Carbon nanotube resin-based composite material and preparation method thereof

Abstract

The present invention discloses a carbon nanotube resin-based composite material and a preparation method thereof. The preparation method comprises: uniformly mixing carbon nanotubes, an organic dispersant with a curing function, a resin and a solvent to form a carbon nanotube dispersion; then removing the solvent to obtain a carbon nanotube resin-based composite material, wherein the organic dispersant contains an amine group. The method of the present invention prepares a carbon nanotube resin-based composite material in situ, and the selected dispersant is an organic dispersant, and the dispersant contains an amine group, which has a dispersing effect and can cure the resin at the same time, and can enhance the interface bonding between the carbon nanotube and the resin matrix, thereby solving the problem that the resin in the carbon nanotube film is difficult to be uniformly infiltrated in the traditional process, and a carbon nanotube resin-based composite material with excellent mechanical properties is prepared, and the problem that the dispersant in the traditional process reduces the mechanical properties of the composite material, and the process of removing the dispersant is complicated and the effect is not ideal is solved.

Description

Technical Field

[0001] The invention relates to a carbon nanotube resin-based composite material and a preparation method thereof, belonging to the technical field of nanocomposite materials. Background Art

[0002] Carbon nanotubes (CNTs) have a high aspect ratio and excellent mechanical and electrical properties, and are considered to be ideal reinforcements for preparing high-quality composite materials. The huge specific surface area of ​​carbon nanotubes can enhance the interaction with the resin matrix, thereby generating higher stress transfer and energy dissipation, significantly improving the strength and toughness of composite materials.

[0003] The preparation methods of carbon nanotube resin-based composite materials mainly include blending and impregnation. Among them, the blending method is to directly disperse carbon nanotube powder in the resin matrix. This method is simple to operate, has low process cost, and can achieve large-scale production. However, due to the poor dispersion and orientation of carbon nanotubes in the matrix, and the existence of solvent residues and low carbon nanotube content, the prepared composite material has poor performance. The impregnation method can prepare high-content carbon nanotube composite materials with a certain degree of orientation, but there are problems in the preparation process such as the difficulty of resin entering the carbon nanotube tubes, inconsistent resin content in the inner and outer layers of the impregnated structure, and a complicated impregnation process. The mechanical properties of carbon nanotube composites prepared by the blending method and the impregnation method are poor, and the excellent mechanical properties of carbon nanotubes cannot be fully utilized.

[0004] In addition, some researchers use aqueous dispersants to disperse carbon nanotubes in water and use aqueous carbon nanotube dispersions to prepare carbon nanotube film products. The prepared film has a small porosity and contains a large amount of residual dispersants, which seriously affects the performance of the final composite material. Although the dispersants are removed through subsequent process methods, there are still problems such as difficulty in complete removal and damage to the intrinsic structure of carbon nanotubes.

[0005] Moreover, when further preparing composite materials, the carbon nanotube film needs to be impregnated with resin. The wet-process carbon nanotube film currently prepared by the industry has low porosity and high carbon nanotube stacking density. The resin is often enriched on the surface of the film, and the internal resin impregnation is poor, resulting in unsatisfactory mechanical properties. Summary of the invention

[0006] The main purpose of the present invention is to provide a carbon nanotube resin-based composite material (ie, carbon nanotube film prepreg) and a preparation method thereof, so as to overcome the deficiencies of the prior art.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0008] An embodiment of the present invention provides a method for preparing a carbon nanotube resin-based composite material, which comprises:

[0009] uniformly mixing carbon nanotubes, an organic dispersant with a curing function, a resin and a solvent to form a carbon nanotube dispersion;

[0010] Then, the solvent is removed to obtain a carbon nanotube resin-based composite material, wherein the organic dispersant contains an amine group.

[0011] In some embodiments, the organic dispersant includes any one or a mixture of two or more of unsaturated polyamine amide, unsaturated polycarboxylic acid polymer and polysiloxane copolymer, alkyl ammonium salt solution of acidic copolymer containing hydroxyl functional group, and amino polymer containing pyrene structure.

[0012] The embodiment of the present invention also provides a carbon nanotube resin-based composite material prepared by the above preparation method.

[0013] Compared with the prior art, the beneficial effects of the present invention are at least:

[0014] The method provided by the present invention prepares a carbon nanotube resin-based composite material in situ, and the selected dispersant is an organic dispersant. The dispersant contains an amine group, which has a dispersing effect and can solidify the resin at the same time, thereby enhancing the interface bonding between the carbon nanotubes and the resin matrix, solving the problem that the resin in the carbon nanotube film is difficult to be uniformly infiltrated in the traditional process, and preparing a carbon nanotube resin-based composite material with excellent mechanical properties. It also solves the problem that the dispersant in the traditional process will reduce the mechanical properties of the composite material, and the process of removing the dispersant is complicated and the effect is not ideal. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a mechanical test curve diagram of the product obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0017] In view of the shortcomings of the traditional technical solutions, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice. The main purpose is to achieve uniform dispersion of carbon nanotubes in the resin solution by using a modified dispersant / curing agent with both dispersing and curing functions, orient the carbon nanotubes through the shear force of pipeline extrusion, and obtain an oriented carbon nanotube prepreg product through continuous filtration, drying, winding and other process steps. The technical solution, its implementation process and principle will be further explained as follows.

[0018] One aspect of an embodiment of the present invention provides a method for preparing a carbon nanotube resin-based composite material, comprising:

[0019] uniformly mixing carbon nanotubes, an organic dispersant with a curing function, a resin and a solvent to form a carbon nanotube dispersion;

[0020] Then, the solvent is removed to obtain a carbon nanotube resin-based composite material, wherein the organic dispersant contains an amine group.

[0021] In some embodiments, the organic dispersant preferably includes any one or a combination of two or more of unsaturated polyamine amide, low molecular weight unsaturated polycarboxylic acid polymer and polysiloxane copolymer, alkyl ammonium salt solution of acidic copolymer containing hydroxyl functional group, amino polymer containing pyrene structure, etc., but is not limited thereto. The dispersant selected in the present invention is an organic dispersant with curing function, which contains an amine group, has a dispersing effect and can cure the resin at the same time, can enhance the interface bonding between carbon nanotubes and resin matrix, solves the problem that dispersant in traditional process will reduce the mechanical properties of composite materials, and the process of removing dispersant is complicated and the effect is not ideal, and solves the problem that resin is difficult to be uniformly infiltrated in carbon nanotube film.

[0022] In the present invention, an organic dispersant containing an amine group is selected, and the composite material finally prepared has better performance. The main function of the amine group is to improve the performance of the product.

[0023] In some embodiments, the type of carbon nanotubes includes any one of single-walled carbon nanotubes, multi-walled carbon nanotubes, etc. or a mixture of the two, but is not limited thereto. Any proportion of a single component or two components can be used to prepare carbon nanotube film prepregs, and the final product has different mechanical properties.

[0024] In some embodiments, the type of resin selected includes any one or a mixture of two of difunctional epoxy resin, trifunctional epoxy resin, etc., and cyanamide pre-reaction. Among them, the difunctional or trifunctional epoxy resin can be compounded in any proportion, and the mass ratio of dicyandiamide is 100:5a according to the functional number a resin component after compounding. Too much dicyandiamide will increase the annual of the system, shorten the trial period, and affect the mechanical properties, while too little dicyandiamide will affect the final mechanical properties.

[0025] Furthermore, the solvent includes any one or a combination of two or more of ethanol, isopropanol, DMF, NMP, xylene, isobutanol, etc., but is not limited thereto.

[0026] In some embodiments, the mass ratio of the carbon nanotubes, the organic dispersant, the resin and the solvent is 1-8:1-50:10-40:100.

[0027] Among them, the content ratio of the carbon nanotubes is adjustable from 1 to 8. A lower content will reduce the production efficiency, while a higher content will affect the dispersion effect; the content ratio of the organic dispersant is adjustable from 1 to 50. A lower content will result in poor dispersion effect, while a higher content will reduce the mechanical properties; the content ratio of the resin is adjustable from 10 to 40. A lower content will affect the mechanical properties, while a higher content will affect the dispersion effect; the content ratio of the solvent is 100. A further decrease will affect the dispersion effect, while a higher content will reduce the production efficiency.

[0028] In some embodiments, the mixing method includes any one or a combination of two or more of mechanical stirring, ultrasound, high-pressure homogenization, microfluidization and the like, but is not limited thereto.

[0029] Furthermore, the parameters of the mechanical stirring can be set according to the rotation speed and time. Specifically, the stirring speed is 100-500 rpm, the time is 10-60 min, and the optimal time is 20 min of magnetic stirring.

[0030] Furthermore, the ultrasonic parameter setting can be calculated according to frequency, power and time. Specifically, the ultrasonic frequency is 10-50kHz, the power is 20-200W, and the time is 10-60min.

[0031] Furthermore, the parameters of the high-pressure homogenization can be set according to the set pressure, time and processing volume. Specifically, the pressure is 100-400 Bar, the time and processing volume are 5-20 min / 100 mL, and the optimal high-pressure homogenization is 200 bar 5 min / 100 mL.

[0032] Furthermore, the micro jet parameter setting can be calculated according to the set pressure and the number of times. Specifically, the pressure is 600-1000 Bar, the number of times is 6-10 times, and the optimal is 1000 bar micro jet 6 times.

[0033] In some embodiments, the preparation method includes: using at least filter paper and a suction filtration device to remove the solvent, and then encapsulating to obtain the carbon nanotube resin-based composite material. In the present invention, the carbon nanotube resin-based composite material is prepared by suction filtration, and the solvent can be recycled.

[0034] Furthermore, the preparation method comprises: sequentially filtering, drying and rolling to obtain an oriented carbon nanotube resin-based composite material.

[0035] In summary, the present invention disperses carbon nanotube powder in a resin organic solution through an organic dispersant / curing agent, prepares a carbon nanotube film containing resin in situ, and successfully prepares a carbon nanotube resin-based composite material with excellent mechanical properties.

[0036] Another aspect of the embodiments of the present invention further provides a high carbon nanotube resin-based composite material prepared by the above preparation method.

[0037] Furthermore, the carbon nanotube resin-based composite material includes a resin matrix and a continuous strip-shaped prepreg formed by carbon nanotubes uniformly dispersed in the resin matrix, wherein the carbon nanotubes are oriented.

[0038] Furthermore, the tensile strength of the carbon nanotube resin-based composite material is 1.5 to 3 GPa.

[0039] To sum up, in the above technical scheme, the present invention prepares a carbon nanotube resin-based composite material in situ, and the selected dispersant is an organic dispersant. The dispersant contains an amine group, which has a dispersing effect and can solidify the resin at the same time, thereby enhancing the interface bonding between the carbon nanotubes and the resin matrix, solving the problem that the resin in the carbon nanotube film is difficult to be uniformly infiltrated in the traditional process, and a carbon nanotube prepreg with excellent mechanical properties is prepared. It also solves the problem that the dispersant in the traditional process will reduce the mechanical properties of the composite material, and the process of removing the dispersant is complicated and the effect is not ideal.

[0040] Embodiments of the present invention will be described in detail below. However, the present invention may be implemented in many different forms, and the invention should not be construed as being limited to the specific embodiments set forth herein. Instead, these embodiments are provided to explain the principles and practical applications of the invention, thereby enabling other persons skilled in the art to better understand the various embodiments of the present invention and the various modifications suitable for specific intended applications.

[0041] Unless otherwise specified, all raw materials, production equipment, testing equipment, etc. used in the following examples can be obtained from commercial sources. The testing methods used are also known testing methods in the art.

[0042] Example 1

[0043] Trifunctional epoxy resin TDE85 and difunctional epoxy resin E51 were compounded in a mass ratio of 3:2, and the compounded resin was mixed with dicyandiamide in a mass ratio of 100:13 using a three-roll grinder and set aside.

[0044] In this embodiment, single-walled carbon nanotubes are selected for dispersion treatment, an amino polymer containing a pyrene structure is used as a dispersant, the resin component configured in the above process is used as a matrix phase, and DMF is used as a solvent. The mass ratio of carbon nanotubes, dispersant, resin, and solvent is 4:8:20:100 for mixing, and the dispersion of carbon nanotubes is achieved by a high-pressure homogenization method. The dispersion process conditions are 200 bar 5 min / 100 mL. After the dispersion is completed, a stable carbon nanotube dispersion is obtained.

[0045] The carbon nanotube dispersion is squeezed out through a flat needle onto the surface of the translated filter paper, and the vacuum filtration state is maintained under the filter paper. The carbon nanotube film that has completed the filtration process enters the drying area for heating and drying before being rolled up. The orientation of the carbon nanotubes is achieved through the shearing action inside the needle, and the solvent in the filtration bottle can be recycled (including resin and dispersant). The prepared carbon nanotube resin-based composite material needs to be sealed and frozen at 20°C.

[0046] According to the test sample preparation requirements, the carbon nanotube resin-based composite material was thawed and cut into a size of 3cm*1cm. After hot pressing and curing at 150℃ / 2h, its tensile strength was measured, and the measured value was 2.5~3GPa.

[0047] Example 2

[0048] Trifunctional epoxy resin TDE85 and difunctional epoxy resin E51 were compounded in a mass ratio of 3:2, and the compounded resin was mixed with dicyandiamide in a mass ratio of 100:13 using a three-roll grinder and set aside.

[0049] In this embodiment, single-walled carbon nanotubes are selected for dispersion treatment, an alkyl ammonium salt solution of an acidic copolymer containing a hydroxyl functional group is used as a dispersant, the resin component configured in the above process is used as a matrix phase, and NMP is used as a solvent. The mass ratio of carbon nanotubes, dispersant, resin, and solvent is 1:1:10:100 for mixing, and the dispersion of carbon nanotubes is achieved by a high-pressure homogenization method. The dispersion process conditions are 100 bar 15 min / 100 mL. After the dispersion is completed, a stable carbon nanotube dispersion is obtained.

[0050] The carbon nanotube dispersion is squeezed out through a flat needle onto the surface of the translated filter paper, and the vacuum filtration state is maintained under the filter paper. The carbon nanotube film that has completed the filtration process enters the drying area for heating and drying before being rolled up. The orientation of the carbon nanotubes is achieved through the shearing action inside the needle, and the solvent in the filtration bottle can be recycled (including resin and dispersant). The prepared carbon nanotube film prepreg needs to be sealed and frozen at 20°C.

[0051] According to the test sample preparation requirements, the carbon nanotube resin-based composite material was thawed and cut into a size of 3cm*1cm. After hot pressing and curing at 150℃ / 2h, its tensile strength was measured, and the measured value was 1.5~1.8GPa.

[0052] Example 3

[0053] Trifunctional epoxy resin TDE85 and difunctional epoxy resin E51 were compounded in a mass ratio of 3:2, and the compounded resin was mixed with dicyandiamide in a mass ratio of 100:13 using a three-roll grinder and set aside.

[0054] In this embodiment, single-walled carbon nanotubes are selected for dispersion treatment, unsaturated polycarboxylic acid polymer and polysiloxane copolymer are used as dispersants, the resin component configured in the above process is used as the matrix phase, and isopropanol is used as the solvent. The mass ratio of carbon nanotubes, dispersant, resin, and solvent is 8:50:40:100 for mixing, and the dispersion of carbon nanotubes is achieved by high-pressure homogenization. The dispersion process conditions are 400 bar 20 min / 100 mL. After the dispersion is completed, a stable carbon nanotube dispersion is obtained.

[0055] The carbon nanotube dispersion is squeezed out through a flat needle onto the surface of the translated filter paper, and the vacuum filtration state is maintained under the filter paper. The carbon nanotube film that has completed the filtration process enters the drying area for heating and drying before being rolled up. The orientation of the carbon nanotubes is achieved through the shearing action inside the needle, and the solvent in the filtration bottle can be recycled (including resin and dispersant). The prepared carbon nanotube film prepreg needs to be sealed and frozen at 20°C.

[0056] According to the test sample preparation requirements, the carbon nanotube resin-based composite material was thawed and cut into a size of 3cm*1cm. After hot pressing and curing at 150℃ / 2h, its tensile strength was measured, and the measured value was 1.6~1.8GPa.

[0057] Example 4

[0058] The present embodiment is different from the embodiment 1 in that the carbon nanotubes are multi-walled carbon nanotubes, the organic dispersant is unsaturated polyamine amide, the solvent is xylene and isobutyl alcohol, and the mixing method is micro jet, the pressure is 1000 Bar, and the number of times is 6.

[0059] According to the test sample preparation requirements, the carbon nanotube resin-based composite material was thawed and cut into a size of 3cm*1cm. After hot pressing and curing at 150℃ / 2h, its tensile strength was measured, and the measured value was 2.1~2.3GPa.

[0060] Example 5

[0061] The present embodiment is different from the embodiment 1 in that the solvent is ethanol, the mixing method is micro jet, the pressure is 600 Bar, and the number of times is 10.

[0062] According to the test sample preparation requirements, the carbon nanotube resin-based composite material was thawed and cut into a size of 3cm*1cm. After hot pressing and curing at 150℃ / 2h, its tensile strength was measured, and the measured value was 2.0~2.1GPa.

[0063] Example 6

[0064] Compared with Example 1, the present embodiment is different in that mechanical stirring is used as the mixing method, the rotation speed is 100 to 500 rpm, and the time is 10 to 60 minutes.

[0065] According to the test sample preparation requirements, the carbon nanotube resin-based composite material was thawed and cut into a size of 3cm*1cm. After hot pressing and curing at 150℃ / 2h, its tensile strength was measured, and the measured value was 1.6~2.3GPa.

[0066] Example 7

[0067] Compared with Example 1, the present embodiment is different in that: ultrasound is used as the mixing method, the frequency of the ultrasound is 10 to 50 kHz, the power is 20 to 200 W, and the time is 10 to 60 min.

[0068] According to the test sample preparation requirements, the carbon nanotube resin-based composite material was thawed and cut into a size of 3cm*1cm. After hot pressing and curing at 150℃ / 2h, its tensile strength was measured, and the measured value was 1.8~2.4GPa.

[0069] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0070] Comparative Example 1

[0071] The difference between this comparative example and Example 1 is that the dispersant used does not contain an amine group.

[0072] According to the test sample preparation requirements, the carbon nanotube resin-based composite material was thawed and cut into a size of 3cm*1cm. After hot pressing and curing at 150℃ / 2h, its tensile strength was measured, and the measured value was 0.5~0.8GPa.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 1 is that the carbon nanotubes, the dispersant, the resin, and the solvent are mixed in a mass ratio of 1:1:10:200.

[0075] It is not possible to obtain a continuously formed carbon nanotube ribbon when a carbon nanotube dispersion is extruded through a flat needle.

[0076] Comparative Example 3

[0077] The difference between this comparative example and Example 1 is that the carbon nanotubes, the dispersant, the resin and the solvent are mixed in a mass ratio of 8:50:40:50.

[0078] After the dispersion treatment, it can be seen that there is an obvious agglomeration state in the dispersion, and a stable carbon nanotube dispersion cannot be obtained.

[0079] Although the present invention has been described with reference to illustrative embodiments, it will be appreciated by those skilled in the art that various other changes, omissions and / or additions may be made without departing from the spirit and scope of the present invention and that the elements of the embodiments may be replaced by substantial equivalents. In addition, many modifications may be made without departing from the scope of the present invention to adapt specific circumstances or materials to the teachings of the present invention. Therefore, it is not intended herein to limit the present invention to the disclosed specific embodiments for performing the present invention, but it is intended that the present invention will include all embodiments within the scope of the appended claims. In addition, unless specifically stated, any use of the terms first, second, etc. does not indicate any order or importance, but rather uses the terms first, second, etc. to distinguish one element from another.

Claims

1. A method for preparing a carbon nanotube resin-based composite material, characterized in that: include: uniformly mixing carbon nanotubes, an organic dispersant with a curing function, a resin and a solvent to form a carbon nanotube dispersion; Then, the solvent is removed to obtain a carbon nanotube resin-based composite material, wherein the organic dispersant contains an amine group; The mass ratio of the carbon nanotubes, the organic dispersant, the resin and the solvent is 1-8:1-50:10-40:100; The organic dispersant is selected from any one or a combination of two or more of unsaturated polyamine amide, unsaturated polycarboxylic acid polymer and polysiloxane copolymer, alkyl ammonium salt solution of acidic copolymer containing hydroxyl functional group, and amino polymer containing pyrene structure; The carbon nanotube resin-based composite material comprises a resin matrix and a continuous strip prepreg formed by carbon nanotubes uniformly dispersed in the resin matrix, wherein the carbon nanotubes are oriented; the tensile strength of the carbon nanotube resin-based composite material is 1.5-3 GPa; The resin is selected from any one of bifunctional epoxy resin and trifunctional epoxy resin or a mixture of the two.

2. The preparation method according to claim 1, characterized in that: The carbon nanotubes are selected from any one of single-walled carbon nanotubes and multi-walled carbon nanotubes or a mixture of the two.

3. The preparation method according to claim 1, characterized in that: The solvent is selected from any one of ethanol, isopropanol, DMF, NMP, xylene, and isobutanol, or a combination of two or more thereof.

4. The preparation method according to claim 1, characterized in that: The mixing method is selected from any one of mechanical stirring, ultrasound, high-pressure homogenization, and microfluidization, or a combination of two or more thereof.

5. The preparation method according to claim 4, characterized in that: The mechanical stirring speed is 100-500 rpm, and the time is 10-60 min.

6. The preparation method according to claim 4, characterized in that: The frequency of the ultrasound is 10-50 kHz, the power is 20-200 W, and the time is 10-60 min.

7. The preparation method according to claim 4, characterized in that: The pressure of the high-pressure homogenization is 100-400 Bar, and the time and processing volume are 5-20 min / 100 mL.

8. The preparation method according to claim 4, characterized in that: The pressure of the micro jet is 600-1000 Bar, and the number of times is 6-10 times.

9. The preparation method according to claim 1, characterized in that: include: At least use filter paper and suction filtration to remove the solvent.

10. The preparation method according to claim 1, characterized in that: include: The oriented carbon nanotube resin-based composite material is obtained through sequential filtering, drying and winding.

11. A carbon nanotube resin-based composite material prepared by the preparation method according to any one of claims 1 to 10.

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