Graphene-polyimide composite yarn and preparation method and application thereof

Abstract

The invention belongs to the technical field of composite materials, and particularly relates to a graphene-polyimide composite yarn and a preparation method and application thereof. The preparation method of the graphene-polyimide composite yarn comprises the following steps: preparing a graphene oxide solution with the concentration of 1-10 mg / mL; pouring the graphene oxide solution into a spinning tank, controlling the polyimide yarn by two motors, infiltrating the polyimide yarn in the graphene oxide solution of the spinning tank, leading out the polyimide yarn after infiltrating, and directly drying the polyimide yarn under the action of hot air to obtain the graphene oxide coated polyimide yarn; and performing thermal reduction on the graphene oxide coated polyimide yarn, performing reduction treatment with hydroiodic acid, repeatedly washing with ethanol and deionized water, and drying to obtain the graphene-polyimide multi-dimensional sensing yarn. According to the preparation method, conductivity and sensing performance of traditional yarn are achieved, and the traditional yarn is endowed with excellent conductivity and sensing functionality.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and specifically relates to a graphene-polyimide composite yarn and a preparation method and application thereof. Background Art

[0002] With the rapid development of smart wearable technology and AI technology, flexible smart wearable sensors can be used to detect human movement. With the help of smart wearable technology, two-dimensional fabrics that are in close contact with the human body will usher in huge development opportunities and challenges. Traditional yarns have the one-dimensional material characteristics of light weight, bendability, and flexibility, but they do not have conductivity and the ability to recognize external stimuli, which greatly weakens the development of traditional yarns in the field of wearable sensing. How to rely on traditional yarns and fabrics to build yarns and fabrics with conductivity and sensing is a new challenge facing the traditional textile industry.

[0003] Nowadays, yarn or fabric sensing requires two or more conductive yarns to be interwoven to achieve sensing. For example, patent documents with publication numbers CN109307565A and CN115597747A disclose sensing by interweaving, and patent documents with publication numbers CN117127299A and CN117626490A disclose the use of two or more yarns blended or wrapped into blended yarns. However, how to achieve multi-dimensional sensing of a single yarn is a difficult point in development. Therefore, a one-dimensional yarn with a simple process flow is developed to prepare multi-dimensional sensing on a large scale, so as to achieve multi-dimensional recognition and sensing of different forms of external stimuli; and a two-dimensional fabric with multi-dimensional sensing is constructed based on the one-dimensional yarn, so as to achieve multi-dimensional sensing from multi-dimensional sensing of one-dimensional yarn to multi-dimensional sensing of two-dimensional fabric; the above research will broaden the application of traditional yarns in the field of wearable sensing.

[0004] In addition, traditional yarns and fabrics do not have the protection and performance in harsh environments, let alone conductive properties. When faced with multiple harsh environments such as ultra-low temperatures such as liquid nitrogen, ultra-high temperatures, strong acids, and strong alkalis, traditional yarns and clothing do not have any protective effect, and the harsh environment will directly invade the human body and cause serious harm to the human body. In such harsh environments, protective yarns, fabrics, and clothing will be able to resist the impact of the harsh environment on the human body to the maximum extent, and protect and mitigate the damage to the human body to the maximum extent. Under the protective effect of protective fabrics and clothing, special operations workers can successfully complete the necessary cleaning and obstacle removal work in harsh environments, avoiding further damage to the surrounding people and the environment caused by the harsh environment. Yarns and fabrics with protective characteristics should not only have basic properties such as resistance to ultra-low temperatures, high temperatures, acid and alkali, but also have good wearing performance. Summary of the invention

[0005] Based on the above-mentioned shortcomings and deficiencies in the prior art, one of the objects of the present invention is to at least solve one or more of the above-mentioned problems in the prior art. In other words, one of the objects of the present invention is to provide a graphene-polyimide composite yarn and a preparation method and application thereof that meet one or more of the above-mentioned needs.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0007] A method for preparing a graphene-polyimide composite yarn comprises the following steps:

[0008] (1) preparing a graphene oxide solution with a concentration of 1 to 10 mg / mL;

[0009] (2) pouring the graphene oxide solution into a spinning tank, the polyimide yarn is controlled by two motors, immersed in the graphene oxide solution in the spinning tank, and then led out and directly dried under the action of hot air to obtain the graphene oxide coated polyimide yarn;

[0010] (3) The graphene oxide-coated polyimide yarn is subjected to thermal reduction and then reduced with hydroiodic acid, and then repeatedly washed and dried with ethanol and deionized water to obtain a graphene-polyimide composite yarn.

[0011] As a preferred embodiment, in step (2), the fineness of the polyimide yarn is 10 to 50 seconds, and the number of yarn strands is 1 to 5;

[0012] The two motors have the same speed, which is 5 to 50 rpm;

[0013] The number of layers of graphene oxide coating is 3 to 15;

[0014] The hot air temperature is 120~300℃.

[0015] As a preferred embodiment, in step (3), the temperature of thermal reduction is 280-320° C., and the reduction time is 3-8 hours;

[0016] The temperature of hydroiodic acid reduction is 60-100°C, and the reduction time is 20-60 minutes;

[0017] The drying temperature is 50-80°C.

[0018] The present invention also provides a graphene-polyimide composite yarn prepared by the preparation method described in any of the above schemes, which is a multidimensional sensing yarn for detecting bending at different angles and different pressures, wherein the bending angle detection range is 0 to 180°, and the pressure detection range is 1 to 500g;

[0019] Also used in conductive yarns.

[0020] The present invention also provides a method for preparing a graphene-polyimide composite fabric, comprising the following steps:

[0021] The conventional yarn and the graphene-polyimide composite yarn as described in the above scheme are used as warp and weft respectively to weave mutually interwoven fabrics to obtain the graphene-polyimide composite fabric.

[0022] As a preferred embodiment, the traditional yarn is one or more of cotton yarn, wool yarn, silk, linen yarn, polyester, nylon, acrylic fiber, polypropylene fiber, vinylon, spandex, chloroprene, polyimide yarn, rayon, and blended yarn;

[0023] The graphene-polyimide composite yarn has a fineness of 20 to 50s and a yarn strand number of 1 to 5;

[0024] The interwoven fabric structure is a combination of one or more of plain weave, twill weave, satin weave, variable weave and complex weave.

[0025] The present invention also provides a graphene-polyimide composite fabric prepared by the preparation method described in any of the above schemes, which is used for sensing bending strain and pressure, wherein the sensing range of bending strain is 0 to 180°, and the sensing range of pressure is 0 to 500g;

[0026] Also used as conductive fabric.

[0027] The present invention also provides a method for preparing a graphene-polyimide multidimensional sensor, based on the graphene-polyimide composite yarn described in the above scheme, PDMS encapsulation is performed to construct a one-dimensional yarn-based wearable sensor;

[0028] The PDMS packaging process includes: injecting a PDMS solution containing a curing agent into a silicone hose, fixing the graphene-polyimide composite yarn in the silicone hose along the axial center line, and extending both ends of the graphene-polyimide composite yarn outside the silicone hose respectively, and setting metal tape as electrodes on the extended part; after the PDMS is cured, cutting and removing the silicone hose to obtain a one-dimensional graphene-polyimide yarn multidimensional sensor with a flexible protective layer.

[0029] The present invention also provides a method for preparing a graphene-polyimide multidimensional sensor, based on the graphene-polyimide composite fabric described in the above scheme, PDMS encapsulation is performed to construct a two-dimensional yarn-based wearable sensor;

[0030] The PDMS encapsulation process includes: making a PDMS solution containing a curing agent into a flexible film as a flexible substrate, then placing the graphene-polyimide composite fabric on the flexible substrate, and then pouring and curing the PDMS solution to obtain a two-dimensional graphene-polyimide multidimensional sensor.

[0031] The present invention also provides a graphene-polyimide multidimensional sensor as described in any of the above schemes, which is used for multidimensional sensing of torsion, stretching and pressing.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The preparation method of the present invention can realize the sensing, ultra-low temperature resistance, high temperature resistance, acid and alkali resistance and conductive properties of the traditional yarn, giving the traditional yarn excellent functionality;

[0034] (2) Graphene oxide can be prepared by the Hummers method, and ordinary polyimide yarn is widely available, and is even more widely available as a source of traditional interwoven yarn;

[0035] (3) The process flow adopted by the present invention is simple, and yarns with multi-dimensional sensing performance and conductive properties that are resistant to ultra-low temperature, high temperature, acid and alkali can be prepared on a large scale and in batches, and two-dimensional multifunctional fabrics can be prepared on a large scale. The whole process can be automated to a certain extent and is easy to operate;

[0036] (4) The present invention can realize the multi-dimensional sensing performance of one-dimensional yarn and the multi-dimensional sensing of two-dimensional fabric, and realize the preparation of a complete system from the preparation of a single yarn to the preparation of a two-dimensional fabric and its packaged sensor;

[0037] (5) The present invention can achieve the ultra-low temperature resistance, high temperature resistance, acid and alkali resistance and conductive properties of one-dimensional yarn, and realize the weaving system from the preparation of one-dimensional functional yarn to two-dimensional functional fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is an electronic photograph of the graphene-polyimide yarn of Example 1 of the present invention;

[0039] Figure 2 This is a signal change diagram of the graphene-polyimide yarn used as a bending strain sensor in Example 1 of the present invention;

[0040] Figure 3 This is an electronic photograph of the PDMS-encapsulated graphene-polyimide yarn sensor of Example 2 of the present invention;

[0041] Figure 4 This is a signal change diagram of the graphene-polyimide yarn multidimensional sensor of Example 2 of the present invention used to detect multidimensional sensing of torsion, stretching and pressing;

[0042] Figure 5 This is a scanning electron microscope photograph of the graphene-polyimide multidimensional sensing fabric of Example 3 of the present invention;

[0043] Figure 6This is a signal change diagram of the graphene-polyimide multi-dimensional sensing fabric for detecting and identifying bending strain according to Example 3 of the present invention;

[0044] Figure 7 This is an electronic photograph of the graphene-polyimide composite fabric of Example 7 of the present invention. DETAILED DESCRIPTION

[0045] In order to more clearly illustrate the embodiments of the present invention, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other accompanying drawings and other implementation methods can be obtained based on these accompanying drawings without creative work.

[0046] The preparation method of the graphene-polyimide multidimensional sensing yarn of the present invention comprises the following steps:

[0047] (1) preparing a graphene oxide solution with a concentration of 1 to 10 mg / mL as a coating solution at 25° C.;

[0048] (2) pouring the graphene oxide solution into a spinning tank, the polyimide yarn is controlled by two motors, the graphene oxide solution soaked in the spinning tank is directly dried under the action of hot air, and a tight coating is formed on the surface of the polyimide yarn;

[0049] (3) The obtained graphene oxide coated polyimide yarn is pre-heat-reduced and then further reduced with hydroiodic acid. After the treatment, it is repeatedly washed with ethanol and deionized water and dried to obtain graphene-polyimide yarn.

[0050] The typical values ​​of the concentration of the graphene oxide solution prepared in the above step (1) are 5, 8, and 10 mg / mL, respectively.

[0051] The polyimide yarn used in the above step (1) has a fineness of 10 to 50s and a yarn strand number of 1 to 5.

[0052] The hot air temperature in the above step (2) is 120-300°C.

[0053] In the above step (2), the moving speed and stable tension of the polyimide yarn during the coating process are controlled, and the rotation speeds of the two motors used are the same, and the range is 5 to 50 rpm.

[0054] In the above step (2), the number of times polyimide is coated on graphene oxide, that is, the number of coating layers formed, is 3 to 15 layers.

[0055] The temperature of the pre-heat reduction in the above step (3) is 280-320°C, and the reduction time is 3-8 hours. The reagent used for the further chemical reduction is hydroiodic acid, the reduction temperature is 60-100°C, and the reduction time is 20-60 minutes.

[0056] In the above step (3), the reagents used to remove the residual hydroiodic acid in the reduction reaction are anhydrous ethanol and deionized water, respectively. The number of repeated washings is 6 to 10 times, and the drying temperature after washing is 50 to 80°C.

[0057] The above-mentioned graphene-polyimide multidimensional sensing yarn can be directly used as a multidimensional sensing yarn for detecting bending at different angles and different pressures. The graphene-polyimide multidimensional sensing yarn can detect bending angles and pressures, with the bending angle detection range of 0 to 180° and the pressure detection range of 1 to 500g.

[0058] Furthermore, the present invention constructs a graphene-polyimide multidimensional sensing fabric based on multidimensional sensing yarn, and the preparation method thereof comprises the following steps:

[0059] The commonly used traditional yarn is used as the weft and the above-mentioned graphene-polyimide multidimensional sensing yarn is used as the warp to weave into an interwoven fabric; or the traditional yarn is used as the warp and the above-mentioned graphene-polyimide multidimensional sensing yarn is used as the weft to weave into a graphene-polyimide multidimensional sensing fabric.

[0060] Among them, the traditional yarn is one or more yarns such as cotton yarn, wool yarn, silk, linen yarn, polyester, nylon, acrylic fiber, polypropylene fiber, vinylon, spandex, chloroprene, rayon, etc., and blended yarns prepared by blending them together, as a kind of warp or weft.

[0061] The count of the graphene-polyimide multidimensional sensing yarn can be adjusted as needed, preferably 20 to 50s, and the number of yarn strands is 1 to 5. The count and thickness of the commonly used traditional yarn are commonly used counts and can be adjusted as needed.

[0062] The interweaving method is a kind of weaving, knitting or braiding, and the warp and weft are interwoven into a two-dimensional fabric. In addition, the interwoven fabric structure is one or more structures such as plain weave, twill, satin, variable structure and complex structure.

[0063] The graphene-polyimide multidimensional sensing fabric can sense bending strain and pressure. The sensing range of bending strain is 0 to 180°, and the sensing range of pressure is 0 to 500g.

[0064] The present invention also constructs a one-dimensional yarn-based wearable sensor based on the prepared graphene-polyimide multidimensional sensing yarn; in addition, a two-dimensional fabric-based wearable sensor can be prepared based on the constructed graphene-polyimide multidimensional sensing fabric.

[0065] (a) Based on graphene-polyimide multidimensional sensing yarn, PDMS is used for encapsulation to construct a one-dimensional yarn-based wearable sensor; wherein, the number of strands of the graphene-polyimide multidimensional sensing yarn is 1 or several twisted multi-strand yarns, and the number of strands of the yarn can be adjusted and prepared as needed; specifically, PDMS is encapsulated by preparing a solution with a ratio of solution mass: curing agent mass = 10:1, and then the solution is injected into a silicone hose after stirring evenly. The prepared conductive graphene-polyimide yarn is fixed in the silicone hose along the axial centerline, and the conductive yarn is longer than the silicone tube, and metal tape is attached to the excess part as an electrode. PDMS is cured at 60°C for 2h, and after cutting and removing the silicone hose mold, a one-dimensional graphene-polyimide yarn multidimensional sensor with a flexible protective layer is obtained.

[0066] (b) Based on the graphene-polyimide multidimensional sensing fabric, PDMS was used for encapsulation to prepare a fabric-based wearable sensor. Specifically, PDMS encapsulation is to prepare a solution of PDMS in a ratio of solution mass: curing agent mass = 10:1, and prepare a flexible film as a flexible substrate; then the graphene-polyimide multidimensional sensing fabric is placed on the flexible substrate, and then the PDMS solution is poured and cured at 60°C for 2h to obtain a two-dimensional fabric-based wearable sensor.

[0067] Embodiment 1:

[0068] The method for preparing the graphene-polyimide yarn of this embodiment comprises the following steps:

[0069] A graphene oxide aqueous solution with a concentration of 8 mg / mL was stirred at 25°C for 30 minutes with a magnetic stirrer at a speed of 300 rpm. After stirring, it was added as a coating solution into a spinning tank with a length of 20 cm, a width of 3 cm, and a height of 4 cm. There were two rollers in the tank to ensure that the yarn could be completely immersed in the coating solution and could rotate;

[0070] A polyimide yarn with a fineness of 20s is released by a motor at a speed of 10rpm and passes through a spinning tank. Then, the yarn adsorbed with graphene oxide solution is driven by another motor at a speed of 10rpm and passes through a quartz tube for drying. Hot air at a temperature of 200°C is blown into the quartz tube to dry the yarn; the dried yarn is completely collected and regarded as a coating, and the coating process is repeated 5 times to obtain a graphene oxide-polyimide yarn with a coating number of 5; the coated yarn is heated at 300°C for pre-reduction for 8h, and then further reduced with hydroiodic acid at 80°C for 30min. Finally, the reduced yarn is repeatedly washed with anhydrous ethanol and deionized water for 8 times, and then completely dried at 70°C to obtain the graphene-polyimide yarn.

[0071] The two ends of the prepared graphene-polyimide yarn are connected to copper wires and directly used as sensors for detecting bending strain. After testing, it can realize the detection of bending angles of 0-180°. At the same time, the prepared graphene-polyimide yarn is directly used to detect pressure, which can realize the detection of pressure.

[0072] The prepared graphene-polyimide yarn was further encapsulated with PDMS. Specifically, PDMS was prepared into a solution with a ratio of solution mass: curing agent mass = 10:1, and the solution was injected into a silicone hose after being stirred evenly. The prepared graphene-polyimide yarn was fixed in the silicone hose along the axial center line, and the yarn was longer than the silicone tube, and metal tape was attached to the excess part as an electrode; PDMS was cured at 60°C for 2h, and after cutting and removing the silicone hose mold, a one-dimensional graphene-polyimide yarn multidimensional sensor with a flexible protective layer was obtained.

[0073] like Figure 1 As shown, the electron photograph of the graphene-polyimide yarn of this embodiment shows that a layer of graphene is tightly wrapped on its surface, and there is no obvious breakage of the surface coating, and the overall shape of the yarn is regular.

[0074] like Figure 2 As shown, the changes in the sensing application of the graphene-polyimide yarn of this embodiment at different bending angles indicate that it has the ability of bending strain sensing.

[0075] The above results show that the prepared graphene-polyimide yarn is capable of detecting bending strain and pressure, realizing multi-dimensional sensing of a single yarn.

[0076] Embodiment 2:

[0077] The method for preparing the graphene-polyimide yarn of this embodiment comprises the following steps:

[0078] A 10 mg / mL graphene oxide aqueous solution was stirred at 25°C for 60 minutes using a magnetic stirrer at a rotation speed of 200 rpm. After stirring, it was added as a coating solution into a spinning tank with a length of 20 cm, a width of 3 cm, and a height of 4 cm. There were two rollers in the tank to ensure that the yarn could be completely immersed in the coating solution and could rotate.

[0079] A polyimide yarn with a fineness of 20s is released by a motor at a speed of 10rpm and passes through a spinning tank. The yarn that is drawn out and adsorbed with graphene oxide solution is then driven by another motor at a speed of 10rpm and passes through a quartz tube for drying. Hot air at a temperature of 200°C is blown into the quartz tube to dry the yarn; the dried yarn is completely collected and regarded as a coating, and the coating process is repeated 7 times to obtain a graphene oxide-polyimide yarn with a coating number of 7; the coated yarn is heated at 300°C for pre-reduction for 8h, and then further reduced with hydroiodic acid at 80°C for 30min. Finally, the reduced yarn is repeatedly washed with anhydrous ethanol and deionized water for 6 times and completely dried at 70°C to obtain the graphene-polyimide yarn.

[0080] The two ends of the prepared graphene-polyimide yarn were connected to copper wires, and the prepared graphene-polyimide yarn was further encapsulated with PDMS to obtain the encapsulated graphene-polyimide yarn multidimensional sensor, such as Figure 3 As shown, the electron photo of the PDMS encapsulated graphene-polyimide yarn sensor. Figure 4 As shown, after testing, it is possible to detect a bending angle of 0-180°; at the same time, the prepared graphene-polyimide yarn can be directly used to detect pressure, which can realize the detection of pressure; and it can sense torsion and stretching.

[0081] Embodiment 3:

[0082] The preparation method of the graphene-polyimide multidimensional sensing fabric of this embodiment comprises the following steps:

[0083] The graphene-polyimide yarn prepared in Example 1 is used as the warp, and the pure polyimide yarn is used as the weft. Both the warp and the weft are single. They are woven on a rapier prototype machine, and plain weave is selected as the structure of the fabric to weave a graphene-polyimide interwoven fabric, i.e., a graphene-polyimide multidimensional sensing fabric.

[0084] like Figure 5 As shown, the warp and weft distribution structure of graphene-polyimide multidimensional sensing fabric; Figure 6 As shown, graphene-polyimide multidimensional sensing fabric can be used to detect bending strain and pressure, realizing multi-dimensional sensing.

[0085] Embodiment 4:

[0086] The preparation method of the graphene-polyimide multidimensional sensing yarn of this embodiment comprises the following steps:

[0087] A 5 mg / mL graphene oxide solution was stirred at 25°C for 30 minutes by a magnetic stirrer at a speed of 300 rpm. After stirring, it was added to the spinning tank as a coating solution. The polyimide yarn with a fineness of 20s was released by a motor at a speed of 10 rpm and passed through the spinning tank. After that, the yarn drawn out and adsorbed with the graphene oxide solution was driven by another motor at a speed of 10 rpm and passed through a quartz tube for drying. Hot air at a temperature of 200°C was blown into the quartz tube to dry the yarn. The dried yarn was completely collected and regarded as a coating. The coating process was repeated 8 times to obtain a graphene oxide-polyimide yarn with a coating number of 8. The coated yarn was heated at 300°C for pre-reduction for 8 hours, and then further reduced with hydroiodic acid at 80°C for 30 minutes. Finally, the reduced yarn was repeatedly washed 8 times with anhydrous ethanol and deionized water and completely dried at 70°C to obtain the graphene-polyimide yarn.

[0088] The prepared graphene-polyimide yarns were used as warp and weft respectively, and were woven into cross-woven pure fabrics by weaving each other, and the warp and weft were connected to copper wires respectively. PDMS was prepared into a solution with a ratio of solution mass: curing agent mass = 10:1, and a flexible film was prepared as a substrate. Then the prepared pure graphene-polyimide fabric was placed on a flexible substrate, and the PDMS solution was poured and cured at 60°C for 2h to obtain a two-dimensional fabric-based wearable sensor. The test showed that the bending angle could be detected; at the same time, the prepared graphene-polyimide yarn was directly used to detect pressure, which could realize the detection of pressure.

[0089] Embodiment 5:

[0090] The method for preparing the ultra-low temperature resistant, high temperature resistant, acid and alkali resistant conductive composite yarn of this embodiment comprises the following steps:

[0091] A 5 mg / mL graphene oxide solution was stirred at 25°C for 30 minutes with a magnetic stirrer at a speed of 300 rpm. After stirring, it was added as a coating solution into a spinning tank with a length of 20 cm, a width of 3 cm, and a height of 4 cm. The tank had two rollers to ensure that the yarn could be completely immersed in the coating solution and could rotate.

[0092] The polyimide yarn with a fineness of 20s was released by a motor at a speed of 10rpm and passed through the spinning tank. After that, the yarn drawn out and adsorbed with graphene oxide solution was driven by another motor at a speed of 10rpm and passed through a quartz tube for drying. Hot air at a temperature of 200°C was blown into the quartz tube to dry the yarn. The dried yarn was completely collected and regarded as one coating. The coating process was repeated 5 times to obtain a graphene oxide-polyimide yarn with a coating number of 5;

[0093] The coated yarn was pre-reduced by heating at 300°C for 8 hours, and then further reduced with hydroiodic acid at 80°C for 30 minutes. Finally, the reduced yarn was repeatedly washed 8 times with anhydrous ethanol and deionized water and completely dried at 70°C to obtain graphene-polyimide yarn.

[0094] Embodiment 6:

[0095] The method for preparing the ultra-low temperature resistant, high temperature resistant, acid and alkali resistant conductive composite yarn of this embodiment comprises the following steps:

[0096] A graphene oxide solution with a concentration of 8 mg / mL was stirred for 30 minutes at 25°C using a magnetic stirrer with a rotation speed of 300 rpm. After stirring, it was added as a coating solution into a spinning tank with a length of 20 cm, a width of 3 cm, and a height of 4 cm. The tank had two rollers to ensure that the yarn could be completely immersed in the coating solution and could rotate.

[0097] The polyimide yarn with a fineness of 20s was released by a motor at a speed of 10rpm and passed through the spinning tank. After that, the yarn drawn out and adsorbed with graphene oxide solution was driven by another motor at a speed of 10rpm and passed through a quartz tube for drying. Hot air at a temperature of 200°C was blown into the quartz tube to dry the yarn. The dried yarn was completely collected and regarded as one coating. The coating process was repeated 5 times to obtain a graphene oxide-polyimide yarn with a coating number of 5;

[0098] The coated yarn was pre-reduced by heating at 300°C for 8 hours, and then further reduced with hydroiodic acid at 80°C for 30 minutes. Finally, the reduced yarn was repeatedly washed 8 times with anhydrous ethanol and deionized water and completely dried at 70°C to obtain graphene-polyimide yarn.

[0099] Embodiment 7:

[0100] The preparation method of the ultra-low temperature resistant, high temperature resistant, acid and alkali resistant conductive composite fabric of this embodiment comprises the following steps:

[0101] A graphene oxide solution with a concentration of 8 mg / mL was stirred for 30 minutes at 25°C using a magnetic stirrer with a rotation speed of 300 rpm. After stirring, it was added as a coating solution into a spinning tank with a length of 20 cm, a width of 3 cm, and a height of 4 cm. The tank had two rollers to ensure that the yarn could be completely immersed in the coating solution and could rotate.

[0102] The polyimide yarn with a fineness of 20s was released by a motor at a speed of 10rpm and passed through the spinning tank. After that, the yarn drawn out and adsorbed with graphene oxide solution was driven by another motor at a speed of 10rpm and passed through a quartz tube for drying. Hot air at a temperature of 200°C was blown into the quartz tube to dry the yarn. The dried yarn was completely collected and regarded as one coating. The coating process was repeated 5 times to obtain a graphene oxide-polyimide yarn with a coating number of 5;

[0103] The coated yarn was pre-reduced by heating at 300°C for 8 hours, and then further reduced with hydroiodic acid at 80°C for 30 minutes. Finally, the reduced yarn was repeatedly washed with anhydrous ethanol and deionized water for 8 times, and then completely dried at 70°C to obtain the graphene-polyimide composite yarn.

[0104] The graphene-polyimide composite yarn prepared above is used as the warp, the pure polyimide yarn is used as the weft, the warp and the weft are both single, and plain weave is selected as the basic structure of the fabric. The fabric is woven on a rapier prototype machine to produce a graphene-polyimide interwoven fabric, such as Figure 7 shown.

[0105] Embodiment 8:

[0106] The preparation method of the ultra-low temperature resistant, high temperature resistant, acid and alkali resistant conductive composite fabric of this embodiment comprises the following steps:

[0107] A 5 mg / mL graphene oxide solution was stirred at 25°C for 30 min using a magnetic stirrer at a speed of 300 rpm, and then added into the spinning tank as a coating solution.

[0108] The polyimide yarn with a fineness of 20s was released by a motor at a speed of 10rpm and passed through the spinning slot. After that, the yarn drawn out and adsorbed with graphene oxide solution was driven by another motor at a speed of 10rpm and passed through a quartz tube for drying. Hot air at a temperature of 200°C was blown into the quartz tube to dry the yarn. The dried yarn was completely collected and regarded as one coating. The coating process was repeated 8 times to obtain a graphene oxide-polyimide yarn with a coating number of 8;

[0109] The coated yarn was pre-reduced by heating at 300°C for 8 hours, and then further reduced with hydroiodic acid at 80°C for 30 minutes. Finally, the reduced yarn was repeatedly washed with anhydrous ethanol and deionized water for 8 times, and then completely dried at 70°C to obtain the graphene-polyimide composite yarn.

[0110] The prepared graphene-polyimide composite yarns are used as warp and weft respectively and are woven into a cross-woven pure fabric.

[0111] Verification of the ultra-low temperature resistant, high temperature resistant, acid and alkali resistant conductive composite yarn and fabric thereof of this embodiment:

[0112] (1) Ultra-low temperature resistance test and results: The prepared graphene-polyimide composite yarn was directly placed in a liquid nitrogen environment (-196°C) and repeatedly immersed to test the conductive properties of the graphene-polyimide composite yarn. The results showed that the graphene-polyimide yarn still had conductive properties.

[0113] (2) High temperature resistance test and results: The prepared graphene-polyimide composite yarn was placed in a high temperature environment of 300°C for 3 hours. The results showed that the graphene-polyimide composite yarn still had conductive properties.

[0114] (3) Strong acid and alkali resistance test and results: The prepared graphene-polyimide composite yarn was corroded in a strong acid hydroiodic acid and a strong base sodium hydroxide environment. The results showed that the graphene-polyimide composite yarn had a complete structure and was still conductive, showing excellent resistance to strong acids and alkalis.

[0115] In view of the numerous embodiments of the scheme of the present invention, the raw materials and dosage involved can be selected according to actual needs within the limited range, and the experimental data of each embodiment is huge and numerous, which is not suitable for listing and explaining one by one here, but the content required to be verified and the final conclusion obtained in each embodiment are similar. Therefore, the verification content of each embodiment will not be explained one by one here.

[0116] The above description is only a detailed description of the preferred embodiments and principles of the present invention. For ordinary technicians in this field, according to the ideas provided by the present invention, there will be changes in the specific implementation methods, and these changes should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a graphene-polyimide composite yarn, characterized in that: The following steps are involved: (1) preparing a graphene oxide solution with a concentration of 1 to 10 mg / mL; (2) pouring the graphene oxide solution into a spinning tank, the polyimide yarn is controlled by two motors, immersed in the graphene oxide solution in the spinning tank, and then led out and directly dried under the action of hot air to obtain the graphene oxide coated polyimide yarn; (3) The graphene oxide-coated polyimide yarn is subjected to thermal reduction and then reduced with hydroiodic acid, and then repeatedly washed and dried with ethanol and deionized water to obtain a graphene-polyimide composite yarn.

2. The preparation method according to claim 1, characterized in that: In the step (2), the fineness of the polyimide yarn is 10 to 50 seconds, and the number of yarn strands is 1 to 5; The two motors have the same speed, which is 5 to 50 rpm; The number of layers of graphene oxide coating is 3 to 15; The hot air temperature is 120~300℃.

3. The preparation method according to claim 1, characterized in that: In the step (3), the temperature of thermal reduction is 280-320° C., and the reduction time is 3-8 hours; The temperature of hydroiodic acid reduction is 60-100°C, and the reduction time is 20-60 minutes; The drying temperature is 50-80°C.

4. The graphene-polyimide composite yarn prepared by the preparation method according to any one of claims 1 to 3, characterized in that: Multi-dimensional sensing yarn for detecting bending at different angles and different pressures, with a bending angle detection range of 0 to 180° and a pressure detection range of 1 to 500g; Also used as conductive yarn.

5. A method for preparing a graphene-polyimide composite fabric, characterized in that: The following steps are involved: The conventional yarn and the graphene-polyimide composite yarn as claimed in claim 4 are used as warp and weft respectively to weave mutually interwoven fabrics to obtain the graphene-polyimide composite fabric.

6. The preparation method according to claim 5, characterized in that: The traditional yarn is one or more of cotton yarn, wool yarn, silk, linen yarn, polyester, nylon, acrylic fiber, polypropylene fiber, vinylon, spandex, chloroprene, polyimide yarn, rayon, and blended yarn; The graphene-polyimide composite yarn has a fineness of 20 to 50s and a yarn strand number of 1 to 5; The interwoven fabric structure is a combination of one or more of plain weave, twill weave, satin weave, variable weave and complex weave.

7. The graphene-polyimide composite fabric obtained by the preparation method according to claim 5 or 6, characterized in that: Used for sensing bending strain and pressure. The sensing range of bending strain is 0-180°, and the sensing range of pressure is 0-500g. Also used as conductive fabric.

8. A method for preparing a graphene-polyimide multidimensional sensor, characterized in that: Based on the graphene-polyimide composite yarn as claimed in claim 4, PDMS encapsulation is performed to construct a one-dimensional yarn-based wearable sensor; The PDMS packaging process includes: injecting a PDMS solution containing a curing agent into a silicone hose, fixing the graphene-polyimide composite yarn in the silicone hose along the axial center line, and extending both ends of the graphene-polyimide composite yarn outside the silicone hose respectively, and setting metal tape as electrodes on the extended part; after the PDMS is cured, cutting and removing the silicone hose to obtain a one-dimensional graphene-polyimide yarn multidimensional sensor with a flexible protective layer.

9. A method for preparing a graphene-polyimide multidimensional sensor, characterized in that: Based on the graphene-polyimide composite fabric as claimed in claim 7, PDMS encapsulation is performed to construct a two-dimensional yarn-based wearable sensor; The PDMS encapsulation process includes: making a PDMS solution containing a curing agent into a flexible film as a flexible substrate, then placing the graphene-polyimide composite fabric on the flexible substrate, and then pouring and curing the PDMS solution to obtain a two-dimensional graphene-polyimide multidimensional sensor.

10. The graphene-polyimide multidimensional sensor according to claim 8 or 9, characterized in that: Multi-dimensional sensing for twist, stretch, and compression.

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