Modified nonwoven fabric and method for producing the same

Abstract

The application discloses a modified non-woven fabric and a preparation method thereof. The method is characterized in that graphene oxide and graphene are prepared into a mixed multi-layer graphene spraying liquid through ultrasonic intercalation, and then the mixed multi-layer graphene spraying liquid is adhered to a non-woven fabric through a spraying process to modify the non-woven fabric. The modified non-woven fabric is not easy to fall off, is stable in structure, can effectively avoid tearing of fibers of the non-woven fabric in a stretching process, and improves the overall breaking strength of the non-woven fabric.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to a modified nonwoven fabric and its preparation method. Background Technology

[0002] Nonwoven fabric is a type of non-woven material. It is made by directly forming fibers from polymer chips, short fibers, or filaments into a web through airflow or mechanical means, then reinforcing it through hydroentangling, needle punching, or thermal rolling, and finally finishing processes. It is a new type of fiber product with a soft, breathable, and planar structure. Its advantages include no fiber shedding, strength, durability, silky softness, and it also serves as a reinforcing material. Furthermore, it has a cotton-like feel. Compared to cotton fabrics, nonwoven products are easier to shape and less expensive to produce.

[0003] However, nonwoven fabrics have lower strength and durability compared to woven fabrics, cannot be washed like other fabrics, and because the fibers in nonwoven fabrics are arranged in a certain direction, they are prone to tearing at right angles. Therefore, improvements in production methods mainly focus on improving methods to prevent tearing.

[0004] Graphene is a typical two-dimensional layered material with thin sheets and a large specific surface area, reaching 2630 m². 2 With a density of / g, graphene possesses extremely high mechanical strength, exceeding that of diamond in hardness. It also exhibits excellent toughness, allowing it to be bent. The carbon atoms in graphene are tightly bonded with uniform bond energy, enabling the sheets to twist under external force without breaking, thus maintaining structural stability. Therefore, graphene materials are often used as modifiers for other materials and in the preparation of composite materials.

[0005] The main methods for preparing graphene include mechanical exfoliation, redox methods, and vapor-phase precipitation. However, these methods typically result in relatively stable structures and strong chemical inertness, making further chemical modification difficult. Furthermore, they are prone to stacking and agglomeration, which affects their performance.

[0006] To solve the above problems, it is necessary to develop a novel method for graphene-modified nonwoven fabrics. This method should not only effectively prevent the graphene from stacking and agglomerating, but also increase its adhesion to the surface of the nonwoven fabric, forming a stable skeletal support that is not easy to fall off. Summary of the Invention

[0007] The purpose of this invention is to provide a modified nonwoven fabric and its preparation method. The nonwoven fabric modification method of this application can effectively avoid fiber tearing during the stretching process of the nonwoven fabric and improve the overall tensile strength of the nonwoven fabric.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing modified nonwoven fabric involves using ultrasonic intercalation to prepare a mixed multilayer graphene spray liquid from graphene oxide and graphene. The mixed multilayer graphene spray liquid is then adhered to the nonwoven fabric via a spraying process to modify it, forming a stable multilayer mixed graphene framework and improving the tensile strength of the nonwoven fabric. The method specifically includes the following steps: (1) Preparation of graphene oxide dispersion: The following steps are performed: In an ice-water bath, 85-100 parts of concentrated sulfuric acid and 5-15 parts of concentrated phosphoric acid are added sequentially to a three-necked flask, and the mixture is stirred vigorously for 5-10 minutes. Then, 5-8 parts of potassium permanganate are slowly added, and the mixture is stirred vigorously for 30 minutes. Finally, 0.5-2 parts by mass of flake graphene powder are slowly added, and the mixture is stirred vigorously for 1-3 hours. The water bath temperature is adjusted to 40-60℃, and the reaction is carried out for 12-24 hours. After the reaction is completed, the unreacted solid particles are filtered out. Under stirring conditions, 50-60 parts of hydrogen peroxide are added, and the mixture is allowed to stand overnight. The mixture is washed with deionized water until neutral, and then freeze-dried to obtain graphene oxide powder GO. Graphene oxide powder GO is weighed and added to deionized water at a weight ratio of (1:5) to (1:10). The mixture is stirred until it is completely dispersed and then transferred to a hydrothermal reactor for hydrothermal reaction. Freeze-drying yields graphene oxide powder (GO) X According to graphene oxide powder GO X The dispersion solution was prepared by dispersing graphene oxide powder (GO) at a weight ratio of (1:50) to (1:150). X The graphene oxide dispersion was prepared by adding it to the dispersion solution and mechanically ultrasonically dispersing it for 3-6 hours with an ultrasonic intensity of 60%.

[0009] (2) Preparation of graphene dispersion: Weigh flake graphite powder and 304 stainless steel sand, with a material-to-bead ratio of (1:20) to (1:30) by mass. Add the graphite powder and 304 stainless steel sand together to a ball mill jar, and add surfactant and intercalating agent. Ball mill for 10-15 hours. Add solvent to the ball-milled material according to the proportion, and sieve to remove the 304 stainless steel sand. Disperse the ball-milled slurry by mechanical ultrasonication for 6-9 hours with an ultrasonic intensity of 60%. After centrifugation for 15 minutes, discard the lower precipitate. Take the upper dispersion, disperse it by mechanical ultrasonication for 3-5 hours with an ultrasonic intensity of 60%. Centrifuge for 15 minutes, discard the lower precipitate. Take the upper dispersion, disperse it by mechanical ultrasonication for 3-5 hours with an ultrasonic intensity of 60%. Centrifuge for 30 minutes, discard the lower precipitate, and freeze-dry the upper dispersion to obtain monolayer graphene. Weigh out monolayer graphene according to the weight ratio of monolayer graphene to solvent of (1:50) to (1:150), add monolayer graphene to solvent, and mechanically and ultrasonically disperse for 3-6 hours with ultrasonic intensity of 60% to obtain graphene oxide dispersion.

[0010] (3) Preparation of mixed dispersion: Mix graphene oxide dispersion and graphene dispersion by volume, and mechanically ultrasonically disperse for 3-6 hours with an ultrasonic intensity of 60% to obtain mixed multilayer graphene spraying liquid.

[0011] (4) Nonwoven fabric modification: The mixed multilayer graphene spray liquid is sprayed onto the surface of the nonwoven fabric, dried with hot air, cut, and rolled up to make modified nonwoven fabric.

[0012] In the above technical solution, the concentrated sulfuric acid is 98% concentrated sulfuric acid, and the concentrated phosphoric acid is 85% concentrated phosphoric acid. All the amounts of the reactants mentioned above are parts by weight.

[0013] Further, in step (1), the hydrothermal reaction time is 1-15 h, and the hydrothermal reaction temperature is 120-190 °C. Preferably, it is 1-8 h at 120-150 °C. More preferably, it is 4 h at 130 °C.

[0014] Furthermore, in step (1) GO X The value of X is 10-60.

[0015] Furthermore, the dispersion solution in step (1) is one or more of water, methanol, and ethanol.

[0016] Furthermore, in step (2), the particle size of the flake graphite powder is 500-2000 mesh. Preferably, it is 1000 mesh.

[0017] Further, in step (2), the 304 stainless steel sand is composed of the following parts by weight: 0.2mm, 10 parts; 0.4mm, 4 parts; 0.6mm, 3 parts; 0.8mm, 2 parts; 1.0mm, 1 part.

[0018] Furthermore, in step (2), the surfactant is sodium dodecyl sulfate, and the intercalating agent is an alkylamine, specifically one or more of propylamine, butylamine, and hexylamine.

[0019] Furthermore, in step (2), the first centrifugation speed is 3000 rpm, the second centrifugation speed is 5000 rpm, and the third centrifugation speed is 8000 rpm.

[0020] Furthermore, in step (3), the volume ratio of the graphene oxide dispersion to the graphene dispersion is (1:3)-(3:1), preferably 2:1.

[0021] Further, in step (4), the nozzle output rate is 40-400 mL / min. Preferably, the nozzle output rate is 40-200 mL / min. The hot air temperature is 120℃. The winding speed is 0.2~1 m / s.

[0022] The beneficial effects of this invention are: (1) This invention utilizes a hydrothermal reduction method, adjusting the degree of oxidation of graphene oxide by modifying the hydrothermal reaction time and temperature. Graphene oxide with different oxidation degrees exhibits different adhesiveness. Selecting a suitable degree of oxidation helps enhance the adhesion of the composite material, playing a crucial role in improving its performance. This application found that when the hydrothermal reaction temperature is controlled at 130℃ and the reaction time is 4h, the prepared GO... 30 It has the best adhesion and can significantly improve the tensile strength of nonwoven fabrics.

[0023] (2) The present invention uses mechanical exfoliation (through multiple mechanical ultrasonic dispersion) to prepare monolayer graphene, and the resulting monolayer graphene has a complete crystal lattice and high mechanical strength.

[0024] (3) Using mechanical ultrasound to intercalate graphene oxide into graphene layers to form a mixed multilayer graphene structure can effectively avoid the stacking and accumulation of single graphene.

[0025] (4) Adhesive graphene oxide can firmly adhere the mixed multilayer graphene structure to the surface of nonwoven fabric, making it difficult to peel off.

[0026] (5) The stable graphene skeleton structure prepared in this application can effectively avoid the tearing and breakage of fibers during the stretching process of nonwoven fabric, effectively improve the overall breaking strength and breaking elongation of nonwoven fabric, and obtain a modified nonwoven fabric with excellent performance. Attached Figure Description

[0027] Figure 1 The results show the tensile strength test results of graphene oxide modified nonwoven fabrics with different oxidation levels.

[0028] Figure 2 The tensile strength test results of the modified nonwoven fabrics prepared in the examples and comparative examples are shown. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0030] A method for preparing a modified nonwoven fabric specifically includes the following steps: (1) Preparation of graphene oxide dispersion: The following steps are performed: In an ice-water bath, 85-100 parts by weight of concentrated sulfuric acid and 5-15 parts by weight of concentrated phosphoric acid are added sequentially and stirred vigorously for 5-10 minutes. Then, 5-8 parts by weight of potassium permanganate are slowly added and stirred vigorously for 30 minutes. Then, 0.5-2 parts by weight of flake graphene powder are slowly added and stirred vigorously for 1-3 hours. The water bath heating temperature is adjusted to 40-60℃ and the reaction is carried out for 12-24 hours. After the reaction is completed, the unreacted solid particles are filtered out. Under stirring conditions, 50-60 parts by weight of hydrogen peroxide are added and the mixture is left to stand overnight. The mixture is washed with deionized water until neutral and then freeze-dried to obtain graphene oxide powder GO. Graphene oxide powder GO is added to deionized water at a weight ratio of 1:5-10 and stirred until completely dispersed. The mixture is then transferred to a hydrothermal reactor for hydrothermal reaction (reaction temperature 120-190℃, time 1-15 hours) and freeze-dried to obtain graphene oxide powder GO. X According to graphene oxide powder GO X The dispersion solution is prepared at a weight ratio of 1:50~150, with graphene oxide powder (GO) added. X The graphene oxide dispersion was prepared by adding it to the dispersion solution and mechanically ultrasonically dispersing it for 3-6 hours with an ultrasonic intensity of 60%. (2) Preparation of graphene dispersion: Weigh flake graphite powder and 304 stainless steel sand, with a mass ratio of 1:20~30; put the graphite powder and 304 stainless steel sand into a ball mill jar, add surfactant and intercalating agent, and ball mill for 10-15 hours; add solvent to the ball-milled material according to the proportion, and sieve to remove 304 stainless steel sand; the ball-milled slurry is then mechanically ultrasonically dispersed for 6-9 hours with an ultrasonic intensity of 60%; after centrifugation for 15 minutes, discard the lower precipitate; take the upper layer of dispersion. The dispersion was mechanically and ultrasonically dispersed for 3-5 hours at an ultrasonic intensity of 60%; centrifuged for 15 minutes and the lower precipitate was discarded; the upper dispersion was mechanically and ultrasonically dispersed for 3-5 hours at an ultrasonic intensity of 60%; centrifuged for 30 minutes and the lower precipitate was discarded; the upper dispersion was freeze-dried to obtain monolayer graphene; monolayer graphene was added to the solvent at a weight ratio of 1:50~150 and mechanically and ultrasonically dispersed for 3-6 hours at an ultrasonic intensity of 60% to obtain graphene oxide dispersion. (3) Preparation of mixed dispersion: The graphene oxide dispersion and the graphene dispersion were mixed at a volume ratio of (1:3)-(3:1), and mechanically ultrasonically dispersed for 3-6 hours with an ultrasonic intensity of 60% to obtain a mixed multilayer graphene spraying liquid. (4) Nonwoven fabric modification: The mixed multilayer graphene spray liquid is sprayed onto the surface of the nonwoven fabric, dried with hot air, cut, and rolled up to make modified nonwoven fabric.

[0031] Example 1 (1) Preparation of graphene oxide dispersion: The following steps were performed: In an ice-water bath, 90 parts of concentrated sulfuric acid and 10 parts of concentrated phosphoric acid were added sequentially to a three-necked flask, and the mixture was stirred vigorously for 5 minutes. Then, 5 parts of potassium permanganate were slowly added, and the mixture was stirred vigorously for 30 minutes. Finally, 1 part of flake graphene powder was slowly added, and the mixture was stirred vigorously for 1 hour. The water bath temperature was adjusted to 50°C, and the reaction was carried out for 24 hours. After the reaction was completed, the unreacted solid particles were filtered out. Under stirring conditions, 50 parts of hydrogen peroxide were added, and the mixture was allowed to stand overnight. The mixture was washed with deionized water until neutral, and then freeze-dried to obtain graphene oxide powder GO. Graphene oxide powder GO was weighed and added to deionized water at a ratio of 1:5 by weight. The mixture was stirred until it was completely dispersed and then transferred to a hydrothermal reactor. The hydrothermal reaction was carried out for 1 hour at a temperature of 120°C. Graphene oxide powder GO was obtained by freeze-drying. 50 Weigh out graphene oxide powder (GO). 50 Add water at a ratio of 1:100 and mechanically and ultrasonically disperse for 3-6 hours at an ultrasonic intensity of 60%. This yields a graphene oxide dispersion.

[0032] (2) Preparation of graphene dispersion: Weigh flake graphite powder and 304 stainless steel grit, with a particle ratio of 1:20. Add the graphite powder and steel grit together to the ball mill jar according to the following mass ratio: 0.2mm, 10 parts; 0.4mm, 4 parts; 0.6mm, 3 parts; 0.8mm, 2 parts; 1.0mm, 1 part. Add surfactant and intercalating agent. Ball mill for 10-15 hours. Add solvent to the ball-milled material according to the ratio and sieve to remove steel grit. Disperse the ball-milled slurry mechanically and ultrasonically for 6-9 hours, with an ultrasonic intensity of 60%. Centrifuge at 3000 rpm for 15 minutes and discard the lower precipitate. Take the upper dispersion and disperse mechanically and ultrasonically for 3-5 hours, with an ultrasonic intensity of 60%. Centrifuge at 5000 rpm for 15 minutes and discard the lower precipitate. Take the upper dispersion and disperse mechanically and ultrasonically for 3-5 hours, with an ultrasonic intensity of 60%. Centrifuge at 8000 rpm for 30 min, discard the lower precipitate, and freeze-dry the upper dispersion to obtain monolayer graphene. Weigh the monolayer graphene, add solvent at a ratio of 1:100, and mechanically and ultrasonically disperse for 3-6 h at an ultrasonic intensity of 60% to obtain a graphene oxide dispersion.

[0033] (3) Preparation of mixed dispersion: Mix graphene oxide dispersion and graphene dispersion in a volume ratio of 3:1, and mechanically ultrasonically disperse for 3-6 hours with an ultrasonic intensity of 60% to obtain mixed dispersion.

[0034] (4) Nonwoven fabric modification: The mixed graphene spray liquid is sprayed onto the surface of the nonwoven fabric, dried with hot air at 120°C, cut, and rolled up to make modified nonwoven fabric.

[0035] Example 2 (1) Preparation of graphene oxide dispersion: The following steps were performed: In an ice-water bath, 90 parts of concentrated sulfuric acid and 10 parts of concentrated phosphoric acid were added sequentially to a three-necked flask, and the mixture was stirred vigorously for 5 minutes. Then, 5 parts of potassium permanganate were slowly added, and the mixture was stirred vigorously for 30 minutes. Finally, 1 part of flake graphene powder was slowly added, and the mixture was stirred vigorously for 1 hour. The water bath temperature was adjusted to 50°C, and the reaction was carried out for 24 hours. After the reaction was completed, the unreacted solid particles were filtered out. Under stirring conditions, 50 parts of hydrogen peroxide were added, and the mixture was allowed to stand overnight. The mixture was washed with deionized water until neutral, and then freeze-dried to obtain graphene oxide powder GO. Graphene oxide powder GO was weighed and added to deionized water at a ratio of 1:5 by weight. The mixture was stirred until it was completely dispersed and then transferred to a hydrothermal reactor. The hydrothermal reaction was carried out for 8 hours at a temperature of 190°C. Graphene oxide powder GO was then freeze-dried to obtain graphene oxide powder GO. 20 Weigh out graphene oxide powder (GO). 20 Add water at a ratio of 1:100 and mechanically and ultrasonically disperse for 3-6 hours at an ultrasonic intensity of 60%. This yields a graphene oxide dispersion.

[0036] (2) Preparation of graphene dispersion: Weigh flake graphite powder and 304 stainless steel grit, with a particle ratio of 1:20. Add the graphite powder and steel grit together to the ball mill jar according to the following mass ratio: 0.2mm, 10 parts; 0.4mm, 4 parts; 0.6mm, 3 parts; 0.8mm, 2 parts; 1.0mm, 1 part. Add surfactant and intercalating agent. Ball mill for 10-15 hours. Add solvent to the ball-milled material according to the ratio and sieve to remove steel grit. Disperse the ball-milled slurry mechanically and ultrasonically for 6-9 hours, with an ultrasonic intensity of 60%. Centrifuge at 3000 rpm for 15 minutes and discard the lower precipitate. Take the upper dispersion and disperse mechanically and ultrasonically for 3-5 hours, with an ultrasonic intensity of 60%. Centrifuge at 5000 rpm for 15 minutes and discard the lower precipitate. Take the upper dispersion and disperse mechanically and ultrasonically for 3-5 hours, with an ultrasonic intensity of 60%. Centrifuge at 8000 rpm for 30 min, discard the lower precipitate, and freeze-dry the upper dispersion to obtain monolayer graphene. Weigh the monolayer graphene, add solvent at a ratio of 1:100, and mechanically and ultrasonically disperse for 3-6 h at an ultrasonic intensity of 60% to obtain a graphene oxide dispersion.

[0037] (3) Preparation of mixed dispersion: Mix graphene oxide dispersion and graphene dispersion in a volume ratio of 3:1, and mechanically ultrasonically disperse for 3-6 hours with an ultrasonic intensity of 60% to obtain mixed dispersion.

[0038] (4) Nonwoven fabric modification: The mixed graphene spray liquid is sprayed onto the surface of the nonwoven fabric, dried with hot air at 120°C, cut, and rolled up to make modified nonwoven fabric.

[0039] Example 3 (1) Preparation of graphene oxide dispersion: The following steps were performed: In an ice-water bath, 90 parts of concentrated sulfuric acid and 10 parts of concentrated phosphoric acid were added sequentially to a three-necked flask, and the mixture was stirred vigorously for 5 minutes. Then, 5 parts of potassium permanganate were slowly added, and the mixture was stirred vigorously for 30 minutes. Finally, 1 part of flake graphene powder was slowly added, and the mixture was stirred vigorously for 1 hour. The water bath temperature was adjusted to 50°C, and the reaction was carried out for 24 hours. After the reaction was completed, the unreacted solid particles were filtered out. Under stirring conditions, 50 parts of hydrogen peroxide were added, and the mixture was allowed to stand overnight. The mixture was washed with deionized water until neutral, and then freeze-dried to obtain graphene oxide powder GO. Graphene oxide powder GO was weighed and added to deionized water at a ratio of 1:5 by weight. The mixture was stirred until it was completely dispersed and then transferred to a hydrothermal reactor. The hydrothermal reaction was carried out for 4 hours at a temperature of 130°C. Graphene oxide powder GO was obtained by freeze-drying. 30 Weigh out graphene oxide powder (GO). 30 Add water at a ratio of 1:100 and mechanically and ultrasonically disperse for 3-6 hours at an ultrasonic intensity of 60%. This yields a graphene oxide dispersion.

[0040] (2) Preparation of graphene dispersion: Weigh flake graphite powder and 304 stainless steel grit, with a particle ratio of 1:20. Add the graphite powder and steel grit together to the ball mill jar according to the following mass ratio: 0.2mm, 10 parts; 0.4mm, 4 parts; 0.6mm, 3 parts; 0.8mm, 2 parts; 1.0mm, 1 part. Add surfactant and intercalating agent. Ball mill for 10-15 hours. Add solvent to the ball-milled material according to the ratio and sieve to remove steel grit. Disperse the ball-milled slurry mechanically and ultrasonically for 6-9 hours, with an ultrasonic intensity of 60%. Centrifuge at 3000 rpm for 15 minutes and discard the lower precipitate. Take the upper dispersion and disperse mechanically and ultrasonically for 3-5 hours, with an ultrasonic intensity of 60%. Centrifuge at 5000 rpm for 15 minutes and discard the lower precipitate. Take the upper dispersion and disperse mechanically and ultrasonically for 3-5 hours, with an ultrasonic intensity of 60%. Centrifuge at 8000 rpm for 30 min, discard the lower precipitate, and freeze-dry the upper dispersion to obtain monolayer graphene. Weigh the monolayer graphene, add solvent at a ratio of 1:100, and mechanically and ultrasonically disperse for 3-6 h at an ultrasonic intensity of 60% to obtain a graphene oxide dispersion.

[0041] (3) Preparation of mixed dispersion: Mix graphene oxide dispersion and graphene dispersion in a volume ratio of 2:1, and mechanically ultrasonically disperse for 3-6 hours with an ultrasonic intensity of 60% to obtain mixed dispersion.

[0042] (4) Nonwoven fabric modification: The mixed graphene spray liquid is sprayed onto the surface of the nonwoven fabric, dried with hot air at 120°C, cut, and rolled up to make modified nonwoven fabric.

[0043] Example 4 (1) Preparation of graphene oxide dispersion: The following steps were performed: In an ice-water bath, 90 parts of concentrated sulfuric acid and 10 parts of concentrated phosphoric acid were added sequentially to a three-necked flask, and the mixture was stirred vigorously for 5 minutes. Then, 5 parts of potassium permanganate were slowly added, and the mixture was stirred vigorously for 30 minutes. Finally, 1 part of flake graphene powder was slowly added, and the mixture was stirred vigorously for 1 hour. The water bath temperature was adjusted to 50°C, and the reaction was carried out for 24 hours. After the reaction was completed, the unreacted solid particles were filtered out. Under stirring conditions, 50 parts of hydrogen peroxide were added, and the mixture was allowed to stand overnight. The mixture was washed with deionized water until neutral, and then freeze-dried to obtain graphene oxide powder GO. Graphene oxide powder GO was weighed and added to deionized water at a ratio of 1:5 by weight. The mixture was stirred until it was completely dispersed and then transferred to a hydrothermal reactor. The hydrothermal reaction was carried out for 4 hours at a temperature of 130°C. Graphene oxide powder GO was obtained by freeze-drying. 30 Weigh out graphene oxide powder (GO). 30 Add water at a ratio of 1:100 and mechanically and ultrasonically disperse for 3-6 hours at an ultrasonic intensity of 60%. This yields a graphene oxide dispersion.

[0044] (2) Preparation of graphene dispersion: Weigh flake graphite powder and 304 stainless steel grit, with a particle ratio of 1:20. Add the graphite powder and steel grit together to the ball mill jar according to the following mass ratio: 0.2mm, 10 parts; 0.4mm, 4 parts; 0.6mm, 3 parts; 0.8mm, 2 parts; 1.0mm, 1 part. Add surfactant and intercalating agent. Ball mill for 10-15 hours. Add solvent to the ball-milled material according to the ratio and sieve to remove steel grit. Disperse the ball-milled slurry mechanically and ultrasonically for 6-9 hours, with an ultrasonic intensity of 60%. Centrifuge at 3000 rpm for 15 minutes and discard the lower precipitate. Take the upper dispersion and disperse mechanically and ultrasonically for 3-5 hours, with an ultrasonic intensity of 60%. Centrifuge at 5000 rpm for 15 minutes and discard the lower precipitate. Take the upper dispersion and disperse mechanically and ultrasonically for 3-5 hours, with an ultrasonic intensity of 60%. Centrifuge at 8000 rpm for 30 min, discard the lower precipitate, and freeze-dry the upper dispersion to obtain monolayer graphene. Weigh the monolayer graphene, add solvent at a ratio of 1:100, and mechanically and ultrasonically disperse for 3-6 h at an ultrasonic intensity of 60% to obtain a graphene oxide dispersion.

[0045] (3) Preparation of mixed dispersion: Mix graphene oxide dispersion and graphene dispersion in a volume ratio of 1:2, and mechanically ultrasonically disperse for 3-6 hours with an ultrasonic intensity of 60% to obtain mixed dispersion.

[0046] (4) Nonwoven fabric modification: The mixed graphene spray liquid is sprayed onto the surface of the nonwoven fabric, dried with hot air at 120°C, cut, and rolled up to make modified nonwoven fabric.

[0047] Example 5 (1) Preparation of graphene oxide dispersion: The following steps were performed: In an ice-water bath, 90 parts of concentrated sulfuric acid and 10 parts of concentrated phosphoric acid were added sequentially to a three-necked flask, and the mixture was stirred vigorously for 5 minutes. Then, 5 parts of potassium permanganate were slowly added, and the mixture was stirred vigorously for 30 minutes. Finally, 1 part of flake graphene powder was slowly added, and the mixture was stirred vigorously for 1 hour. The water bath temperature was adjusted to 50°C, and the reaction was carried out for 24 hours. After the reaction was completed, the unreacted solid particles were filtered out. Under stirring conditions, 50 parts of hydrogen peroxide were added, and the mixture was allowed to stand overnight. The mixture was washed with deionized water until neutral, and then freeze-dried to obtain graphene oxide powder GO. Graphene oxide powder GO was weighed and added to deionized water at a ratio of 1:5 by weight. The mixture was stirred until it was completely dispersed and then transferred to a hydrothermal reactor. The hydrothermal reaction was carried out for 4 hours at a temperature of 130°C. Graphene oxide powder GO was obtained by freeze-drying. 30 Weigh out graphene oxide powder (GO). 30 Add water at a ratio of 1:100 and mechanically and ultrasonically disperse for 3-6 hours at an ultrasonic intensity of 60%. This yields a graphene oxide dispersion.

[0048] (2) Preparation of graphene dispersion: Weigh flake graphite powder and 304 stainless steel grit, with a particle ratio of 1:20. Add the graphite powder and steel grit together to the ball mill jar according to the following mass ratio: 0.2mm, 10 parts; 0.4mm, 4 parts; 0.6mm, 3 parts; 0.8mm, 2 parts; 1.0mm, 1 part. Add surfactant and intercalating agent. Ball mill for 10-15 hours. Add solvent to the ball-milled material according to the ratio and sieve to remove steel grit. Disperse the ball-milled slurry mechanically and ultrasonically for 6-9 hours, with an ultrasonic intensity of 60%. Centrifuge at 3000 rpm for 15 minutes and discard the lower precipitate. Take the upper dispersion and disperse mechanically and ultrasonically for 3-5 hours, with an ultrasonic intensity of 60%. Centrifuge at 5000 rpm for 15 minutes and discard the lower precipitate. Take the upper dispersion and disperse mechanically and ultrasonically for 3-5 hours, with an ultrasonic intensity of 60%. Centrifuge at 8000 rpm for 30 min, discard the lower precipitate, and freeze-dry the upper dispersion to obtain monolayer graphene. Weigh the monolayer graphene, add solvent at a ratio of 1:100, and mechanically and ultrasonically disperse for 3-6 h at an ultrasonic intensity of 60% to obtain a graphene oxide dispersion.

[0049] (3) Preparation of mixed dispersion: Mix graphene oxide dispersion and graphene dispersion in a volume ratio of 1:3, and mechanically ultrasonically disperse for 3-6 hours with an ultrasonic intensity of 60% to obtain mixed dispersion.

[0050] (4) Nonwoven fabric modification: The mixed graphene spray liquid is sprayed onto the surface of the nonwoven fabric, dried with hot air at 120°C, cut, and rolled up to make modified nonwoven fabric.

[0051] Comparative Example 1 The difference from Example 5 is that the nonwoven fabric modification is only sprayed with graphene oxide dispersion.

[0052] Comparative Example 2 The difference from Example 5 is that the nonwoven fabric modification is only sprayed with graphene dispersion.

[0053] The tensile strength of the modified nonwoven fabric was tested according to GB / T 24218.3 standard.

[0054] Different degrees of graphene oxide oxidation result in varying oxidizing properties and adhesiveness, which is crucial for subsequent modification of nonwoven fabrics. Selecting an appropriate degree of oxidation helps enhance adhesion and improves the performance of composite materials. Excessive oxidation may damage the nonwoven fabric fiber structure, while insufficient oxidation leads to low adhesion and ineffective bonding. Figure 1 The figure shows the tensile strength test results of graphene oxide-modified nonwoven fabrics with different oxidation degrees. As can be seen from the figure, GO... 30 The graphene oxide-modified nonwoven fabric exhibits the strongest tensile strength.

[0055] The tensile strength test results of the modified nonwoven fabrics in Examples 1-5 and Comparative Examples 1-2 are as follows: Figure 2 As shown. By Figure 2 It is known that graphene-coated nonwoven fabrics show a slight improvement in tensile strength, but the improvement is not significant. This is because graphene tends to agglomerate on the surface of the nonwoven fabric and is easily peeled off during stretching, reducing its mechanical support and failing to fully utilize the high mechanical strength of graphene. Nonwoven fabrics coated with graphene oxide show a significant improvement in tensile strength, due to the good adhesion of graphene oxide, which strongly adheres to the surface of the nonwoven fabric and is not easily detached. Multilayer graphene frameworks prepared by mixing graphene and graphene oxide retain the high strength of graphene while also possessing adhesive properties, preventing the stacking and agglomeration of individual graphene materials, forming a stable graphene framework structure, and effectively improving the mechanical strength of the modified nonwoven fabric. Furthermore, a 2:1 volume ratio of graphene to graphene oxide achieves the optimal effect, resulting in the highest improvement in tensile strength of the modified nonwoven fabric.

Claims

1. A method for preparing a modified nonwoven fabric, characterized in that, A mixed multilayer graphene spraying liquid is prepared by ultrasonic intercalation of graphene oxide and graphene. The mixed multilayer graphene spraying liquid is then adhered to a nonwoven fabric for modification via a spraying process, including the following steps: (1) Preparation of graphene oxide dispersion: The following steps are performed: In an ice-water bath, 85-100 parts by weight of concentrated sulfuric acid and 5-15 parts by weight of concentrated phosphoric acid are added sequentially and stirred vigorously for 5-10 minutes. Then, 5-8 parts by weight of potassium permanganate are slowly added and stirred vigorously for 30 minutes. Then, 0.5-2 parts by weight of flake graphene powder are slowly added and stirred vigorously for 1-3 hours. The water bath heating temperature is adjusted to 40-60℃ and the reaction is carried out for 12-24 hours. After the reaction is completed, the unreacted solid particles are filtered out. Under stirring conditions, 50-60 parts by weight of hydrogen peroxide are added and the mixture is left to stand overnight. The mixture is washed with deionized water until neutral and then freeze-dried to obtain graphene oxide powder GO. Graphene oxide powder GO is added to deionized water at a weight ratio of 1:5-10 and stirred until completely dispersed. The mixture is then transferred to a hydrothermal reactor for hydrothermal reaction and freeze-dried to obtain graphene oxide powder GO. X According to graphene oxide powder GO X The dispersion solution is prepared at a weight ratio of 1:50~150, with graphene oxide powder (GO) added. X The graphene oxide dispersion was prepared by adding it to the dispersion solution and mechanically ultrasonically dispersing it for 3-6 hours with an ultrasonic intensity of 60%. (2) Preparation of graphene dispersion: Weigh flake graphite powder and 304 stainless steel sand, with a mass ratio of 1:20~30; put the graphite powder and 304 stainless steel sand into a ball mill jar, add surfactant and intercalating agent, and ball mill for 10-15 hours; add solvent to the ball-milled material according to the proportion, and sieve to remove 304 stainless steel sand; the ball-milled slurry is then mechanically ultrasonically dispersed for 6-9 hours with an ultrasonic intensity of 60%; after centrifugation for 15 minutes, discard the lower precipitate; take the upper layer of dispersion. The dispersion was mechanically and ultrasonically dispersed for 3-5 hours at an ultrasonic intensity of 60%; centrifuged for 15 minutes and the lower precipitate was discarded; the upper dispersion was mechanically and ultrasonically dispersed for 3-5 hours at an ultrasonic intensity of 60%; centrifuged for 30 minutes and the lower precipitate was discarded; the upper dispersion was freeze-dried to obtain monolayer graphene; monolayer graphene was added to the solvent at a weight ratio of 1:50~150 and mechanically and ultrasonically dispersed for 3-6 hours at an ultrasonic intensity of 60% to obtain graphene oxide dispersion. (3) Preparation of mixed dispersion: The graphene oxide dispersion and the graphene dispersion were mixed at a volume ratio of (1:3)-(3:1), and mechanically ultrasonically dispersed for 3-6 hours with an ultrasonic intensity of 60% to obtain a mixed multilayer graphene spraying liquid. (4) Nonwoven fabric modification: The mixed multilayer graphene spray liquid is sprayed onto the surface of the nonwoven fabric, dried with hot air, cut, and rolled up to make modified nonwoven fabric.

2. The method for preparing the modified nonwoven fabric according to claim 1, characterized in that, In step (1), the hydrothermal reaction time is 1-15 hours and the hydrothermal reaction temperature is 120-190℃.

3. The method for preparing the modified nonwoven fabric according to claim 1, characterized in that, In step (1), GO X The value of X is 10-60.

4. The method for preparing the modified nonwoven fabric according to claim 1, characterized in that, In step (1), the dispersion solution is one or more of water, methanol, and ethanol.

5. The method for preparing the modified nonwoven fabric according to claim 1, characterized in that, In step (2), the particle size of the flake graphene powder is 500-2000 mesh.

6. The method for preparing the modified nonwoven fabric according to claim 1, characterized in that, In step (2), the 304 stainless steel sand is composed of 10 parts of 0.2mm, 4 parts of 0.4mm, 3 parts of 0.6mm, and 2 parts of 0.8mm. 1.0mm, 1 piece.

7. The method for preparing the modified nonwoven fabric according to claim 1, characterized in that, In step (2), the surfactant is sodium dodecyl sulfate, and the intercalating agent is an alkylamine, specifically one or more of propylamine, butylamine, and hexylamine.

8. The method for preparing the modified nonwoven fabric according to claim 1, characterized in that, In step (2), the first centrifugation speed is 3000 rpm, the second centrifugation speed is 5000 rpm, and the third centrifugation speed is 8000 rpm.

9. The method for preparing the modified nonwoven fabric according to claim 1, characterized in that, In step (3), the ratio of graphene oxide dispersion to graphene dispersion is 2:

1.

10. The method for preparing the modified nonwoven fabric according to claim 1, characterized in that, In step (4), the spraying process uses a nozzle with a liquid output of 40-400 mL / min, a hot air temperature of 120℃, and a winding speed of 0.2-1 m / s.

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