阅读说明：本技术 功能化石墨烯-碳纳米管制备羧基丁腈橡胶阻尼材料的方法 (Method for preparing carboxyl nitrile rubber damping material from functionalized graphene-carbon nano tube ) 是由 朱旻昊 陈多礼 樊小强 张�林 王洵 于 2020-06-30 设计创作，主要内容包括：本申请提供了功能化石墨烯-碳纳米管制备羧基丁腈橡胶阻尼材料的方法,属于高分子材料及材料制备领域。本申请提供的功能化石墨烯-碳纳米管制备羧基丁腈橡胶阻尼材料的方法,首先通过改性碳纳米管与功能化石墨烯分别进行修饰后,通过硅烷偶联剂第二次修饰,提高3-氨基丙基三乙氧基硅烷的接枝率,通过混合改性碳纳米管与功能化石墨烯得到混合填料,然后通过混合填料与羧基丁腈橡胶胶乳混合、破乳、混炼、硫化,制备得到弹性模量在全段温域明显增加,动态力学性能得到显著增强的阻尼材料。(The application provides a method for preparing a carboxyl nitrile rubber damping material from functionalized graphene-carbon nanotubes, belonging to the field of high polymer materials and material preparation. According to the method for preparing the carboxyl nitrile rubber damping material from the functionalized graphene-carbon nano tube, firstly, after the modified carbon nano tube and the functionalized graphene are respectively modified, the grafting ratio of 3-aminopropyltriethoxysilane is improved through second modification of a silane coupling agent, a mixed filler is obtained through mixing the modified carbon nano tube and the functionalized graphene, then the mixed filler and carboxyl nitrile rubber latex are mixed, demulsified, mixed and vulcanized, and the damping material with the elastic modulus obviously increased in the whole temperature range and the dynamic mechanical property obviously enhanced is prepared.)

1. The method for preparing the carboxyl nitrile rubber damping material by the functionalized graphene-carbon nano tube is characterized by comprising the following steps of:

preparing a graphite material into a modified graphene intermediate suspension; heating, stirring and mixing the modified graphene intermediate suspension and a first silane coupling agent according to a volume ratio of 25-50:1, centrifugally cleaning and drying to obtain functionalized graphene;

dispersing carbon nanotubes in a dispersion medium through ultrasonic oscillation, adding dopamine, uniformly stirring, adding a trihydroxymethyl aminomethane buffer solution, adjusting the pH value to 8.2-8.7, and stirring and mixing to obtain a dopamine-deposited carbon nanotube mixed solution;

stirring and uniformly mixing the dopamine deposition carbon nanotube mixed solution and a second silane coupling agent at constant temperature, then centrifugally cleaning, and drying to obtain a modified carbon nanotube;

mixing the modified carbon nano tube with the functionalized graphene to prepare a mixed filler;

and mixing the mixed filler with the carboxylic nitrile rubber latex, demulsifying, mixing and vulcanizing to prepare the composite carboxylic nitrile rubber damping material.

2. The method for preparing the carboxylated nitrile rubber damping material from the functionalized graphene-carbon nanotubes according to claim 1, wherein the preparation method of the modified graphene intermediate suspension comprises the following steps: taking graphite as an electrode, and carrying out electrochemical stripping in an ionic liquid solution;

the ionic liquid solution is prepared from 1-butyl sulfonic acid-3-methylimidazole hydrogen sulfate ionic liquid and deionized water according to the volume ratio of 1: 1-1.5.

3. The method for preparing a carboxylated nitrile rubber damping material from functionalized graphene-carbon nanotubes as claimed in claim 2, wherein the voltage for electrochemical stripping is DC 5-7V, the current is 1-1.5A, and the time for electrochemical stripping is 220-.

4. The method for preparing the carboxylated nitrile rubber damping material from the functionalized graphene-carbon nanotubes according to claim 1, wherein the mass ratio of the carbon nanotubes to the dispersion medium is 1-3: mixing at a ratio of 1-4 parts by volume; the addition amount of the dopamine is 1-3 parts by mass;

preferably, the dispersion medium is water, and the carbon nanotubes are multi-walled carbon nanotubes;

the first silane coupling agent and the first silane coupling agent are both 3-aminopropyltriethoxysilane, and the amount of the 3-aminopropyltriethoxysilane is 0.02-0.03 parts by volume.

5. The method for preparing the carboxyl nitrile rubber damping material from the functionalized graphene-carbon nanotubes according to claim 3, wherein the heating, stirring and mixing temperature is 55-63 ℃ and the time is 5-8 h;

the ultrasonic oscillation time is 8-15min, and the stirring and mixing time is 200-300 min.

6. The method for preparing the carboxylated nitrile rubber damping material from the functionalized graphene-carbon nanotubes as claimed in claim 1, wherein the temperature of the constant-temperature stirring is 57.5-65.3 ℃ and the time is 270-340 min; the rotation speed of the centrifugal cleaning is 3750-4400 rpm; the drying is vacuum drying, and the temperature of the vacuum drying is 56.8-66.4 ℃.

7. The method for preparing the carboxylated nitrile rubber damping material from the functionalized graphene-carbon nanotubes according to claim 1, wherein the mixed filler is prepared by mixing the modified carbon nanotubes and the functionalized graphene according to a ratio of 1: 1-2.

8. The method for preparing the carboxylated nitrile rubber damping material from the functionalized graphene-carbon nanotubes according to claim 7, wherein the mass ratio of the mixed filler to the carboxylated nitrile rubber is 1-1.5:100, and the mixing times are 8-13.

9. The method for preparing the carboxylated nitrile rubber damping material from the functionalized graphene-carbon nanotubes as claimed in claim 1, wherein the temperature for the vulcanization is 140-155 ℃, and the pressure is 9-12 MPa.

10. The method for preparing the carboxylated nitrile rubber damping material from the functionalized graphene-carbon nanotubes according to claim 9, wherein the vulcanization time is 8-13 min.

Technical Field

The application relates to the field of high polymer materials and material preparation, in particular to a method for preparing a carboxyl nitrile rubber damping material from functionalized graphene-carbon nanotubes.

Background

The strong vibration generated by the high-speed train in full-speed operation can reduce the service life of parts of the high-speed train, thereby causing economic waste. Adding rubber damping materials at key parts is a very effective means at present. In order to improve the comprehensive performance of the damping rubber and reduce the cost, the adjustment of the dynamic mechanical properties of the rubber by adding the filler is the key point of the current research. When the carbon nano-filler is added into the rubber matrix, the carbon nano-filler can increase the interaction interface with the rubber matrix, and in the vibration process, more interaction interfaces can increase the friction of the interface, so that the dynamic mechanical property of the composite material is increased. In the existing technology for preparing the polymer damping material by using the carbon nano filler, the interaction between the carbon nano filler and a polymer matrix is weak, and the carbon nano filler is easy to agglomerate in the matrix, so that the composite material prepared by using the carbon nano filler has unstable phenomena of elastic modulus reduction and damping value reduction in a dynamic mechanical property test.

Content of application

The application discloses a method for preparing a carboxyl nitrile rubber damping material by using functionalized graphene-carbon nanotubes, which comprises the following steps:

carrying out electrochemical stripping on the graphite material to prepare a modified graphene intermediate suspension; stirring and mixing the modified graphene intermediate suspension and a first silane coupling agent according to the volume ratio of 25-50:1, centrifugally cleaning, and drying to obtain functionalized graphene;

dispersing carbon nanotubes in a dispersion medium through ultrasonic oscillation, adding dopamine, uniformly stirring, adding a trihydroxymethyl aminomethane buffer solution, adjusting the pH value to 8.2-8.7, and stirring and mixing to obtain a dopamine-deposited carbon nanotube mixed solution;

stirring and uniformly mixing the dopamine deposition carbon nanotube mixed solution and a second silane coupling agent at constant temperature, then centrifugally cleaning, and drying to obtain a modified carbon nanotube;

mixing the modified carbon nano tube with the functionalized graphene to prepare a mixed filler;

and mixing the mixed filler with the carboxylic nitrile rubber latex, demulsifying, mixing and vulcanizing to prepare the composite carboxylic nitrile rubber damping material.

The carboxyl nitrile rubber damping material prepared by the method can obtain excellent performance of increasing both the elastic modulus and the damping value, and simultaneously, the use of highly toxic substances is reduced by selecting and using an intermediate modification reagent polydopamine, so that the carboxyl nitrile rubber damping material is environment-friendly and green and is beneficial to industrial production.

Mixing the two functional nano fillers according to a ratio, then mixing the two functional nano fillers with the carboxylic nitrile rubber latex, and performing demulsification, double-roller open mixing and hot-pressing vulcanization processes to obtain the functional graphene and functional carbon nanotube mixed filler for preparing the carboxylic nitrile rubber damping material. Especially, the aqueous solution of the mixed filler and the carboxylic nitrile rubber latex are demulsified and mixed after being mixed, which is beneficial to improving the performance of the material.

In some embodiments of the foregoing, the method of preparing the modified graphene intermediate suspension comprises: taking graphite as an electrode, and carrying out electrochemical stripping in an ionic liquid solution;

the ionic liquid solution is prepared from 1-butyl sulfonic acid-3-methylimidazole bisulfate ionic liquid and deionized water according to the volume ratio of 1: 1-1.5.

In the embodiment, a graphene intermediate suspension is prepared by taking a graphite rod as an electrode and performing electrochemical stripping in a 1-butylsulfonic acid-3-methylimidazole hydrogen sulfate ionic liquid solution by using an electrochemical stripping method. The ionic liquid is prepared from the 1-butyl sulfonic acid-3-methylimidazole hydrogen sulfate ionic liquid and deionized water according to the proportion of 1:1-1.5, so that the electrochemical stripping efficiency is improved, and the quality of the prepared graphene intermediate suspension is improved.

In some embodiments, the voltage of the electrochemical stripping is DC 5-7V, the current is 1-1.5A, and the time of the electrochemical stripping is 220-300 min.

In some of the foregoing embodiments, the carbon nanotubes are mixed with the dispersion medium in an amount of 1 to 3 parts by mass: mixing at a ratio of 1-4 parts by volume; the adding amount of the dopamine is 1 to 3 parts by mass;

preferably, the dispersion medium is water, and the carbon nanotubes are multi-walled carbon nanotubes;

the first silane coupling agent and the first silane coupling agent are both 3-aminopropyltriethoxysilane, and the amount of the 3-aminopropyltriethoxysilane is 0.02-0.03 volume parts;

there are many kinds of silane coupling agents, and 3-aminopropyltriethoxysilane is a preferred silane coupling agent in the present application.

The carbon nanotube is another allotrope of carbon found after C60, and has a small radial dimension, the outer diameter of the tube is generally from several nanometers to tens of nanometers, and the inner diameter of the tube is smaller, and some of the tubes are only about 1 nm; the length of the fiber is generally in micron order, and the length-diameter ratio is very large and can reach 10³～10⁶。

The unique structure of carbon nanotubes dictates that it possess many specific physical and chemical properties. The covalent bond of C ═ C constituting the carbon nanotube is the most stable chemical bond in nature, so that the carbon nanotube has very excellent mechanical properties. Theoretical calculation shows that the carbon nanotube has extremely high strength and extremely high toughness. The theoretical value estimates that young's modulus can reach 5TPa, strength is about 100 times that of steel, and weight density is only 1/6 of steel. Treacy et al first used TEM to measure the mean square amplitude of multi-walled carbon nanotubes at temperatures ranging from room temperature to 800 degrees, and thereby derived that the mean Young's modulus of multi-walled carbon nanotubes was about 1.8 Tpa. While Salvetat et al measured the Young's modulus of a small diameter single-walled carbon nanotube and derived that its shear modulus was 1 Tpa. Wong et al measured the average flexural strength of multi-walled carbon nanotubes by atomic force microscopy to be 14.2 + -10.8 GPa, while the flexural strength of carbon fibers was only 1 GPa. Carbon nanotubes, whether they are strength or toughness, are far superior to any fiber and are considered future "super fibers".

The carbon nano tube is coated with the dopamine with the maximum utilization rate by mixing the carbon nano tube and the dispersion medium water in a proper proportion and adding the appropriate dopamine.

Mixing 0.02-0.03 volume part of 3-aminopropyltriethoxysilane with the modified polydopamine-coated carbon nanotube solution, and continuing to perform second modification to improve the dispersibility of the carbon nanotubes.

By using the carbon nano tube and the graphene at the same time, the functions of the material can be mutually promoted and improved.

In some of the foregoing embodiments, the temperature of the thermal agitation mixing is 55-63 ℃ for 5-8 hours;

the time of ultrasonic oscillation is 8-15min, and the time of stirring and mixing is 200-300 min.

In the embodiment, the rapid and uniform dispersion of the carbon nanotubes or graphene is accelerated by heating and stirring or ultrasonic vibration.

In some embodiments, the temperature of the constant-temperature stirring is 57.5-65.3 ℃, and the time is 270-340 min; the rotation speed of centrifugal cleaning is 3750-4400 rpm; the drying is vacuum drying, and the temperature of the vacuum drying is 56.8-66.4 ℃.

In the embodiment, the coupling of dopamine and a coupling agent is accelerated by stirring at constant temperature, so that the grafting rate is improved; the water is removed by centrifugation and drying, which is more beneficial to the subsequent mixing.

In some embodiments, the mixed filler is prepared by mixing the modified carbon nanotubes and the functionalized graphene according to a ratio of 1: 1-2.

The mixed filler is prepared by mixing the modified carbon nano tube and the functionalized graphene, and can better improve the elastic modulus of the material. The surfaces of the two modified nano materials are distributed with a large amount of Si elements, O elements and N elements, wherein the increase of the Si elements shows that the high-density modification of KH500 is realized, and the hydroxyl groups on KH550 easily form hydrogen bonds, which is beneficial to the attachment of modified graphene sheets on the modified carbon nanotubes.

In some embodiments of the present application, the mass ratio of the mixed filler to the carboxylated nitrile rubber is 1-1.5:100, and the number of mixing times is 8-13.

In the examples, the mass ratio of the mixed filler to the carboxylated nitrile rubber is 1-1.5:100, enabling better information to be prepared by better ratios.

And through multiple times of mixing, the dispersion of the mixed filler in the carboxyl nitrile rubber is facilitated, and the material with more consistent performance is prepared.

In some of the foregoing embodiments, the temperature of the sulfidation is 140 ℃ and 155 ℃ and the pressure is 9-12 MPa.

In the embodiment, the compounding and reaction of the modified carbon nano tube and the carboxyl nitrile butadiene rubber are facilitated through the reaction at high temperature and high pressure.

In some of the foregoing embodiments, the time for vulcanization is 8-13 min.

Compared with the prior art, the beneficial effect of this application includes: according to the method for preparing the carboxyl nitrile rubber damping material from the functionalized graphene-carbon nano tube, firstly, after the modified carbon nano tube and the functionalized graphene are respectively modified, the grafting ratio of 3-aminopropyltriethoxysilane is improved through second modification of a silane coupling agent, a mixed filler is obtained through mixing the modified carbon nano tube and the functionalized graphene, then the mixed filler and carboxyl nitrile rubber latex are mixed, demulsified, mixed and vulcanized, and the damping material with the elastic modulus obviously increased in the whole temperature range and the dynamic mechanical property obviously enhanced is prepared.

Drawings

FIG. 1 is a transmission electron microscope image of an equivalent amount of mixed filler of functionalized graphene and functionalized carbon nanotubes in an aqueous solution in an experimental example;

FIG. 2 is an element distribution diagram of an equivalent mixed filler of functionalized graphene and functionalized carbon nanotubes in an aqueous solution in an experimental example;

FIG. 3 is a curve of the variation of the elastic modulus with temperature of damping materials prepared by using proportional fillers for different functionalized graphene and functionalized carbon nanotubes in an experimental example;

FIG. 4 is a graph of the change of the elastic modulus with temperature after high-temperature aging of different materials in the experimental examples;

FIG. 5 is an electron microscope image of the carboxylated nitrile rubber damping material prepared in the experimental example.

Description of terms: R-XNBR is a carboxylated nitrile rubber latex; MWCNTS are carbon nanotubes;

MWCNTS-P-KH550 is a polydopamine-silane coupling agent modified carbon nanotube; MLG3-KH550 represents functionalized graphene.

Detailed Description

Embodiments of the present application will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present application and should not be construed as limiting the scope of the present application. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The features and properties of the present application are described in further detail below with reference to examples.