Disclosure of Invention
Aiming at the problems in the prior art, the invention provides the carbon nano material conductive polymer fiber and the preparation method thereof, which have the advantages of increasing the conductive capability without reducing the tensile strength of the polymer fiber and solve the problems of the prior art that the processing technology or the material of the organic polymer is not changed.
The invention is realized in such a way, and the invention provides a carbon nano-material conductive polymer fiber, which comprises the following components: an inner layer of columnar organic polymer fibers; the outer layer is a conductive layer, and the conductivity of the outer layer exceeds 100S/m; the material of the outer layer comprises carbon nano material particles, the carbon nano material particles are partially embedded into the surface of the inner layer, and at least part of the carbon nano material particles are mutually contacted to form a conductive path. Through the arrangement, the outer layer is additionally arranged on the outer surface of the inner layer (the columnar organic polymer fiber), the material of the outer layer comprises carbon nano material particles, the carbon nano material particles are partially embedded into the surface of the inner layer, and at least part of the carbon nano material particles are mutually contacted to form a conductive path, so that the conductive performance of the inner layer 1 is changed.
Preferably, the outer layer has a thickness of less than 50 nm.
Preferably, the material of the outer layer further comprises carbon black particles and/or graphene particles; the inner layer is made of at least one of polyethylene fibers, polypropylene fibers, polylactic acid fibers, nylon fibers, polyester fibers and polyacrylonitrile fibers.
With the above arrangement, by increasing the diversity of materials, it is possible to increase the stability of the manufactured carbon nanomaterial conductive polymer fiber, for example, a material that is easily ineffective in a specific environment, and to increase the stability of the manufactured carbon nanomaterial conductive polymer fiber by increasing the diversity of materials.
Preferably, the molecular weight of the organic polymer of the inner layer is 40000-600000, and the molecular chain configuration is linear, cross-linked or branched, wherein the branched molecular chain configuration is more convenient for embedding the carbon nano material particles.
When the molecular weight of the inner organic polymer is less than 40000, molecular chains are sparse, and carbon nano material particles are not favorably embedded into the inner organic polymer; when the molecular weight of the inner organic polymer is more than 600000, the entanglement between molecular chains is large, which is not beneficial to embedding carbon nano material particles into the inner organic polymer. Preferably, the molecular weight of the organic polymer of the inner layer is 70000-120000, so that the carbon nano material particles are more conveniently embedded.
The invention provides a preparation method of a carbon nano-material conductive polymer fiber, which comprises the following steps:
cleaning impurities on the surface of the organic polymer fiber of the inner layer;
uniformly depositing a carbon nano material particle solution on the surface of the inner layer organic polymer fiber, and drying to obtain a blank which is formed by mutually adhering at least part of carbon nano material particles and forming a conductive path;
applying an electric current to the blank, the carbon nanomaterial particles being electrically conductive to each other, causing the carbon nanomaterial particles to soften and the carbon nanomaterial particles to locally heat the inner organic polymer fiber;
and embedding the carbon nano material particles between the macromolecular chain segments on the surface of the inner-layer organic polymer fiber by microwave and/or ultrasonic assistance, anchoring the carbon nano material particles, and forming an outer layer to obtain the carbon nano material conductive polymer fiber.
By the preparation method, the carbon nano material particles are hot-melted on the surface of the inner layer organic polymer fiber,
preferably, the method for cleaning impurities on the surface of the inner layer organic polymer fiber comprises the following steps:
cleaning the surface of the organic polymer fiber of the inner layer; after the inner layer organic polymer fiber is thrown off, drying in an oven, and melting the oil agent on the surface of the inner layer organic polymer fiber; and cleaning and drying again.
Through the arrangement, acetone can be used as a cleaning agent to clean the surface of the organic polymer fiber of the inner layer, and rapid cleaning can be realized through stirring; under the condition that the organic polymer fiber of the inner layer is longer, the inner layer is wound and dried; the carbon nano material particles can be uniformly dried at the temperature of 60-80 ℃, so that oil agent and impurities on the surface of the inner layer polymer fiber can be removed, and the carbon nano material particles can be conveniently deposited on the surface of the inner layer polymer fiber.
Preferably, the method for uniformly depositing the carbon nano material particle solution on the surface of the inner layer organic polymer fiber and drying to obtain the blank which is at least partially attached with the carbon nano material particles and forms the conductive path comprises the following steps: placing the inner layer organic polymer fiber into a carbon nano material particle solution, and uniformly depositing carbon nano material particles in the carbon nano material particle solution on the surface of the inner layer organic polymer fiber to obtain a deposited polymer fiber; and drying the deposited polymer fibers in an oven at 56-63 ℃ for 9-11 hours to obtain the blank, wherein the mass ratio of the carbon nano material particles after drying accounts for 3% -12% of the blank.
In the setting, the deposited polymer fiber is dried in a 60 ℃ oven for 9-11 hours to obtain the blank, and the mass ratio of the carbon nano material particles accounts for 4% -7% of the blank.
In the above arrangement, the mass ratio of the carbon nano material particles is more than 7% of the blank, which causes the carbon nano material particles to stack and easily fall off, so that the formed conductive polymer fiber of the carbon nano material particles is unstable, and the conductivity is not obviously improved, thereby wasting the carbon nano material. The mass ratio of the carbon nano material particles is less than 4% of the blank, so that the carbon nano material particles are sparse, part of the carbon nano material particles are not contacted with each other, and the electric conductivity is obviously reduced. Preferably, when the mass ratio of the carbon nano material particles accounts for 6% of the blank, the conductivity of the carbon nano material conductive polymer fiber obtained subsequently is more than 100S/m.
Preferably, the method of applying an electric current to the billet comprises: communicating the blank with a power source through a metal clamp; applying a cyclic alternating current directly to the blank, wherein the cyclic alternating current is applied to the carbon nanomaterial particles. And circulating alternating current is adopted to apply multiple times of electric heat impact on the fibers, so that a circulating environment of high temperature and cooling of the surface layer of the fibers is provided, and the nano material is stably anchored between the molecular chain segments of the surface layer of the polymer fibers. The purpose of applying multiple electric heat shocks to the fibers by using circulating alternating current is to prevent thermal decomposition of the polymer at too high a temperature.
Preferably, the method for embedding microwave and/or ultrasonic-assisted carbon nano material particles between the macromolecular segments on the surface of the inner-layer organic polymer fiber comprises the following steps:
the microwave and/or ultrasonic auxiliary time is the same as the electric cycle heating time, so as to ensure that the surface carbon nano material can be embedded into the fiber. The simultaneous application of microwaves and ultrasound increases the effectiveness and efficiency of the surface.
Compared with the prior art, the invention has the following beneficial effects:
1. in the invention, the carbon nano material particles are hot-melted on the surface of the organic polymer fiber of the inner layer by using a method combining electric current electrothermal treatment and ultrasonic/microwave auxiliary treatment, so that the electric conduction is carried out through the carbon nano material particles of the outer layer under the condition that the processing technology and the material of the organic polymer of the inner layer are not changed. Further, since the thickness of the outer layer is smaller than that of the inner layer, the influence on the mechanical strength of the inner layer is small, and the tensile strength of the inner layer is not affected.
2. In the invention, the material of the outer layer also comprises carbon black particles and/or graphene particles; the inner layer is made of at least one of polyethylene fibers, polypropylene fibers, polylactic acid fibers, nylon fibers, polyester fibers and polyacrylonitrile fibers. By increasing the diversity of materials, the stability of the prepared carbon nano material conductive polymer fiber can be increased, and the carbon nano material conductive polymer fiber is more applicable to the environment.
3. In the invention, alternating current is applied to the fiber coated with the carbon nano material, so that the carbon nano layer generates heat, and the joule heat gradually softens the fiber surface layer (promotes the activity of molecular chain segments of the fiber surface layer); under the assistance of ultrasound, the carbon nano material is embedded between the molecular chain segments on the surface layer of the fiber, and the good anchoring between the conductive nano material and the fiber is realized by a simple physical method.
Detailed Description
In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings.
The structure of the present invention will be described in detail below with reference to the accompanying drawings.
Referring to fig. 1, fig. 2 and fig. 3, a carbon nanomaterial conductive polymer fiber according to an embodiment of the present invention includes:
the inner layer 1, the inner layer 1 is columnar organic polymer fiber;
the outer layer 2 is a conductive layer, and the conductivity of the conductive layer is over 100S/m;
the material of the outer layer 2 comprises carbon nano material particles, the carbon nano material particles are partially embedded into the surface of the inner layer 1, and at least part of the carbon nano material particles are contacted with each other to form a conductive path.
Through the above arrangement, the outer layer 2 is additionally arranged on the outer surface of the columnar organic polymer fiber of the inner layer 1, the material of the outer layer 2 comprises carbon nano material particles, the carbon nano material particles are partially embedded into the surface of the inner layer 1, and at least part of the carbon nano material particles are mutually contacted to form a conductive path, so that the conductivity of the inner layer 1 is changed. The carbon nano material particles are hot-melted on the surface of the organic polymer fiber of the inner layer, so that the electric conduction is carried out through the carbon nano material particles of the outer layer under the condition that the processing technology and the material of the organic polymer of the inner layer are not changed. Further, since the thickness of the outer layer is smaller than that of the inner layer, the influence on the mechanical strength of the inner layer is small and the tensile strength of the inner layer is not affected.
In the present embodiment and the following description, the inner layer without electric conductivity is taken as an example, however, the inner layer may be conductive polymer fiber, and in this case, the electric conductivity of the inner layer can be further increased by adding the outer layer.
The outer layer has a thickness of less than 50 nanometers.
Further, the material of the outer layer 2 also comprises carbon black particles and/or graphene particles; the material of the inner layer 1 comprises at least one of polyethylene fiber, polypropylene fiber, polylactic acid fiber, nylon fiber, polyester fiber and polyacrylonitrile fiber.
With the above arrangement, by increasing the variety of materials, it is possible to increase the stability of the manufactured carbon nanomaterial conductive polymer fiber, for example, a material that is easily deteriorated in a specific environment, and to increase the stability of the manufactured carbon nanomaterial conductive polymer fiber by increasing the variety of materials.
Preferably, the molecular weight of the organic polymer of the inner layer is 40000-600000, and the molecular chain configuration is linear, cross-linked or branched, wherein the branched molecular chain configuration is more convenient for embedding the carbon nano-material particles.
When the molecular weight of the inner-layer organic polymer is less than 40000, molecular chains are sparse, and carbon nano material particles are not favorably embedded into the inner-layer organic polymer; when the molecular weight of the inner organic polymer is more than 600000, the entanglement between molecular chains is large, which is not beneficial to embedding carbon nano material particles into the inner organic polymer. Preferably, the molecular weight of the organic polymer of the inner layer is 70000-120000, so that the carbon nano material particles are more conveniently embedded.
Referring to fig. 4 and 5, a method for preparing a carbon nanomaterial conductive polymer fiber according to an embodiment of the present invention includes the following steps:
s1, cleaning impurities on the surface of an inner layer organic polymer fiber;
s2, uniformly depositing a carbon nano material particle solution on the surface of the inner-layer organic polymer fiber, and drying to obtain a blank which is formed by mutually adhering at least part of carbon nano material particles and forming a conductive path;
s3, applying current to the blank, wherein the carbon nano material particles are mutually conductive, so that the carbon nano material particles are softened, and the carbon nano material particles locally heat the inner-layer organic polymer fibers;
and S4, embedding microwave and/or ultrasonic-assisted carbon nano material particles between the macromolecular chain segments on the surface of the inner-layer organic polymer fiber to anchor the carbon nano material particles to form an outer layer, thereby obtaining the carbon nano material conductive polymer fiber.
By the preparation method, the carbon nano material particles are hot-melted on the surface of the organic polymer fiber of the inner layer, so that the electric conduction is carried out through the carbon nano material particles of the outer layer under the condition that the processing technology and the material of the organic polymer of the inner layer are not changed. Further, since the thickness of the outer layer is smaller than that of the inner layer, the influence on the mechanical strength of the inner layer is small, and the tensile strength of the inner layer is not affected. In the above process, the inner organic polymer layer is heated by conducting electricity through the carbon nano material particles, so that the carbon nano material particles are embedded into the surface of the inner organic polymer layer
Referring to fig. 6, in step S1, the method for cleaning impurities on the surface of the inner organic polymer fiber includes:
s11, cleaning the surface of the organic polymer fiber on the inner layer;
s12, after the inner-layer organic polymer fiber is thrown off, drying in an oven, and melting an oil agent on the surface of the inner-layer organic polymer fiber;
and S13, cleaning again and drying.
By the arrangement, acetone can be used as a cleaning agent to clean the surface of the inner layer organic polymer fiber, and rapid cleaning can be realized by stirring; under the condition that the organic polymer fiber of the inner layer is longer, the inner layer is wound and dried; the carbon nano material particles can be uniformly dried at the temperature of 60-80 ℃, so that oil agent and impurities on the surface of the inner layer polymer fiber can be removed, and the carbon nano material particles can be conveniently deposited on the surface of the inner layer polymer fiber.
Referring to fig. 7, in step S2, a method for uniformly depositing a carbon nano material particle solution on the surface of the inner organic polymer fiber layer and drying the carbon nano material particle solution to obtain a blank in which at least some carbon nano material particles are attached to each other and a conductive path is formed includes:
s21, placing the inner-layer organic polymer fiber in a carbon nano material particle solution to enable carbon nano material particles in the carbon nano material particle solution to be uniformly deposited on the surface of the inner-layer organic polymer fiber to obtain a deposited polymer fiber;
and S22, drying the deposited polymer fibers in an oven at 56-63 ℃ for 9-11 hours to obtain the blank, wherein the mass ratio of the carbon nano material particles after drying accounts for 3% -12% of the blank.
In the above arrangement, preferably, the deposited polymer fiber is dried in an oven at 60 ℃ for 9-11 hours to obtain the blank, and the mass ratio of the carbon nano material particles is 4% -7% of the blank.
In the above arrangement, the carbon nano material particles account for more than 7% of the blank by mass, which may cause the carbon nano material particles to stack and easily fall off, making the formed conductive polymer fiber of the carbon nano material particles unstable, and the improvement of the conductivity is not obvious, thereby wasting the carbon nano material. The mass ratio of the carbon nano material particles is less than 4% of the blank, so that the carbon nano material particles are sparse, part of the carbon nano material particles are not contacted with each other, and the electric conductivity is obviously reduced. Preferably, when the mass ratio of the carbon nano material particles accounts for 6% of the blank, the conductivity of the carbon nano material conductive polymer fiber obtained subsequently is more than 100S/m.
Referring to fig. 8, in step S3, the method of applying current to the blank includes:
s31, communicating the blank with a power supply through a metal clamp;
and step S32, directly applying a circulating alternating current to the blank, wherein the circulating alternating current is applied to the carbon nano-material particles.
And S33, applying electric heat impact on the fiber for multiple times by adopting circulating alternating current to provide a circulating environment with high temperature and temperature reduction of the surface layer of the fiber, so that the nano material is stably anchored between the molecular chain segments of the surface layer of the polymer fiber.
The purpose of applying multiple electric heat shocks to the fibers with circulating alternating current is to prevent thermal decomposition of the polymer at too high a temperature.
Further, the current of 0.04A-0.07A is applied to the blank, the conduction time is 0.1-0.25 second, the conduction is carried out again after the interval time is 46-65 seconds, and the steps are circularly carried out.
Preferably, a current of 0.05A is applied to the blank for a conduction time of 0.2 seconds with an interval of 60 seconds. The test results that at a current of 0.05A, a local temperature of 250 c is reached in 0.4s for the inner layer, for example the inner layer is a polyethylene fiber, which has a melting temperature between 110 and 130 c. Through the arrangement, the current 'on' time is 0.2 second, the interval 'off' time is 60 seconds, the instantaneous temperature of the polyethylene fiber can be 130 ℃, and therefore the carbon nano material particles form a continuous and compact conductive network on the surface of the polymer fiber.
When a current of 0.05A is applied to the blank and the conduction time is less than 0.1 second, an effective conduction current is difficult to form and the surface of the inner layer is difficult to melt.
When the conduction time is longer than 0.25 second, the current is longer than 0.07A, the melting degree of the surface of the inner layer is too large, the carbon nano material particles are embedded into the inner layer too much, the particles exposed on the surface of the inner layer are difficult to attach, and the conductivity is reduced.
In step S4, the method for embedding microwave and/or ultrasonic assisted carbon nano material particles between the macromolecular segments on the surface of the inner layer organic polymer fiber comprises:
the microwave and/or ultrasonic auxiliary time is the same as the electric cycle heating time, so as to ensure that the surface carbon nano material can be embedded into the fiber.
The microwave and ultrasound are applied simultaneously, increasing the effect of the surface.
On the basis of the above, the following verification was also performed:
(1) Referring to fig. 9, the inventors tested the resistance change (length 6 cm) of the carbon nanomaterial/polymer fiber during the electrothermal/ultrasonic process, which decreased from 800 ohms at the first heating to 330 ohms, and stabilized at about 330 ohms (1 d) for the next multiple cycles. The large decrease in resistance during the first heating cycle is presumably due to oxidation of the carbon nanotubes on the outer surface of the carbon nanotube coating and partial thermal degradation of the carbon nanotubes in air. The stable resistance after multiple heating cycles indicates that a uniformly welded carbon nanotube structure with stable resistance is formed on the surface of the polymer fiber, and the structure in the polymer fiber is not thermally degraded. Due to the large ratio of the radius of the polymer fiber to the thickness of the carbon nanotube coating, the high temperature at the surface of the fiber has little effect on the physical and mechanical properties of the polymer fiber to ensure that the polymer fiber filaments remain intact.
(2) The carbon nano-material conductive polymer fiber prepared by the preparation method of the carbon nano-material conductive polymer fiber has the appearance characterization.
The hot-melt embedded carbon nanomaterial conductive polymer fibers exhibit good mechanical bonding. The carbon nano tube is embedded into the surface layer of the inner layer and anchored therein, and the hot-melt carbon nano tube can be subjected to ultrasonic action in an aqueous solution without falling off. SEM images show the welded carbon nanotube structure on the inner layer after electrothermal shock (see fig. 2 and 3). The carbon nano tubes are embedded into the inner layer to form a mutually cross-linked net structure. After the electrothermal/ultrasonic impact, the cross-section of the inner layer remained circular with no change in diameter. The melting of the carbon nanotubes into the inner surface structure is seen on the cross section, which further proves that the melting of the inner layer and the melting of the carbon nanotubes both occur locally on the inner surface, and the inner structure undergoes only slight thermal degradation and structural change.
(3) Mechanical properties: tensile properties of electrically hot-melt carbon nanomaterial conductive polymer fibers and untreated polymer fibers at 25 ℃ at a draw rate of 2mm/min (fig. 10), sample length of 5cm, exemplified by polyethylene fibers. The tensile strength and modulus of the polymer fiber are respectively 2.86 GPa and 110.4GPa, and the tensile strength and modulus of the electric melting carbon nano material conductive polymer fiber are respectively 2.97 GPa and 106.9GPa. The results show that the electric hot melting carbon nano material conductive polymer fiber shows similar mechanical properties with the original polymer fiber in the aspects of tensile strength, modulus and toughness, which shows that the electric hot melting can not damage the mechanical properties of the original carbon nano tube. In addition, it was further confirmed that the welding of the carbon nanotubes to the inner layer occurred mainly at the inner layer surface without affecting the overall performance. Therefore, the electric hot melt impact can make the carbon nano tube and the inner layer well combined without damaging the whole mechanical property.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.