Preparation method of graphene modified polyamide fiber

Abstract

The invention relates to the technical field of fibers, and discloses a graphene modified polyamide fiber preparation method, which comprises: mixing 0.05-0.5 part by weight of graphene oxide, 1-4 parts by weight of carboxyl-terminated hyperbranched polyesteramide and nylon 6, and carrying out melt blending spinning, drafting and cooling setting in a spinning machine to obtain the graphene modified polyamide fiber. The hyperbranched polyesteramide has good compatibility with nylon 6, plays a good toughening role, improves the interfacial compatibility of graphene oxide and nylon 6, and improves the breaking strength and elongation at break of the fiber. The end group of the hyperbranched polyesteramide contains a large amount of hydrophilic carboxyl, and the main chain contains hydrophilic amido bonds, so that the moisture regain of the polyamide fiber can be improved, and the hydrophilic moisture absorption performance can be improved.

Description

Technical Field

[0001] The invention relates to the field of fiber technology, and in particular to a method for preparing graphene-modified nylon fiber. Background Art

[0002] Nylon fiber is mainly made of nylon through electrospinning, melt spinning and other methods. It has good chemical stability, mechanical strength, heat resistance and other properties. It is widely used in clothing, home textile products, industrial cables, etc. Traditional nylon fiber has a low moisture regain and poor hydrophilic and hygroscopic properties, resulting in poor wearing comfort of nylon fiber textiles. It is of great significance to improve the hydrophilic and hygroscopic properties, mechanical strength and other properties of nylon fiber.

[0003] As a nanofiller with excellent comprehensive properties, graphene oxide can improve the mechanical strength, heat resistance, antibacterial properties of polymer materials such as fibers, plastics, and rubber. Chinese patent CN117604676B discloses a tensile nylon fiber and a preparation method thereof, wherein graphene oxide is reacted with chloroacetic acid, oxalyl chloride, aminopropyl dimethoxymethylsilane, dimethyl dimethoxysilane, aminopropyl dimethyl methoxysilane, maleic anhydride, and acetic anhydride to obtain modified graphene, which is melt-spun with modified nylon to obtain nylon fibers with good tensile resistance, antistatic, and flame retardant properties. However, the reaction raw materials and preparation method of the modified graphene in the patent are very complicated, not suitable for industrial production, and do not improve the moisture regain and hydrophilic hygroscopicity of the nylon fiber. Summary of the invention

[0004] The invention solves the problem of low breaking strength and poor hydrophilicity of nylon fiber, can increase the moisture regain of nylon fiber, and improves the hydrophilic moisture absorption performance.

[0005] The technical solution of the present invention is: a method for preparing graphene-modified nylon fiber: (1) Add 100 parts by weight of AB2 monomer (structural formula: ), 2.5-3.5 parts by weight of p-toluenesulfonic acid, vacuumize, carry out melt polycondensation reaction, add ether to precipitate after cooling, filter and dry to obtain carboxyl-terminated hyperbranched polyamide ester. The reaction formula is:

[0006] (2) Add 0.05-0.5 parts by weight of graphene oxide and 1-4 parts by weight of terminal carboxyl hyperbranched polyamide into a mixer, mix them for 2-3 hours, then add 100 parts by weight of nylon 6 and mix them for 30-60 minutes; finally, melt-blending and spinning the materials in a spinning machine, stretching them, cooling and shaping them, and obtaining graphene-modified nylon fibers.

[0007] Preferably, the temperature during the melt polycondensation reaction in (1) is 135-150° C., and the reaction time is 5-8 h.

[0008] Preferably, the temperature during melt blending spinning in (2) is 255-265° C., and the spinning speed is 500-900 m / min.

[0009] Preferably, the temperature during stretching in (2) is 120-125°C, and the stretching ratio is 3.5-4 times.

[0010] Preferably, the preparation method of AB2 monomer is: add N,N-dimethylformamide, 100 parts by weight of 1,3-diamino-2-hydroxypropane, and 222-234 parts by weight of succinic anhydride into a reaction kettle, introduce nitrogen, carry out amidation reaction at 0-5°C for 8-10 hours, perform vacuum distillation, wash with ether, and dry to obtain AB2 monomer. The reaction formula is:

[0011] The technical effect of the present invention is as follows: the present invention reacts 1,3-diamino-2-hydroxypropane with succinic anhydride to obtain an AB2 monomer containing one hydroxyl group and two carboxyl groups, and then performs an esterification melt polycondensation reaction to obtain a hyperbranched polyamide ester with terminal carboxyl groups. The polyamide is then blended with graphene oxide and nylon 6, and melt-spun to obtain modified nylon fibers.

[0012] The carboxyl-terminated hyperbranched polyamide ester of the present invention contains the same amide structural unit as nylon 6 polyamide, so that the hyperbranched polyamide ester has good compatibility with nylon 6, has little effect on the strength of nylon fiber, and can play a good toughening role, so that the nylon fiber has a higher elongation at break while maintaining a higher breaking strength.

[0013] The hyperbranched polyamide ester of the present invention contains a large number of terminal carboxyl groups, which form stable hydrogen bonds and other interactive forces with carboxyl groups, hydroxyl groups and other groups on the surface of graphene oxide, so as to be coated on the surface of graphene oxide. The coated and modified graphene oxide has better interface compatibility with nylon 6, is more evenly dispersed in the nylon fiber matrix, and significantly improves the breaking strength of the fiber.

[0014] The end groups of the hyperbranched polyamide ester of the invention contain a large number of hydrophilic carboxyl groups, and the main chain contains hydrophilic amide bonds, which can increase the moisture regain of nylon fibers and improve the hydrophilic moisture absorption performance. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with specific examples, but the protection scope of the present invention is not limited thereto. The following nylon 6, model polymer J2700, was purchased from Shanghai Tinger Plastic Technology Co., Ltd.

[0016] Graphene, with specifications of thickness 0.55-1.2 nm and diameter 0.5-3 μm; graphene oxide, with specifications of thickness 0.55-1.2 nm and diameter 0.5-3 μm, were purchased from Beijing Dekedaojin Technology Co., Ltd. Example 1

[0017] (1) Add 25 mL of N,N-dimethylformamide solvent, 5 g of 1,3-diamino-2-hydroxypropane, and 11.1 g of succinic anhydride into a reaction kettle, introduce nitrogen, react at 0°C for 10 h, distill under reduced pressure, wash with ether, and dry to obtain AB2 monomer.

[0018] (2) Add 8 g of AB2 monomer and 0.25 g of p-toluenesulfonic acid into a reaction kettle, evacuate the mixture, heat to 140°C, react for 7 h, cool the mixture, add ether to precipitate the mixture, filter the mixture, and dry the mixture to obtain a carboxyl-terminated hyperbranched polyamide ester.

[0019] (3) Add 0.5 g of graphene oxide and 10 g of end-carboxyl hyperbranched polyamide into a mixer and mix for 2 h. Then add 1 kg of nylon 6 and mix for 30 min. Finally, melt-blended and spun the materials in a spinning machine at a spinning temperature of 260 °C and a spinning speed of 900 m / min. Then, stretch the materials in a stretching machine at a temperature of 125 °C and a stretching ratio of 4. Finally, cool and shape the materials to obtain graphene-modified nylon fiber. Example 2

[0020] (1) Add 30 mL of N,N-dimethylformamide solvent, 5 g of 1,3-diamino-2-hydroxypropane, and 11.7 g of succinic anhydride into a reaction kettle, introduce nitrogen, react at 5°C for 8 h, distill under reduced pressure, wash with ether, and dry to obtain AB2 monomer.

[0021] (2) Add 8 g of AB2 monomer and 0.2 g of p-toluenesulfonic acid into a reaction kettle, evacuate the mixture, heat to 150° C., react for 5 h, cool the mixture, add ether to precipitate the mixture, filter the mixture, and dry the mixture to obtain a carboxyl-terminated hyperbranched polyamide ester.

[0022] (3) Add 3 g of graphene oxide and 25 g of end-carboxyl hyperbranched polyamide into a mixer and mix for 3 h. Then add 1 kg of nylon 6 and mix for 60 min. Finally, melt-blended and spun the materials in a spinning machine at a spinning temperature of 255 °C and a spinning speed of 800 m / min. Then, stretch the materials in a stretching machine at a temperature of 120 °C and a stretching ratio of 4. Finally, cool and shape the materials to obtain graphene-modified nylon fiber. Example 3

[0023] (1) Prepare AB2 monomer according to the method of Example 1.

[0024] (2) Add 8 g of AB2 monomer and 0.28 g of p-toluenesulfonic acid into a reaction kettle, evacuate the mixture, heat to 135° C., react for 8 h, cool the mixture, add ether to precipitate the mixture, filter the mixture, and dry the mixture to obtain a carboxyl-terminated hyperbranched polyamide ester.

[0025] (3) Add 5 g of graphene oxide and 40 g of end-carboxyl hyperbranched polyamide into a mixer and mix for 3 h. Then add 1 kg of nylon 6 and mix for 60 min. Finally, melt-blended and spun the materials in a spinning machine at a spinning temperature of 265 °C and a spinning speed of 500 m / min. Then, stretch the materials in a stretching machine at a temperature of 120 °C and a stretching ratio of 3.5. Finally, cool and shape the materials to obtain graphene-modified nylon fibers.

[0026] Comparative Example 1 (1) 1 kg of nylon 6 is melt-spun in a spinning machine at a spinning temperature of 260°C and a spinning speed of 900 m / min; it is then stretched in a stretching machine at a temperature of 125°C and a stretching ratio of 4 times; and finally cooled and shaped to obtain nylon fiber.

[0027] Comparative Example 2 (1) 0.5 g of graphene oxide and 1 kg of nylon 6 were mixed for 30 min; finally, the materials were melt-blended and spun in a spinning machine at a spinning temperature of 260 ° C and a spinning speed of 900 m / min; then, the materials were stretched in a stretching machine at a temperature of 125 ° C and a stretching ratio of 4 times; finally, the materials were cooled and shaped to obtain graphene-modified nylon fibers.

[0028] Comparative Example 3 (1) Carboxyl-terminated hyperbranched polyamide ester was prepared according to the method of Example 1.

[0029] (2) Add 10 g of end-carboxyl hyperbranched polyamide ester and 1 kg of nylon 6 into a mixer and mix for 30 min; then melt-blend and spin the materials in a spinning machine at a spinning temperature of 260 ° C and a spinning speed of 900 m / min; then stretch the materials in a stretching machine at a temperature of 125 ° C and a stretching ratio of 4 times; finally cool and shape the materials to obtain modified nylon fiber.

[0030] Comparative Example 4 (1) Carboxyl-terminated hyperbranched polyamide ester was prepared according to the method of Example 1.

[0031] (2) Add 0.5 g of graphene and 10 g of end-carboxyl hyperbranched polyamide into a mixer and mix for 2 h. Then add 1 kg of nylon 6 and mix for 30 min. Finally, melt-blended and spun the materials in a spinning machine at a spinning temperature of 260 °C and a spinning speed of 900 m / min. Then, stretch the materials in a stretching machine at a temperature of 125 °C and a stretching ratio of 4. Finally, cool and shape the materials to obtain graphene-modified nylon fiber.

[0032] Comparative Example 5 (1) Add 8 g of 3-hydroxyglutaric acid as AB2 monomer (CAS No. 638-18-6) and 0.25 g of p-toluenesulfonic acid into a reaction kettle, evacuate the mixture, heat to 140°C, react for 7 h, cool, add ether for precipitation, filter and dry to obtain a carboxyl-terminated hyperbranched polyester.

[0033] (2) Add 0.5 g of graphene oxide and 10 g of end-carboxyl hyperbranched polyester into a mixer and mix for 2 h. Then add 1 kg of nylon 6 and mix for 30 min. Finally, melt-blended and spun the materials in a spinning machine at a spinning temperature of 260 °C and a spinning speed of 900 m / min. Then, stretch the materials in a stretching machine at a temperature of 125 °C and a stretching ratio of 4. Finally, cool and shape the materials to obtain graphene-modified nylon fiber.

[0034] Comparative Example 6 The terminal hydroxyl hyperbranched polyamide ester was prepared by the method described in the article "Research on Modification of Terminal Hydroxyl Hyperbranched Polyamide Ester" in the journal "Chemistry and Adhesion", Vol. 36, No. 6, 2014.

[0035] (1) Add 50 mmol of succinic anhydride and 15 mL of N,N-dimethylacetamide to a reaction kettle. In an ice bath, add 15 mL of N,N-dimethylacetamide solution containing 50 mmol of diethanolamine under a nitrogen atmosphere. Stop the reaction when the acid value of the system is 1 / 2 of the initial acid value. Then add 0.25 g of p-toluenesulfonic acid, heat to 120°C, and react by vacuum distillation for 8 hours. Heat the crude product with acetone and ether solution for extraction. After standing, remove the insoluble matter from the lower layer and dry it to obtain a terminal hydroxyl hyperbranched polyamide ester.

[0036] (2) Add 0.5 g of graphene oxide and 10 g of end-hydroxyl hyperbranched polyamide into a mixer and mix for 2 h. Then add 1 kg of nylon 6 and mix for 30 min. Finally, melt-blended and spun the materials in a spinning machine at a spinning temperature of 260 °C and a spinning speed of 900 m / min. Then, stretch the materials in a stretching machine at a temperature of 125 °C and a stretching ratio of 4. Finally, cool and shape the materials to obtain graphene-modified nylon fiber.

[0037] The tensile breaking properties of the fiber are tested according to the national standard GB / T 14337-2022. The moisture regain of the fiber is tested according to the national standard GB / T 6503-2017.

[0038] Table 1 Nylon fiber performance test

[0039] As can be seen from the above table, compared with the nylon fiber of Comparative Example 1, graphene oxide and carboxyl-terminated hyperbranched polyamide ester are added in Example 1, and the hyperbranched polyamide ester contains the same amide structural unit as nylon 6 polyamide, so that the compatibility of hyperbranched polyamide ester and nylon 6 is very good, the strength effect on nylon fiber is very small, and a good toughening effect can be played, so that nylon fiber has a higher elongation at break while maintaining a high breaking strength. At the same time, the end group of hyperbranched polyamide ester contains a large amount of hydrophilic carboxyls, and the main chain contains hydrophilic amide bonds, which can improve the hydrophilic hygroscopicity of nylon fiber and show a higher regain. And hyperbranched polyamide ester contains a large amount of carboxyl groups, and forms interaction forces such as stable hydrogen bonds with groups such as carboxyl and hydroxyl groups on the surface of graphene oxide, so as to be coated on the surface of graphene oxide, the interface compatibility of the coated modified graphene oxide and nylon 6 is better, and it is more evenly dispersed in the nylon fiber matrix, and the breaking strength of the fiber is significantly improved. In Examples 2-3, different amounts of graphene oxide and carboxyl-terminated hyperbranched polyamide were added, and the nylon fiber showed good tensile breaking properties and moisture regain, good mechanical properties, and high hydrophilic hygroscopicity.

[0040] Compared with Comparative Example 1, Comparative Example 2 only adds graphene oxide, and its compatibility with nylon 6 is poor. Although the breaking strength of nylon fiber is improved, the breaking elongation is significantly reduced, and the moisture regain of nylon fiber is low, and the hydrophilic hygroscopicity is poor.

[0041] Compared with Comparative Example 1, Comparative Example 3 only adds terminal carboxyl hyperbranched polyamide ester. While maintaining a high breaking strength, the nylon fiber has a higher breaking elongation, a high regain, and good hydrophilic hygroscopicity. However, no graphene oxide is added, resulting in the nylon fiber having a lower breaking strength than Example 1.

[0042] The graphene surface added in Comparative Example 4 does not contain groups such as carboxyl and hydroxyl groups, and cannot form hydrogen bonds and other interaction forces with the terminal carboxyl groups of the hyperbranched polyamide ester, cannot be coated on the surface of graphene oxide, and cannot improve the compatibility between graphene and nylon 6, resulting in the breaking strength and breaking elongation of the nylon fiber being lower than those in Example 1.

[0043] In Comparative Example 5, 3-hydroxyglutaric acid is used as the AB2 monomer, and the terminal carboxyl hyperbranched polyester obtained by esterification and polycondensation does not contain an amide bond structural unit, has poor compatibility with nylon 6, has a poor toughening effect, and does not improve the interface compatibility between graphene oxide and nylon 6, resulting in the breaking strength and breaking elongation of the nylon fiber being lower than those in Example 1, and the terminal carboxyl hyperbranched polyester does not contain a hydrophilic amide bond, resulting in a lower moisture regain than in Example 1.

[0044] The terminal hydroxyl hyperbranched polyamide ester prepared in Comparative Example 6 does not contain carboxyl groups, and the hydrophilicity of hydroxyl groups is lower than that of carboxyl groups, resulting in the nylon fiber having a lower regain than that in Example 1, and lower breaking strength and elongation at break. This may be because the interaction between its terminal hydroxyl groups and the surface of graphene oxide is weaker than the interaction between the terminal carboxyl groups of the hyperbranched polyamide ester in Example 1 and the surface of graphene oxide, resulting in the compatibility between graphene oxide and nylon 6 being lower than that in Example 1, and the reinforcement effect is not good.

Claims

1. A method for preparing graphene-modified nylon fiber, characterized in that: The preparation method is as follows: (1) Add the structural formula into the reactor. AB2 monomer and p-toluenesulfonic acid are added, vacuumized, melt polycondensed, cooled, precipitated, filtered, and dried to obtain a carboxyl-terminated hyperbranched polyamide ester; (2) 0.05-0.5 parts by weight of graphene oxide and 1-4 parts by weight of carboxyl-terminated hyperbranched polyamide ester are added to a mixer for primary mixing, and then 100 parts by weight of nylon 6 are added for secondary mixing; finally, the materials are melt-blended and spun in a spinning machine, stretched, cooled and shaped to obtain graphene-modified nylon fibers.

2. The method for preparing graphene-modified nylon fiber according to claim 1, characterized in that: The amount of AB2 monomer used in (1) is 100 parts by weight, and the amount of p-toluenesulfonic acid is 2.5-3.5 parts by weight.

3. The method for preparing graphene-modified nylon fiber according to claim 1, characterized in that: The temperature during the melt polycondensation reaction in (1) is 135-150° C., and the reaction time is 5-8 hours.

4. The method for preparing graphene-modified nylon fiber according to claim 1, characterized in that: The time for the first mixing in (2) is 2-3 hours; the time for the second mixing is 30-60 minutes.

5. The method for preparing graphene-modified nylon fiber according to claim 1, characterized in that: The temperature during melt blending spinning in (2) is 255-265° C., and the spinning speed is 500-900 m / min.

6. The method for preparing graphene-modified nylon fiber according to claim 1, characterized in that: The temperature during the stretching in (2) is 120-125°C, and the stretching ratio is 3.5-4 times.

7. The method for preparing graphene-modified nylon fiber according to claim 1, characterized in that: The preparation method of the AB2 monomer is as follows: N,N-dimethylformamide, 1,3-diamino-2-hydroxypropane and succinic anhydride are added into a reaction kettle, nitrogen is introduced, amidation reaction is carried out, vacuum distillation is performed, washing is performed, and drying is performed to obtain the AB2 monomer.

8. The method for preparing graphene-modified nylon fiber according to claim 7, characterized in that: The amount of 1,3-diamino-2-hydroxypropane used is 100 parts by weight, and the amount of succinic anhydride used is 222-234 parts by weight.

9. The method for preparing graphene-modified nylon fiber according to claim 7, characterized in that: The temperature during the amidation reaction is 0-5°C, and the reaction time is 8-10h.

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