Six-membered cyclic ornithine derivative monomer, modified nylon 6 and preparation method of six-membered cyclic ornithine derivative monomer

Abstract

The invention discloses a six-membered cyclic ornithine derivative monomer, modified nylon 6 and a preparation method of the six-membered cyclic ornithine derivative monomer, relates to the technical field of polymer synthesis, and solves the problem of application limitation of ornithine in the field of high polymer materials and the problem that preparation of nylon 6 depends on non-renewable resources and is serious in homogenization in the prior art. According to the invention, ornithine is used as a raw material, a series of six-membered cyclic ornithine derivative monomers are prepared through cyclization and upper protection, and the monomers and caprolactam are subjected to ring-opening copolymerization to obtain the modified nylon 6 material. The raw material of the six-membered cyclic ornithine derivative monomer is derived from biomass resource ornithine, the six-membered cyclic ornithine derivative monomer has the characteristics of greenness, environmental protection, energy conservation and low carbon, and the preparation method is simple, high in product yield, low in production cost and suitable for large-scale production; the main chain of the prepared nylon 6 contains renewable ornithine, consumption of non-renewable resources such as petroleum can be reduced, functional side groups can be introduced into the main chain of the nylon 6, and the printing and dyeing performance and moisture absorption performance of the nylon 6 material are improved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer synthesis, and in particular to a six-membered cyclic ornithine derivative monomer, modified nylon 6 and a preparation method thereof. Background Art

[0002] As an important engineering plastic, nylon 6 (polycaprolactam) is widely used in textiles, automobiles, electronic products, packaging materials and other fields due to its excellent physical and chemical properties. It has become an indispensable material in modern industry and life. However, the raw materials of existing nylon 6 mainly come from non-renewable resources such as petroleum, and its large-scale production and application have caused serious resource consumption and environmental pollution problems. With the increasing global attention to energy crisis and environmental pollution, finding renewable materials to replace (or partially replace) petroleum resources to produce nylon 6 has become an urgent problem to be solved. At the same time, the current nylon 6 is seriously homogenized. With the continuous improvement of people's quality of life, the demand for functional nylon 6 products with excellent printing and dyeing properties, high hygroscopicity and other properties will grow rapidly.

[0003] Replacing (or partially replacing) petroleum resources with renewable biomass resources to produce nylon 6 can not only effectively alleviate the problem of resource shortage, but also reduce greenhouse gas emissions, which is in line with the dual carbon goals and sustainable development needs. Amino acids are a renewable biomass resource with abundant output, low price, and rich functional side groups. They are an ideal building block for polymer materials. Ornithine is a basic amino acid with two amino groups in the molecule. It is mainly prepared by microbial fermentation. In vivo, ornithine mainly participates in the urea cycle and plays an important role in the excretion of ammonia nitrogen in the body. In vitro, ornithine can be used as a medical reagent and injection, and can also be used with arginine to prepare foaming beverages to restore fatigue. It has a wide range of applications in the food and pharmaceutical industries, but the application of ornithine in the field of polymer materials needs to be developed. Summary of the invention

[0004] In order to solve the problem of application limitations of ornithine in the field of polymer materials in the prior art and the problem that the preparation of nylon 6 relies on non-renewable resources and is severely homogenized, the present invention proposes a six-membered cyclic ornithine derivative monomer, modified nylon 6 and a preparation method thereof. The technical solution of the present invention is as follows:

[0005] A six-membered cyclic ornithine derivative monomer, the structural formula of which is shown in formula (I):

[0006]

[0007] In the formula (I), a and b are any natural numbers between 0 and 8.

[0008] A method for preparing the above-mentioned six-membered cyclic ornithine-derived monomer comprises the following steps:

[0009] S1: dissolving ornithine hydrochloride in methanol, adding concentrated sulfuric acid dropwise thereto for reaction, and then performing a reflux reaction to obtain a reaction solution;

[0010] S2: adding methanol to the reaction solution prepared in S1, mechanically stirring, continuing to add sodium hydroxide to react, then distilling off the methanol, adding ethyl acetate to reflux, then filtering and distilling under reduced pressure, and finally recrystallizing with ethyl acetate to obtain aminovalerolactam in a white solid state;

[0011] S3: dissolving the aminovalerolactam prepared in S2 in methanol, adding formaldehyde solution and palladium carbon, reacting under a hydrogen atmosphere, filtering, concentrating to obtain a crude product, and recrystallizing the crude product to obtain a six-membered cyclic ornithine-derived monomer, wherein a and b in formula (I) are both 0;

[0012] Alternatively, the aminovalerolactam prepared by S2 is dissolved in acetonitrile, potassium carbonate is added, and a bromohydrocarbon containing a+1 carbon atoms or a bromohydrocarbon containing b+1 carbon atoms is added, or a bromohydrocarbon containing a+1 carbon atoms is first added and then a bromohydrocarbon containing b+1 carbon atoms is added, refluxed, and recrystallized to obtain a six-membered cyclic ornithine derivative monomer;

[0013] Furthermore, the reaction concentration of ornithine hydrochloride in S1 is 1.5 to 10 mol / L;

[0014] Furthermore, the time for the reaction of adding concentrated sulfuric acid dropwise in S1 is 2 to 8 hours;

[0015] Furthermore, the reflux reaction time in S1 is 3 to 12 hours;

[0016] Further, the amount of methanol added to S2 is 5 to 25 times the amount of methanol added to S1, and the amount of methanol added is preferably 15 to 25 times the amount of methanol in S1;

[0017] Further, the amount of ethyl acetate added in S2 is 8 to 12 times the amount of methanol added in S1;

[0018] Further, the concentration of sodium hydroxide in S2 is 1 to 8 mol / L, preferably 6 to 8 mol / L;

[0019] Further, the temperature for adding sodium hydroxide to the S2 for reaction is 20 to 70° C., preferably 50 to 70° C.;

[0020] Furthermore, the time for adding sodium hydroxide to S2 to react is 5 to 15 hours, preferably 5 hours;

[0021] Further, the concentration of aminovalerolactam in S3 is 0.1 to 10 mol / L, preferably 0.2 to 0.6 mol / L;

[0022] Further, in S3, the molar ratio of aminovalerolactam to palladium carbon and formaldehyde is 1:0.01-0.05:2-2.2, or the molar ratio of aminovalerolactam to potassium carbonate and bromohydrocarbon is 1:1-1.2:2-2.2;

[0023] Furthermore, the solvent used for the recrystallization in S3 is one or a combination of at least two of ethyl acetate, isopropyl acetate, isoamyl acetate, ethylene carbonate, and propylene carbonate.

[0024] A modified nylon 6 is prepared from the above six-membered cyclic ornithine-derived monomer and caprolactam, and its structural formula is shown in formula (II):

[0025]

[0026] In the formula (II), n is any natural number between 20 and 200, a and b are any natural numbers between 0 and 8, and m is in the range of 0 <m<1。

[0027] A method for preparing the modified nylon 6 comprises the following steps:

[0028] In a nitrogen atmosphere, the six-membered cyclic ornithine-derived monomer and caprolactam are added to a dry polymerization tube, an activator is added, the tube is vacuum dried, and then a catalyst is added to carry out a polymerization reaction; after the polymerization reaction is completed, a good solvent is added to dissolve the monomer, and then the monomer is precipitated in a poor solvent, and the product is centrifuged and dried to obtain a modified nylon 6;

[0029] Furthermore, the structural formula of the activator is shown in formula (III):

[0030]

[0031] In the formula (III), R is any one of methyl, ethyl, phenyl, tert-butylphenyl and trifluoromethylphenyl;

[0032] Further, the catalyst is one or a combination of at least two of a carbene reagent, a guanidine reagent, an amidine reagent, a phosphazene reagent, an alkali metal, an alkali metal oxide, an alkali metal hydroxide, an alkali metal hydride, and an alkali metal alkoxide, preferably one or a combination of at least two of bis(trimethylsilyl)potassium amide (KHMDS), sodium hydride (NaH), potassium hydride (KH), phosphazene base (t-BuP4), potassium tert-butoxide (t-BuOK), sodium methoxide (MeONa), potassium methoxide (MeOK), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), sodium (Na), and potassium (K);

[0033] Furthermore, the molar ratio of the six-membered cyclic ornithine-derived monomer to caprolactam is 0.01 to 0.5:1;

[0034] Furthermore, the molar ratio of the total amount of the six-membered cyclic ornithine-derived monomer and caprolactam to the activator and catalyst is 10 to 200:1:1, preferably 50 to 100:1:1;

[0035] Furthermore, the vacuum drying temperature is 0.5 to 1 h;

[0036] Further, the polymerization reaction temperature is 65 to 225°C, preferably 145 to 185°C;

[0037] Furthermore, the polymerization reaction time is 1 to 48 hours, preferably 3 to 12 hours;

[0038] Furthermore, the good solvent is one or a combination of at least two of trifluoroethanol, hexafluoroisopropanol, trifluoroacetic acid, and formic acid;

[0039] Furthermore, the poor solvent is one or a combination of at least two of ethyl acetate, ethyl ether, petroleum ether, and dichloromethane.

[0040] Compared with the prior art, the present invention solves the problem of application limitation of ornithine in the field of polymer materials and the problem that the preparation of nylon 6 relies on non-renewable resources and has serious homogeneity in the prior art. The specific beneficial effects are:

[0041] 1. First, the present invention uses ornithine, a renewable biomass resource, as a raw material, and prepares a six-membered cyclic ornithine derivative monomer through steps such as cyclization and upper protection. The monomer can be copolymerized with caprolactam, and functional groups are introduced into the side chain of nylon 6 to give it more functionality, such as high hygroscopicity and good printing and dyeing properties. At the same time, the process for preparing the six-membered cyclic ornithine derivative monomer of the present invention is simple, the reaction conditions are mild, and the product yield is high, which effectively reduces the energy consumption and production cost in the production process. Therefore, the present invention provides a method for synthesizing a six-membered cyclic ornithine derivative monomer that is efficient, low-cost, and green and environmentally friendly, which provides a new way for the application of ornithine in the synthetic polymer industry, and at the same time helps to promote the innovative development of my country's high-end nylon 6 industry.

[0042] 2. The present invention uses a six-membered cyclic ornithine-derived monomer to copolymerize with caprolactam, introduces a renewable ornithine component into the main chain of nylon 6, and prepares modified nylon 6, which can effectively reduce dependence on non-renewable resources and conform to the current concept of green chemistry and sustainable development. At the same time, compared with traditional nylon 6, the nylon 6 prepared in the present invention not only retains excellent mechanical properties and heat resistance, but also exhibits significant hygroscopicity and printing and dyeing properties, greatly broadening its application range in textiles and other high-end fields; and its preparation method is simple, efficient, low in production cost, suitable for large-scale production, and provides a practical technical route for the industrial application of high-performance, green and environmentally friendly nylon 6 materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The hydrogen nuclear magnetic resonance spectrum of aminovalerolactam prepared in Example 1;

[0044] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the six-membered cyclic ornithine-derived monomer M1 prepared in Example 2;

[0045] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the modified nylon 6 prepared in Example 27;

[0046] Figure 4 Schematic diagram of the synthetic route of six-membered cyclic ornithine-derived monomers and modified nylon 6. DETAILED DESCRIPTION

[0047] In order to make the technical solution of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the specification of the present invention. It should be noted that the following embodiments are only used to better understand the technical solution of the present invention and should not be understood as a limitation to the present invention.

[0048] Example 1.

[0049] Weigh 504g of ornithine hydrochloride (3mol) and 1.5L of methanol in a 2L three-necked flask, add 176mL of concentrated sulfuric acid (98%) using a constant pressure dropping funnel, and stir mechanically; after reacting for 2h, transfer it to a 2L single-necked flask and reflux for 8h, then transfer it to a 50L reactor, add 30L of methanol, stir mechanically, continue to add 480g of sodium hydroxide (12mol), react at room temperature for 10h, then evaporate the methanol, add 18L of ethyl acetate to reflux, then filter and distill under reduced pressure, and finally recrystallize with ethyl acetate to obtain 274g of aminovalerolactam in a white solid state, with a yield of 80%. According to nuclear magnetic hydrogen spectrum analysis, its purity is 95%, Figure 1 is the hydrogen nuclear magnetic resonance spectrum of aminovalerolactam prepared in this example, 1 H NMR (D2O, 400MHz) δ3.25-3.35, 3.15-3.25, 1.50-2.15.

[0050] Example 2.

[0051] 11.4 g of aminovalerolactam (0.1 mol) prepared in Example 1 was dissolved in 200 mL of methanol, and 17 mL of formaldehyde solution (mass fraction 37%, 0.22 mol) and 1 g of palladium carbon (10%) were added, and the mixture was reacted overnight under a hydrogen atmosphere, and then filtered and concentrated to obtain a crude product, which was recrystallized from ethyl acetate to obtain 13 g of a six-membered cyclic ornithine-derived monomer M1, with a yield of 92%. The purity was 97% according to H NMR analysis. Figure 2 is the hydrogen nuclear magnetic resonance spectrum of the six-membered cyclic ornithine-derived monomer M1 prepared in this example, 1 H NMR (D2O, 400MHz) δ3.25-3.35, 3.15-3.24, 2.25-2.35, 1.65-2.05.

[0052] Example 3.

[0053] 11.4 g of aminovalerolactam (0.1 mol) prepared in Example 1 was dissolved in 50 mL of acetonitrile, 24.0 g of ethyl bromide (0.22 mol) and 13.8 g of potassium carbonate (0.1 mol) were added, and the mixture was reacted overnight at 85° C., and then filtered and concentrated to obtain a crude product, which was recrystallized from ethyl acetate to obtain 13.6 g of a six-membered cyclic ornithine-derived monomer M2, with a yield of 80%. The purity was 96% according to H NMR analysis. 1 H NMR (CDCl3, 400MHz) δ7.50, 3.47, 3.16-3.20, 2.40, 1.49-2.01, 1.02.

[0054] Example 4.

[0055] 11.4 g of aminovalerolactam (0.1 mol) prepared in Example 1 was dissolved in 100 mL of acetonitrile, 27.1 g of bromopropane (0.22 mol) and 15.2 g of potassium carbonate (0.11 mol) were added, and the mixture was reacted overnight at 85° C., and then filtered and concentrated to obtain a crude product. The crude product was recrystallized from isopropyl acetate to obtain 12 g of a six-membered cyclic ornithine-derived monomer M3, with a yield of 61%. The purity was 96% according to H NMR analysis. 1 H NMR (CDCl3, 400MHz) δ7.39, 3.57, 3.12-3.25, 2.43, 1.30-2.01, 1.43, 0.87.

[0056] Example 5.

[0057] 11.4 g of aminovalerolactam (0.1 mol) prepared in Example 1 was dissolved in 100 mL of acetonitrile, 28.8 g of 1-bromobutane (0.21 mol) and 15.2 g of potassium carbonate (0.11 mol) were added, and the mixture was reacted overnight at 85° C., and then filtered and concentrated to obtain a crude product. The crude product was recrystallized from isoamyl acetate to obtain 12 g of a six-membered cyclic ornithine-derived monomer M4, with a yield of 53%. The purity was 97% according to H NMR analysis. 1 H NMR (CDCl3, 400MHz) δ7.47, 3.50, 3.13-3.20, 2.43, 1.49-2.01, 1.37, 1.29, 0.91.

[0058] Example 6.

[0059] 11.4 g of aminovalerolactam (0.1 mol) prepared in Example 1 was dissolved in 200 mL of acetonitrile, and 34.6 g of 1-bromohexane (0.21 mol) and 16.5 g of potassium carbonate (0.12 mol) were added, and the mixture was reacted at 85° C. overnight. Then, the mixture was filtered and concentrated to obtain a crude product, which was recrystallized from propylene carbonate to obtain 14 g of a six-membered cyclic ornithine-derived monomer M5, with a yield of 50%. The purity was 97% according to H NMR analysis. 1 H NMR (CDCl3, 400MHz) δ7.47, 3.52, 3.10-3.25, 2.45, 1.49-2.01, 1.39, 1.26, 1.31, 0.88.

[0060] Example 7.

[0061] 11.4 g of aminovalerolactam (0.1 mol) prepared in Example 1 was dissolved in 200 mL of acetonitrile, and 38.6 g of 1-bromooctane (0.20 mol) and 16.5 g of potassium carbonate (0.12 mol) were added, and the mixture was reacted at 85° C. overnight. Then, the mixture was filtered and concentrated to obtain a crude product, which was recrystallized from ethyl acetate to obtain 13 g of a six-membered cyclic ornithine-derived monomer M6, with a yield of 38%. The purity was 98% according to H NMR analysis. 1 H NMR (CDCl3, 400MHz) δ7.47, 3.45, 3.15-3.25, 2.44, 1.45-2.01, 1.25-1.37, 0.85.

[0062] Example 8.

[0063] 11.4g of aminovalerolactam (0.1mol) prepared in Example 1 was dissolved in 500mL of acetonitrile, and 14.4g of 1-bromobutane (0.105mol) and 16.5g of potassium carbonate (0.12mol) were first added, and the mixture was reacted at 85°C for 4h, and then 17.3g of 1-bromohexane (0.105mol) was added, and the reaction was continued for 4h, and then filtered and concentrated to obtain a crude product, which was recrystallized from ethyl acetate to obtain 8g of six-membered cyclic ornithine-derived monomer M7, with a yield of 31%. The purity was 96% according to H NMR analysis. 1 H NMR (CDCl3, 400MHz) δ7.44, 3.46, 3.17-3.25, 2.44, 1.28-2.01, 0.91, 0.85. The following Table 1 shows the six-membered cyclic ornithine derivative monomer M1-7 prepared in Example 2-8 and its yield:

[0064] Table 1

[0065]

[0066] Example 9.

[0067] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol KHMDS, and then react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 11400. The modified nylon 6 was characterized by nuclear magnetic resonance. 1H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.2%.

[0068] Example 10.

[0069] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and then react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 11200. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.6%.

[0070] Example 11.

[0071] Weigh 310 mg of initiator 1 (2 mmol, R = methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol KH, and then react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. Centrifuge and dry to obtain a modified nylon 6 material with a yield of 50% and a weight-average molecular weight of 10200. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.8%.

[0072] Example 12.

[0073] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol t-BuP4, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 13200. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.0%.

[0074] Example 13.

[0075] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol t-BuOK, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 7600. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.0%.

[0076] Example 14.

[0077] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol MeONa, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 12600. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.1%.

[0078] Example 15.

[0079] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol MeOK, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 13600. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.1%.

[0080] Example 16.

[0081] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL baked round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol DBU, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. Add trifluoroethanol to dissolve, and precipitate the polymer solution in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether is 1:1. Centrifuge and dry to obtain a modified nylon 6 material with a yield of 50% and a weight-average molecular weight of 7600. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.6%.

[0082] Example 17.

[0083] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol TBD, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 7800. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.7%.

[0084] Example 18.

[0085] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol Na, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 11300. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.6%.

[0086] Example 19.

[0087] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol K, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 10300. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.8%.

[0088] Example 20.

[0089] Weigh 338 mg of initiator 2 (2 mmol, R is ethyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 10500. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.2%.

[0090] Example 21.

[0091] Weigh 434 mg of initiator 3 (2 mmol, R is phenyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 10700. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.2%.

[0092] Example 22.

[0093] Weigh 546 mg of initiator 4 (2 mmol, R is tert-butylphenyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction is completed, trifluoroethanol is added to dissolve, and the polymer solution is precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether is 1:1. Centrifuge and dry to obtain a modified nylon 6 material with a yield of 50% and a weight-average molecular weight of 9700. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.0%.

[0094] Example 23.

[0095] Weigh 570 mg of initiator 5 (2 mmol, R is trifluoromethylphenyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 9600. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.0%.

[0096] Example 24.

[0097] Weigh 155 mg of initiator 1 (1 mmol, R is methyl), 0.71 g of the six-membered cyclic ornithine-derived monomer M1 (5 mmol) obtained in Example 2, and 10.74 g of caprolactam (95 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 1 mmol NaH, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 16300. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400MHz) δ3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.3%. The thermal decomposition temperature of the modified nylon 6 was tested to be 373°C, the melting temperature was 214°C, the tensile strength was 55MPa, and the elongation at break was 6%.

[0098] Example 25.

[0099] Weigh 155 mg of initiator 1 (1 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 1 mmol NaH, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 15200. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400MHz) δ3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.6%. The thermal decomposition temperature of the modified nylon 6 was tested to be 364°C, the melting temperature was 212°C, the tensile strength was 49MPa, and the elongation at break was 10%.

[0100] Example 26.

[0101] Weigh 155 mg of initiator 1 (1 mmol, R is methyl), 2.13 g of the six-membered cyclic ornithine-derived monomer M1 (15 mmol) obtained in Example 2, and 9.605 g of caprolactam (85 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 1 mmol NaH, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 18700. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400MHz) δ3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be about 2.6%. The thermal decomposition temperature of the modified nylon 6 was tested to be 368°C, the melting temperature was 211°C, the tensile strength was 45MPa, and the elongation at break was 20%.

[0102] Example 27.

[0103] Weigh 155 mg of initiator 1 (1 mmol, R is methyl), 2.84 g of the six-membered cyclic ornithine-derived monomer M1 (20 mmol) obtained in Example 2, and 9.04 g of caprolactam (80 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 1 mmol NaH, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 20300. The modified nylon 6 was characterized by nuclear magnetic resonance, such as Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the modified nylon 6 prepared in this example, 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. Figure 4 The figure is a schematic diagram of the synthesis route of the six-membered cyclic ornithine derivative monomer and the modified nylon 6. The molar percentage of the six-membered cyclic ornithine derivative monomer in the obtained copolymer is calculated to be 4.2%. The thermal decomposition temperature of the modified nylon 6 is tested to be 370°C, the melting temperature is 209°C, the tensile strength is 40MPa, and the elongation at break is 50%.

[0104] Example 28.

[0105] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 65 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 12500. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.7%.

[0106] Example 29.

[0107] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 105 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 12800. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.3%.

[0108] Example 30.

[0109] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 9900. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.9%.

[0110] Example 31.

[0111] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 3 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 7600. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.7%.

[0112] Example 32.

[0113] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 6 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 12900. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.1%.

[0114] Embodiment 33

[0115] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.42 g of the six-membered cyclic ornithine-derived monomer M1 (10 mmol) obtained in Example 2, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 12 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 12400. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.60, 3.00-3.30, 2.60-2.75, 2.08-2.31, 0.81-1.80. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 1.4%.

[0116] Example 34.

[0117] Weigh 310 mg of initiator 1 (2 mmol, R is methyl), 1.70 g of the six-membered cyclic ornithine-derived monomer M2 (10 mmol) obtained in Example 3, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 12 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 10200. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.39, 3.10-3.25, 2.40-2.55, 2.05-2.20, 1.25-1.75, 1.03. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.9%.

[0118] Example 35.

[0119] Weigh 155 mg of initiator 1 (1 mmol, R = methyl), 1.98 g of the six-membered cyclic ornithine-derived monomer M3 (10 mmol) obtained in Example 4, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, evacuate at 40 ° C for 30 min, add 2 mmol NaH, and react in an oil bath at 185 ° C for 12 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 9900. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.47, 3.10-3.20, 2.35-2.45, 2.15-2.20, 1.25-1.70, 0.87. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be about 0.7%.

[0120] Example 36.

[0121] Weigh 155 mg of initiator 1 (1 mmol, R is methyl), 2.26 g of the six-membered cyclic ornithine-derived monomer M4 (10 mmol) obtained in Example 5, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 12 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 7600. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.65, 3.15-3.35, 2.45-2.55, 2.10-2.25, 1.28-1.80, 0.91. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.6%.

[0122] Example 37.

[0123] Weigh 155 mg of initiator 1 (1 mmol, R is methyl), 2.82 g of the six-membered cyclic ornithine-derived monomer M5 (10 mmol) obtained in Example 6, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 12 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 7400. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.55, 3.15-3.35, 2.35-2.45, 2.15-2.25, 1.25-1.61, 0.88. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.5%.

[0124] Example 38.

[0125] Weigh 155 mg of initiator 1 (1 mmol, R is methyl), 3.38 g of the six-membered cyclic ornithine-derived monomer M6 (10 mmol) obtained in Example 7, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 12 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. After centrifugation and drying, the modified nylon 6 material was obtained with a yield of 50% and a weight-average molecular weight of 6600. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400 MHz) δ 3.45, 3.20-3.39, 2.20-2.45, 2.01-2.15, 1.10-1.90, 0.87. The molar percentage of the six-membered cyclic ornithine-derived monomer in the obtained copolymer was calculated to be 0.2%.

[0126] Example 39.

[0127] Weigh 155 mg of initiator 1 (1 mmol, R is methyl), 2.54 g of the six-membered cyclic ornithine derivative monomer M7 (10 mmol) obtained in Example 8, and 10.17 g of caprolactam (90 mmol) in a 250 mL dry round-bottom flask, ventilate at 40 ° C for 30 min, continue to add 2 mmol NaH, and react in an oil bath at 185 ° C for 12 h under nitrogen protection. After the reaction, trifluoroethanol was added to dissolve the product, and the polymer solution was precipitated in ethyl acetate / ether, wherein the volume ratio of ethyl acetate to ether was 1:1. Centrifuge and dry to obtain a modified nylon 6 material with a yield of 50% and a weight-average molecular weight of 8200. The modified nylon 6 was characterized by nuclear magnetic resonance. 1 H NMR (DMSO-d6, 400MHz) δ 3.50, 3.25-3.47, 2.35-2.50, 2.05-2.25, 1.27-1.90, 0.80-0.95. The molar percentage of the six-membered cyclic ornithine derivative monomer in the obtained copolymer was calculated to be 0.6%. The following Table 2 shows the polymerization results of the six-membered cyclic ornithine derivative monomer and caprolactam prepared in Examples 9-39:

[0128] Table 2

[0129]

[0130]

[0131] Table 3 below shows the performance comparison results of the modified nylon 6 prepared in Examples 24-27 and the conventional nylon 6:

[0132] Table 3

[0133]

[0134] According to the data in Table 3, the modified nylon 6 prepared in Examples 24-27 retains the excellent heat resistance and mechanical properties of traditional nylon 6 to a great extent, and in the preparation process, ornithine, a renewable biomass resource, is used as a raw material, and a six-membered cyclic ornithine derivative monomer is prepared through steps such as cyclization and protection, thereby preparing modified nylon 6, which effectively reduces the dependence of traditional nylon 6 on non-renewable resources such as petroleum, and is in line with the current concepts of green chemistry and sustainable development; and the preparation method of modified nylon 6 is simple and efficient, with low production cost, and is suitable for large-scale production, which further promotes the development of the bio-based nylon 6 industry and provides a practical technical route for the industrial application of high-performance, green and environmentally friendly nylon 6 materials.

[0135] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0136] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0137] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents covered by the present invention.

Claims

1. A six-membered cyclic ornithine-derived monomer, characterized in that: The structural formula is shown in formula (I): In the formula (I), a and b are any natural numbers between 0 and 8.

2. A method for preparing a six-membered cyclic ornithine-derived monomer as claimed in claim 1, characterized in that: The following steps are involved: S1: dissolving ornithine hydrochloride in methanol, adding concentrated sulfuric acid dropwise thereto for reaction, and then performing a reflux reaction to obtain a reaction solution; S2: adding methanol to the reaction solution prepared in S1, mechanically stirring, continuing to add sodium hydroxide to react, then distilling off the methanol, adding ethyl acetate to reflux, then filtering and distilling under reduced pressure, and finally recrystallizing with ethyl acetate to obtain aminovalerolactam; S3: dissolving the aminovalerolactam prepared in S2 in methanol, adding formaldehyde solution and palladium carbon, reacting under a hydrogen atmosphere, filtering, concentrating to obtain a crude product, and recrystallizing the crude product to obtain a six-membered cyclic ornithine derivative monomer; Alternatively, the aminovalerolactam prepared by S2 is dissolved in acetonitrile, potassium carbonate is added, and then a bromohydrocarbon containing a+1 carbon atoms or a bromohydrocarbon containing b+1 carbon atoms is added, or a bromohydrocarbon containing a+1 carbon atoms is first added and then a bromohydrocarbon containing b+1 carbon atoms is added, reflux reaction is carried out, and a six-membered cyclic ornithine derivative monomer is obtained after recrystallization.

3. The method for preparing a six-membered cyclic ornithine-derived monomer according to claim 2, characterized in that: The reaction concentration of ornithine hydrochloride in S1 is 1.5-10 mol / L; the reaction time of adding concentrated sulfuric acid dropwise is 2-8 hours; and the reflux reaction time is 3-12 hours.

4. The method for preparing a six-membered cyclic ornithine-derived monomer according to claim 2, characterized in that: The amount of methanol added to S2 is 5 to 25 times the amount of methanol added to S1; the concentration of sodium hydroxide is 1 to 8 mol / L; the temperature for adding sodium hydroxide to react is 20 to 70° C., and the time for adding sodium hydroxide to react is 5 to 15 hours.

5. The method for preparing a six-membered cyclic ornithine-derived monomer according to claim 2, characterized in that: The concentration of aminovalerolactam in S3 is 0.1-10 mol / L; the molar ratio of aminovalerolactam to palladium carbon and formaldehyde is 1:0.01-0.05:2-2.2, or the molar ratio of aminovalerolactam to potassium carbonate and bromohydrocarbon is 1:1-1.2:2-2.2; the solvent used for recrystallization is one or a combination of at least two of ethyl acetate, isopropyl acetate, isoamyl acetate, ethylene carbonate and propylene carbonate.

6. A modified nylon 6, characterized in that: The modified nylon 6 is prepared from the six-membered cyclic ornithine-derived monomer according to claim 1 and caprolactam, and the structural formula of the modified nylon 6 is shown in formula (II): In the formula (II), n is any natural number between 20 and 200, and m is in the range of 0 <m<1。 7. A method for preparing modified nylon 6 as claimed in claim 6, characterized in that: The following steps are involved: Under a nitrogen atmosphere, the six-membered cyclic ornithine-derived monomer and caprolactam are added to a dry polymerization tube, and an activator is continuously added, the tube is vacuum dried, and then a catalyst is added to carry out a polymerization reaction; after the polymerization reaction is completed, a good solvent is added to dissolve the monomer, and then the monomer is precipitated in a poor solvent, and the product is centrifuged and dried to obtain modified nylon 6.

8. The method for preparing modified nylon 6 according to claim 7, characterized in that: The structural formula of the activator is shown in formula (III): In the formula (III), R is any one of methyl, ethyl, phenyl, tert-butylphenyl and trifluoromethylphenyl; The catalyst is one or a combination of at least two of a carbene reagent, a guanidine reagent, an amidine reagent, a phosphazene reagent, an alkali metal, an alkali metal oxide, an alkali metal hydroxide, an alkali metal hydride, and an alkali metal alkoxide; The molar ratio of the six-membered cyclic ornithine derivative monomer to caprolactam is 0.01 to 0.5:1; The molar ratio of the total amount of the six-membered cyclic ornithine derivative monomer and caprolactam to the activator and the catalyst is 10-200:1:

1.

9. The method for preparing modified nylon 6 according to claim 8, characterized in that: The catalyst is one or a combination of at least two of potassium bis(trimethylsilyl)amide, sodium hydride, potassium hydride, phosphazene base, potassium tert-butoxide, sodium methoxide, potassium methoxide, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, sodium, and potassium.

10. The method for preparing modified nylon 6 according to claim 7, characterized in that: The temperature of the vacuum drying is 0.5 to 1 h; the temperature of the polymerization reaction is 65 to 225° C.; the time of the polymerization reaction is 1 to 48 h; the good solvent is one or a combination of at least two of trifluoroethanol, hexafluoroisopropanol, trifluoroacetic acid, and formic acid; the poor solvent is one or a combination of at least two of ethyl acetate, ether, petroleum ether, and dichloromethane.

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