Biboron structure-containing organosilicon thermosetting polyamide elastomer and preparation method thereof

Abstract

The invention discloses an organosilicone thermosetting polyamide elastomer containing a diboron structure and a preparation method of the organosilicone thermosetting polyamide elastomer, and belongs to the technical field of high polymer material preparation. The organosilicone thermosetting polyamide elastomer containing the linked boron structure is prepared by the following steps: pre-polymerizing nylon salt to obtain a small-molecular-weight polyamide prepolymer, acidifying, mixing with small-molecular-weight poly-linked boron siloxane, copolymerizing at high temperature and vacuum under the action of a catalyst, and curing to form chemical crosslinking, thereby obtaining the organosilicone thermosetting polyamide elastomer containing the linked boron structure. According to the invention, by introducing organic silicon with a boron-linked structure, a polyamide chain segment forms chemical network cross-linking, and the conversion of the polyamide elastomer from a thermoplastic elastomer to a thermosetting elastomer is realized, so that the mechanical strength and high-temperature resistance of the material are remarkably improved, and meanwhile, good elongation at break is kept; according to the invention, a series of products with different performance ranges are obtained by regulating and controlling the ratio of polyamide to polyborosiloxane of the organosilicone thermosetting polyamide elastomer containing the biboron structure, so that different requirements of users on the products are met.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material preparation, and in particular relates to a boron-containing organosilicon thermosetting polyamide elastomer and a preparation method thereof. Background Art

[0002] Polyamide elastomer is a typical block copolymer with polyamide as hard segment and polyether or polyester as soft segment. As a thermoplastic elastomer, it combines the properties of rubber and thermoplastics. It can be plasticized and molded at high temperature, and can show high elasticity of rubber materials at room temperature. It has excellent toughness, chemical resistance, wear resistance and other advantages. Therefore, it has been widely welcomed in many fields, such as electronics industry, sports equipment, biomedical materials, etc.

[0003] The first successful development and commercialization of polyamide elastomers can be traced back to 1979, by the German Hüls company (later renamed Diamide, now part of the Lanxess Group). Currently, major international manufacturers include Arkema Chemicals of France, which produces Elastomers and Evonik from Germany E series polyamide elastomer. In China, the main manufacturers include Cangzhou Xuyang Technology Co., Ltd., Zhejiang Xinyuan Technology Co., Ltd. and Baling Petrochemical, etc. However, compared with the international level, my country's overall industrialization level in this field still has a certain gap, and most of the products needed in the market are still highly dependent on imports.

[0004] As research on thermoplastic elastomers such as polyamide elastomers has deepened, it has been found that they are insufficient in strength and high temperature resistance. Despite their many advantages, they are difficult to use in high-strength or high-temperature environments. In contrast, thermosetting elastomers usually have higher mechanical strength and elasticity, can withstand greater external forces and deformations, and exhibit good resilience. This property enables thermosetting elastomers to perform well in situations where they need to withstand high loads and frequent deformations. In addition, thermosetting elastomers have good high temperature resistance and a high decomposition temperature, which allows them to maintain stable performance in high temperature environments without significant physical and chemical changes due to temperature increases.

[0005] Therefore, how to transform polyamide elastomers into thermosetting elastomers to improve their mechanical strength and high temperature resistance is a problem that needs to be solved at present.

[0006] In recent years, boron-containing polysiloxane has attracted much attention from the academic community due to its unique viscoelastic properties. This type of material exhibits extraordinary non-Newtonian fluid behavior, showing solid-like properties at high strain rates and liquid-like properties at low strain rates. Its excellent mechanical properties make it a high-quality component for improving the mechanical properties of plastics. For example, the addition of polyborosiloxane to EVA material can effectively enhance the tear strength and damping properties of the material (Li Hui. Research on dynamic mechanical properties of natural rubber and thermoplastic elastomer modified by polyborosiloxane [D]. Xi'an University of Technology, 2020.). The newly developed polyborosiloxane has a more stable cross-linked network structure than polyborosiloxane, and its effect on improving plastic properties is also better. For example, the tear strength of EVA material modified with polyborosiloxane is significantly improved (Wu Jinrong. A plastic modified with polyborosiloxane and its preparation method: 202111567254.8 [P]. 2024-05-28.). In addition, boron-containing polysiloxanes have been used in various industries as heat-resistant adhesives, flame retardants, heat-resistant coatings, etc. due to their high thermal stability. They can be added to plastics as an excellent high-temperature resistant component for modification (Wu Yanjin, Wu Mingjun, Li Meijiang. Research Progress on Preparation and Application of Polyborosiloxane [J]. Polymer Bulletin, 2012, (02): 94-98.).

[0007] Polyborosiloxane is a multifunctional polymer with a cross-linked network structure rich in hydroxyl functional groups. Theoretically, this polymer has the potential to cross-link with polyamide through chemical reactions, thereby building a more complex network structure system. This process is intended to promote the transformation of polyamide elastomers from thermoplastic to thermosetting elastomers, thereby significantly improving their mechanical strength properties and resistance to high temperature environments. Summary of the invention

[0008] In view of the problem that the mechanical strength and high temperature resistance of the current polyamide elastomer are insufficient, the present invention provides a boron-containing organosilicon thermosetting polyamide elastomer and a preparation method thereof.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A boron-containing silicone thermosetting polyamide elastomer is obtained by prepolymerizing nylon salt to obtain a low molecular weight polyamide prepolymer and acidifying it, then mixing it with a low molecular weight polyborosiloxane, copolymerizing it under the action of a catalyst at high temperature and vacuum for a certain period of time, and curing it to form chemical crosslinks.

[0011] Furthermore, the nylon salt is obtained by reacting, mixing and crystallizing a dicarboxylic acid (especially a dicarboxylic acid having 4 to 20 carbon atoms, preferably a dicarboxylic acid having 6 to 18 carbon atoms) and an aliphatic or aromatic diamine (especially an aliphatic or aromatic diamine having 2 to 20 carbon atoms, preferably an aliphatic or aromatic diamine having 6 to 14 carbon atoms) in deionized water in an equimolar ratio.

[0012] Further, the structural formula of the nylon salt is: + H3N(diamine)NH3 +- OOC(dicarboxylic acid)COO - .

[0013] Preferably, the dicarboxylic acid is any one of the following: cyclohexyl-1,4-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, octadecanedioic acid, terephthalic acid, isophthalic acid.

[0014] Preferably, the aliphatic or aromatic diamine is any one of the following: 1,6-hexanediamine, 1,10-decanediamine, 1,12-diaminododecane, 4,4'-diaminodiphenylmethane, 3.3'-dimethyl-4.4'diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, isophoronediamine, 2,6-bis(aminomethyl)pyridine.

[0015] Preferably, the dicarboxylic acid is sebacic acid, the aliphatic or aromatic diamine is decanediamine, and the nylon salt is nylon 1010 salt.

[0016] Furthermore, the preparation method of the low molecular weight polyamide prepolymer is as follows: adding dicarboxylic acid and aliphatic or aromatic diamine in equal molar ratios to a polymerization reactor, randomly adding an appropriate amount of deionized water and 0.5% antioxidant, and after the materials are completely dissolved, adding a small amount of acidifier for acidification, sealing the reactor and replacing the air in the reactor with high-purity nitrogen, repeating 3 to 5 times, starting the heating device, and when the temperature reaches 150° C., starting the stirrer to stir at a rate of 150 r / min, and maintaining this temperature for a constant temperature reaction for 30 minutes to ensure that the materials are fully melted and evenly mixed;

[0017] Then, the temperature of the reaction system was raised to 200°C and maintained at this temperature for 2 h.

[0018] Afterwards, the pressure in the reactor is gradually reduced by adjusting the valve until it reaches normal pressure;

[0019] Finally, the reaction product is taken out from the lower discharge port of the reactor, and after cooling, crushing and drying, a low molecular weight polyamide prepolymer is obtained;

[0020] The amount of deionized water added is 30% to 45% of the total mass of the dicarboxylic acid and the aliphatic or aromatic diamine. Preferably, the amount of deionized water added is 40% of the mass of the dicarboxylic acid and the diamine.

[0021] The antioxidant is one of antioxidant 1010, antioxidant 1076, antioxidant 1098, antioxidant 168, antioxidant 626, antioxidant 264, antioxidant 2246, antioxidant 3000, and antioxidant 3300. Preferably, the antioxidant is antioxidant 1098;

[0022] The acidulant is one of dibasic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and octadecanedioic acid. Preferably, the acidulant is sebacic acid.

[0023] Furthermore, the preparation method of the low molecular weight polyborosiloxane is: dissolving terminal hydroxyl polydimethylsiloxane and tetrahydroxydiborane in an appropriate amount of anhydrous methanol solvent at a mass ratio of 200:1, stirring them at 35°C for 15 minutes, mixing and stirring them for 1 hour, and removing the anhydrous methanol solvent by a rotary evaporator at 55°C and -0.1MPa to obtain a low molecular weight polyborosiloxane.

[0024] A method for preparing a boron-containing organosilicon thermosetting polyamide elastomer comprises the following steps: fully stirring and mixing a polyamide prepolymer and polyborosiloxane in a certain mass ratio and an appropriate amount of a catalyst at a certain temperature, pouring the mixture into a stainless steel mold, placing the mixture in a vacuum oven to maintain a negative pressure of -0.1 MPa, and heating and curing the mixture at a constant temperature to obtain the boron-containing organosilicon thermosetting polyamide elastomer.

[0025] Furthermore, the mass ratio of the polyamide prepolymer to the polyborosiloxane is 1 to 4:1, preferably, the mass ratio is 2:1.

[0026] Furthermore, the catalyst is one or a combination of two of hypophosphorous acid, potassium acetate, dibutyltin dilaurate, and tetrabutyl titanate; the catalyst is added in an amount of 0.1% to 2% of the total mass of the polyamide prepolymer and polyborosiloxane, preferably, the catalyst is added in an amount of 0.5% to 0.8% of the material addition.

[0027] Furthermore, the mixing temperature of the polyamide prepolymer and polyborosiloxane is 160°C to 210°C; the copolymerization temperature of the polyamide prepolymer and polyborosiloxane is in a gradient heating manner, preferably, reacting at 210°C-230°C for 1-3h, and then reacting at 250°C-270°C for 3-5h.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] (1) By introducing organic silicon with a boron-linked structure, the polyamide segments form a chemical network cross-linking, realizing the transformation of the polyamide elastomer from a thermoplastic elastomer to a thermosetting elastomer, thereby significantly improving the mechanical strength and high temperature resistance of the material while maintaining a good elongation at break;

[0030] (2) The ratio of polyamide to polyborosiloxane in the boron-containing silicone thermosetting polyamide elastomer of the present invention can be adjusted in a wide range. By adjusting the ratio of the two, a series of products with different performance ranges can be obtained, thereby meeting the different requirements of users for products. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a schematic diagram of the synthesis of polyamide prepolymers according to the present invention.

[0033] Figure 2 This is a schematic diagram of the synthesis of the boron-containing organosilicon thermosetting polyamide elastomer of the present invention. DETAILED DESCRIPTION

[0034] In order to gain a deeper understanding of the present invention, we will provide a comprehensive and detailed description of the present invention. However, the present invention has multiple implementations and is not limited to the specific examples listed herein. The presentation of these examples is intended to deepen the comprehensive understanding of the disclosure of the present invention.

[0035] In the following examples, unless otherwise specified, the materials and reagents used can be purchased from commercial channels.

[0036] For specific technical details or conditions not explicitly stated in the examples, reference may be made to the techniques or conditions described in existing literature in the art, or implementation may be carried out in accordance with the instructions of relevant products.

[0037] Example 1

[0038] A method for preparing a thermosetting polyamide elastomer containing a boron-containing organosilicon structure

[0039] (1) 1461 g of adipic acid, 1162 g of hexamethylenediamine, 1049 g of deionized water, and 13.1 g of antioxidant 1098 were added to a polymerization reactor. After the materials were completely dissolved, 10 g of adipic acid was added for acidification. The reactor was sealed and the air in the reactor was replaced with high-purity nitrogen. This process was repeated 3-5 times. The heating device was started. When the temperature reached 150° C., the stirrer was started to stir at a rate of 150 r / min, and the temperature was maintained for a constant temperature reaction for 30 min to ensure that the materials were fully melted and uniformly mixed. Subsequently, the temperature of the reaction system was increased to 200° C., and the temperature was maintained for a constant temperature reaction for 2 h. Thereafter, the pressure in the reactor was gradually reduced by adjusting the valve until it reached a normal pressure state. Finally, the reaction product was taken out from the lower discharge port of the reactor, and after cooling, crushing, and drying steps, a low molecular weight polyamide 66 prepolymer was obtained.

[0040] (2) dissolving 1000 g of hydroxy-terminated polydimethylsiloxane in 500 mL of anhydrous methanol solvent, dissolving 5 g of tetrahydroxydiborane in 50 mL of anhydrous methanol solvent, stirring them at 35° C. for 15 min, mixing and stirring them for 1 h, and removing the anhydrous methanol solvent by a rotary evaporator at 55° C. and −0.1 MPa to obtain a low molecular weight polydiboranosiloxane;

[0041] (3) 2000 g of polyamide 66 prepolymer, 1000 g of polyborosiloxane, and 15 g of hypophosphorous acid were mixed and stirred at 200 °C, poured into a stainless steel mold, placed in a vacuum oven and maintained at a negative pressure of -0.1 MPa, reacted at 230 °C for 2.5 h, and then heated to 270 °C for 4 h to obtain a boron-containing silicone thermosetting polyamide 66 elastomer with a polyamide to polyborosiloxane content ratio of 2:1.

[0042] Example 2

[0043] A method for preparing a boron-containing silicone thermosetting polyamide elastomer, comprising the following steps: (3) mixing 1800 g of a polyamide 66 prepolymer, 600 g of polyborosiloxane, and 12 g of hypophosphorous acid, stirring the mixture at 200° C., pouring the mixture into a stainless steel mold, placing the mixture in a vacuum oven and maintaining a negative pressure of -0.1 MPa, reacting the mixture at 230° C. for 2.5 h, and then heating the mixture to 270° C. for 4 h to obtain a boron-containing silicone thermosetting polyamide 66 elastomer having a polyamide to polyborosiloxane content ratio of 3:1.

[0044] Example 3

[0045] A method for preparing a boron-containing silicone thermosetting polyamide elastomer, the steps are the same as those of Example 1, except that: (3) 2000 g of a polyamide 66 prepolymer, 500 g of polyborosiloxane, and 12.5 g of hypophosphorous acid are mixed and fully stirred at 200° C., poured into a stainless steel mold, placed in a vacuum oven and maintained at a negative pressure of -0.1 MPa, reacted at 230° C. for 2.5 h, and then heated to 270° C. for 4 h to obtain a boron-containing silicone thermosetting polyamide 66 elastomer with a polyamide to polyborosiloxane content ratio of 4:1.

[0046] Example 4

[0047] A method for preparing a thermosetting polyamide elastomer containing a biboron structure of organic silicon, comprising: (1) adding 1348 g of sebacic acid, 1149 g of decanediamine, 1124 g of deionized water, and 12.5 g of antioxidant 1098 to a polymerization reactor, and after the materials are completely dissolved, adding 10 g of sebacic acid for acidification, sealing the reactor and replacing the air in the reactor with high-purity nitrogen, repeating the process 3-5 times, starting a heating device, and when the temperature reaches 150° C., starting a stirrer to stir at a rate of 150 r / min, and maintaining the temperature for a constant temperature reaction for 30 min to ensure that the materials are fully melted and evenly mixed; then, raising the temperature of the reaction system to 200° C., and maintaining the temperature for a constant temperature reaction for 2 h; then, gradually reducing the pressure in the reactor by adjusting a valve until it reaches a normal pressure state; finally, taking out the reaction product from the lower discharge port of the reactor, and obtaining a low molecular weight polyamide 1010 prepolymer after cooling, crushing, and drying.

[0048] (2) dissolving 1000 g of hydroxy-terminated polydimethylsiloxane in 500 mL of anhydrous methanol solvent, dissolving 5 g of tetrahydroxydiborane in 50 mL of anhydrous methanol solvent, stirring them at 35° C. for 15 min, mixing and stirring them for 1 h, and removing the anhydrous methanol solvent by a rotary evaporator at 55° C. and −0.1 MPa to obtain a low molecular weight polydiboranosiloxane;

[0049] (3) 2000 g of polyamide 1010 prepolymer, 1000 g of polyborosiloxane, and 15 g of hypophosphorous acid were mixed and stirred at 200 °C, poured into a stainless steel mold, placed in a vacuum oven and maintained at a negative pressure of -0.1 MPa, reacted at 220 °C for 2.5 h, and then heated to 260 °C for 4 h to obtain a boron-containing silicone thermosetting polyamide 1010 elastomer with a polyamide to polyborosiloxane content ratio of 2:1.

[0050] Comparative Example 1

[0051] (1) 1461 g of adipic acid, 1162 g of hexamethylenediamine, 1049 g of deionized water, and 13.1 g of antioxidant 1098 were added to a polymerization reactor. After the materials were completely dissolved, 10 g of adipic acid was added for acidification. The reactor was sealed and the air in the reactor was replaced with high-purity nitrogen. This process was repeated 3-5 times. The heating device was started. When the temperature reached 150° C., the stirrer was started to stir at a rate of 150 r / min, and the temperature was maintained for a constant temperature reaction for 30 min to ensure that the materials were fully melted and uniformly mixed. Subsequently, the temperature of the reaction system was increased to 200° C., and the temperature was maintained for a constant temperature reaction for 2 h. Thereafter, the pressure in the reactor was gradually reduced by adjusting the valve until it reached a normal pressure state. Finally, the reaction product was taken out from the lower discharge port of the reactor, and after cooling, crushing, and drying steps, a low molecular weight polyamide 66 prepolymer was obtained.

[0052] (2) 2000 g of polyamide 66 prepolymer, 1000 g of terminal hydroxyl polydimethylsiloxane, and 15 g of hypophosphorous acid were mixed and stirred at 200° C., poured into a stainless steel mold, placed in a vacuum oven and maintained at a negative pressure of -0.1 MPa, reacted at 230° C. for 2.5 h, and then heated to 270° C. for 4 h to obtain a silicone-containing thermoplastic polyamide 66 elastomer with a polyamide to terminal hydroxyl polydimethylsiloxane content ratio of 2:1.

[0053] Comparative Example 2

[0054] (1) 1348 g of sebacic acid, 1149 g of decanediamine, 1124 g of deionized water, and 12.5 g of antioxidant 1098 are added to a polymerization reactor. After the materials are completely dissolved, 10 g of sebacic acid is added for acidification. The reactor is sealed and the air in the reactor is replaced with high-purity nitrogen. This process is repeated 3-5 times. The heating device is started. When the temperature reaches 150° C., the stirrer is started to stir at a rate of 150 r / min, and the temperature is maintained for a constant temperature reaction for 30 min to ensure that the materials are fully melted and evenly mixed. Subsequently, the temperature of the reaction system is increased to 200° C., and the temperature is maintained for a constant temperature reaction for 2 h. Thereafter, the pressure in the reactor is gradually reduced by adjusting the valve until it reaches a normal pressure state. Finally, the reaction product is taken out from the lower discharge port of the reactor, and after cooling, crushing, and drying steps, a low molecular weight polyamide 1010 prepolymer is obtained.

[0055] (2) 2000 g of polyamide 1010 prepolymer, 1000 g of terminal hydroxyl polydimethylsiloxane, and 15 g of hypophosphorous acid were mixed and stirred at 200° C., poured into a stainless steel mold, placed in a vacuum oven and maintained at a negative pressure of -0.1 MPa, reacted at 220° C. for 2.5 h, and then heated to 260° C. for 4 h to obtain a silicone-containing thermoplastic polyamide 1010 elastomer with a polyamide to terminal hydroxyl polydimethylsiloxane content ratio of 2:1.

[0056] Mechanical properties test:

[0057] According to GB / T1040.2-2022 standard "Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics", the mechanical properties (tensile strength and elongation at break) of the polyamide elastomer materials of the above-mentioned Examples 1-4 and Comparative Examples 1-2 were tested. Among them, the total length l3 is 170mm, the length l1 of the narrow parallel part is 80.0±2mm, the radius r is 24±1mm, the distance l2 of the wide parallel part is 109.3±3.2mm, the end width b2 is 20.0±0.2mm, the narrow part width b1 is 10.0±0.2mm, the preferred thickness h is 4.0±0.2mm, the gauge length L0 is 75.0±0.5mm, and the initial distance L between the clamps is 115±1mm. The specimens are derived from the above-mentioned polyamide elastomer materials cured and molded in a specific stainless steel mold. The number of specimens in each group is 5, and the results are averaged.

[0058] Thermal performance test:

[0059] The 5% weight loss temperature of the polyamide elastomer materials of the above-mentioned Examples 1-4 and Comparative Examples 1-2 was determined by thermogravimetric analysis test, and this was used as a basis for judging the high temperature resistance of the materials.

[0060] The test results of mechanical properties and thermal properties of the polyamide elastomer materials of Examples 1 to 4 and Comparative Examples 1 to 2 and foreign polyamide elastomer material samples with polyether as the soft segment are shown in Table 1:

[0061] Table 1 Performance test results of different polyamide elastomer materials

[0062]

[0063] It can be seen from the mechanical properties and thermal properties test results of the above embodiments and comparative examples that: compared with the chain polyamide elastomer with terminal hydroxyl polydimethylsiloxane as the soft segment, the polyamide introduces the boron-containing structured organic silicon so that the polyamide segments form a chemical network cross-linking and are transformed from a thermoplastic elastomer to a thermosetting elastomer, which can significantly improve its tensile strength and high temperature resistance, and still has a good elongation at break;

[0064] Compared with traditional thermoplastic polyamide elastomer materials with polyether as the soft segment, the tensile strength is slightly improved, the elongation at break is slightly reduced but still good, and the high temperature resistance is significantly enhanced.

[0065] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in the field. Although the illustrative specific embodiments of the present invention are described above to facilitate the understanding of the present invention by the technical personnel in the field, it should be clear that the present invention is not limited to the scope of the specific embodiments. For the ordinary technical personnel in the field, as long as various changes are within the spirit and scope of the present invention defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A boron-containing silicone thermosetting polyamide elastomer, characterized in that: The prepolymer of low molecular weight polyamide is obtained by prepolymerizing nylon salt and acidifying, and then mixed with low molecular weight polyborosiloxane, copolymerized under the action of catalyst at high temperature and vacuum for a certain period of time, and cured to form chemical crosslinking.

2. The boron-containing organosilicon thermosetting polyamide elastomer according to claim 1, characterized in that: The nylon salt is obtained by reacting and mixing a dicarboxylic acid and an aliphatic or aromatic diamine in deionized water in an equimolar ratio and then crystallizing. The structural formula of the nylon salt is: + H3N(diamine)NH3 +- OOC(dicarboxylic acid)COO - .

3. The boron-containing organosilicon thermosetting polyamide elastomer according to claim 1, characterized in that: The dicarboxylic acid is any one of the following: cyclohexyl-1,4-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, octadecanedioic acid, terephthalic acid, isophthalic acid; the aliphatic or aromatic diamine is any one of the following: 1,6-hexanediamine, 1,10-decanediamine, 1,12-diaminododecane, 4,4'-diaminodiphenylmethane, 3.3'-dimethyl-4.4'diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, isophoronediamine, 2,6-bis(aminomethyl)pyridine.

4. The boron-containing organosilicon thermosetting polyamide elastomer according to claim 1, characterized in that: The preparation method of the low molecular weight polyamide prepolymer is as follows: adding dicarboxylic acid and aliphatic or aromatic diamine in equal molar ratios into a polymerization reactor, then adding an appropriate amount of deionized water and 0.5% antioxidant, adding a small amount of acidifier for acidification after the materials are completely dissolved, replacing the air with high-purity nitrogen under sealed conditions, heating to a temperature of 150° C., stirring at a rate of 150 r / min, and maintaining this temperature for a constant temperature reaction for 30 minutes; then raising the temperature of the reaction system to 200° C. for a constant temperature reaction for 2 hours; then gradually reducing the pressure in the reactor until it reaches a normal pressure state; finally taking out the reaction product, cooling, crushing and drying it to obtain a low molecular weight polyamide prepolymer.

5. The boron-containing organosilicon thermosetting polyamide elastomer according to claim 4, characterized in that: The added amount of the deionized water is 30% to 45% of the total mass of the dicarboxylic acid and the aliphatic or aromatic diamine; the antioxidant is one of antioxidant 1010, antioxidant 1076, antioxidant 1098, antioxidant 168, antioxidant 626, antioxidant 264, antioxidant 2246, antioxidant 3000, and antioxidant 3300; the acidulant is one of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and octadecanedioic acid.

6. The boron-containing organosilicon thermosetting polyamide elastomer according to claim 1, characterized in that: The preparation method of the low molecular weight polyborosiloxane is as follows: dissolving terminal hydroxyl polydimethylsiloxane and tetrahydroxydiborane in an appropriate amount of anhydrous methanol solvent at a mass ratio of 200:1, stirring them at 35°C for 15 minutes, mixing and stirring them for reaction for 1 hour, and removing the anhydrous methanol solvent by a rotary evaporator at 55°C and -0.1MPa to obtain the low molecular weight polyborosiloxane.

7. A method for preparing a boron-containing silicone thermosetting polyamide elastomer, characterized in that: A certain mass ratio of polyamide prepolymer, polyborosiloxane and an appropriate amount of catalyst are fully stirred and mixed at a certain temperature, poured into a stainless steel mold, placed in a vacuum oven to maintain a negative pressure of -0.1MPa, heated and cured at a constant temperature to obtain a boro-containing silicone thermosetting polyamide elastomer.

8. The method for preparing a boron-containing organosilicon thermosetting polyamide elastomer according to claim 7, characterized in that: The mass ratio of the polyamide prepolymer to the polyborosiloxane is 1 to 4:

1.

9. The method for preparing a boron-containing organosilicon thermosetting polyamide elastomer according to claim 7, characterized in that: The catalyst is one or a combination of two of hypophosphorous acid, potassium acetate, dibutyltin dilaurate and tetrabutyl titanate; the added amount of the catalyst is 0.1% to 2% of the total mass of the polyamide prepolymer and the polyborosiloxane.

10. The method for preparing a boron-containing organosilicon thermosetting polyamide elastomer according to claim 7, characterized in that: The mixing temperature of the polyamide prepolymer and polyborosiloxane is 160°C to 210°C; the copolymerization temperature of the polyamide prepolymer and polyborosiloxane adopts a gradient heating method, reacting at 210°C to 230°C for 1 to 3 hours, and then reacting at 250°C to 270°C for 3 to 5 hours.

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