阅读说明：本技术 一种具有反应活性的可修饰碳纳米管及其制备方法 (Modifiable carbon nanotube with reactivity and preparation method thereof ) 是由 袁立焕 魏珍 沈小宁 王永利 刘家园 于 2019-11-15 设计创作，主要内容包括：本发明提供了一种具有反应活性的可修饰碳纳米管及其制备方法,本发明以原始碳纳米管为原料,通过强酸纯化、羧基化形成羧基反应点,在相转移剂作用下,将含双键的卤代烃修饰体成功接入到碳纳米管表面,最终制备含有一定量反应活性点具有反应活性的可修饰碳纳米管；本发明制备方法简单,过程容易控制,重复性强；避免了溶剂的使用；所制备的具有反应活性的可修饰碳纳米管表面含有大量的反应活性基团；碳纳米管结构保护完整,不影响碳纳米管原用功能特性；所制备的具有反应活性的可修饰碳纳米管可通过进一步设计修饰,实现碳纳米管的功能化,也可通过接枝聚合反应制备复合材料。(The invention has provided a modifiable carbon nanotube with reaction activity and its preparation method, the invention regards original carbon nanotube as raw materials, through the strong acid purification, carboxyl reaction point of formation, under the influence of phase transfer agent, insert the halohydrocarbon modifier containing double bond to the surface of carbon nanotube successfully, prepare and contain certain amount of reactive site and modifiable carbon nanotube with reaction activity finally; the preparation method is simple, the process is easy to control, and the repeatability is strong; the use of solvents is avoided; the surface of the prepared carbon nano tube which has reactivity and can be modified contains a large number of reactive groups; the carbon nano tube has complete protection, and the original functional characteristics of the carbon nano tube are not influenced; the prepared carbon nano tube with reactivity and capable of being modified can be further modified by design to realize the functionalization of the carbon nano tube, and can also be used for preparing a composite material by graft polymerization.)

1. A modifiable carbon nanotube with reactivity is characterized by being prepared by the following method:

(1) mixing the carbon nano tube, the acid agent and the oxidant, performing ultrasonic treatment, centrifuging, and washing to obtain a mixture with a pH value: 6.5-7.0, and obtaining a carboxylated carbon nanotube; mixing the obtained carboxylated carbon nanotube with sodium hydroxide and deionized water, ultrasonically dispersing, centrifuging, and washing until the pH value is: 7.0-7.5, drying and grinding to obtain a sodium carboxylated carbon nanotube;

the mass ratio of the carbon nano tube, the acid agent, the oxidant, the sodium hydroxide and the deionized water is 0.1-10: 100: 20-100: 0.1-10: 0.1 to 10;

(2) mixing the sodium-modified carboxylated carbon nano tube obtained in the step (1) with deionized water, a phase transfer agent and a double-bond-containing halohydrocarbon modifier, heating to boil, carrying out reflux reaction for 8-24 hours under a stirring condition, after the reaction is finished, centrifuging, washing, drying and grinding a product, extracting with tetrahydrofuran for 2-24 hours at 80-85 ℃, finally drying and grinding to obtain the modified carbon nano tube with reaction activity;

the mass ratio of the sodium carboxylated carbon nanotube to deionized water, the phase transfer agent and the double-bond-containing halogenated hydrocarbon modifier is 0.01-10: 100: 0.005-1: 0.01 to 10.

2. The reactive modifiable carbon nanotube according to claim 1, wherein in the step (1), the carbon nanotube is a multi-walled carbon nanotube or a single-walled carbon nanotube having an inner diameter of 5 to 10nm, an outer diameter of 10 to 50nm, and a length of 10 to 30 μm.

3. The reactive modifiable carbon nanotube according to claim 1, wherein in the step (1), the acid agent is one or more selected from concentrated sulfuric acid, concentrated nitric acid, concentrated hydrochloric acid, and permanganic acid.

4. The reactive modifiable carbon nanotube according to claim 1, wherein in the step (1), said oxidant is one or more selected from concentrated sulfuric acid, concentrated nitric acid, potassium permanganate, aqueous hydrogen peroxide, and ammonium peroxodisulfate.

5. The reactive modifiable carbon nanotube according to claim 1, wherein in the step (2), the phase transfer agent is one or more selected from the group consisting of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetra-n-octylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, and tetradecyltrimethylammonium chloride.

6. The reactive modifiable carbon nanotube according to claim 1, wherein in the step (2), said double bond-containing halocarbon modifier is one or more selected from the group consisting of allyl bromide, 4-chloromethylstyrene, allyl chloride, 6-chloro-1-hexene, 6-bromo-1-hexene, 10-bromo-1-decene, and 11-chloro-1-undecene.

Technical Field

The invention relates to the technical field of carbon nanotube modification, in particular to a modifiable carbon nanotube with reactivity and a preparation method thereof.

Background

The carbon nano tube has unique surface effect, small size effect and quantum size effect, and the unique hollow tubular structure endows the carbon nano tube with excellent mechanical, magnetic, thermal and other properties, so that the carbon nano tube is widely applied to the advanced fields of aerospace materials, medical treatment, electronics and the like. With the continuous perfection of the preparation technology of the carbon nano tube, people can produce a large amount of carbon nano tubes with low cost, but have some problems, such as chemical inertness on the surface of the carbon nano tube, lack of active groups, and easy mutual winding, which causes the low solubility of the carbon nano tube in various solvents and uneven dispersion in a polymer matrix; in addition, van der waals forces, large aspect ratios, and high specific surface areas make carbon nanotubes highly susceptible to agglomeration and entanglement. These severely restrict the application of carbon nanotubes in many fields, and it is necessary to improve the surface properties of carbon nanotubes by surface functionalization modification, and solve the problems of compatibility and dispersibility.

The surface functionalization modification of carbon nanotubes is generally classified into covalent functionalization and non-covalent functionalization. The covalent functionalization method achieves the purpose of improving the dispersibility of the carbon nano tube by forming functional groups on the surface of the carbon nano tube, but the process has certain damage to the structure of the carbon nano tube, thereby influencing the electrical property and the mechanical property of the carbon nano tube. The non-covalent functionalization method is mainly to modify the carbon nano-tube by using a surfactant, a macromolecule or a biological macromolecule, the treated carbon nano-tube can keep the structural integrity of the carbon nano-tube to the maximum extent, but the amount of the modifier on the treated carbon nano-tube needs to be controlled, and the modification extent is limited. The use amount of the modifier is too large, which not only increases the cost, but also influences the interface combination of the carbon nano tube and the matrix material. The physical method is simple and easy to operate, and mainly adopts an adsorption or loading mode to carry out functional modification on the surface of the single-walled carbon nanotube or the multi-walled carbon nanotube; the chemical method is to introduce some chemical reagents capable of performing functional modification on the surface of the carbon nanotube and react with the carbon nanotube to achieve the purpose of the functional modification on the surface of the carbon nanotube. The general chemical modification method only introduces some functional segments for increasing compatibility on the surface of the carbon nano tube.

Disclosure of Invention

The invention aims to provide a modifiable carbon nano tube with a large number of reactive sites on the surface and reactivity and a preparation method thereof, wherein the method can effectively keep the original structure and performance of the carbon nano tube. The method takes an original carbon nano tube as a raw material, forms a carboxyl reaction point through strong acid purification and carboxylation, successfully accesses a double-bond-containing halohydrocarbon modifier to the surface of the carbon nano tube under the action of a phase transfer agent, and finally prepares the modifiable carbon nano tube containing a certain amount of reaction active points and having reaction activity.

The technical scheme of the invention is as follows:

a modifiable carbon nanotube with reactivity is prepared by the following method:

(1) mixing the carbon nano tube, an acid agent and an oxidant, performing ultrasonic treatment (0.5-15 h), centrifuging, and washing to a pH value: 6.5-7.0, and obtaining a carboxylated carbon nanotube; mixing the obtained carboxylated carbon nanotube with sodium hydroxide and deionized water, ultrasonically dispersing (1-30 min), centrifuging, and washing to obtain a mixture with a pH value: 7.0-7.5, drying (110 ℃) and grinding to obtain a sodium carboxylated carbon nanotube (the carboxyl content is not lower than 3.0 wt%);

the mass ratio of the carbon nano tube, the acid agent, the oxidant, the sodium hydroxide and the deionized water is 0.1-10: 100: 20-100: 0.1-10: 0.1 to 10;

the carbon nano tube is a multi-wall carbon nano tube or a single-wall carbon nano tube, the inner diameter of the carbon nano tube is 5-10 nm, the outer diameter of the carbon nano tube is 10-50 nm, and the length of the carbon nano tube is 10-30 mu m;

the acid agent is one or more of concentrated sulfuric acid (98 wt%), concentrated nitric acid (65 wt%), concentrated hydrochloric acid (37 wt%) and permanganic acid (98 wt%);

the oxidant is one or more of concentrated sulfuric acid (98 wt%), concentrated nitric acid (65 wt%), potassium permanganate, aqueous hydrogen peroxide (30 wt%) and ammonium peroxydisulfate;

(2) mixing the sodium-modified carboxylated carbon nanotube obtained in the step (1) with deionized water, a phase transfer agent and a double-bond-containing halohydrocarbon modifier, heating to boil, carrying out reflux reaction for 8-24 h under the condition of stirring (100-200 rpm), after the reaction is finished, centrifuging and washing a product, drying (80-110 ℃) and grinding, extracting with Tetrahydrofuran (THF) for 2-24 h at 80-85 ℃, finally drying (50-70 ℃, 1-15 h), and grinding to obtain the reactive-modified carbon nanotube;

the mass ratio of the sodium carboxylated carbon nanotube to deionized water, the phase transfer agent and the double-bond-containing halogenated hydrocarbon modifier is 0.01-10: 100: 0.005-1: 0.01 to 10;

the phase transfer agent is one or more of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetra-n-octylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride and tetradecyltrimethylammonium chloride;

the double-bond-containing halohydrocarbon modifier is one or more of allyl bromide, 4-chloromethyl styrene, allyl chloride, 6-chloro-1-hexene, 6-bromo-1-hexene, 10-bromo-1-decene and 11-chloro-1-undecene.

In the invention, the conductivity of the deionized water is less than 0.055 mu S/cm (25 ℃);

the power of the ultrasonic is 500-2000 w, and the temperature is 30-40 ℃;

the washing was performed using 95% aqueous ethanol.

The invention adopts carbon nano-tubes as main raw materials, and the carbon nano-tubes are subjected to mixed acid purification, carboxylation and sodium treatment, and then are subjected to esterification reaction with double-bond halohydrocarbon in deionized water under the action of a phase transfer catalyst and the stirring action of strong mechanical force external force, so that the modification of the double-bond halohydrocarbon on the carbon nano-tubes is realized, and finally the modifiable carbon nano-tubes with reaction activity are obtained.

The invention utilizes the principle of phase transfer esterification reaction, carboxylate of the carbon nano tube and alkyl halide carry out esterification reaction under the action of a phase transfer catalyst, and the modified group enables the carbon nano tube to have certain characteristics, thereby finally obtaining the modifiable carbon nano tube with the surface containing a large amount of reactive groups and having the reactivity.

The formula and the method provided by the invention have the advantages that the modified carbon nano tube with the reaction activity overcomes the defects of chemical inertness and lack of active groups on the surface of the carbon nano tube, avoids the use of a solvent, overcomes the defects of complex reaction and poor repeatability, can realize large-scale preparation, expands the application range of the carbon nano tube, and can be used for preparing composite materials, nano electronic devices, batteries, super capacitors, field emission displays, sensor medicine, optics, catalyst carriers and the like.

The invention has the following advantages:

1. the preparation method is simple, the process is easy to control, and the repeatability is strong;

2. the use of solvents is avoided;

3. the surface of the prepared carbon nano tube which has reactivity and can be modified contains a large number of reactive groups;

4. the carbon nano tube has complete protection, and the original functional characteristics of the carbon nano tube are not influenced;

5. the prepared carbon nano tube with reactivity and capable of being modified can be further modified by design to realize the functionalization of the carbon nano tube, and can also be used for preparing a composite material by graft polymerization.

The modified carbon nano tube with the reactivity, which is prepared by the invention, has high production efficiency and low cost, and can be used in the fields of biotechnology, medicine, aerospace materials, chemical catalysis, electronic products and the like.

Detailed Description

The present invention is further illustrated by the following specific examples, but the scope of the invention is not limited thereto.