CN104060344A - Method for preparing oriented carbon nanotube/polyester material - Google Patents

Abstract

The invention relates to a method for preparing an oriented carbon nanotube/polyester material. The method mainly comprises the following steps: taking polyester and oriented carbon nanotube bundles as raw materials, and carrying out spinning and vacuum molding to obtain a high-oriented carbon nanotube/polyester material. The method is simple in operation process, and applicable to large-scale production. The prepared polyester product has potential advantages in the aspects of thermal properties, mechanical performance and the like.

Description

A kind of preparation method of aligned carbon nanotube/polyester material

technical field

The invention belongs to the field of polymer material preparation, and in particular relates to a preparation method of an aligned carbon nanotube/polyester material.

Background technique

Polyester is a general term for polymers obtained by polycondensation of polyols and polybasic acids. It mainly refers to linear thermoplastic resins such as polyethylene terephthalate, polybutylene terephthalate and polyarylate. This kind of resin can be used to be processed into fibers, films, and plastic products, and has a wide range of applications in the fields of textiles, optics, electronics, automobiles, aviation, and medical treatment. With the multi-level application of products, polyester products are required to have high heat resistance and high mechanical properties. Traditional polyester products can no longer meet the development trend of product performance.

In recent years, close attention has been paid to the aligned carbon nanotube/polymer materials. Compared with disordered carbon nanotube/polymer materials, due to the orientation control of carbon nanotubes, carbon nanotubes The tube array is uniform and orderly, with less entanglement. Compared with disordered carbon nanotube/polymer materials, it shows better strength, elasticity, fatigue resistance, and force, heat, and electrical anisotropy, and is favored. . The preparation process of aligned carbon nanotubes/polymer materials has a great influence on the alignment of aligned carbon nanotubes in polymers, which further determines the final properties of aligned carbon nanotubes/polymer materials.

At present, there have been related reports on the preparation method of oriented carbon nanotubes/thermoplastic polymers. The main reason is that the reorientation of carbon nanotubes can be realized by using the alignment in the force field/flow field. The process is simple and easy to achieve large-scale synthesis. However, it is only limited to good local micro-orientation and poor macro-orientation; using the in-situ growth synthesis method combined with the carbon nanotube preparation process, carbon nanotubes can be grown in situ on the surface of the polymer matrix to obtain aligned carbon nanotubes/ Polymer materials, but this process must take into account both the preparation of carbon nanotubes and the molding of composite materials. The process conditions are harsh and it is difficult to produce products on a large scale.

Therefore, how to simply and effectively realize the alignment of carbon nanotubes in polymers and realize the large-scale production of aligned carbon nanotubes/polymers is of great significance for improving the performance of polymers and their applications.

Contents of the invention

The purpose of this invention is to provide a kind of preparation method of oriented carbon nanotube/polyester material, and this method is simple and effective, is suitable for suitability for suitability for industrialized production; The oriented carbon nanotube/polyester material prepared thus has improved the performance of traditional polyester product and Expand the application field of polyester.

In order to achieve the above-mentioned purpose of the invention, the technical scheme adopted in the present invention is: a kind of preparation method of oriented carbon nanotube/polyester material, comprises the following steps:

(1) After the polyester is fully mixed with the oriented carbon nanotube bundles, the spinning composition is obtained; after the spinning composition is dried, the oriented carbon nanotubes/polyester filaments are obtained through melt spinning and thermal stretching; the oriented carbon nanotubes The mass ratio of the tube bundle to the polyester is (0.1-2.5):100; the polyester is unmodified polyester or additive-modified polyester;

(2) Put the above-mentioned aligned carbon nanotubes/polyester filaments into a mold, and form them by hot pressing to obtain an aligned carbon nanotube/polyester material; the aligned carbon nanotubes/polyester filaments are parallel to each other.

In the above technical scheme, the polyester in the spinning composition can be modified with additives; the additives are commonly used additives for polyester fibers, which can further improve the spinnability and other properties of the spinning composition, such as diethylene glycol, 1,3- One or more of propylene glycol, silicon dioxide, titanium dioxide, sodium chloride, and calcium chloride.

In the above technical solution, in step (1), there is no special requirement for the mixing method of the raw materials, as long as the raw materials can be mixed uniformly; The spinning composition can be obtained by mixing the raw materials in the molten state of the polyester, and extruding and granulating.

In the above technical solution, in step (1), the aligned carbon nanotube bundles in the spinning composition are aligned multi-walled carbon nanotube bundles with a length of 30-100 μm.

In the above technical solution, in step (1), the spinning composition is dried at 120-130° C. under vacuum conditions before spinning.

In the above technical solution, in step (1), the polyester is one or more of polyethylene terephthalate, polybutylene terephthalate and polyarylate.

In the above technical solution, in step (2), the vacuum degree during hot pressing is 0.1 MPa; the pressure is 5-15 MPa; and the time is 5-10 min. When polyester is polyethylene terephthalate, in step (2), the temperature during thermocompression molding is 250～260 ℃; When polyester is polybutylene terephthalate, step (2) Among them, the temperature during thermocompression molding is 200-220°C; when the polyester is polyarylate, in step (2), the temperature during thermocompression molding is 285-295°C. Under this condition, the aligned carbon nanotubes will not flow in the polyester, and the aligned carbon nanotubes in the obtained aligned carbon nanotube/polyester material are highly oriented macroscopically.

In the above technical solution, melt spinning is one of the main methods for preparing polyester fibers, which mainly includes steps such as polymer melting, melt filtration, spinneret forming (spinning), and post-processing (stretching). Related parameters during spinning, such as spinning temperature and stretching temperature, can be selected according to the type of polyester.

In the present invention, the sufficient mixing of the raw materials improves the dispersibility of the oriented carbon nanotubes in the polyester, and at the same time, the oriented carbon nanotubes/polyester fiber filaments are prepared first, and then the fiber filaments are arranged in parallel and then hot-pressed to further improve the orientation. The dispersion of carbon nanotubes in polyester is beneficial to the micro-orientation of oriented carbon nanotubes in polyester; the spinning composition with all components mixed uniformly increases the orientation of oriented carbon nanotubes by melt spinning and stretching. The orientation of the tubes in the polyester fiber, and then the aligned carbon nanotubes/polyester fiber filaments are arranged in parallel, hot-pressed, and the orientation of the aligned carbon nanotubes is prevented from flowing in the polyester during hot-pressing, resulting in a change in orientation, which can Effectively guarantee the macroscopic high orientation of aligned carbon nanotubes in polyester.

Owing to above-mentioned technical scheme uses, the present invention has following advantage compared with prior art:

1. The present invention utilizes oriented carbon nanotube bundles and polyester to mix and spin to obtain modified polyester fiber filaments, and then arranges the polyester fiber filaments in parallel and heat-presses to obtain a new oriented carbon nanotube/polyester material; it has excellent Excellent thermal and mechanical properties, meeting the development trend of high-performance polyester materials.

2. In the preparation method disclosed by the present invention, the oriented carbon nanotube bundles are fully mixed with the polyester, and then the oriented carbon nanotube/polyester material with high microscopic orientation and macroscopic orientation is beneficial to be obtained after spinning and parallel hot pressing of the fiber filaments, effectively solving the problem of The problem of poor orientation of carbon nanotubes in polymer materials in the existing preparation methods is solved.

3. In the preparation method disclosed in the present invention, the sources of raw materials are extensive, the preparation process is simple and controllable, only conventional operations are required, it is environmentally friendly and easy to industrialize.

Description of drawings

Fig. 1 is the SEM photo of highly oriented carbon nanotube/polyethylene phthalate material in embodiment 1;

Fig. 2 is the SEM photograph of carbon nanotube/polyethylene phthalate material in comparative example 1;

Fig. 3 is the SEM photo of highly oriented carbon nanotube/polyarylate material in embodiment 2;

Fig. 4 is the SEM photograph of carbon nanotube/polyarylate material in comparative example 2;

Fig. 5 is the SEM photo of highly oriented carbon nanotube/polybutylene terephthalate material in embodiment 3;

6 is an SEM photo of the carbon nanotube/polybutylene terephthalate material in Comparative Example 3.

Detailed ways

Below in conjunction with accompanying drawing and embodiment, comparative example the present invention will be further described:

Example 1

1000g of polyethylene phthalate (containing diethylene glycol (mass percentage: 1.29%) and titanium dioxide (mass percentage: 0.3%)) and 1g of aligned multi-walled carbon nanotube bundles were mixed mechanically, under vacuum conditions, at 120~ After fully drying at 130°C, use a spinning machine to spin at 280°C, and then heat-stretch at 80°C to obtain oriented carbon nanotube/polyester fiber filaments; arrange the above-mentioned fiber filaments in parallel and closely in a mold, and heat them in a vacuum Press molding (vacuum: 0.1MPa; temperature: 255°C; pressure: 10MPa) for 5 minutes to obtain an oriented carbon nanotube/polyester material, which is denoted as a highly oriented carbon nanotube/polyethylene phthalate material. The mechanical properties and thermal properties are listed in Table 1.

Comparative example 1

1000g polyethylene phthalate (containing diethylene glycol (mass percentage: 1.29%) and titanium dioxide (mass percentage: 0.3%)) and 1g non-oriented multi-walled carbon nanotubes were mixed mechanically, under vacuum conditions, at 120 After drying at ~130°C, use a spinning machine to spin at 280°C, and then heat-stretch at 80°C to obtain carbon nanotube/polyester fiber filaments; arrange the above-mentioned fiber filaments in a mold parallel to each other closely, and the arrangement direction is the same as Consistent with Example 1, through vacuum hot pressing (vacuum: 0.1MPa; temperature: 255°C; pressure: 10MPa) for 5 minutes, the carbon nanotube/polyester material is obtained, which is recorded as carbon nanotube/polyethylene phthalate The mechanical properties and thermal properties of diester materials are shown in Table 1.

Accompanying drawing 1 is the SEM figure of the highly oriented carbon nanotube/polyester material prepared in embodiment 1, wherein (a) figure is the material sectional view of molding along the fiber axial direction, (b) figure is the vertical fiber axial molding Material sectional view; As can be seen from (a) figure, carbon nanotube highly oriented; As can be seen from (b) figure, carbon nanotube is uniformly dispersed in polyester material; Accompanying drawing 2 is the carbon prepared in comparative example 1 SEM image of nanotube/polyester material, where (a) is a cross-section of the material formed along the fiber axis, and few oriented carbon tubes are observed in the figure; (b) is a cross-section of the material formed perpendicular to the fiber axis Figure, the dispersion of carbon tubes in the figure is worse than that of the highly oriented carbon nanotubes/polyethylene phthalate material.

Example 2

1000g of polyarylate (unmodified) and 3g of oriented multi-walled carbon nanotube bundles were mechanically stirred and mixed, fully dried at 120~130°C under vacuum conditions, spun at 300°C by a spinning machine, and then heated at 100°C Stretching to obtain oriented carbon nanotube/polyarylate fiber filaments. Arrange the above-mentioned fiber filaments parallel to each other closely in a mold, and form them by vacuum hot pressing (vacuum degree: 0.1MPa; temperature: 290°C; pressure: 15MPa) for 5 minutes to obtain an oriented carbon nanotube/polyester material, which is recorded as high The mechanical properties and thermal properties of the aligned carbon nanotube/polyarylate material are shown in Table 1.

Comparative example 2

Mix 1000g of polyarylate (unmodified) with 3g of non-oriented multi-walled carbon nanotubes mechanically, and dry them fully at 120~130°C under vacuum conditions, put them into a mold, and form them by vacuum hot pressing (vacuum degree: 0.1MPa; temperature: 290°C; pressure: 15MPa) for 5 minutes, a carbon nanotube/polyester material can be obtained, which is recorded as carbon nanotube/polyarylate material, and its mechanical properties and thermal properties are shown in Table 1.

Accompanying drawing 3 is the SEM figure of highly oriented carbon nanotube/polyarylate material in embodiment 2, wherein (a) figure is the sectional view along the fiber axial molding material, (b) figure is the cross section of the vertical fiber axial molding material Figure; As can be seen from the (a) figure, the material is highly oriented along the cross-section carbon nanotubes in the fiber axial direction; as can be seen from the (b) figure, the carbon nanotubes are uniformly dispersed in the polyester material; Accompanying drawing 4 is a pair of The SEM image of the carbon nanotube/polyarylate material prepared in Ratio 2, where (a) is a cross-sectional view of the molded material along the fiber axis, and there are few oriented carbon tubes observed in the figure; (b) is a vertical A cross-sectional view of the fiber axially formed material, where the dispersion of carbon tubes is poorer than that of the highly oriented carbon nanotube/polyarylate material.

Example 3

1000g of polybutylene terephthalate (containing silicon dioxide (mass percentage: 0.3%)) and 25g of oriented multi-walled carbon nanotube bundles were mechanically stirred and mixed. Spinning at 230°C and then thermally stretching at 30°C to obtain oriented carbon nanotube/polyester fiber filaments. Arrange the above-mentioned fiber filaments parallel to each other closely in a mold, and form them by vacuum hot pressing (vacuum degree: 0.1MPa; temperature: 210°C; pressure: 5MPa) for 5 minutes to obtain an aligned carbon nanotube/polyester material, which is recorded as high The mechanical properties and thermal properties of the oriented carbon nanotube/polybutylene terephthalate material are shown in Table 1.

Comparative example 3

1000g of polybutylene terephthalate (containing silicon dioxide (mass percentage: 0.3%)) and 25g of aligned multi-walled carbon nanotube bundles were mechanically stirred and mixed, fully dried at 120°C under vacuum, and then placed into a mold , after vacuum hot pressing (vacuum degree: 0.1MPa; temperature: 210°C; pressure: 5MPa) for 5 minutes, carbon nanotube/polyester material can be obtained, which is recorded as carbon nanotube/polybutylene terephthalate material , and its mechanical and thermal properties are listed in Table 1.

Accompanying drawing 5 is the SEM figure of highly oriented carbon nanotube/polybutylene terephthalate material in embodiment 3, wherein (a) figure is the material sectional view of shaping along fiber axis, (b) is vertical fiber axis The cross-sectional view of the molded material; it can be seen from (a) that the carbon nanotubes in the cross section of the material along the axial direction of the fiber are highly oriented; it can be seen from (b) that the carbon nanotubes are uniformly dispersed in the polyester material. Accompanying drawing 6 is the SEM figure of the carbon nanotube/polybutylene terephthalate material prepared in Comparative Example 3, wherein (a) figure is the material sectional view of molding along the fiber axial direction, and the carbon tube observed in the figure Orientation is poorer than in highly oriented carbon nanotubes/polybutylene terephthalate materials; (b) is a cross-sectional view of the material formed vertically to the axial direction of the fiber, and the dispersion of carbon tubes in the figure is compared with that of highly oriented carbon nanotubes The tube/polybutylene terephthalate material is poor.

Table 1 Properties of highly oriented carbon nanotube/polyester material and carbon nanotube/polyester material

performance Example 1 Comparative example 1 Example 2 Comparative example 2 Example 3 Comparative example 3 Tensile ^Strengtha (MPa) 88 56 143 116 86 36 Bending strength ^b (MPa) 160 100 193 161 67 42 Impact strength ^c (KJ/m ² ) 10 7.5 12.8 10.6 12 7.6 T _d ^d (℃) 393 389 453 446 299 293

^a : Tensile strength is tested according to ASTM D638;

^b : Bending strength is tested according to ASTM D790;

^c : Charpy notched impact strength is tested according to ASTM D6110;

^d : T _d : Thermal decomposition temperature corresponding to 5% weight loss.

As can be seen from Table 1, the mechanical properties and thermal properties of the aligned carbon nanotube/polyester material obtained by the present invention are excellent, and its reason is that the aligned carbon nanotube/polyester material obtained by the present invention realizes the alignment of the aligned carbon nanotube in the microcosm Orientation to a certain extent, and through fiber spinning, the macroscopic orientation of oriented carbon nanotubes is further improved; carbon nanotubes in oriented carbon nanotubes/polyester materials are highly oriented and uniformly dispersed, which is conducive to improving the performance of polyester materials.

Claims (7)

1. a preparation method of oriented carbon nanotube/polyester material, is characterized in that, comprises the following steps: (1) After the polyester is fully mixed with the oriented carbon nanotube bundles, the spinning composition is obtained; after the spinning composition is dried, the oriented carbon nanotubes/polyester filaments are obtained through melt spinning and thermal stretching; the oriented carbon nanotubes The mass ratio of the tube bundle to the polyester is (0.1-2.5):100; the polyester is unmodified polyester or additive-modified polyester; (2) Put the above-mentioned aligned carbon nanotubes/polyester filaments into a mold, and form them by hot pressing to obtain an aligned carbon nanotube/polyester material; the aligned carbon nanotubes/polyester filaments are parallel to each other. 2. according to the preparation method of the described alignment carbon nanotube/polyester material of claim 1, it is characterized in that: described additive is diethylene glycol, 1,3-propanediol, silicon dioxide, titanium dioxide, sodium chloride, chlorinated One or more of calcium. 3. The method for preparing aligned carbon nanotube/polyester material according to claim 1, characterized in that in step (1), the aligned carbon nanotube bundles are aligned multi-walled carbon nanotube bundles with a length of 30-100 μm. 4. The preparation method of oriented carbon nanotube/polyester material according to claim 1, characterized in that: in step (1), the spinning composition is dried at 120-130° C. under vacuum conditions before spinning deal with. 5. according to the preparation method of the described alignment carbon nanotube/polyester material of claim 1, it is characterized in that: in step (1), described polyester is polyethylene terephthalate, polybutylene terephthalate diester or polyarylate. 6. according to the preparation method of the described orientation carbon nanotube/polyester material of claim 5, it is characterized in that: in step (2), the vacuum degree during thermocompression molding is 0.1MPa; Pressure is 5～15MPa; Time is 5 ~10min. 7. according to the preparation method of the described alignment carbon nanotube/polyester material of claim 6, it is characterized in that: when polyester is polyethylene terephthalate, in step (2), the temperature during thermocompression molding It is 250～260 ℃; When polyester is polybutylene terephthalate, in step (2), the temperature during thermocompression molding is 200～220 ℃; When polyester is polyarylate, step (2) ), the temperature during hot pressing is 285-295°C.