A self-reinforced nylon material and a method for producing the same
By introducing a benzocyclobutane structure into the nylon backbone and utilizing a mechanically induced crosslinking reaction, a self-reinforced nylon material was prepared, solving the problem of easy failure of nylon materials during long-term service and realizing the self-reinforcing effect of the material under stress, which is suitable for the field of engineering plastics.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-31
- Publication Date
- 2026-03-31
AI Technical Summary
Existing nylon materials are prone to unpredictable failures during long-term service and lack self-reinforcing properties, making it difficult to impart self-reinforcing properties to commercial polymer materials through simple preparation steps.
A benzocyclobutane structure was introduced into the nylon backbone via interfacial polycondensation. Self-reinforcement was achieved by using a mechanically induced ring-opening isomerization reaction and a cycloaddition reaction of a bifunctional crosslinking agent, thus preparing a self-reinforced nylon material.
When materials are subjected to destructive stress, cross-linking reactions enhance the mechanical properties of the materials, reducing the risk of component failure, making them suitable for engineering plastic applications under harsh service conditions.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic intelligent polymer materials technology, specifically relating to a self-reinforced nylon material and its preparation method. Background Technology
[0002] Mechanical stress typically causes the breakage of covalent bonds in the molecular chains of polymer materials, leading to polymer failure. Furthermore, most polymers cannot recover once damaged. In contrast, biological tissues often spontaneously heal or self-reinforce themselves to resist external stress after mechanical damage. Therefore, the design and fabrication of self-reinforcing polymers has recently become a focus of attention. These materials can respond to mechanical stress and resist potentially destructive stresses by forming new chemical networks.
[0003] There are two main methods for endowing synthetic polymers with self-reinforcing properties: force-induced crosslinking and force-induced polymerization. In force-induced crosslinking systems, self-reinforcing properties are achieved through force-induced crosslinking reactions between molecular chains. The crosslinking sites are initially hidden within the molecular structure. When external mechanical force exceeds a certain threshold, these hidden crosslinking sites can be revealed through force-induced isomerization reactions, subsequently reacting with crosslinking agent molecules in the matrix to enhance the material's mechanical properties (Nature Chemistry, 2013, 5, 757; Angew. Chem. Int. Ed., 2016, 55, 3040). In force-induced polymerization systems, mechanical force generally induces the generation of active free radicals, which then trigger the polymerization of monomers in the system to form new polymer chains, achieving the purpose of reinforcement (Science, 2019, 363, 504). However, these developed technical routes still face significant difficulties in practical applications, making it impossible to endow commercial polymers with self-reinforcing properties through simple preparation steps. Nylon is a widely used engineering plastic with advantages such as good wear resistance, excellent mechanical properties, and strong dyeability. Therefore, it is often used in various engineering plastics applications. However, traditional nylon materials do not possess self-reinforcing properties and are prone to unpredictable failures during long-term service. Therefore, the design of simple and universally applicable self-reinforcing nylon materials and their preparation methods are of great practical significance. Summary of the Invention
[0004] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a self-reinforced nylon material and its preparation method. As mentioned above, benzocyclobutane, as a type of four-membered ring, is easily subjected to ring-opening isomerization when subjected to mechanical disturbance. The structure formed after ring opening readily undergoes a [4+2] cycloaddition reaction with the unsaturated structure. The benzocyclobutane structure can be introduced into the nylon backbone using interfacial polycondensation. When this nylon material is subjected to potentially destructive stress, the benzocyclobutane structure in the backbone undergoes ring-opening isomerization. At this point, a cross-linking reaction can occur through the cycloaddition reaction between the bifunctional cross-linking agent and this ring-opening structure, thus achieving a self-reinforcing effect.
[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:
[0006] (I) This invention provides a method for preparing a self-reinforced nylon material, comprising the following steps:
[0007] S1. Dissolve the diamine compound M3 in an alkaline solution;
[0008] S2. Dissolve compound M1 and diacyl halide compound M2 in dichloromethane solvent, and carefully pour the solution obtained in step S1 into it;
[0009] S3. Continuously extract the film formed at the interface between dichloromethane and aqueous solution in step S2, and obtain the initial nylon material after washing and drying.
[0010] S4. Dissolve the nylon obtained in step S3 in a highly polar solvent and add the self-reinforcing crosslinking agent therein;
[0011] S5. Remove the solvent from the solution obtained in step S4 to obtain the final self-reinforced nylon material.
[0012] Furthermore, the chemical structural formula of compound M1 is as follows:
[0013]
[0014] In the formula, R1 group is one of -CH3, -H, -NO2, and -OCH3; R2 group is one of -Cl and -Br; and n1 ranges from 1 to 8.
[0015] Furthermore, the chemical structural formula of the diacyl halide compound M2 is as follows:
[0016]
[0017] In the formula, R3 is one of -Cl or -Br; n2 ranges from 1 to 9.
[0018] Furthermore, the chemical structural formula of the diamine compound M3 is as follows:
[0019] The range of n3 is 1-9.
[0020] Furthermore, the self-reinforcing crosslinking agent has one of the following structures:
[0021]
[0022] Furthermore, the molar ratio of compound M1 to diacyl halide compound M2 is 1:20 to 20:0, preferably 1:1; the molar ratio of the total amount of compound M1 and diacyl halide compound M2 to the amount of diamine compound M3 is 2:1 to 1:2, preferably 1:1.1; the molar ratio of the self-reinforcing crosslinking agent to diamine compound M3 is 1:22 to 300, preferably 1:22 to 60.
[0023] Furthermore, in S1, the alkali in the alkaline solution is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, tetramethylguanidine, and 1,8-diazabicyclo[5.4.0]undec-7-ene; the mass concentration of the alkali in the alkaline solution is 1%-5%.
[0024] Furthermore, in S4, the highly polar solvent is one or more of N,N-dimethylacetamide, N,N-dimethylformamide, methylpyrrolidone, dimethyl sulfoxide, hexamethylphosphoramide, formic acid, acetic acid, butyric acid, n-butanol, and ethanol.
[0025] Furthermore, in S1, the molar ratio of diamine compound M3 to the volume of alkaline solution is 1:3 to 1:6 mmol / mL.
[0026] Furthermore, in S2, compound M1 is prepared as follows: dicarboxylated benzocyclobutane is dissolved in dichloromethane solvent, N,N-dimethylformamide catalyst is added dropwise, and then oxalyl chloride is dissolved in dichloromethane and added dropwise to the above solution. After the system is reacted at room temperature for 10 h, the solvent is removed by vacuum distillation at 45 °C to obtain compound M1.
[0027] Furthermore, the ratio of dicarboxylated benzocyclobutane to dichloromethane solvent is 1 g: 10 mL; the ratio of oxalyl chloride to dichloromethane solvent is 4.58 g: 5 mL; and the molar ratio of dicarboxylated benzocyclobutane to oxalyl chloride is 1:4.
[0028] (ii) The present invention also provides a self-reinforced nylon material prepared by the above preparation method, which is prepared from compound M1, diacyl halide compound M2, diamine compound M3 and self-reinforced crosslinking agent.
[0029] Beneficial effects
[0030] The self-reinforced nylon material designed in this invention contains benzocyclobutane structural units in its polymer backbone. When the material is subjected to destructive stress, the benzocyclobutane structure in the backbone undergoes ring-opening isomerization. At this point, a cycloaddition reaction occurs between the bifunctional crosslinking agent and this ring-opening structure, resulting in a crosslinking reaction that achieves self-reinforcement. The technical route proposed in this invention is relatively simple, requires low cost, and the prepared nylon material can be used in engineering plastics applications with harsh service conditions, reducing the risk of component failure. Attached Figure Description
[0031] Figure 1 This is a stress-strain curve diagram of the spline in an embodiment of the present invention;
[0032] Figure 2 This is a stress-strain curve diagram of the comparative example sample of the present invention;
[0033] Figure 3 This is a flowchart illustrating the preparation route of the self-reinforced nylon material SN-1 in Example 1 of the present invention;
[0034] Figure 4 This is a flowchart illustrating the preparation route of the self-reinforced nylon material SN-2 in Example 2 of the present invention;
[0035] Figure 5 This is a flowchart illustrating the preparation process of Comparative Example 1RN-1 of the present invention;
[0036] Figure 6 This is a flowchart illustrating the preparation route of comparative example 2RN-2 of the present invention;
[0037] Figure 7 This is a diagram showing the structural changes of the self-reinforced nylon material of the present invention before and after being subjected to stress. Detailed Implementation
[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0039] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the reagents, methods and equipment used are conventional reagents, methods and equipment in this technical field.
[0040] Example 1: Preparation of self-reinforced nylon material SN-1
[0041] For preparation route, please refer to Figure 3The preparation method of self-reinforced nylon material SN-1 includes the following steps:
[0042] a) 2 g (1 eq, 9.1 mmol) of dicarboxylated benzocyclobutane was dissolved in 20 mL of dichloromethane. One drop of N,N-dimethylformamide catalyst was added dropwise. Then, 4.58 g of oxalyl chloride (4 eq, 36.4 mmol) was dissolved in 5 mL of dichloromethane and added dropwise to the above solution. The system was reacted at room temperature for 10 h, and the solvent was removed by vacuum distillation at 45 °C to obtain compound M1.
[0043] b) Prepare 60 mL of a 3% sodium hydroxide aqueous solution and dissolve 2.32 g of hexamethylenediamine M3 (2.2 eq, 20.0 mmol) in the alkaline solution.
[0044] c) Dissolve M1 (1 eq, 9.1 mmol) and 1.66 g adipic acid chloride M2 (1 eq, 9.1 mmol) obtained in step a in dichloromethane solvent, and carefully pour the solution obtained in step b into it.
[0045] d) Continuously extract the film formed at the interface between dichloromethane and aqueous solution in step c, wash it three times with water, and dry it to obtain the initial nylon material.
[0046] e) Dissolve the nylon obtained in step d in N,N-dimethylformamide, and add bismaleimide self-reinforcing crosslinking agent M6 (0.05 eq, 0.455 mmol). After mixing evenly, remove the N,N-dimethylformamide solvent from the system to obtain the final self-reinforcing nylon material SN-1.
[0047] Example 2: Preparation of self-reinforced nylon material SN-2
[0048] For preparation route, please refer to Figure 4 The preparation method of self-reinforced nylon material SN-2 includes the following steps:
[0049] a) 2 g (1 eq, 9.1 mmol) of dicarboxylated benzocyclobutane was dissolved in 20 mL of dichloromethane. One drop of N,N-dimethylformamide catalyst was added dropwise. Then, 4.58 g of oxalyl chloride (4 eq, 36.4 mmol) was dissolved in 5 mL of dichloromethane and added dropwise to the above solution. The system was reacted at room temperature for 10 h, and the solvent was removed by vacuum distillation at 45 °C to obtain compound M1.
[0050] b) Prepare 60 mL of a 3% sodium hydroxide aqueous solution and dissolve 1.16 g of hexamethylenediamine M3 (1.1 eq, 10.0 mmol) in the alkaline solution.
[0051] c) Dissolve the M1 (1 eq, 9.1 mmol) obtained in step a in dichloromethane solvent, and carefully pour the solution obtained in step b into it.
[0052] d) Continuously extract the film formed at the interface between dichloromethane and aqueous solution in step c, wash it three times with water, and dry it to obtain the initial nylon material.
[0053] e) Dissolve the nylon obtained in step d in N,N-dimethylformamide, and add the bismaleimide self-reinforcing crosslinking agent M6 (0.05 eq, 0.455 mmol). After mixing thoroughly, remove the N,N-dimethylformamide solvent from the system to obtain the final self-reinforcing nylon material SN-2.
[0054] Example 3: Preparation of self-reinforced nylon material SN-3
[0055] The preparation method of self-reinforced nylon material SN-3 is the same as that of Example 1, and will not be repeated here. The difference from Example 1 is that the molar ratio of M1, M2, M3 and crosslinking agent M6 is 1:1:3:0.05.
[0056] Example 4: Preparation of self-reinforced nylon material SN-4
[0057] The preparation method of self-reinforced nylon material SN-4 is the same as that of Example 1, and will not be repeated here. The difference from Example 1 is that the molar ratio of M1, M2, M3 and crosslinking agent M6 is 1:1:3:0.01.
[0058] Example 5: Preparation of self-reinforced nylon material SN-5
[0059] The preparation method of self-reinforced nylon material SN-5 is the same as that of Example 1, and will not be repeated here. The difference from Example 1 is that the self-reinforced crosslinking agent used in step e is p-divinylbenzene M4.
[0060] Comparative Example 1: Preparation of RN-1
[0061] For preparation route, please refer to Figure 5 The preparation method of RN-1 includes the following steps:
[0062] a) Prepare 60 mL of 3% sodium hydroxide aqueous solution and dissolve 1.16 g of hexamethylenediamine M3 (1.1 eq, 10.0 mmol) in the alkaline solution.
[0063] b) Dissolve 1.66 g adipicoyl chloride M2 (1 eq, 9.1 mmol) in dichloromethane solvent and carefully pour the solution obtained in step a into it.
[0064] c) Continuously extract the film formed at the interface between dichloromethane and aqueous solution in step b, wash it three times with water, and dry it to obtain the initial nylon material.
[0065] d) Dissolve the nylon obtained in step c in N,N-dimethylformamide, and add bismaleimide self-reinforcing crosslinking agent M6 (0.05 eq, 0.455 mmol). After mixing evenly, remove the N,N-dimethylformamide solvent from the system to obtain the control nylon material RN-1.
[0066] Comparative Example 2: Preparation of RN-2
[0067] For preparation route, please refer to Figure 6 The preparation method of RN-2 includes the following steps:
[0068] a) 2 g (1 eq, 9.1 mmol) of dicarboxylated benzocyclobutane was dissolved in 20 mL of dichloromethane. One drop of N,N-dimethylformamide catalyst was added dropwise. Then, 4.58 g of oxalyl chloride (4 eq, 36.4 mmol) was dissolved in 5 mL of dichloromethane and added dropwise to the above solution. The system was reacted at room temperature for 10 h, and the solvent was removed by vacuum distillation at 45 °C to obtain compound M1.
[0069] b) Prepare 60 mL of a 3% sodium hydroxide aqueous solution and dissolve 2.32 g of hexamethylenediamine M3 (2.2 eq, 20.0 mmol) in the alkaline solution.
[0070] c) Dissolve M1 (1 eq, 9.1 mmol) and 1.66 g adipic acid chloride M2 (1 eq, 9.1 mmol) obtained in step a in dichloromethane solvent, and carefully pour the solution obtained in step b into it.
[0071] d) The film formed at the interface between dichloromethane and aqueous solution in step c is continuously extracted, washed with water three times, and dried to obtain the control nylon material RN-2.
[0072] The composition and proportion of M1, M2, M3 and crosslinking agent in Examples 1-5 and Comparative Examples 1-2 are shown in Table 1.
[0073] Table 1
[0074] Group M1 equivalent M2 equivalent M3 equivalent Crosslinking agent category Crosslinking agent equivalent SN-1 1 1 2.2 M6 0.05 SN-2 1 0 1.1 M6 0.05 SN-3 1 1 3 M6 0.05 SN-4 1 1 3 M6 0.01 SN-5 1 1 2.2 M4 0.05 RN-1 0 1 1.1 M6 0.05 RN-2 1 1 2.2 M6 0
[0075] Test Example – Performance Measurement
[0076] (I) Testing Method:
[0077] Uniaxial tensile testing was performed using a universal tensile testing machine at a tensile rate of 30 mm / min.
[0078] (II) Results and Analysis:
[0079] Table 2
[0080]
[0081] Referring to Table 2, compared with the comparative example RN-1, the SN-1 spline exhibits significant self-reinforcing behavior during tensile testing. The strain hardening point of RN-1 is 27.6%, while that of the SN-1 spline is only 22.2% (Table 2). Figure 1 The decrease in this value indicates that during the tensile process, the benzocyclobutane structure in the main chain of the SN-1 sample is activated and opens, simultaneously reacting with the self-reinforcing crosslinking agent in the matrix, thus resisting external stress. For the RN-2 sample without the added self-reinforcing crosslinking agent, the strain hardening behavior during tensile testing is significantly delayed, with a final fracture strength of only 44.6 MPa, significantly lower than that of the SN-1 sample (Table 2). This phenomenon further confirms that the self-reinforcing behavior of the SN-1 sample is based on the reaction between the ring-opening benzocyclobutane and the crosslinking agent. Comparing Examples 1 and 3 reveals that the content of the diamine compound M3 should not be too high. The elastic modulus, yield strength, and fracture strength of the SN-3 sample are all lower than those of the SN-1 sample. The main reason for this phenomenon is that excessively high M3 content leads to a deviation of the functional group equivalent ratio of acyl chloride and amino groups from 1:1, making it difficult to obtain nylon materials with higher molecular weights. Comparing Examples 1 and 2 reveals that increasing the M1 content is detrimental to the initial mechanical properties of the final nylon material. The initial elastic modulus of the SN-2 spline is 78% of that of the SN-1 spline, but its strain hardening behavior occurs earlier. Figure 1 The main reason is that increasing the content of benzocyclobutane in the SN-2 main chain structure promotes the reaction between the self-reinforcing crosslinking agent molecules and the final ring-opening benzocyclobutane. The content of the self-reinforcing crosslinking agent should not be too low, as a low content will lead to a decrease in its reaction efficiency with the ring-opening benzocyclobutane. As can be seen from Example 4, when the equivalent of M6 in the formulation is reduced to 0.01, its tensile strength is only 77% of that of the SN-1 specimen.
[0082] The type of self-reinforcing crosslinking agent also has a significant impact on the self-reinforcing properties of the final nylon material. When divinylbenzene (M4) is used as the self-reinforcing crosslinking agent, at the same crosslinking agent content, the tensile strength of the SN-5 sample is 45.3 MPa, which is 75% of that of the SN-1 sample. Electron-deficient double bonds are more conducive to undergoing [4+2] cycloaddition reactions with open-ring benzocyclobutane. The double bonds in divinylbenzene have a certain degree of electronegativity, resulting in a slower rate of [4+2] cycloaddition reactions, thus failing to provide timely self-reinforcement against destructive stress.
[0083] Therefore, it can be seen that the self-reinforced nylon material provided by this invention can enhance its mechanical properties through a subsequent [4+2] cycloaddition crosslinking reaction when subjected to destructive stress. This technical route is relatively simple, requires low cost, and the prepared nylon material can be used in some engineering plastics applications with harsh service conditions, reducing the risk of component failure.
[0084] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0085] The above-described embodiments are merely illustrative of several implementations of the present invention, and their descriptions are relatively specific and detailed. However, the scope of protection of the present invention is not limited to the above-described embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.
Claims
1. A method of making a self-reinforced nylon material, characterized by, The method comprises the following steps: S1, dissolving a diamine compound M3 in a basic solution; S2, dissolving a compound M1 and a diacyl halide compound M2 in dichloromethane solvent, and pouring the solution obtained in step S1 into the dichloromethane solvent; S3, extracting the film formed at the interface between dichloromethane and aqueous solution in step S2, and obtaining an initial nylon material after washing with water and drying; S4, dissolving the nylon material obtained in step S3 in a strong polar solvent, and adding a self-reinforced crosslinking agent; S5, removing the solvent in the solution obtained in step S4 to obtain a self-reinforced nylon material; The chemical structural formula of the compound M1 is: In the formula, R1 is one of -CH3, -H, -NO2 and -OCH3; R2 is one of -Cl and -Br; n1 is in the range of 1-8; The self-reinforced crosslinking agent is one of the following structures: 、 、 ； The molar ratio of the compound M1 to the diacyl halide compound M2 is 1:20 to 20:0; the total amount of substance of the compound M1 and the diacyl halide compound M2 to the amount of substance of the diamine compound M3 is 2:1 to 1:2; the amount of substance of the self-reinforced crosslinking agent to the amount of substance of the diamine compound M3 is 1:22~300.
2. The method according to claim 1, wherein the chemical structural formula of the diacyl halide compound M2 is: In the formula, R3 is one of -Cl and -Br; n2 is in the range of 1-9.
3. The method according to claim 1, wherein the chemical structural formula of the diamine compound M3 is:
4. The method according to claim 1, wherein in step S1, the base in the basic solution is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, tetramethyl guanidine and 1,8-diazabicyclo[5.4.0]undec-7-ene; the mass concentration of the base in the basic solution is 1%-5%.
5. The method according to claim 1, wherein in step S4, the strong polar solvent is one or more of N,N-dimethylacetamide, N,N-dimethylformamide, methyl pyrrolidone, dimethyl sulfoxide, hexamethyl phosphoramide, formic acid, acetic acid, butyric acid, n-butanol and ethanol. wherein n3 ranges from 1 to 9.
6. A self-reinforced nylon material prepared by the method of any one of claims 1-5.
Citation Information
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