Preparation method of graphene modified polyamide fiber

Abstract

The present invention relates to the field of fiber technology, and discloses a preparation method of graphene-modified polyamide fiber. In the present invention, 0.05-0.5 parts by weight of graphene oxide, 1-4 parts by weight of carboxyl-terminated hyperbranched polyamide ester, and nylon 6 are mixed, and then melt-blended spinning and drawing are carried out in a spinning machine, followed by cooling and shaping to obtain graphene-modified polyamide fiber. The hyperbranched polyamide ester of the present invention has good compatibility with nylon 6, plays a good toughening role, and at the same time improves the interfacial compatibility between graphene oxide and nylon 6, and improves the breaking strength and elongation at break of the fiber. The end groups of the hyperbranched polyamide ester contain a large number of hydrophilic carboxyl groups, and the main chain contains hydrophilic amide bonds, which can improve the moisture regain rate of the polyamide fiber and improve the hydrophilic moisture absorption performance.

Description

Technical Field

[0001] The present invention relates to the technical field of fibers, and specifically to a preparation method of graphene-modified polyamide fibers. Background Art

[0002] Polyamide fibers are mainly made of nylon by methods such as electrospinning and melt spinning, and have good properties such as chemical stability, mechanical strength, and heat resistance, and are widely used in clothing, home textile products, industrial ropes, etc. Traditional polyamide fibers have a relatively low moisture regain and poor hydrophilic moisture absorption, resulting in poor wearing comfort of polyamide fiber textiles. It is of great significance to improve the hydrophilic moisture absorption and mechanical strength of polyamide fibers.

[0003] As a nano-filler with excellent comprehensive properties, graphene oxide can improve the mechanical strength, heat resistance, antibacterial properties, etc. of polymer materials such as fibers, plastics, and rubbers. Chinese Patent CN117604676B discloses a tensile polyamide fiber and its preparation method, in which graphene oxide is reacted with chloroacetic acid, oxalyl chloride, aminopropyl dimethoxymethyl silane, dimethyl dimethoxysilane, aminopropyl dimethyl methoxysilane, maleic anhydride, acetic anhydride, etc. to obtain modified graphene, and melt spinning is carried out with modified polyamide to obtain polyamide fibers with good tensile resistance, antistatic, flame retardant and other properties. However, the reaction raw materials and preparation method of the modified graphene in this patent are very complex, not suitable for industrial production, and do not improve the moisture regain and hydrophilic moisture absorption of polyamide fibers. Summary of the Invention

[0004] The present invention solves the problems of relatively low breaking strength and poor hydrophilicity of polyamide fibers, and can improve the moisture regain of polyamide fibers and improve the hydrophilic moisture absorption performance.

[0005] The technical solution of the present invention is: a preparation method of graphene-modified polyamide fibers:

[0006] (1) Add 100 parts by weight of AB2 monomer (structural formula is ) and 2.5 - 3.5 parts by weight of p-toluenesulfonic acid to the reaction kettle, evacuate, carry out melt polycondensation reaction, add ether for precipitation after cooling, filter and dry to obtain end-carboxyl hyperbranched polyamide ester. The reaction formula is:

[0007]

[0008] (2) Add 0.05 - 0.5 parts by weight of graphene oxide and 1 - 4 parts by weight of end-carboxyl hyperbranched polyamide ester to the mixer, carry out primary mixing for 2 - 3 h, then add 100 parts by weight of nylon 6 and carry out secondary mixing for 30 - 60 min; finally, melt blend spin and draw the material in the spinning machine, and cool and shape it to obtain graphene-modified polyamide fibers.

[0009] Preferably, in (1), the temperature during the melt polycondensation reaction is 135 - 150 °C, and the reaction time is 5 - 8 h.

[0010] Preferably, in (2), the temperature during the melt blending and spinning is 255 - 265 °C, and the spinning speed is 500 - 900 m / min.

[0011] Preferably, in (2), the temperature during drawing is 120 - 125 °C, and the draw ratio is 3.5 - 4 times.

[0012] Preferably, the preparation method of the AB2 monomer is as follows: 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, and carry out an amidation reaction at 0 - 5 °C for 8 - 10 h. Then perform vacuum distillation, wash with ether, and dry to obtain the AB2 monomer. The reaction formula is:

[0013]

[0014] The technical effects of the present invention: In the present invention, 1,3-diamino-2-hydroxypropane and succinic anhydride are reacted to obtain an AB2 monomer containing one hydroxyl group and two carboxyl groups, and then an esterification melt polycondensation reaction is carried out to obtain a hyperbranched polyamide ester with terminal carboxyl groups. Then, it is blended with graphene oxide and nylon 6, and melt spun to obtain a modified polyamide fiber.

[0015] The hyperbranched polyamide ester with terminal carboxyl groups of the present invention contains the same amide structural units as nylon 6 polyamide, so that the compatibility between the hyperbranched polyamide ester and nylon 6 is very good, the influence on the strength of the polyamide fiber is very small, and it can play a good toughening role, enabling the polyamide fiber to have a higher elongation at break while maintaining a relatively high breaking strength.

[0016] The hyperbranched polyamide ester of the present invention contains a large number of terminal carboxyl groups, which form stable hydrogen bonds and other interaction forces with the carboxyl groups, hydroxyl groups, etc. on the surface of graphene oxide, thereby coating on the surface of graphene oxide. After the coating modification, the interfacial compatibility between graphene oxide and nylon 6 is better, and it is more uniformly dispersed in the polyamide fiber matrix, significantly improving the breaking strength of the fiber.

[0017] The terminal groups of the hyperbranched polyamide ester of the present invention contain a large number of hydrophilic carboxyl groups, and the main chain contains hydrophilic amide bonds, which can improve the moisture regain rate of the polyamide fiber and improve the hydrophilic moisture absorption performance. Specific Embodiments

[0018] The following further illustrates the present invention with specific examples, but the protection scope of the present invention is not limited thereto. The following nylon 6, model J2700, is purchased from Shanghai Ting'er Plastic Technology Co., Ltd.

[0019] Graphene, with a specification of thickness 0.55 - 1.2 nm and diameter 0.5 - 3 μm; graphene oxide, with a specification of thickness 0.55 - 1.2 nm and diameter 0.5 - 3 μm, purchased from Beijing Decod Island Gold Technology Co., Ltd. Example 1

[0020] (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 the reaction kettle, introduce nitrogen, react at 0 °C for 10 h, carry out vacuum distillation, wash with ether, and dry to obtain the AB2 monomer.

[0021] (2) Add 8 g of the AB2 monomer and 0.25 g of p - toluenesulfonic acid into the reaction kettle, evacuate, heat to 140 °C, react for 7 h, add ether for precipitation after cooling, filter and dry to obtain the carboxyl - terminated hyperbranched polyamide ester.

[0022] (3) Add 0.5 g of graphene oxide and 10 g of the carboxyl - terminated hyperbranched polyamide ester into the mixer, mix for 2 h, then add 1 kg of nylon 6 and mix for 30 min; finally, carry out melt - blending spinning of the material in the spinning machine, the spinning temperature is 260 °C, and the spinning speed is 900 m / min; then carry out drawing through the drawing machine, the temperature is 125 °C, and the drawing ratio is 4 times; finally, cool and shape to obtain the graphene - modified polyamide fiber. Example 2

[0023] (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 the reaction kettle, introduce nitrogen, react at 5 °C for 8 h, carry out vacuum distillation, wash with ether, and dry to obtain the AB2 monomer.

[0024] (2) Add 8 g of the AB2 monomer and 0.2 g of p - toluenesulfonic acid into the reaction kettle, evacuate, heat to 150 °C, react for 5 h, add ether for precipitation after cooling, filter and dry to obtain the carboxyl - terminated hyperbranched polyamide ester.

[0025] (3) Add 3 g of graphene oxide and 25 g of the carboxyl - terminated hyperbranched polyamide ester into the mixer, mix for 3 h, then add 1 kg of nylon 6 and mix for 60 min; finally, carry out melt - blending spinning of the material in the spinning machine, the spinning temperature is 255 °C, and the spinning speed is 800 m / min; then carry out drawing through the drawing machine, the temperature is 120 °C, and the drawing ratio is 4 times; finally, cool and shape to obtain the graphene - modified polyamide fiber. Example 3

[0026] (1) Prepare the AB2 monomer according to the method of Example 1.

[0027] (2) Add 8 g of AB2 monomer and 0.28 g of p-toluenesulfonic acid into the reaction kettle, evacuate to vacuum, heat to 135 °C, react for 8 h, add ether for precipitation after cooling, filter and dry to obtain carboxyl-terminated hyperbranched polyamide ester.

[0028] (3) Add 5 g of graphene oxide and 40 g of carboxyl-terminated hyperbranched polyamide ester into a mixer, mix for 3 h, then add 1 kg of nylon 6 and mix for 60 min; finally, melt-blend and spin the material in a spinning machine at a spinning temperature of 265 °C and a spinning speed of 500 m / min; then draw the fiber through a drawing machine at a temperature of 120 °C and a draw ratio of 3.5 times; finally, cool and shape to obtain graphene-modified polyamide fiber.

[0029] Comparative Example 1

[0030] (1) Melt-spin 1 kg of nylon 6 in a spinning machine at a spinning temperature of 260 °C and a spinning speed of 900 m / min; then draw the fiber through a drawing machine at a temperature of 125 °C and a draw ratio of 4 times; finally, cool and shape to obtain polyamide fiber.

[0031] Comparative Example 2

[0032] (1) Mix 0.5 g of graphene oxide and 1 kg of nylon 6 for 30 min; finally, melt-blend and spin the material in a spinning machine at a spinning temperature of 260 °C and a spinning speed of 900 m / min; then draw the fiber through a drawing machine at a temperature of 125 °C and a draw ratio of 4 times; finally, cool and shape to obtain graphene-modified polyamide fiber.

[0033] Comparative Example 3

[0034] (1) Prepare carboxyl-terminated hyperbranched polyamide ester according to the method of Example 1.

[0035] (2) Add 10 g of carboxyl-terminated hyperbranched polyamide ester and 1 kg of nylon 6 into a mixer, mix for 30 min; then melt-blend and spin the material in a spinning machine at a spinning temperature of 260 °C and a spinning speed of 900 m / min; then draw the fiber through a drawing machine at a temperature of 125 °C and a draw ratio of 4 times; finally, cool and shape to obtain modified polyamide fiber.

[0036] Comparative Example 4

[0037] (1) Prepare carboxyl-terminated hyperbranched polyamide ester according to the method of Example 1.

[0038] (2) Add 0.5 g of graphene and 10 g of carboxyl-terminated hyperbranched polyamide ester into a mixer and mix for 2 h. Then add 1 kg of nylon 6 and mix for 30 min. Finally, melt-blend and spin the material in a spinning machine at a temperature of 260 °C and a spinning speed of 900 m / min. Then draw it through a drawing machine at a temperature of 125 °C with a draw ratio of 4 times. Finally, cool and shape it to obtain graphene-modified polyamide fiber.

[0039] Comparative Example 5

[0040] (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, heat to 140 °C, react for 7 h, add ether for precipitation after cooling, filter and dry to obtain carboxyl-terminated hyperbranched polyester.

[0041] (2) Add 0.5 g of graphene oxide and 10 g of carboxyl-terminated hyperbranched polyester into a mixer and mix for 2 h. Then add 1 kg of nylon 6 and mix for 30 min. Finally, melt-blend and spin the material in a spinning machine at a temperature of 260 °C and a spinning speed of 900 m / min. Then draw it through a drawing machine at a temperature of 125 °C with a draw ratio of 4 times. Finally, cool and shape it to obtain graphene-modified polyamide fiber.

[0042] Comparative Example 6

[0043] Prepare hydroxyl-terminated hyperbranched polyamide ester by referring to the method in the reference journal "Chemistry and Adhesion", Vol. 36, No. 6, 2014, the literature "Study on the Modification of Hydroxyl-Terminated Hyperbranched Polyamide Ester".

[0044] (1) Add 50 mmol of succinic anhydride and 15 mL of N,N-dimethylacetamide into a reaction kettle. Under ice bath and nitrogen atmosphere, add 15 mL of N,N-dimethylacetamide solution containing 50 mmol of diethanolamine. 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 carry out vacuum distillation reaction for 8 h. Extract the crude product with acetone and ether solution, take the insoluble matter in the lower layer after standing, and dry to obtain hydroxyl-terminated hyperbranched polyamide ester.

[0045] (2) Add 0.5 g of graphene oxide and 10 g of hydroxyl-terminated hyperbranched polyamide ester into a mixer and mix for 2 h. Then add 1 kg of nylon 6 and mix for 30 min. Finally, melt-blend and spin the material in a spinning machine at a temperature of 260 °C and a spinning speed of 900 m / min. Then draw it through a drawing machine at a temperature of 125 °C with a draw ratio of 4 times. Finally, cool and shape it to obtain graphene-modified polyamide fiber.

[0046] Test the tensile fracture properties of the fibers according to GB / T 14337-2022. Test the moisture regain of the fibers according to GB / T 6503-2017.

[0047] Table 1 Performance Test of Nylon Fibers

[0048]

[0049] As can be seen from the above table, compared with the nylon fibers in Comparative Example 1, graphene oxide and carboxyl-terminated hyperbranched polyamide ester are added in Example 1. The hyperbranched polyamide ester contains the same amide structural unit as nylon 6 polyamide, which makes the compatibility between the hyperbranched polyamide ester and nylon 6 very good, has little influence on the strength of the nylon fibers, and can play a good toughening role, enabling the nylon fibers to have a higher elongation at break while maintaining a relatively high breaking strength. At the same time, the end groups of the hyperbranched polyamide ester contain a large number of hydrophilic carboxyl groups, and the main chain contains hydrophilic amide bonds, which can improve the hydrophilic moisture absorption of the nylon fibers and show a higher moisture regain. And the hyperbranched polyamide ester contains a large number of carboxyl terminals, which form stable hydrogen bonds and other interaction forces with the carboxyl, hydroxyl and other groups on the surface of graphene oxide, thus coating on the surface of graphene oxide. The interfacial compatibility between the coated and modified graphene oxide and nylon 6 is better, and it is more uniformly dispersed in the nylon fiber matrix, significantly improving the breaking strength of the fibers. Different amounts of graphene oxide and carboxyl-terminated hyperbranched polyamide ester are added in Examples 2-3, and the nylon fibers show good tensile fracture properties and moisture regain, good mechanical properties, and high hydrophilic moisture absorption.

[0050] Compared with Comparative Example 1, only graphene oxide is added in Comparative Example 2, and the compatibility with nylon 6 is poor. Although the breaking strength of the nylon fibers is improved, the elongation at break decreases significantly, and the moisture regain of the nylon fibers is low, and the hydrophilic moisture absorption is poor.

[0051] Compared with Comparative Example 1, only carboxyl-terminated hyperbranched polyamide ester is added in Comparative Example 3. The nylon fibers have a higher elongation at break while maintaining a relatively high breaking strength, and have a high moisture regain and good hydrophilic moisture absorption. However, without adding graphene oxide, the breaking strength of the nylon fibers is lower than that in Example 1.

[0052] The graphene added in Comparative Example 4 does not contain carboxyl, hydroxyl and other groups on its surface, and cannot form hydrogen bonds and other interaction forces with the carboxyl terminals of the hyperbranched polyamide ester, and cannot coat on the surface of graphene oxide, so it cannot improve the compatibility between graphene and nylon 6, resulting in the breaking strength and elongation at break of the nylon fibers being lower than those in Example 1.

[0053] In Comparative Example 5, 3-hydroxyglutaric acid was used as the AB2 monomer, and the resulting carboxyl-terminated hyperbranched polyester obtained by esterification polycondensation did not contain an amide bond structural unit. Its compatibility with nylon 6 was poor, the toughening effect was not good, and it did not improve the interfacial compatibility between graphene oxide and nylon 6 well, resulting in the breaking strength and elongation at break of the polyamide fiber being lower than those in Example 1. Moreover, since the carboxyl-terminated hyperbranched polyester did not contain hydrophilic amide bonds, the moisture regain was lower than that in Example 1.

[0054] The hydroxyl-terminated hyperbranched polyamide ester prepared in Comparative Example 6 did not contain carboxyl groups, and the hydrophilicity of hydroxyl groups was lower than that of carboxyl groups, resulting in the moisture regain of the polyamide fiber being lower than that in Example 1, and the breaking strength and elongation at break being relatively low. It may be that the interaction force between the hydroxyl groups at its ends and the surface of graphene oxide is weaker than the interaction force between the carboxyl groups at the ends of the hyperbranched polyamide ester in Example 1, resulting in the compatibility between graphene oxide and nylon 6 being lower than that in Example 1 and the enhancement effect being poor.

Claims

1. A preparation method of graphene-modified polyamide fiber, characterized in that, The preparation method is as follows: (1) Add the AB2 monomer with the structural formula and p-toluenesulfonic acid into the reaction kettle, evacuate to vacuum, carry out melt polycondensation reaction, precipitate after cooling, filter and then dry to obtain the carboxyl-terminated hyperbranched polyamide ester; (2) Add 0.05-0.5 parts by weight of graphene oxide and 1-4 parts by weight of carboxyl-terminated hyperbranched polyamide ester into a mixer for primary mixing, then add 100 parts by weight of nylon 6 for secondary mixing; finally, melt-blend spin and draw the material in a spinning machine, and cool and shape it to obtain graphene-modified polyamide fiber; The preparation method of the AB2 monomer is: add N,N-dimethylformamide, 1,3-diamino-2-hydroxypropane, and succinic anhydride into a reaction kettle, introduce nitrogen, carry out amidation reaction, distill under reduced pressure, wash, and dry to obtain the AB2 monomer; The dosage of 1,3-diamino-2-hydroxypropane is 100 parts by weight, and the dosage of succinic anhydride is 222-234 parts by weight.

2. The preparation method of the graphene-modified polyamide fiber according to claim 1, characterized in that, In (1), the dosage of the AB2 monomer is 100 parts by weight, and the dosage of p-toluenesulfonic acid is 2.5-3.5 parts by weight.

3. The preparation method of the graphene-modified polyamide fiber according to claim 1, wherein, In (1), the temperature during the melt polycondensation reaction is 135-150 °C, and the reaction time is 5-8 h.

4. The preparation method of the graphene-modified polyamide fiber according to claim 1, wherein, In (2), the time for primary mixing is 2-3 h; the time for secondary mixing is 30-60 min.

5. The preparation method of the graphene-modified polyamide fiber according to claim 1, wherein, In (2), the temperature during melt-blend spinning is 255-265 °C, and the spinning speed is 500-900 m / min.

6. The preparation method of the graphene-modified polyamide fiber according to claim 1, characterized in that, In (2), the temperature during drawing is 120-125 °C, and the draw ratio is 3.5-4 times.

7. The preparation method of the graphene-modified polyamide fiber according to claim 1, wherein, In the preparation method of the AB2 monomer, the temperature during the amidation reaction is 0-5 °C, and the reaction time is 8-10 h.

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