High-toughness nylon material and synthesis method thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to a high-toughness nylon material and a synthesis method thereof. The preparation method adopts a three-step strategy of'protection-polycondensation-hydrolytic conversion ', and comprises the following steps: firstly, reacting a 4-p-toluenesulfonyl aminophenol protective agent with a polyether amine prepolymer with an ester bond side chain to protect an ester bond; secondly, the protected prepolymer and dicarboxylic acid are subjected to efficient polycondensation at the temperature of 160-230 DEG C, and a high-molecular-weight nylon polymer is obtained; and finally, by controlling acid hydrolysis conditions, removing a protecting group, and converting an ester bond side chain into an active carboxylic acid side chain at the same time. The method breaks through the traditional synthesis bottleneck, and the prepared nylon material has excellent mechanical properties brought by high molecular weight and functionality endowed by carboxylic acid side chains, and has important industrial application value.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to high-toughness nylon materials and their synthesis methods. Background Technology

[0002] Nylon, as a class of engineering plastics with excellent comprehensive properties, is widely used in automotive, electronics, textile and other fields. To meet the demand for higher performance, such as improving the flexibility and elasticity of materials, a mainstream modification approach is to introduce flexible polyether segments into the nylon backbone. Furthermore, in order to endow materials with special functionalities (such as improving dye affinity, introducing biodegradable sites, etc.), researchers have tried to introduce ester bond (-COO-) structures on the side chains of polyether segments.

[0003] Chinese patent application CN118620199A, published on September 10, 2024, discloses a method for synthesizing high-performance nylon elastomers. However, this technology faces a fundamental technical contradiction in industrial production: on the one hand, the synthesis of nylon relies on melt polycondensation at high temperatures to remove small molecules generated in the reaction, thereby obtaining a sufficiently high molecular weight to ensure that the material possesses excellent mechanical properties; on the other hand, the ester bonds on the side chains are prone to hydrolysis or transesterification under high temperature and acidic or alkaline environments in the presence of water, leading to the destruction of its structure, loss of expected functionality, and even affecting the regularity of the main chain.

[0004] To protect the fragile ester bonds, existing technologies have had to adopt a compromise: conducting polycondensation reactions at lower temperatures. However, this low-temperature strategy directly leads to a series of insurmountable problems: slow polycondensation reaction rates, long production cycles, and high energy consumption; incomplete reactions at low temperatures, making polymer chain growth difficult and resulting in lower molecular weights of the final product; and low-molecular-weight nylon materials cannot meet the requirements for high-performance applications in terms of key mechanical properties such as tensile strength, flexural strength, and impact toughness, showing little advantage over traditional nylon.

[0005] Therefore, there is an urgent need in this field for a novel synthesis method that can overcome the technical bottlenecks between "ester bond protection" and "high-temperature polycondensation" and achieve the preparation of truly high-molecular-weight, high-performance, high-toughness nylon materials with ether ester structure by using an efficient high-temperature polycondensation process without destroying the ester bond side chains. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a high-toughness nylon material. Through an innovative "protection-deprotection" strategy, the polycondensation reaction temperature is successfully raised to 160-230℃, breaking through the bottleneck of the prior art which cannot use high temperature to protect ester bonds. This makes it possible to efficiently synthesize high-toughness nylon with ester bond side chains. Not only is high-temperature and efficient polycondensation achieved to obtain a high molecular weight nylon backbone, but also active carboxylic acid groups are successfully introduced into the side chains, opening up new avenues for the functional application of the material.

[0007] Another objective of this invention is to provide a method for preparing high-toughness nylon materials, with clear steps, well-defined process parameters, good repeatability, and not limited to specific prepolymer structures. It has good application prospects for various polyetheramines with ester bond side chains and has high industrial application value.

[0008] This invention is achieved using the following technical solution: The method for synthesizing the high-toughness nylon material includes the following steps: (1) Provide a polyetheramine prepolymer with ester side chains; (2) The polyetheramine prepolymer is reacted with an ester bond protector to combine the ester bond protector with the ester bond side chain to form a protected polyetheramine prepolymer; (3) The protected polyetheramine prepolymer is subjected to a polycondensation reaction with a dicarboxylic acid, wherein the polycondensation reaction is carried out at a temperature of 160-230°C to generate a high molecular weight nylon polymer. (4) The high molecular weight nylon polymer is subjected to hydrolysis treatment to remove the ester bond protectant and convert the ester bond side chain into a carboxylic acid side chain, thereby obtaining the high toughness nylon material containing carboxylic acid side chain.

[0009] This is the core technical idea of ​​the present invention, namely the three-step strategy of "protection-high temperature polycondensation-deprotection". Step (2) is the key premise of the present invention. By chemically protecting the active ester bond side chain, it is temporarily "deactivated" and can withstand the subsequent high temperature environment. Step (3) is the core innovation of the present invention. The polycondensation temperature is raised to the efficient reaction range of 160-230℃, which is impossible to achieve in the existing synthesis of nylon with ester bond side chain. This high temperature significantly accelerates the reaction rate and is conducive to the removal of small molecule by-products, thereby obtaining a high molecular weight polymer. Step (4) is a necessary step to complete the entire synthesis. Through controllable acid hydrolysis, the connection between the protecting group and the side chain is selectively cut off, and the original ester structure is transformed into a more chemically active carboxylic acid structure, so that the final product is endowed with new functionality while possessing high toughness.

[0010] As a preferred embodiment, the polyetheramine prepolymer with ester side chains in step (1) is prepared by reacting ethylene glycol with an epoxy compound at a molar ratio of 1:3 to generate a polyether diol, and then subjecting the polyether diol to end-amino grouping; wherein the epoxy compound is a mixture of propylene oxide and glycidyl butyrate.

[0011] The polyether segments introduced by propylene oxide provide the basis for the material's flexibility and toughness; glycidyl butyrate is responsible for introducing ester bonds on the side chains. Through terminal amination, a prepolymer with active terminal amino groups is obtained, enabling it to participate in subsequent nylon polycondensation reactions. The method of this invention is not only applicable to this type of prepolymer but also effective for other polyetheramine prepolymers with ester-bonded side chains, demonstrating the method's versatility.

[0012] As a preferred embodiment, the ester bond protectant is 4-p-toluenesulfonylaminophenol.

[0013] 4-Toluenesulfonamide phenol has a stable structure, and its phenolic hydroxyl group can react with the ester bond to form a more stable new structure, thus effectively protecting the ester bond. More importantly, the formed protective structure can be selectively broken under subsequent acidic conditions, achieving "deprotection" without damaging the nylon backbone and the restored ester bond side chains.

[0014] As a preferred embodiment, the 4-p-toluenesulfonylaminophenol is prepared by reacting p-toluenesulfonyl chloride and 4-aminophenol in acetone solvent at 28-33°C for 100-130 min, wherein the molar ratio of p-toluenesulfonyl chloride to 4-aminophenol is 1:(1.05-1.3).

[0015] Using p-toluenesulfonyl chloride and 4-aminophenol as raw materials, this process is low-cost, operates under mild and easily controlled reaction conditions (28-33℃), and yields high results. A slight excess of 4-aminophenol in the molar ratio ensures complete reaction of the relatively expensive p-toluenesulfonyl chloride, improving raw material utilization. This process is stable and reliable, making it suitable for industrial production.

[0016] As a preferred embodiment, in step (2), the mass ratio of the polyetheramine prepolymer to the ester bond protectant is 100:(9-13); the reaction is carried out at a temperature of 110-140°C for 50-70 minutes.

[0017] As a preferred option, the dicarboxylic acid in step (3) is an aliphatic dicarboxylic acid.

[0018] The aliphatic dicarboxylic acid mentioned is adipic acid or sebacic acid.

[0019] Aliphatic dicarboxylic acids are commonly used monomers in the synthesis of nylon, such as adipic acid (used to prepare nylon 66) and sebacic acid (used to prepare flexible nylon). Their selection directly affects the chain segment length, crystallinity, melting point, and mechanical properties of the final nylon material. The method of this invention is compatible with a variety of dicarboxylic acids.

[0020] As a preferred embodiment, step (3) further includes a neutralization and salt formation step before the polycondensation reaction: the protected polyetheramine prepolymer and the dicarboxylic acid are reacted in an aqueous solution at 60-70°C with a molar ratio of 1:(1.01-1.2).

[0021] As a preferred embodiment, acetic acid accounting for 1-10% of the mass of the dicarboxylic acid is added to the salt-forming reaction; after neutralization and salt formation, the reaction system is prepared into an aqueous solution with a total mass concentration of 40-50%, and then a polycondensation reaction is carried out.

[0022] Acetic acid acts as a catalyst and pH stabilizer here, promoting the amidation reaction. Maintaining the concentration of the nylon salt aqueous solution at 40%-50% is an optimized process parameter. Too low a concentration results in high energy consumption for water evaporation; too high a concentration leads to high system viscosity, which is detrimental to mass and heat transfer and subsequent reactions. This concentration range represents the optimal balance between energy consumption and reaction efficiency.

[0023] As a preferred embodiment, the dissociation in step (4) is achieved by acid hydrolysis, which includes stirring the high molecular weight nylon polymer in a hydrochloric acid solution with a concentration of 1.6-2.5 mol / L for 100-140 min at a temperature of 70-90℃.

[0024] Acid hydrolysis using hydrochloric acid solutions of the specific concentrations described above can efficiently sever the connection between the protecting group and the ester bond. Simultaneously, these conditions are relatively mild, sufficient to avoid significant degradation of the amide bonds in the nylon backbone and the restored ester bond side chains. The reaction time and concentration have been optimized to ensure complete deprotection without introducing side reactions.

[0025] The high-toughness nylon material is prepared by the synthesis method of the high-toughness nylon material described above.

[0026] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention, through an innovative “protection-deprotection” strategy, successfully raises the polycondensation reaction temperature to 160-230℃, breaking through the bottleneck of existing technologies that cannot use high temperatures to protect ester bonds, thus making it possible to efficiently synthesize high-toughness nylon with ester bond side chains. At high temperatures, the polycondensation reaction rate is greatly increased, the reaction is more complete, which is conducive to obtaining nylon polymers with higher molecular weights, while shortening the production cycle and reducing unit energy consumption.

[0027] (2) Due to the high molecular weight polymer obtained, the nylon material prepared by this invention has mechanical properties far exceeding those of traditional low-temperature synthesized products. More importantly, this invention successfully introduces active carboxylic acid groups (-COOH) into the side chains of the material through the final hydrolysis conversion step. This not only achieves a unity of performance and function, but also endows the material with new application potential, such as: serving as dye affinity sites to improve the dyeability of the material; serving as reactive sites for subsequent grafting, crosslinking and other modifications; improving the hydrophilicity and biocompatibility of the material, etc.

[0028] (3) The method provided by the present invention has clear steps, clear process parameters, good repeatability, and is not limited to specific prepolymer structures. It has good application prospects for various polyetheramines with ester bond side chains and has high industrial application value. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] The present invention provides a method for synthesizing a high-toughness nylon material, comprising the following steps: (1) providing a polyetheramine prepolymer with ester bond side chains; (2) reacting the polyetheramine prepolymer with an ester bond protectant, so that the ester bond protectant combines with the ester bond side chains to form a protected polyetheramine prepolymer; (3) subjecting the protected polyetheramine prepolymer to a polycondensation reaction with a dicarboxylic acid, wherein the polycondensation reaction is carried out at a temperature of 160-230°C to generate a high molecular weight nylon polymer; (4) dissociating the ester bond protectant from the high molecular weight nylon polymer to restore the ester bond side chains, thereby obtaining the high-toughness nylon material.

[0031] In this invention, the starting material used in step (1) is a polyetheramine prepolymer with ester bond side chains. Preferably, the prepolymer is prepared by reacting ethylene glycol with an epoxy compound at a molar ratio of 1:3 to generate a polyether diol, and then terminally amination of the polyether diol; wherein the epoxy compound is a mixture of propylene oxide and glycidyl butyrate. In this preparation method, the introduction of propylene oxide can form flexible polyether segments in the main chain, giving the material a high toughness foundation; glycidyl butyrate is responsible for introducing ester bond structures into the side chains; the final terminal amination results in the prepolymer having active amino groups at both ends that can participate in the polycondensation reaction. It should be emphasized that the method protected by this invention is not limited to the prepolymer prepared by this specific method, and has the same protection and synthesis effect on any other polyetheramine prepolymer with ester bond side chains known to those skilled in the art.

[0032] In this invention, the ester bond protectant used in step (2) serves to temporarily protect the ester bond side chains during the high-temperature polycondensation stage, preventing hydrolysis or side reactions. Preferably, the ester bond protectant is 4-toluenesulfonylaminophenol. This protectant has a stable structure, can effectively bind with the ester bond to form a high-temperature resistant protective structure, and is easily dissociated under subsequent acidic conditions to restore the ester bond. This invention does not impose any special restrictions on the source of the ester bond protectant; commercially available products can be used, or it can be prepared in-house.

[0033] Furthermore, the preferred preparation process for 4-p-toluenesulfonylaminophenol is as follows: p-toluenesulfonyl chloride and 4-aminophenol are reacted in acetone solvent at 28-33°C for 100-130 min, wherein the molar ratio of p-toluenesulfonyl chloride to 4-aminophenol is 1:1.05-1.3. This preparation method is mild, simple to operate, and has a high yield, making it suitable for industrial production.

[0034] During the protection reaction in step (2), the mass ratio of the polyetheramine prepolymer to the ester bond protectant is preferably 100:(9-13). This ratio ensures that the ester bond side chains are adequately protected while avoiding the cost and post-processing problems caused by excessive protectant. The temperature of the protection reaction is preferably 110-140℃, and the reaction time is preferably 50-70 min. Under these conditions, the protection reaction can be carried out rapidly and completely.

[0035] In this invention, the dicarboxylic acid mentioned in step (3) is another monomer that, together with the protected polyetheramine prepolymer, constitutes the nylon backbone. Preferably, the dicarboxylic acid is an aliphatic dicarboxylic acid, more preferably adipic acid or sebacic acid. This invention does not impose any special restrictions on the source of the dicarboxylic acid; commercially available products well-known to those skilled in the art can be used.

[0036] Prior to the polycondensation reaction in step (3), a neutralization and salt formation step is preferably included. Specifically, the protected polyetheramine prepolymer and the dicarboxylic acid are reacted in an aqueous solution at 60-70°C in a molar ratio of 1:(1.01-1.2) to form a nylon salt. Precise control of the molar ratio is crucial for the preparation of high molecular weight nylon. Further, to optimize the neutralization and subsequent polycondensation reaction, acetic acid at 1-10% of the mass of the dicarboxylic acid can be added as a catalyst during the salt formation reaction. After neutralization and salt formation, the reaction system is prepared as an aqueous solution with a total mass concentration of 40-50%, which is a preferred range balancing reaction efficiency and system viscosity.

[0037] The key feature of this invention is that the polycondensation reaction is carried out at a temperature of 160-230°C. It is precisely because the ester bond side chains are effectively protected that the reaction system can withstand this high temperature. This temperature range is significantly higher than the temperature that existing technologies can withstand to protect the ester bonds, which greatly increases the polycondensation reaction rate and promotes the effective removal of small water molecules generated in the reaction, thereby obtaining a high molecular weight nylon polymer. This is the core reason why this invention can significantly improve the final performance of the material.

[0038] In this invention, step (4) is a deprotection step, the purpose of which is to dissociate the protecting groups from the nylon polymer and restore the original structure of the ester bonds. Preferably, this dissociation is achieved by acid hydrolysis. Specifically, the high molecular weight nylon polymer obtained by polycondensation is stirred in a hydrochloric acid solution with a concentration of 1.6-2.5 mol / L for 100-140 min at a temperature of 70-90°C. These acid hydrolysis conditions have been optimized to efficiently remove the protecting groups while having minimal impact on the amide bonds of the nylon backbone and the restored ester bond side chains.

[0039] The preparation method provided by this invention, through the synergistic effect of the above steps, has a clear process route and controllable conditions, and can stably prepare high-performance nylon materials that combine high toughness and specific functions.

[0040] To further illustrate the present invention, detailed descriptions are provided below through the following embodiments. Embodiment 1 is the preferred embodiment. The polyetheramine prepolymers used in the embodiments and comparative examples were all obtained by terminal amination of polyether diols prepared from ethylene glycol and an epoxide compound in a molar ratio of 1:3, wherein the epoxide compound was a mixture of propylene oxide and glycidyl butyrate in a molar ratio of 1:1. This method provides the same protective effect for other polyetheramine prepolymers with ester bond side chains. Unless otherwise specified, the raw materials used in the following embodiments of the present invention are all commercially available products.

[0041] Raw materials used in the examples and comparative examples: Ethylene glycol and propylene oxide: Sinopharm Chemical Reagent Co., Ltd.; Glycidyl butyrate: Purity >95%, Shanghai Maclean Biochemical Technology Co., Ltd.; Adipic acid: Industrial grade, Hualu Hengsheng Chemical Co., Ltd.; Sebacic acid: Industrial grade, purity ≥99.5%, Shandong Sider Chemical Technology Co., Ltd.

[0042] p-Toluenesulfonyl chloride: Analytical grade (AR), ≥99.0%, Sinopharm Chemical Reagent Co., Ltd.; 4-Aminophenol: Analytical grade (AR), ≥98.0%, Shanghai Aladdin Biochemical Technology Co., Ltd.; Acetic acid: Analytical grade (AR), ≥99.5%, Beijing Chemical Plant; Hydrochloric acid: Analytical grade (AR), concentration 36-38%, Beijing Chemical Plant; Acetone: Analytical grade (AR), ≥99.5%, Sinopharm Chemical Reagent Co., Ltd.

[0043] Test method: Tensile strength and elongation at break: Tested in accordance with GB / T1040.2-2006 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics".

[0044] Bending strength: Tested according to ISO 178:2019 "Plastics—Determination of flexural properties".

[0045] Notched impact strength of simply supported beams: Tested according to GB / T1043.1-2008 "Determination of impact properties of simply supported plastic beams - Part 1: Non-instrumental impact test" (using type A notch).

[0046] Example 1 s1. Toluenesulfonyl chloride and 4-aminophenol were reacted in acetone at a molar ratio of 1:1.2 for 120 min with stirring. The reaction temperature was controlled at 30℃. After the reaction was completed, 4-toluenesulfonylaminophenol was obtained by filtration, washing and drying as an ester bond protectant.

[0047] s2. The polyetheramine prepolymer and the ester bond protectant were stirred at 120°C for 60 min at a mass ratio of 100:11.

[0048] s3. After preparing adipic acid and ester-protected polyetheramine prepolymer at a molar ratio of 1:1.1, prepare 55% (w / w) aqueous solutions and add them to the reactor. Simultaneously, add acetic acid at 6% (w / w) of the adipic acid mass, stir, and heat to 65°C to carry out a salt-forming reaction. After neutralization and salt formation, prepare a 45% (w / w) aqueous solution, and then heat to 175°C to carry out a polycondensation reaction.

[0049] s4. The material generated by the polycondensation reaction is stirred in a 2.0 mol / L hydrochloric acid solution for 120 min, and then washed and dried to obtain the final product.

[0050] Example 2 s1. Toluenesulfonyl chloride and 4-aminophenol were reacted in acetone at a molar ratio of 1:1.15 and stirred for 110 min. The reaction temperature was controlled at 31℃. After the reaction was completed, 4-toluenesulfonylaminophenol was obtained by filtration, washing and drying as an ester bond protectant.

[0051] s2. The polyetheramine prepolymer and the ester bond protectant were reacted at 115℃ for 65 min by stirring at a mass ratio of 100:10.

[0052] s3. After preparing adipic acid and ester-protected polyetheramine prepolymer at a molar ratio of 1:1.05, prepare 52% (w / w) aqueous solutions and add them to the reactor. Simultaneously, add acetic acid at 5% (w / w) of the adipic acid mass, stir, and heat to 62°C to carry out a salt-forming reaction. After neutralization and salt formation, prepare an aqueous solution with a total system mass concentration of 42%, and then heat to 170°C to carry out a polycondensation reaction.

[0053] s4. The material generated by the polycondensation reaction is stirred in a 1.8 mol / L hydrochloric acid solution for 130 min, and then washed and dried to obtain the final product.

[0054] Example 3 s1. Toluenesulfonyl chloride and 4-aminophenol were reacted in acetone at a molar ratio of 1:1.25 for 125 min with stirring. The reaction temperature was controlled at 29℃. After the reaction was completed, 4-toluenesulfonylaminophenol was obtained by filtration, washing and drying as an ester bond protectant.

[0055] s2. The polyetheramine prepolymer and the ester bond protectant were stirred at 125°C for 55 min at a mass ratio of 100:12.

[0056] s3. After preparing sebacic acid and ester-protected polyetheramine prepolymer at a molar ratio of 1:1.15, prepare 57% (w / w) aqueous solutions and add them to the reactor. Simultaneously, add acetic acid at 8% (w / w) of the sebacic acid mass. Stir and heat to 68°C to carry out a salt formation reaction. After neutralization and salt formation, prepare an aqueous solution with a total system mass concentration of 48%, and then heat to 180°C to carry out a polycondensation reaction.

[0057] s4. The material generated by the polycondensation reaction is stirred in a 2.2 mol / L hydrochloric acid solution for 110 min, and then washed and dried to obtain the final product.

[0058] Example 4 s1. Toluenesulfonyl chloride and 4-aminophenol were reacted in acetone at a molar ratio of 1:1.05 and stirred for 130 min. The reaction temperature was controlled at 28℃. After the reaction was completed, 4-toluenesulfonylaminophenol was obtained by filtration, washing and drying as an ester bond protectant.

[0059] s2. The polyetheramine prepolymer and the ester bond protectant were stirred at 140℃ for 50 min at a mass ratio of 100:9.

[0060] s3. After preparing adipic acid and ester-protected polyetheramine prepolymer at a molar ratio of 1:1.01, prepare 50% (w / w) aqueous solutions and add them to the reactor. Simultaneously, add acetic acid at 4% (w / w) of the adipic acid mass, stir, and heat to 60°C to carry out a salt-forming reaction. After neutralization and salt formation, prepare a 40% (w / w) aqueous solution, and then heat to 185°C to carry out a polycondensation reaction.

[0061] s4. The material generated by the polycondensation reaction is stirred in a 1.6 mol / L hydrochloric acid solution for 140 min, and then washed and dried to obtain the final product.

[0062] Example 5 s1. Toluenesulfonyl chloride and 4-aminophenol were reacted in acetone at a molar ratio of 1:1.3 for 100 min with stirring. The reaction temperature was controlled at 33℃. After the reaction was completed, 4-toluenesulfonylaminophenol was obtained by filtration, washing and drying as an ester bond protectant.

[0063] s2. The polyetheramine prepolymer and the ester bond protectant were stirred at 110°C for 70 min at a mass ratio of 100:13.

[0064] s3. After preparing sebacic acid and ester-protected polyetheramine prepolymer at a molar ratio of 1:1.2, prepare 60% (w / w) aqueous solutions and add them to the reactor. Simultaneously, add 7% (w / w) of acetic acid to the sebacic acid solution, stir, and heat to 70°C to carry out a salt formation reaction. After neutralization and salt formation, prepare a 45% (w / w) aqueous solution, and then heat to 160°C to carry out a polycondensation reaction.

[0065] s4. The material generated by the polycondensation reaction is stirred in a 2.5 mol / L hydrochloric acid solution for 100 min, and then washed and dried to obtain the final product.

[0066] Comparative Example 1 After preparing adipic acid and polyetheramine prepolymer at a molar ratio of 1:1.1, they were separately prepared into 55% aqueous solutions and added to a reaction vessel. At the same time, acetic acid at 8% of the mass of adipic acid was added, and the mixture was stirred and heated to 60°C to carry out a salt formation reaction. Water was added to prepare a 45% aqueous solution of the salt, and the temperature was further raised to 175°C to carry out a polycondensation reaction. After the reaction was completed, the mixture was washed and dried to obtain the final product.

[0067] The mechanical properties of the nylon materials obtained in Examples 1-5 and Comparative Example 1 were measured, and the test results are shown in Table 1.

[0068] Table 1. Performance test results of the nylon materials obtained in Examples 1-5 and Comparative Example 1.

[0069] As shown in Table 1, the nylon materials prepared in Examples 1-5 exhibit significantly higher tensile strength, flexural strength, and notched impact strength than those in Comparative Example 1. This strongly demonstrates that the "protection-high-temperature polycondensation-deprotection" strategy employed in this invention can indeed yield materials with higher molecular weight and superior mechanical properties. Under different combinations of process parameters, the product performance data obtained in Examples 1-5 are stable and consistently at a high level, indicating that the process window proposed in this invention is wide, possessing good reproducibility and industrial operability.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for synthesizing a high-toughness nylon material, characterized in that, Includes the following steps: (1) Provide a polyetheramine prepolymer with ester side chains; (2) The polyetheramine prepolymer is reacted with an ester bond protector to combine the ester bond protector with the ester bond side chain to form a protected polyetheramine prepolymer; (3) The protected polyetheramine prepolymer is subjected to a polycondensation reaction with a dicarboxylic acid, wherein the polycondensation reaction is carried out at a temperature of 160-230°C to generate a high molecular weight nylon polymer. (4) The high molecular weight nylon polymer is subjected to hydrolysis treatment to remove the ester bond protectant and convert the ester bond side chain into a carboxylic acid side chain, thereby obtaining a high toughness nylon material containing a carboxylic acid side chain.

2. The method for synthesizing high-toughness nylon material according to claim 1, characterized in that, The polyetheramine prepolymer with ester side chains in step (1) is prepared by reacting ethylene glycol and an epoxy compound at a molar ratio of 1:3 to generate a polyether diol, and then subjecting the polyether diol to end-amine oxidation; wherein the epoxy compound is a mixture of propylene oxide and glycidyl butyrate.

3. The method for synthesizing high-toughness nylon material according to claim 1, characterized in that, The ester bond protectant is 4-p-toluenesulfonylaminophenol.

4. The method for synthesizing high-toughness nylon material according to claim 3, characterized in that, The 4-p-toluenesulfonylaminophenol is prepared by reacting p-toluenesulfonyl chloride and 4-aminophenol in acetone solvent at 28-33°C for 100-130 min, wherein the molar ratio of p-toluenesulfonyl chloride to 4-aminophenol is 1:(1.05-1.3).

5. The method for synthesizing high-toughness nylon material according to claim 1, characterized in that, In step (2), the mass ratio of the polyetheramine prepolymer to the ester bond protectant is 100:(9-13); the reaction is carried out at a temperature of 110-140℃ for 50-70 minutes.

6. The method for synthesizing high-toughness nylon material according to claim 1, characterized in that, The dicarboxylic acid mentioned in step (3) is an aliphatic dicarboxylic acid.

7. The method for synthesizing high-toughness nylon material according to claim 6, characterized in that, The aliphatic dicarboxylic acid mentioned is adipic acid or sebacic acid.

8. The method for synthesizing high-toughness nylon material according to claim 1, characterized in that, In step (3), before the polycondensation reaction, a neutralization and salt formation step is also included: the protected polyetheramine prepolymer and the dicarboxylic acid are reacted in an aqueous solution at 60-70°C with a molar ratio of 1:(1.01-1.2).

9. The method for synthesizing high-toughness nylon material according to claim 8, characterized in that, In the salt formation reaction, acetic acid accounting for 1-10% of the mass of the dicarboxylic acid was added; after neutralization and salt formation, the reaction system was prepared into an aqueous solution with a total mass concentration of 40-50%, and then polycondensation reaction was carried out; the hydrolysis treatment in step (4) was achieved by acid hydrolysis, which included: stirring the high molecular weight nylon polymer in a hydrochloric acid solution with a concentration of 1.6-2.5 mol / L for 100-140 min.

10. A high-toughness nylon material, characterized in that, It is prepared by the synthesis method of the high-toughness nylon material according to any one of claims 1-9.

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