-tough polyamide elastomer, comprising the following steps: S1. Prepolymerization: Under inert gas protection, 0.04 mol of 1,14-tetradecanoic acid, 0.02 mol of diamine Priamine 1071, and 0.02 mol of polytetrahydrofuran (molecular weight 2000 g / mol) were added to a three-necked flask connected to a mechanical stirrer, a nitrogen inlet, and a condenser. The reaction system was gradually heated to 180°C in an oil bath for 1 hour, and then further heated to 210°C for 1 hour to obtain oligomers. S2, Polycondensation: Add 0.0004 mol of tetrabutyl titanate to the oligomer obtained in step S1, react at 220°C for 1.5 h under vacuum of 150 Pa, then raise the temperature to 240°C for 3 h, discharge the material and dry it under vacuum at 50°C for 12 h to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0034] In this embodiment (the mass ratio of polytetrahydrofuran is 65.5 wt%), the number average molecular weight of the final bio-based low-temperature resistant ultra-tough polyamide elastomer product is 3.86 × 10⁻⁶. 4The product exhibits a molecular structure, excellent low-temperature resistance, and super-toughness, with a glass transition temperature of -71.4°C, a hard segment crystallization temperature of 26.51°C, a melting point of 75.68°C, a tensile strength of 10 MPa, a tensile modulus of 1.2 MPa, and an elongation at break of 2900%. FTIR, DSC, stress-strain, DMTA, and XRD results all confirm that the product possesses the expected molecular structure, excellent low-temperature resistance, and super-toughness.

[0035] Figure 1 The Fourier transform infrared (FTIR) spectrum of the bio-based low-temperature resistant ultra-tough polyamide elastomer in this embodiment shows that the polyetheramide structure was successfully synthesized. Figure 2 This is a differential scanning calorimetry (DSC) curve of the bio-based low-temperature resistant ultra-tough polyamide elastomer in this embodiment; the left figure is the first cooling curve, showing the hard segment crystallization temperature as 26.51℃; the right figure is the second heating curve, showing the melting point as 75.68℃. Figure 3 This is the engineering stress-strain curve of the bio-based low-temperature resistant ultra-tough polyamide elastomer in this embodiment: exhibiting typical characteristics of ultra-tough materials; Figure 4 The DMTA curve of the bio-based low-temperature resistant ultra-tough polyamide elastomer in this embodiment shows a significant glass transition near -70℃ and maintains a high elastic modulus throughout the low-temperature range, further confirming its excellent low-temperature resistance. Figure 5 The XRD curve of the bio-based low-temperature resistant ultra-tough polyamide elastomer in this embodiment shows a diffraction peak at 2θ=20°. Combined with the DSC results, it is determined that there is a crystalline region in the material, but the crystallinity is low, which explains its high elasticity and low-temperature resistance.

[0036] Example 6 This embodiment provides a method for preparing a bio-based, low-temperature resistant, ultra-tough polyamide elastomer, comprising the following steps: S1. Prepolymerization: Under inert gas protection, 0.04 mol of 1,18-octadecanoic acid, 0.02 mol of diamine Priamine 1071, and 0.02 mol of polytetrahydrofuran (molecular weight 2000 g / mol) were added to a three-necked flask connected to a mechanical stirrer, a nitrogen inlet, and a condenser. The reaction system was gradually heated to 180°C in an oil bath for 1 hour, and then heated to 210°C for another hour to obtain oligomers. S2, Polycondensation: Add 0.0004 mol of tetrabutyl titanate to the oligomer obtained in step S1, react at 220°C for 1.5 h under vacuum of 150 Pa, then raise the temperature to 240°C for 3 h, discharge the material and dry it under vacuum at 50°C for 12 h to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0037] In this embodiment (the mass ratio of polytetrahydrofuran is 63.2 wt%), the number average molecular weight of the final bio-based low-temperature resistant ultra-tough polyamide elastomer product is 4.35 × 10⁻⁶. 4 g / mol, glass transition temperature is -73.1°C, hard segment crystallization temperature is 17.13°C, melting point is 74.06°C, tensile strength of the sample is 8.5 MPa, tensile modulus is 1 MPa, and elongation at break is 3270%.

[0038] Example 7 This embodiment provides a method for preparing a polyamide elastomer, including the following steps: S1. Prepolymerization: Under inert gas protection, 0.1 mol of 1,12-dodecanoic acid, 0.09 mol of diamine Priamine 1071, and 0.01 mol of polytetrahydrofuran (molecular weight 2000 g / mol) were added to a three-necked flask connected to a mechanical stirrer, a nitrogen inlet, and a condenser. The reaction system was gradually heated to 180°C in an oil bath for 1 hour, and then heated to 210°C for another hour to obtain oligomers. S2, Polycondensation: Add 0.0004 mol of tetrabutyl titanate to the oligomer obtained in step S1, react at 220°C for 1.5 h under vacuum of 150 Pa, then raise the temperature to 240°C for 3 h, discharge the material and dry it under vacuum at 50°C for 12 h to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0039] In this embodiment (the polytetrahydrofuran content was 21.9 wt%), the number average molecular weight of the final polyamide elastomer product was 1.83 × 10⁻⁶. 4 g / mol, glass transition temperature is 2.25°C, hard segment crystallization temperature is 11.26°C, melting point is 79.81°C, tensile strength of the sample is 38MPa, tensile modulus is 54.3MPa, and elongation at break is 1400%.

[0040] Comparative Example 1 This comparative example provides a method for preparing a polyamide elastomer, comprising the following steps: S1. Prepolymerization: Under inert gas protection, 0.26 mol of 1,12-dodecanoic acid, 0.25 mol of diamine Priamine 1071, and 0.01 mol of polytetrahydrofuran (molecular weight 2000 g / mol) were added to a three-necked flask connected to a mechanical stirrer, a nitrogen inlet, and a condenser. The reaction system was gradually heated to 180°C in an oil bath for 1 hour, and then heated to 210°C for another hour to obtain oligomers. S2, Polycondensation: Add 0.0004 mol of tetrabutyl titanate to the oligomer obtained in step S1, react at 220°C for 1.5 h under vacuum of 150 Pa, then raise the temperature to 240°C for 3 h, discharge the material and dry it under vacuum at 50°C for 12 h to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0041] In this comparative example (where polytetrahydrofuran accounted for 9.4 wt%), the number average molecular weight of the final polyamide elastomer product was 3.05 × 10⁻⁶. 4 g / mol, glass transition temperature is 37°C, melting point is 78.8°C, tensile strength of the sample is 40 MPa, tensile modulus is 80.2 MPa, and elongation at break is 930%.

[0042] Comparative Example 2 This comparative example provides a method for preparing a polyamide elastomer, comprising the following steps: S1. Prepolymerization: Under inert gas protection, 0.04 mol of 1,12-dodecanoic acid, 0.01 mol of diamine Priamine 1071, and 0.03 mol of polytetrahydrofuran (molecular weight 2000 g / mol) were added to a three-necked flask connected to a mechanical stirrer, a nitrogen inlet, and a condenser. The reaction system was gradually heated to 180°C in an oil bath for 1 hour, and then heated to 210°C for another hour to obtain oligomers. S2, Polycondensation: Add 0.0004 mol of tetrabutyl titanate to the oligomer obtained in step S1, react at 220°C for 1.5 h under vacuum of 150 Pa, then raise the temperature to 240°C for 3 h, discharge the material and dry it under vacuum at 50°C for 12 h to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0043] In this comparative example (where polytetrahydrofuran accounted for 80.5 wt%), the number average molecular weight of the final polyamide elastomer product was 3.57 × 10⁻⁶. 4 g / mol, glass transition temperature -18.1°C, soft segment crystallization temperature -24.97°C, melting point 12.76°C, tensile strength of the sample 1.1 MPa, tensile modulus 6.1 MPa, elongation at break 1950%.

[0044] Comparative Example 3 This comparative example provides a method for preparing a polyamide elastomer, comprising the following steps: S1. Prepolymerization: Under inert gas protection, 0.05 mol of 1,12-dodecanoic acid, 0.04 mol of dodecanediamine, and 0.01 mol of polytetrahydrofuran (molecular weight 2000 g / mol) were added to a three-necked flask connected to a mechanical stirrer, a nitrogen inlet, and a condenser. The reaction system was gradually heated to 180°C in an oil bath for 1 hour, and then further heated to 210°C for 1 hour to obtain oligomers. S2, Polycondensation: Add 0.0004 mol of tetrabutyl titanate to the oligomer obtained in step S1, react at 220°C for 1.5 h under vacuum of 150 Pa, then raise the temperature to 240°C for 3 h, discharge the material and dry it under vacuum at 50°C for 12 h to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

[0045] In this comparative example (where polytetrahydrofuran accounted for 50.6 wt%), the number average molecular weight of the final polyamide elastomer product was 3.21 × 10⁻⁶. 4 g / mol, glass transition temperature -55°C, melting point 147°C, tensile strength of the sample 43.12 MPa, tensile modulus 15.04 MPa, elongation at break 920%.

[0046] From Examples 1 to 7 and Comparative Examples 1 to 2, it can be concluded that dimelamine can improve the toughness and ductility of polyamide elastomers, and there is an optimal polyether content. When the soft segment content exceeds 60 wt%, extremely high elongation at break can be obtained, with an elongation at break as high as 3270%. However, excessive polyether content will reduce the strength and elongation of polyamide elastomers.

[0047] Examples 3 and Comparative Example 3 show that, with similar polyether soft segment content, using bio-based dimelamine to replace traditional petroleum-based linear diamine can significantly improve the overall performance of polyamide elastomers, giving them both excellent low-temperature resistance and super toughness.

[0048] Examples 4, 5, and 6 demonstrate that different types and molecular weights of thermoplastic polyamide elastomers can be obtained by changing the type of long-chain dicarboxylic acid reactive monomers, thereby affecting the tensile strength, elongation at break, and thermal properties of the elastomers. A comparison of the performance test results of the examples and comparative examples shows that the diamine-type polyether block amide elastomer prepared by this invention can have its mechanical and thermal properties controlled by designing the molecular structure and adjusting the molecular weight and the ratio of soft to hard segments, thus meeting application requirements. The product testing and characterization methods used in Examples 1-7 and Comparative Examples 1-3 of this invention are shown below: Fourier transform infrared spectroscopy analysis method: Functional group analysis of the sample was performed using an INVENIOS Fourier transform infrared spectrometer; at 4000 to 500 cm⁻¹ -1 The test was conducted within the spectral range, with a cumulative 32 scans.

[0049] X-ray diffraction testing method: A SmartlabSE diffractometer was used for testing, with a Cu target radiation source. The diffraction pattern was acquired within the 2θ range of 5° to 50°, and the scanning rate was 2°·min. -1 .

[0050] Molecular weight determination method: An Agilent 1260 Infinity II system (USA) equipped with two PLgel MIXED-C columns (5 μm particle size, 300 × 7.5 mm) connected in tandem was used; HPLC-grade chloroform was used as the mobile phase, and the column temperature was maintained at 30°C by an oven. Chromatographic separation was performed under isocratic elution conditions at a flow rate of 1.0 mL / min. -1 A calibration curve was established using narrow-distribution polystyrene standards: the standards were dissolved in chloroform (concentration 2 mg·mL⁻¹). -1 The calibration was completed after three repeated injections.

[0051] Dynamic thermomechanical analysis test method: A DMA242E dynamic thermomechanical analyzer was used for testing in tensile mode. The test temperature range was -100℃ to 100℃, and the heating rate was 5℃·min. -1 The frequency is set to 1Hz.

[0052] Methods for testing melting temperature and crystallization temperature: The thermal properties of polyamide were studied using a TAQ20 differential scanning calorimeter (USA). Under nitrogen atmosphere, 6-10 mg of sample was injected at 10 °C / min. -1 The sample was heated to 120℃ at a rate of 10℃ / min and held at that temperature for 5 min; then, it was cooled to -50℃ at a rate of 10℃ / min, and the exothermic crystallization curve was recorded and the corresponding crystallization temperature (T) was read. c Finally, the sample was heated at 10℃·min. -1 Heat the sample to 120°C at a set rate, record the melting curve, and read the corresponding melting point (T). m ).

[0053] Mechanical property testing method: The tensile properties of the material were tested using an Instron 3367 universal testing machine. The copolymer was hot-pressed into a 1 mm thick film, cut into dumbbell-shaped strips, and the samples were left at room temperature for a period of time. Tensile tests were then performed at a speed of 50 mm / min, and at least five tests were performed on each sample.

[0054] In summary, this invention, by adjusting the composition and ratio of dimelamine, long-chain diacid, and polyether, can precisely control the molecular structure and molecular weight of the elastomer. The resulting elastomer possesses excellent low-temperature resistance, ultra-high toughness, and moderate strength, meeting the needs of various application scenarios. The main raw materials of this invention (such as dimelamine) can be derived from natural oils such as castor oil, erucic acid, and oleic acid, reducing dependence on petroleum-based raw materials and conforming to the concept of sustainable development. Both the long-chain diacid and polyether can be selected from bio-based or biodegradable materials, improving the environmental friendliness of the product. This invention adopts a "one-pot" melt polycondensation process, which requires no solvent, has a high reactant concentration, and a simple process. The process is clean and easy to control; the reaction conditions are mild, the catalyst dosage is low, and the cost is controllable; the obtained product is directly in a molten state, which facilitates subsequent extrusion, injection molding, and other processing, reducing energy consumption and improving production efficiency; the elastomer prepared by this invention has excellent comprehensive performance and significant competitive advantages. Compared with traditional petroleum-based polyamide elastomers, the product of this invention performs better in terms of low-temperature resistance, flexibility, and biocompatibility; the preparation process is green and efficient, suitable for large-scale production, and has significant economic and social benefits; this invention is applicable to wearable medical devices, medical instruments, polymer toughening materials, and foaming materials, with a wide range of applications and broad market prospects.

[0055] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A bio-based, low-temperature resistant, ultra-tough polyamide elastomer, characterized in that, It is copolymerized from diamine, long-chain diacid, and polyether, and has the following structure: ; Among them, R1 is selected from C 11 ~C 36 Straight-chain or branched alkylene groups; R2 is selected from C 24 ~C 44 A branched or alkene-bonded aliphatic carbon chain; R3 is selected from C2-C4 straight-chain or branched alkylene groups, m and n are the number of repeating units, where 1 <m<55,5<n<50。 2. The bio-based low-temperature resistant, ultra-tough polyamide elastomer according to claim 1, characterized in that, The diamine is selected from at least one natural oil, such as castor oil, erucic acid, or oleic acid, and has the general structural formula H2N-R2-NH2, where R2 is a C containing a double or single bond. 24 ~C 44 Aliphatic long chains, or molecules containing at least one six-membered ring, including benzene rings, piperidine rings, or naphthalene rings.

3. The bio-based low-temperature resistant ultra-tough polyamide elastomer according to claim 1, characterized in that, The long-chain dicarboxylic acid includes those with C 11 ~C 36 A straight carbon chain or containing C1~C 10 Branched dicarboxylic acids.

4. The bio-based low-temperature resistant ultra-tough polyamide elastomer according to claim 1, characterized in that, The polyether has a number-average molecular weight of 500-3000 g / mol, and the polyether is selected from at least one of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran.

5. The bio-based low-temperature resistant ultra-tough polyamide elastomer according to claim 1, characterized in that, The number-average molecular weight of the bio-based low-temperature resistant supertough polyamide elastomer is 1×10⁻⁶. 4 ~7×10 4 g / mol; The glass transition temperature of the bio-based low-temperature resistant ultra-tough polyamide elastomer is -80~10℃; The elongation at break of the bio-based low-temperature resistant ultra-tough polyamide elastomer is 1300%~3500%; The tensile strength of the bio-based low-temperature resistant ultra-tough polyamide elastomer is 1~50MPa.

6. A method for preparing a bio-based low-temperature resistant, ultra-tough polyamide elastomer as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Prepolymerization: Under inert gas protection, long-chain dicarboxylic acid, diamine and polyether are placed in a reactor in proportion, the reaction temperature is controlled at 160~240°C and the stirring speed is controlled, and the reaction is carried out for 1~4 hours to obtain oligomers. S2. Polycondensation: Add a catalyst to the oligomer obtained in step S1, and carry out a polycondensation reaction for 2-5 hours under vacuum of 80-250 Pa and reaction temperature of 200-280°C to obtain the bio-based low-temperature resistant super-tough polyamide elastomer.

7. The method for preparing the bio-based low-temperature resistant ultra-tough polyamide elastomer according to claim 6, characterized in that, The catalyst is selected from at least one of tetrabutyl titanate, tetraisopropyl titanate, tetrabutyl zirconate, zinc acetate, germanium dioxide, and sodium hypophosphite.

8. The method for preparing the bio-based low-temperature resistant ultra-tough polyamide elastomer according to claim 6, characterized in that, The molar ratio of the diamine to the long-chain dicarboxylic acid is 1.0:1.0~4.0; the mass ratio of the polyether is 10~70wt%; and the catalyst is 0.05~0.2wt% of the total feed mass.

9. The application of a bio-based low-temperature resistant super-tough polyamide elastomer prepared by any one of claims 1 to 5 or any one of claims 6 to 8 in wearable medical devices, medical instruments, polymer toughening materials or foaming materials.

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