Bio-based polyamide material with high tensile strength and preparation process thereof

Abstract

The invention discloses a bio-based polyamide material with high tensile strength and a preparation process thereof, and belongs to the technical field of polyamide preparation. The bio-based polyamide material with high tensile strength is prepared from the following components in parts by weight: 50 to 68 parts of a bio-based monomer, 2.12 to 2.83 parts of an antioxidant, 0.14 to 0.28 part of a catalyst and 0.5 to 1 part of a nucleating agent, the preparation process of the bio-based polyamide material with high tensile strength comprises the following steps: step 1, performing vacuum drying on a bio-based monomer, adding an antioxidant, a catalyst and a nucleating agent, and stirring and mixing to obtain a premix; and 2, adding the premix into a twin-screw extruder, carrying out melt polymerization, granulating, and drying to obtain the bio-based polyamide material with high tensile strength. The polyamide material prepared by the method has excellent tensile strength, thermal stability and weather resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of bio-based polyamide material preparation, and in particular relates to a bio-based polyamide material with high tensile strength and a preparation process thereof. Background Art

[0002] Bio-based polyimide materials are a key research area in the field of high-performance polymers. Their development aims to replace traditional petroleum-based raw materials with renewable resources, achieving the dual goals of environmental friendliness and sustainable development. However, existing bio-based polyimide materials still face significant challenges in key performance indicators, particularly insufficient tensile strength and oxidation resistance, which seriously restrict their large-scale application in high-end fields such as aerospace and electronic packaging.

[0003] Patent CN119842230B discloses a highly heat-resistant bio-based polyamide material and its preparation method, comprising the following raw materials in parts by weight: 45-50 parts of PA56, 7-11 parts of a balanced multi-effect agent for blending fillers and modifiers, 5-8 parts of a flame retardant, 4-7 parts of a silane coupling agent, 3-5 parts of an antioxidant, and 2-4 parts of a lubricant. The bio-based polyamide material of this invention uses bio-based PA56 as a matrix, while adding flame retardants, silane coupling agents, antioxidants, and lubricants as functional additives. The balanced multi-effect agent for blending fillers and modifiers is combined with a stabilizer. Through the coordination and coordination of the raw materials, the resulting bio-based polyamide material has coordinated improvements in dielectric loss, flame retardancy, and wear resistance. At the same time, the product has significant weather resistance and high heat stability. However, the tensile strength, thermal stability, and weather resistance of the bio-based polyamide material obtained by this method still need to be improved. Summary of the Invention

[0004] The purpose of the present invention is to provide a bio-based polyamide material with high tensile strength and a preparation process thereof, so as to solve the technical problems of poor tensile strength, thermal stability and weather resistance of bio-based polyamide materials in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The invention provides a bio-based polyamide material with high tensile strength. The material is composed of the following components in parts by weight: 50-68 parts of a bio-based monomer, 2.12-2.83 parts of an antioxidant, 0.14-0.28 parts of a catalyst, and 0.5-1 parts of a nucleating agent.

[0006] Preferably, the method for preparing the bio-based monomer comprises the following steps: Q1: Add 2,7-dihydroxynaphthalene and 3-fluoro-4-nitrophenol to a container containing N,N-dimethylformamide, stir and dissolve, heat, add potassium carbonate, heat under reflux for reaction, cool after the reaction is completed, add to deionized water, let stand, filter, wash with water, dry, wash, filter, and dry to obtain compound 1; Q2: Compound 1 and Pd / C were added to a container containing ethanol, heated, and hydrazine hydrate was slowly added dropwise. After the reaction was completed, the mixture was filtered while hot, cooled, added to deionized water, allowed to stand for precipitation, filtered, and dried in vacuo to obtain compound 2. Q3: Compound 2 and 2,2-bis(4-hydroxy-3-aminophenyl)propane are added to a container containing dimethylacetamide, stirred until dissolved, and then dimer acid is slowly added. After stirring and reacting, a bio-based monomer is obtained.

[0007] In the above process, the synthesis reaction formula of bio-based monomers is as follows: The results of mass spectrometry analysis of compound 1 were: m / z: 434.08 (100.0%), 435.08 (24.3%), 436.08(4.6%); the results of mass spectrometry analysis of compound 2 were: m / z: 374.13 (100.0%), 375.13 (24.2%), 376.13(3.7%).

[0008] Preferably, in Q1, the molar ratio of 2,7-dihydroxynaphthalene, 3-fluoro-4-nitrophenol and potassium carbonate is (0.05-0.08): (0.1-0.17): (0.1-0.15), the temperature is raised to 130-140°C, the heating reflux reaction temperature is 130-140°C, and the reaction time is 20-24h.

[0009] Preferably, in Q2, the usage ratio of compound 1, Pd / C, ethanol and hydrazine hydrate is (4.12-4.56) g: (0.11-0.15) g: (80-100) mL: (10-20) mL, and the mixture is heated to 80-85° C. and the reflux reaction time is 20-24 h.

[0010] Preferably, in Q3, the molar ratio of compound 2, 2,2-bis(4-hydroxy-3-aminophenyl)propane and dimer acid is (0.45-0.55):(0.05-0.09):(0.5-0.62), and the stirring reaction time is 20-24 h.

[0011] Preferably, the method for preparing the antioxidant comprises the following steps: S1: Add 3-aminophenol to deionized water, stir evenly, add acetic anhydride, mix and stir, filter, and recrystallize to obtain intermediate A; add intermediate A to acetone, stir, add iodomethane and anhydrous potassium carbonate, stir, heat and reflux to react, cool, filter, rotary evaporate, extract, wash, and dry to obtain intermediate B; S2: Under a nitrogen atmosphere, intermediate B and 4-nitrobenzoyl chloride are added to dichloroethane, anhydrous aluminum chloride is added during stirring, the mixture is stirred and then heated to reflux for reaction, after which the reaction is completed, the mixture is cooled, added to an aqueous hydrochloric acid solution, fully stirred, filtered, washed, and recrystallized to obtain intermediate C; under a nitrogen atmosphere, intermediate C and the aqueous hydrochloric acid solution are mixed and stirred, heated to reflux for reaction, after which the reaction is completed, the mixture is cooled, the pH is adjusted, filtered, recrystallized, and dried to obtain intermediate D; S3: Add intermediate D to ethanol, then add Pd / C, stir evenly, and introduce hydrogen. After the reaction is complete, filter, rotary evaporate, recrystallize, and dry to obtain intermediate E; S4: Add 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid to chloroform, add dichlorothionyl dropwise under nitrogen protection, after the addition is complete, heat the temperature to react, and distill under reduced pressure to obtain a light yellow solid F; add the intermediate E to acetonitrile, add a mixed solution of acetonitrile and light yellow solid F dropwise under low temperature, add a mixed solution of triethylamine and acetonitrile under nitrogen protection, stir the reaction, heat the temperature to react, and after the reaction is completed, purify to obtain an antioxidant.

[0012] In the above process, the synthesis reaction formula of the antioxidant is as follows: The results of mass spectrometry analysis of intermediate A were: m / z: 151.06 (100.0%), 152.07 (8.8%); the results of mass spectrometry analysis of intermediate B were: m / z: 165.08 (100.0%), 166.08 (10.2%); the results of mass spectrometry analysis of intermediate C were: m / z: 300.07 (100.0%), 301.08 (16.6%), 302.08 (2.4%); the results of mass spectrometry analysis of intermediate D were: m / z: 258.06 (100.0%), 259.07 (14.3%), 260.07 (1.8%); the results of mass spectrometry analysis of intermediate E were: m / z: 228.09 (100.0%), 229.09 (14.9%); the results of mass spectrometry analysis of the light yellow solid F were: m / z: 296.15 (100.0%), 298.15 (32.0%), 297.16 (18.8%), 299.15 (5.9%), 298.16 (2.1%); the results of mass spectrometry analysis of the antioxidant were: m / z: 748.45 (100.0%), 749.45 (51.8%), 750.45 (14.7%), 751.46 (2.2%).

[0013] Preferably, in S1, the amount ratio of 3-aminophenol, deionized water and acetic anhydride is (10.12-11.78) g: (90-110) mL: (8-12) mL, and the mixing time is 4-6 h; the amount ratio of intermediate A, acetone, iodomethane and anhydrous potassium carbonate is (7.12-7.98) g: (80-90) mL: (7.51-7.88) mL: (20.08-24.16) g. ; In S2, the amount ratio of intermediate B, 4-nitrobenzoyl chloride, dichloroethane and anhydrous aluminum chloride is (6.41-6.82) g: (9.12-10.08) g: (80-100) mL: (8.99-9.09) g, and the stirring reaction time is 1-2 h; the amount ratio of intermediate C and hydrochloric acid aqueous solution is (5.01-5.33) g: (75-100) mL, and the heating reflux reaction time is 4-6 h.

[0014] Preferably, in S3, the amount ratio of intermediate D, ethanol and Pd / C is (2.12-2.41) g: (250-300) mL: (0.09-0.12) g; in S4, the amount ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, chloroform and dichlorothionyl is (5.12-5.98) g: (45-55) mL: (8-12) mL, the heating reaction temperature is 50-55°C, and the reaction time is 5-8 h; the molar ratio of intermediate E and light yellow solid F is (1.8-2.2): (0.8-1.02), the low temperature environment temperature is 0-2°C, the heating reaction temperature is 50-60°C, and the reaction time is 20-24 h.

[0015] Preferably, the preparation process of the bio-based polyamide material with high tensile strength comprises the following steps: Step 1: After vacuum drying the bio-based monomer, an antioxidant, a catalyst, and a nucleating agent are added, and the mixture is stirred to obtain a premix; Step 2: Add the premix to a twin-screw extruder, melt-polymerize, granulate, and dry to obtain a bio-based polyamide material with high tensile strength.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention uses bio-based monomers as the main base material of the polyamide material, and adds antioxidants during the preparation of the polyamide material, so that the prepared polyamide material has excellent mechanical properties, thermal stability and weather resistance.

[0017] 2. The present invention uses the prepared bio-based monomer as the main raw material of polyamide material, which can effectively improve its tensile strength and elongation at break. The naphthalene ring contained in the bio-based monomer imparts high modulus, the dimer acid provides molecular chain mobility, and the amide bonds and phenolic hydroxyl groups contained therein can form intermolecular / intramolecular hydrogen bond networks. The synergistic effect of rigidity and flexibility and the composite effect of multiple hydrogen bond sites jointly improve the mechanical properties of polyamide material.

[0018] 3. The present invention adds the prepared antioxidant to the preparation process of the polyamide material, which can effectively inhibit thermal oxidative degradation and improve thermal stability. At the same time, it can also improve weather resistance and resist ultraviolet light aging. The phenolic hydroxyl groups contained in the antioxidant can capture free radicals and peroxy radicals generated by molecular chain breakage by providing active hydrogen atoms, thereby terminating the chain reaction and improving thermal oxidative stability. At the same time, the conjugated structure of the benzene ring can absorb ultraviolet light energy, reduce photoexcitation and breakage of the polyamide molecular chain, and reduce photodegradation and discoloration during outdoor use. DETAILED DESCRIPTION

[0019] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] Example 1: This example discloses a method for preparing a bio-based monomer, comprising the following steps: Q1: 11.53 g of 2,7-dihydroxynaphthalene and 22.57 g of 3-fluoro-4-nitrophenol were added to a container containing 150 mL of N,N-dimethylformamide, stirred and dissolved, and then heated to 135°C. 17.52 g of potassium carbonate was added and the mixture was heated under reflux at 135°C for 24 h. After the reaction was completed, the mixture was cooled and added to deionized water. The mixture was allowed to stand, filtered, washed with water, dried, washed, filtered, and dried to obtain compound 1. Q2: 4.34 g of compound 1 and 0.13 g of Pd / C were added to a container containing 90 mL of ethanol, heated to 85°C, and 15 mL of hydrazine hydrate was slowly added dropwise. The reaction was refluxed for 24 h. After the reaction was completed, the mixture was filtered while hot, cooled, added to deionized water, allowed to stand and precipitate, filtered, and dried in vacuo to obtain compound 2. Q3: 1.84 g of compound 2 and 0.18 g of 2,2-bis(4-hydroxy-3-aminophenyl)propane were added to a container containing 20 mL of dimethylacetamide and stirred until dissolved. Then, 3.15 g of dimer acid was slowly added and stirred for 24 hours to obtain a bio-based monomer.

[0021] This embodiment discloses a method for preparing an antioxidant, comprising the following steps: S1: Add 10.95 g of 3-aminophenol to 100 mL of deionized water, stir evenly, add 10 mL of acetic anhydride, mix and stir for 4 hours, filter, and recrystallize to obtain intermediate A; add 7.65 g of intermediate A to 85 mL of acetone, stir for 20 minutes, then add 7.63 g of iodomethane and 22.12 g of anhydrous potassium carbonate, stir, heat and reflux to react, cool after completion of the reaction, filter, rotary evaporate, extract, wash, and dry to obtain intermediate B; S2: Under a nitrogen atmosphere, 6.62 g of intermediate B and 9.57 g of 4-nitrobenzoyl chloride were added to 90 mL of dichloroethane, and 9.04 g of anhydrous aluminum chloride was added during stirring. The mixture was stirred for 1 hour and then heated to reflux. After the reaction was completed, the mixture was cooled and added to a 5% by volume hydrochloric acid aqueous solution. The mixture was stirred for 2 hours, filtered, washed, and recrystallized to obtain intermediate C. Under a nitrogen atmosphere, 5.17 g of intermediate C and 87.5 mL of a 20% by volume hydrochloric acid aqueous solution were mixed and stirred, heated to reflux for 4 hours, cooled, and the pH was adjusted with a saturated sodium bicarbonate solution. The mixture was filtered, recrystallized, and dried to obtain intermediate D. S3: 2.25 g of intermediate D was added to 275 mL of ethanol, followed by 0.11 g of Pd / C. After stirring, hydrogen was introduced. After the reaction was complete, the mixture was filtered, rotary evaporated, recrystallized, and dried to obtain intermediate E. S4: Add 5.61 g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid to 50 mL of chloroform, and add 10 mL of dichlorothione dropwise under nitrogen protection. After the addition is complete, heat the reaction at 55°C for 8 hours, and distill under reduced pressure to obtain a light yellow solid F; add 4.75 g of intermediate E to 10 mL of acetonitrile, and add a mixed solution of 50 mL of acetonitrile and 2.71 g of light yellow solid F dropwise at a low temperature of 0°C. Under nitrogen protection, add a mixed solution of 0.8 mL of triethylamine and 8 mL of acetonitrile, stir the reaction, and heat the reaction at 55°C for 24 hours. After the reaction is completed, purify to obtain an antioxidant.

[0022] This embodiment discloses a bio-based polyamide material with high tensile strength, which is composed of the following components in parts by weight: 59 parts of a bio-based monomer, 2.52 parts of an antioxidant, 0.21 parts of sodium hypophosphite, and 0.75 parts of nano-montmorillonite.

[0023] This embodiment discloses a process for preparing a bio-based polyamide material with high tensile strength, comprising the following steps: Step 1: After vacuum drying the bio-based monomer, an antioxidant, sodium hypophosphite and nano-montmorillonite are added, and the mixture is stirred to obtain a premix; Step 2: Add the premix to a twin-screw extruder, melt-polymerize, granulate, and dry to obtain a bio-based polyamide material with high tensile strength.

[0024] Example 2: This example discloses a method for preparing a bio-based monomer, comprising the following steps: Q1: 8.51 g of 2,7-dihydroxynaphthalene and 16.91 g of 3-fluoro-4-nitrophenol were added to a container containing 150 mL of N,N-dimethylformamide, stirred and dissolved, and then heated to 135°C. 13.82 g of potassium carbonate was added and heated under reflux at 135°C for 24 h. After the reaction was completed, the mixture was cooled and added to deionized water. The mixture was allowed to stand, filtered, washed with water, dried, washed, filtered, and dried to obtain compound 1. Q2: Add 4.12 g of compound 1 and 0.11 g of Pd / C to a container filled with 100 mL of ethanol, heat to 85°C, slowly add 20 mL of hydrazine hydrate dropwise, and reflux for 24 h. After the reaction is complete, filter while hot, cool, add to deionized water, let stand and precipitate, filter, and vacuum dry to obtain compound 2; Q3: 1.68 g of compound 2 and 0.13 g of 2,2-bis(4-hydroxy-3-aminophenyl)propane were added to a container containing 20 mL of dimethylacetamide and stirred until dissolved. Then, 2.81 g of dimer acid was slowly added and stirred for 24 hours to obtain a bio-based monomer.

[0025] This embodiment discloses a method for preparing an antioxidant, comprising the following steps: S1: Add 10.12 g of 3-aminophenol to 110 mL of deionized water, stir evenly, add 12 mL of acetic anhydride, mix and stir for 4 hours, filter, and recrystallize to obtain intermediate A; add 7.12 g of intermediate A to 90 mL of acetone, stir for 20 minutes, then add 7.51 g of iodomethane and 20.08 g of anhydrous potassium carbonate, stir, heat and reflux to react, cool, filter, rotary evaporate, extract, wash, and dry to obtain intermediate B; S2: Under a nitrogen atmosphere, 6.41 g of intermediate B and 9.12 g of 4-nitrobenzoyl chloride were added to 100 mL of dichloroethane, and 9.09 g of anhydrous aluminum chloride was added during stirring. The mixture was stirred for 1 hour and then heated to reflux. After the reaction was completed, the mixture was cooled and added to a 5% by volume hydrochloric acid aqueous solution. The mixture was stirred for 2 hours, filtered, washed, and recrystallized to obtain intermediate C. Under a nitrogen atmosphere, 5.01 g of intermediate C was mixed with 75 mL of a 20% by volume hydrochloric acid aqueous solution, stirred, heated to reflux for 4 hours, cooled, adjusted the pH with a saturated sodium bicarbonate solution, filtered, recrystallized, and dried to obtain intermediate D. S3: 2.12 g of intermediate D was added to 250 mL of ethanol, followed by 0.09 g of Pd / C. After stirring, hydrogen was introduced. After the reaction was complete, the mixture was filtered, rotary evaporated, recrystallized, and dried to obtain intermediate E. S4: Add 5.12 g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid to 45 mL of chloroform, and add 12 mL of dichlorothione dropwise under nitrogen protection. After the addition is complete, heat the reaction at 55°C for 8 hours, and distill under reduced pressure to obtain a light yellow solid F; add 4.32 g of intermediate E to 10 mL of acetonitrile, and add a mixed solution of 50 mL of acetonitrile and 2.37 g of light yellow solid F dropwise at a low temperature of 0°C. Under nitrogen protection, add a mixed solution of 0.8 mL of triethylamine and 8 mL of acetonitrile, stir the reaction, and heat the reaction at 55°C for 24 hours. After the reaction is completed, purify to obtain an antioxidant.

[0026] This embodiment discloses a bio-based polyamide material with high tensile strength, which is composed of the following components in parts by weight: 50 parts of a bio-based monomer, 2.12 parts of an antioxidant, 0.14 parts of sodium hypophosphite, and 1 part of nano-montmorillonite.

[0027] This embodiment discloses a process for preparing a bio-based polyamide material with high tensile strength, comprising the following steps: Step 1: After vacuum drying the bio-based monomer, an antioxidant, sodium hypophosphite and nano-montmorillonite are added, and the mixture is stirred to obtain a premix; Step 2: Add the premix to a twin-screw extruder, melt-polymerize, granulate, and dry to obtain a bio-based polyamide material with high tensile strength.

[0028] Example 3: This example discloses a method for preparing a bio-based monomer, comprising the following steps: Q1: 13.61 g of 2,7-dihydroxynaphthalene and 28.75 g of 3-fluoro-4-nitrophenol were added to a container containing 150 mL of N,N-dimethylformamide, stirred and dissolved, and then heated to 135°C. 20.73 g of potassium carbonate was added and the mixture was heated under reflux at 135°C for 24 h. After the reaction was completed, the mixture was cooled and added to deionized water. The mixture was allowed to stand, filtered, washed with water, dried, washed, filtered, and dried to obtain compound 1. Q2: 4.56 g of compound 1 and 0.15 g of Pd / C were added to a container containing 80 mL of ethanol, heated to 85°C, and 10 mL of hydrazine hydrate was slowly added dropwise. The reaction was refluxed for 24 h. After the reaction was completed, the mixture was filtered while hot, cooled, added to deionized water, allowed to stand and precipitate, filtered, and dried in vacuo to obtain compound 2. Q3: 2.06 g of compound 2 and 0.23 g of 2,2-bis(4-hydroxy-3-aminophenyl)propane were added to a container containing 20 mL of dimethylacetamide and stirred until dissolved. Then, 3.49 g of dimer acid was slowly added and stirred for 24 hours to obtain a bio-based monomer.

[0029] This embodiment discloses a method for preparing an antioxidant, comprising the following steps: S1: 11.78 g of 3-aminophenol was added to 90 mL of deionized water, stirred evenly, and then 8 mL of acetic anhydride was added. The mixture was mixed and stirred for 4 h, filtered, and recrystallized to obtain intermediate A. 7.98 g of intermediate A was added to 80 mL of acetone, stirred for 20 min, and then 7.88 g of iodomethane and 24.16 g of anhydrous potassium carbonate were added. The mixture was stirred and heated to reflux for reaction. After the reaction was completed, the mixture was cooled, filtered, rotary evaporated, extracted, washed, and dried to obtain intermediate B. S2: Under a nitrogen atmosphere, 6.82 g of intermediate B and 10.08 g of 4-nitrobenzoyl chloride were added to 80 mL of dichloroethane, and 8.99 g of anhydrous aluminum chloride was added during stirring. The mixture was stirred for 1 hour and then heated to reflux. After the reaction was completed, the mixture was cooled and added to a 5% by volume hydrochloric acid aqueous solution. The mixture was stirred for 2 hours, filtered, washed, and recrystallized to obtain intermediate C. Under a nitrogen atmosphere, 5.33 g of intermediate C was mixed with 100 mL of a 20% by volume hydrochloric acid aqueous solution, stirred, heated to reflux for 4 hours, cooled, adjusted the pH with a saturated sodium bicarbonate solution, filtered, recrystallized, and dried to obtain intermediate D. S3: 2.41 g of intermediate D was added to 300 mL of ethanol, followed by 0.12 g of Pd / C. After stirring, hydrogen was introduced. After the reaction was complete, the mixture was filtered, rotary evaporated, recrystallized, and dried to obtain intermediate E. S4: Add 5.98g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid to 55mL of chloroform, and under nitrogen protection, add 8mL of dichlorothionyl dropwise. After the addition is complete, heat the reaction at 55℃ for 8h, and distill under reduced pressure to obtain a light yellow solid F; add 5.28g of intermediate E to 10mL of acetonitrile, and under a low temperature environment of 0℃, add a mixed solution of 50mL of acetonitrile and 3.03g of light yellow solid F dropwise. Under nitrogen protection, add a mixed solution of 0.8mL of triethylamine and 8mL of acetonitrile, stir the reaction, and heat the reaction at 55℃ for 24h. After the reaction is completed, purify to obtain an antioxidant.

[0030] This embodiment discloses a bio-based polyamide material with high tensile strength, which is composed of the following components in parts by weight: 68 parts of bio-based monomer, 2.83 parts of antioxidant, 0.28 parts of sodium hypophosphite, and 0.5 parts of nano-montmorillonite.

[0031] This embodiment discloses a process for preparing a bio-based polyamide material with high tensile strength, comprising the following steps: Step 1: After vacuum drying the bio-based monomer, an antioxidant, sodium hypophosphite and nano-montmorillonite are added, and the mixture is stirred to obtain a premix; Step 2: Add the premix to a twin-screw extruder, melt-polymerize, granulate, and dry to obtain a bio-based polyamide material with high tensile strength.

[0032] Example 4: This example discloses a method for preparing a bio-based monomer, comprising the following steps: Q1: 9.87 g of 2,7-dihydroxynaphthalene and 20.12 g of 3-fluoro-4-nitrophenol were added to a container containing 150 mL of N,N-dimethylformamide, stirred and dissolved, and then heated to 135°C. 15.12 g of potassium carbonate was added and the mixture was heated under reflux at 135°C for 24 h. After the reaction was completed, the mixture was cooled and added to deionized water. The mixture was allowed to stand, filtered, washed with water, dried, washed, filtered, and dried to obtain compound 1. Q2: 4.27 g of compound 1 and 0.12 g of Pd / C were added to a container containing 85 mL of ethanol, heated to 85°C, and 12 mL of hydrazine hydrate was slowly added dropwise. The reaction was refluxed for 24 h. After the reaction was completed, the mixture was filtered while hot, cooled, added to deionized water, allowed to stand and precipitate, filtered, and dried in vacuo to obtain compound 2. Q3: 1.74 g of compound 2 and 0.15 g of 2,2-bis(4-hydroxy-3-aminophenyl)propane were added to a container containing 20 mL of dimethylacetamide and stirred until dissolved. Then, 2.95 g of dimer acid was slowly added and stirred for 24 hours to obtain a bio-based monomer.

[0033] This embodiment discloses a method for preparing an antioxidant, comprising the following steps: S1: Add 10.52 g of 3-aminophenol to 95 mL of deionized water, stir evenly, add 11 mL of acetic anhydride, mix and stir for 4 hours, filter, and recrystallize to obtain intermediate A; add 7.32 g of intermediate A to 82 mL of acetone, stir for 20 minutes, then add 7.58 g of iodomethane and 21.12 g of anhydrous potassium carbonate, stir, heat and reflux to react, cool, filter, rotary evaporate, extract, wash, and dry to obtain intermediate B; S2: Under a nitrogen atmosphere, 6.51 g of intermediate B and 9.24 g of 4-nitrobenzoyl chloride were added to 85 mL of dichloroethane, and 9.01 g of anhydrous aluminum chloride was added during stirring. The mixture was stirred for 1 hour and then heated to reflux. After the reaction was completed, the mixture was cooled and added to a 5% by volume hydrochloric acid aqueous solution. The mixture was stirred for 2 hours, filtered, washed, and recrystallized to obtain intermediate C. Under a nitrogen atmosphere, 5.08 g of intermediate C was mixed with 80 mL of a 20% by volume hydrochloric acid aqueous solution, stirred, heated to reflux for 4 hours, cooled, adjusted the pH with a saturated sodium bicarbonate solution, filtered, recrystallized, and dried to obtain intermediate D. S3: 2.18 g of intermediate D was added to 260 mL of ethanol, followed by 0.1 g of Pd / C. After stirring, hydrogen was introduced. After the reaction was complete, the mixture was filtered, rotary evaporated, recrystallized, and dried to obtain intermediate E. S4: Add 5.33 g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid to 48 mL of chloroform, and under nitrogen protection, add 9 mL of dichlorothionyl dropwise. After the addition is complete, heat the reaction at 55°C for 8 h, and distill under reduced pressure to obtain a light yellow solid F; add 4.58 g of intermediate E to 10 mL of acetonitrile, and under a low temperature environment of 0°C, add a mixed solution of 50 mL of acetonitrile and 2.48 g of light yellow solid F dropwise. Under nitrogen protection, add a mixed solution of 0.8 mL of triethylamine and 8 mL of acetonitrile, stir the reaction, and heat the reaction at 55°C for 24 h. After the reaction is completed, purify to obtain an antioxidant.

[0034] This embodiment discloses a bio-based polyamide material with high tensile strength, which is composed of the following components in parts by weight: 54 parts of a bio-based monomer, 2.37 parts of an antioxidant, 0.17 parts of sodium hypophosphite, and 0.6 parts of nano-montmorillonite.

[0035] This embodiment discloses a process for preparing a bio-based polyamide material with high tensile strength, comprising the following steps: Step 1: After vacuum drying the bio-based monomer, an antioxidant, sodium hypophosphite and nano-montmorillonite are added, and the mixture is stirred to obtain a premix; Step 2: Add the premix to a twin-screw extruder, melt-polymerize, granulate, and dry to obtain a bio-based polyamide material with high tensile strength.

[0036] Comparative Example 1: Compared with Example 2, in the process of preparing the bio-based polyamide material in Comparative Example 1, bio-based polyamide 56 is used instead of bio-based monomer, and other conditions remain unchanged.

[0037] Comparative Example 2: Compared with Example 2, in Comparative Example 2, no antioxidant was added during the preparation of the bio-based polyamide material, and other conditions remained unchanged.

[0038] The samples prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to performance tests. The tensile properties of the samples were tested according to GB / T 1040.1-2018, the thermal stability of the samples was tested according to GB / T 7141-2008, and the weather resistance of the samples was tested according to GB / T 16422.3-2022. The test results are shown in Table 1: Table 1 The test results in Table 1 demonstrate that the methods of Examples 1-4 can produce bio-based polyamide materials with excellent tensile strength, thermal stability, and weather resistance. A comparison of Comparative Example 1 with Examples 1-4 reveals that the use of bio-based monomers effectively improves the tensile strength of bio-based polyamide materials. A comparison of Comparative Example 2 with Examples 1-4 reveals that the addition of antioxidants effectively enhances the thermal stability and weather resistance of bio-based polyamide materials.

[0039] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0040] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A bio-based polyamide material with high tensile strength, characterized in that: The invention comprises the following components in parts by weight: 50-68 parts of a bio-based monomer, 2.12-2.83 parts of an antioxidant, 0.14-0.28 parts of a catalyst, and 0.5-1 parts of a nucleating agent. The bio-based monomer is obtained by firstly reacting 2,7-dihydroxynaphthalene with 3-fluoro-4-nitrophenol to undergo a nucleophilic substitution reaction, then undergoing a nitro reduction reaction, and finally undergoing a condensation amination reaction with 2,2-bis(4-hydroxy-3-aminophenyl)propane and dimer acid; the antioxidant is obtained by reacting 3-aminophenol as a starting material with acetic anhydride. An acylation reaction occurs, followed by an alkylation reaction with iodomethane in the presence of potassium carbonate, followed by a Friedel-Crafts acylation reaction with 4-nitrobenzoyl chloride catalyzed by anhydrous aluminum chloride, followed by removal of the acetyl protecting group by acidic hydrolysis, followed by Pd / C-catalyzed hydrogenation to reduce the nitro group to an amino group to obtain intermediate E. Simultaneously, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid reacts with thionyl chloride to generate a light yellow solid F. Finally, intermediate E undergoes an amidation reaction with light yellow solid F to prepare an antioxidant.

2. A bio-based polyamide material with high tensile strength according to claim 1, characterized in that: The method for preparing the bio-based monomer comprises the following steps: Q1: Add 2,7-dihydroxynaphthalene and 3-fluoro-4-nitrophenol to a container containing N,N-dimethylformamide, stir and dissolve, heat, add potassium carbonate, heat under reflux for reaction, cool after the reaction is completed, add to deionized water, let stand, filter, wash with water, dry, wash, filter, and dry to obtain compound 1; Q2: Compound 1 and Pd / C were added to a container containing ethanol, heated, and hydrazine hydrate was slowly added dropwise. After the reaction was completed, the mixture was filtered while hot, cooled, added to deionized water, allowed to stand for precipitation, filtered, and dried in vacuo to obtain compound 2. Q3: Compound 2 and 2,2-bis(4-hydroxy-3-aminophenyl)propane are added to a container containing dimethylacetamide, stirred until dissolved, and then dimer acid is slowly added. After stirring and reacting, a bio-based monomer is obtained.

3. The bio-based polyamide material with high tensile strength according to claim 2, characterized in that: In Q1, the molar ratio of 2,7-dihydroxynaphthalene, 3-fluoro-4-nitrophenol and potassium carbonate is (0.05-0.08): (0.1-0.17): (0.1-0.15).

4. The bio-based polyamide material with high tensile strength according to claim 2, characterized in that: In the Q2, the usage ratio of compound 1, Pd / C, ethanol and hydrazine hydrate is (4.12-4.56) g: (0.11-0.15) g: (80-100) mL: (10-20) mL.

5. The bio-based polyamide material with high tensile strength according to claim 2, characterized in that: In Q3, the molar ratio of compound 2, 2,2-bis(4-hydroxy-3-aminophenyl)propane and dimer acid is (0.45-0.55):(0.05-0.09):(0.5-0.62).

6. The bio-based polyamide material with high tensile strength according to claim 1, characterized in that: The preparation method of the antioxidant comprises the following steps: S1: Add 3-aminophenol to deionized water, stir evenly, add acetic anhydride, mix and stir, filter, and recrystallize to obtain intermediate A; add intermediate A to acetone, stir, add iodomethane and anhydrous potassium carbonate, stir, heat and reflux to react, cool, filter, rotary evaporate, extract, wash, and dry to obtain intermediate B; S2: Under a nitrogen atmosphere, intermediate B and 4-nitrobenzoyl chloride are added to dichloroethane, anhydrous aluminum chloride is added during stirring, the mixture is stirred and then heated to reflux for reaction, after which the reaction is completed, the mixture is cooled, added to an aqueous hydrochloric acid solution, fully stirred, filtered, washed, and recrystallized to obtain intermediate C; under a nitrogen atmosphere, intermediate C and the aqueous hydrochloric acid solution are mixed and stirred, heated to reflux for reaction, after which the reaction is completed, the mixture is cooled, the pH is adjusted, filtered, recrystallized, and dried to obtain intermediate D; S3: Add intermediate D to ethanol, then add Pd / C, stir evenly, and introduce hydrogen. After the reaction is complete, filter, rotary evaporate, recrystallize, and dry to obtain intermediate E; S4: Add 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid to chloroform, add dichlorothionyl dropwise under nitrogen protection, after the addition is complete, heat the temperature to react, and distill under reduced pressure to obtain a light yellow solid F; add the intermediate E to acetonitrile, add a mixed solution of acetonitrile and light yellow solid F dropwise under low temperature, add a mixed solution of triethylamine and acetonitrile under nitrogen protection, stir the reaction, heat the temperature to react, and after the reaction is completed, purify to obtain an antioxidant.

7. The bio-based polyamide material with high tensile strength according to claim 6, characterized in that: In S1, the usage ratio of 3-aminophenol, deionized water, and acetic anhydride is (10.12-11.78) g: (90-110) mL: (8-12) mL; the usage ratio of intermediate A, acetone, methyl iodide, and anhydrous potassium carbonate is (7.12-7.98) g: (80-90) mL: (7.51-7.88) mL: (20.08-24.16) g; in S2, the usage ratio of intermediate B, 4-nitrobenzoyl chloride, dichloroethane, and anhydrous aluminum chloride is (6.41-6.82) g: (9.12-10.08) g: (80-100) mL: (8.99-9.09) g; and the usage ratio of intermediate C and aqueous hydrochloric acid solution is (5.01-5.33) g: (75-100) mL.

8. The bio-based polyamide material with high tensile strength according to claim 6, characterized in that: In the S3, the usage ratio of the intermediate D, ethanol, and Pd / C is (2.12-2.41) g: (250-300) mL: (0.09-0.12) g; in the S4, the usage ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, chloroform, and thionyl chloride is (5.12-5.98) g: (45-55) mL: (8-12) mL; and the molar ratio of the intermediate E and the light yellow solid F is (1.8-2.2): (0.8-1.02).

9. The process for preparing a bio-based polyamide material with high tensile strength according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: After vacuum drying the bio-based monomer, an antioxidant, a catalyst, and a nucleating agent are added, and the mixture is stirred to obtain a premix; Step 2: Add the premix to a twin-screw extruder, melt-polymerize, granulate, and dry to obtain a bio-based polyamide material with high tensile strength.

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