CN108641779B

CN108641779B - TiO 22Preparation method of nano-particle coated carbon layer electrorheological composite material

Info

Publication number: CN108641779B
Application number: CN201810378649.5A
Authority: CN
Inventors: 张文玲; 邓丽
Original assignee: Qingdao University
Current assignee: Qingdao University
Priority date: 2018-04-25
Filing date: 2018-04-25
Publication date: 2020-12-15
Anticipated expiration: 2038-04-25
Also published as: CN108641779A

Abstract

The invention belongs to the field of electrorheological intelligent materials, relates to a technology for preparing MXene composite material rheological fluid by an oxidation method, and particularly relates to a technology for obtaining Ti by etching hydrofluoric acid₃C₂T_xFurther adopts hydrogen peroxide water to prepare TiO by thermal oxidation₂A method of @ C composite; mainly comprises the steps of etching and hydrothermal oxidation to prepare a composite material; the preparation raw materials are easy to obtain, the preparation cost is low, and the prepared rheological composite material has a lamellar structure with a higher dielectric constant, low conductivity, high stability and environment-friendly application.

Description

TiO 22Preparation method of nano-particle coated carbon layer electrorheological composite material

The technical field is as follows:

the invention belongs to the field of electrorheological intelligent materials, and relates to a method for preparing MXene (TiO) by an oxidation method₂@ C) composite material rheological fluid technology, in particular to technology for obtaining Ti by etching hydrofluoric acid₃C₂T_xFurther adopts hydrogen peroxide water to prepare TiO by thermal oxidation₂@ C (@ symbol denotes cladding) composite material.

Background art:

the electrorheological fluid is an intelligent dispersion system composed of polarizable particles and an insulating medium, and has quick response and reversible phase change in rheological properties such as shear yield stress, viscosity, modulus and the like under the action of an electric field, so that the electrorheological fluid has important application value and prospect in various fields such as aerospace, robot engineering, ship engineering, automobile engineering, hydraulic engineering, biomedical equipment and the like.

Two-dimensional transition metal carbides, nitrides and carbonitrides (MXenes) have unique two-dimensional layered structures, large specific surface areas, good electrical conductivity, magnetic properties and mechanical properties, and have great potential in the fields of energy storage, photoelectricity, medicine and the like. Due to the unique two-dimensional structure and high dielectric property of MXenes, the graphene-like two-dimensional material is expected to have high electrorheological property. However, the material has good conductivity, and is very easy to break down and unstable at a lower voltage, and cannot meet the requirement of a high-stability electrorheological material. Due to the fact thatThis sought for a TiO₂The preparation method of the nano-particle coated carbon layer electrorheological composite material can prepare the high-stability electrorheological material which simultaneously meets the requirements of a lamellar structure with higher dielectric constant and low conductivity, and has good economic benefit and social benefit.

The invention content is as follows:

the invention aims to overcome the defects in the prior art and seeks to design a TiO₂A method for preparing a nano-particle coated carbon layer electrorheological composite material.

In order to achieve the purpose, the invention relates to TiO₂The preparation process of the current-variable composite material of the nano-particle coated carbon layer comprises the following steps:

(1) etching: dissolving titanium-aluminum carbide powder in 49 wt% hydrofluoric acid according to a molar ratio of 1: 10-1: 25, continuously stirring for about 60-100 hours at room temperature to fully etch an Al layer, then placing the Al layer into a centrifuge tube, performing three times of centrifugal washing by using ultrapure water at a rotating speed of 2000-6000 r/min for 3-10 minutes each time, performing centrifugal washing to neutrality, and drying to obtain powder for later use;

(2) hydrothermal oxidation: adding a certain amount of the powder obtained in the step (1) into ultrapure water, performing ultrasonic treatment until the powder is uniformly dispersed, adding 30 wt% of hydrogen peroxide according to a weight ratio of 4:9, and fully and uniformly stirring; then putting the solution into a polytetrafluoroethylene inner container, reacting at 160-240 ℃ for 16-24h, and cooling to room temperature; then centrifuging, washing and freeze-drying the solution obtained by the reaction to obtain a finished product, namely TiO₂The nano-particles coat the carbon layer electrorheological composite material.

Further, the washing process in the step (2) is as follows: the solution was transferred to a centrifuge tube and centrifuged three times with ultrapure water at 5000 rpm for 3 minutes each time.

Further, the drying process in steps (1) and (2) is as follows: sealing the centrifugal tube, pricking the hole, freezing with liquid nitrogen, and drying in a freeze drier for 1-2 days.

Compared with the prior art, the preparation method has the advantages of easily obtained raw materials, low preparation cost, high dielectric constant lamellar structure and low conductivity of the prepared rheological composite material, high stability and environment-friendly application.

Description of the drawings:

FIG. 1 shows TiO prepared in example₂Scanning electron microscope picture of the nano-particle coated carbon layer electrorheological composite material.

FIG. 2 shows TiO prepared according to the present invention₂The relation graph of the shear stress and the shear rate of the current-variable composite material of the nano-particle coated carbon layer.

FIG. 3 is TiO from Mxene hydrogen peroxide prepared in example₂Viscosity vs shear rate plots for the @ C composite.

The specific implementation mode is as follows:

the following is a further description by way of example and with reference to the accompanying drawings.

Example 1:

TiO obtained by oxidizing Mxene hydroxide according to the present example₂The @ C composite material comprises the following raw materials in parts by mole: 1 part of titanium aluminum carbide, 150 parts of hydrofluoric acid, 100 parts of ultrapure water and 2 parts of hydrogen peroxide.

TiO obtained by oxidizing Mxene with hydrogen peroxide according to the example₂The preparation process of the @ C composite material specifically comprises the following steps:

(1) placing HF in a wide-mouth plastic bottle, fully dissolving titanium aluminum carbide powder in hydrofluoric acid according to the proportion of 1:15 under stirring, washing with water to be neutral after stirring for 70 hours, and freeze-drying;

(2) adding the dried Mxene into ultrapure water according to the proportion of 1:100, carrying out ultrasonic dispersion uniformly, adding 30 wt% of hydrogen peroxide according to the proportion of 1:2, and mixing uniformly;

(3) and (3) transferring the uniform solution obtained in the step (2) into a polytetrafluoroethylene inner container, reacting at 200 ℃ for 20h, and cooling to room temperature. Washing the offwhite product obtained by the reaction with ultrapure water, and freeze-drying to obtain the finished product, namely TiO₂The current-variable composite material of the carbon layer coated by the nano-particles;

(4) further, the washing process in the step (3) is as follows: transferring the solution into a centrifuge tube, and carrying out three times of centrifugal washing by using ultrapure water, wherein the rotating speed of each washing is 5000 r/min, and the time is 3 min;

(5) further, the drying process in the step (3) is as follows: sealing the centrifugal tube, pricking the hole, freezing with liquid nitrogen, and drying in a freeze drier for 1-2 days.

The TiO thus prepared is shown in FIG. 1₂Coated with a carbon layer, TiO₂The particle size is about 200 nm and the layered structure size is about 4-5 microns.

TiO prepared in example₂The carbon layer-coated micro-nano material is fully ground in an agate mortar and then dispersed into 100cS silicone oil (the density is 0.965 g/cubic centimeter) according to the proportion of 12 vol% (namely 33.6 wt%), the obtained suspension is fully oscillated by a vortex oscillation mixer to form uniform electrorheological fluid, and then dynamic characteristic tests of oscillatory shear (comprising strain amplitude scanning test and angular frequency scanning test) and rotational shear (relation between viscosity, shear stress and shear rate) are carried out under the action of an external electric field at room temperature. As shown in fig. 2, in the absence of an electric field, the shear stress increases in proportion to the shear rate, which represents typical newtonian viscous fluid behavior. Under the action of an electric field, the shear stress is obviously increased, the yield stress appears, and in a low shear rate region, a platform region appears. The yield stress can be up to-10³Pa, which meets the pursuit of high stress in the actual industry. As shown in FIG. 3, under the action of an electric field, MXene (TiO) is based on a layered oxide, as compared with the case without the action of an electric field₂@ C) exhibit significant shear-thinning behavior.

Claims

1. TiO 2₂The preparation process of the current-variable composite material of the nano-particle coated carbon layer comprises the following steps:

(1) etching: dissolving titanium aluminum carbide powder in 49 wt% hydrofluoric acid according to a molar ratio of 1: 10-1: 25, continuously stirring for 60-100 hours at room temperature to fully etch an Al layer, then placing the Al layer into a centrifuge tube, performing three times of centrifugal washing by using ultrapure water at a rotating speed of 2000-6000 r/min for 3-10 minutes each time, performing centrifugal washing to neutrality, and drying to obtain powder for later use;

(2) hydrothermal oxidation: adding a certain amount of the powder obtained in the step (1) into ultrapure water, performing ultrasonic treatment until the powder is uniformly dispersed, adding 30 wt% of hydrogen peroxide according to a weight ratio of 4:9, and fully and uniformly stirring; then putting the solution into a polytetrafluoroethylene inner container, reacting at 160-240 ℃ for 16-24h, and cooling to room temperature; then centrifugally washing the solution obtained by the reaction, and freeze-drying to obtain the finished product TiO₂The current-variable composite material of the carbon layer coated by the nano-particles; the centrifugal water washing process comprises the following steps: transferring the solution into a centrifuge tube, and carrying out three times of centrifugal water washing by using ultrapure water, wherein the rotating speed of each time of centrifugal water washing is 5000 r/min, and the time is 3 min; the drying process in the steps (1) and (2) is as follows: sealing the centrifugal tube, pricking the hole, freezing with liquid nitrogen, and drying in a freeze drier for 1-2 days.