CN113817222A

CN113817222A - Method for improving dispersion degree of graphene powder and preparation of modified asphalt

Info

Publication number: CN113817222A
Application number: CN202111083333.1A
Authority: CN
Inventors: 许涛; 徐子航; 王海森
Original assignee: Nanjing Forestry University
Current assignee: Nanjing Forestry University
Priority date: 2021-09-15
Filing date: 2021-09-15
Publication date: 2021-12-21

Abstract

The invention relates to a method for improving the dispersion degree of graphene powder and preparing modified asphalt thereof, belongs to the technical field of modified asphalt preparation, solves the problem of uneven dispersion of graphene powder in asphalt, such as accumulation, agglomeration and the like, and solves the problem of poor compatibility of layered graphene and asphalt. Firstly, soaking graphene powder in a dimethyl sulfoxide solvent for 2 hours, carrying out vacuum filtration on graphene in the solvent to obtain a paste body, soaking the paste body in clear water, standing, carrying out vacuum filtration again, drying the obtained graphene at 170 ℃ for 4 hours, naturally cooling to room temperature, fully grinding to obtain dispersed graphene powder, adding the dispersed graphene powder into 163 ℃ asphalt, stirring until the graphene is completely immersed by the asphalt, and preparing graphene modified asphalt by using a high-speed shearing stirrer; and finally, analyzing the dispersion degree of the graphene in the asphalt by using a scanning electron microscope, a fluorescence microscope and a tomography scanner, adjusting the optimal mixing amount of the graphene dispersed in the asphalt, and further improving the modification effect of the graphene on the asphalt.

Description

Method for improving dispersion degree of graphene powder and preparation of modified asphalt

Technical Field

The invention relates to a method for improving the dispersion degree of graphene powder and preparing modified asphalt thereof, belonging to the technical field of modified asphalt preparation.

Background

In recent years, various modification techniques have been developed to improve the pavement properties of asphalt pavements; blending techniques incorporating small amounts of styrene-butadiene-styrene copolymer (SBS) as a modifier are most commonly employed. However, the SBS polymer has poor compatibility with the matrix asphalt due to large differences of polarity, relative molecular mass and solubility, and 3-6 wt% of SBS modifier is usually used in consideration of modification effect and production cost. Meanwhile, SBS modified asphalt also has the problems of higher requirement on preparation conditions, poorer stability in the storage process and the like, so that the quality of asphalt and asphalt mixture is not easy to control, and the normal use of the asphalt pavement in the service period is influenced.

With the rise of nano-materials in this century, more and more researchers have begun to apply nano-materials to the relatively traditional traffic industry to improve the road performance of asphalt. In recent years, many studies have been made on graphene materials and graphene-modified asphalt, and certain progress has been made. The dispersibility and interface interactivity of the nano material in the asphalt complex are slow, so that irreversible aggregation and connection are generated among the nano materials, the flowing of asphalt is seriously hindered, the defect structure and suboptimal dispersion are further caused, the service performance of the modified asphalt is influenced, and the temperature is one of important factors influencing the compatibility of four components of the nano material and the asphalt.

In recent years, some scholars find that the lipophilicity of SBS modifier is increased by graphene when the graphene modified asphalt is subjected to structural characterization, so that the modifier can be more fully dispersed in the asphalt; the graphene has certain affinity to the asphalt, can be stripped or intercalated by hot asphalt, and can greatly change or even comprehensively improve various properties of the asphalt if the graphene is uniformly dispersed in the asphalt. Meanwhile, the scholars prepare the polyethylene glycol/TiO by a sol-gel method₂The graphene composite phase change material is added into asphalt as a modifier, and the composite phase change material is found to have good crystallization performance, and the effect of each component is only a physical effect and does not generate a chemical reaction; the performance of SBS modified asphalt is improved by using Carbon Nano Tubes (CNTs). The result shows that with the increase of the doping amount of the CNTs, the softening point of the modified asphalt increases with the increase of the doping amount, and the penetration degree and the ductility tend to increase first and then decrease; and compared with the improved effect of the preparation process of ultrasonic oscillation and direct stirring, the ultrasonic oscillation process is considered as the best mode.

Therefore, how to improve the dispersion degree of graphene in asphalt and make the layered graphene material better combined with the asphalt material has become one of the important research problems. Currently, two main methods for improving the dispersion degree of graphene are a physical dispersion method and a chemical modification method. The physical dispersion method specifically comprises a mechanical dispersion method, an ultrasonic dispersion method, a microwave radiation method and the like, and van der waals force between the sheet layers is broken by means of shearing, impacting, ultrasonic cavitation, microwave heating and the like, so that good dispersion is realized.

In recent years, many methods have been tried to modify a layered graphene material, and at present, non-covalent bond and covalent bond modification are the most commonly used graphene chemical modification methods, and mainly a special functional group is grafted on the surface of graphene, and graphene is generally dispersed in a water solvent or an organic solvent containing a modifier, and van der waals force between graphene sheets is overcome by electrostatic force or intermolecular force, so that the dispersion degree of graphene in asphalt is improved.

Disclosure of Invention

(1) Technical problem

The invention provides a method for improving the dispersion degree of graphene powder and preparing modified asphalt thereof, which solves the problem of uneven dispersion of graphene powder in asphalt, such as accumulation, agglomeration and the like, and solves the problem of poor compatibility of layered graphene and asphalt.

(2) Technical scheme

The method aims to solve the technical problems of poor graphene accumulation, agglomeration and asphalt compatibility in the graphene modified asphalt prepared by the conventional method. According to the preparation method, firstly, according to the characteristic of the layered structure of the graphene material, dimethyl sulfoxide (DMSO) is used as a dispersing agent for dispersing layered graphene, the soaked graphene is placed in an oven to be dried for later use, and the graphene subjected to dispersion treatment and asphalt are sheared and stirred by a high-speed shearing machine, so that the dispersion degree of graphene powder and the preparation method of the modified asphalt are improved. The technical scheme of the invention is as follows: the method comprises the steps of adopting dimethyl sulfoxide as a dispersing agent to disperse layered graphene, fully soaking and stirring, filtering to obtain treated graphene, placing the treated graphene in an oven to be fully dried, shearing and stirring the dispersed graphene and asphalt by using a high-speed shearing machine, and finally analyzing the dispersion degree of graphene powder in the asphalt by using the characterization means such as a Scanning Electron Microscope (SEM), a Fluorescence Microscope (FM) and a tomography scanner (ICT) to determine the optimal mixing amount of the graphene powder dispersed in the asphalt and further improve the modification effect of the graphene on the asphalt.

(3) Advantageous effects

In recent years, artificial intelligence and information intelligence have been introduced, and new development directions have been made in road construction. From the macroscopic mechanical angle, the addition of the graphene improves the service performance of the pavement; in the research of the micro mechanism, the graphene changes the original structure of the asphalt material and finally changes the original physical and chemical properties of the asphalt material. The compatibility of the graphene powder and the asphalt component is solved, the dispersion condition of the graphene powder in the asphalt is improved, and the key for improving the performance of the graphene modified asphalt is realized. The invention provides a method for improving the dispersion degree of graphene powder and preparing modified asphalt thereof. The invention solves the problem of uneven dispersion of graphene in asphalt, such as accumulation, agglomeration and the like, and has very important practical significance for improving the comprehensive performance of graphene modified asphalt.

Detailed Description

The invention relates to a method for improving the dispersion degree of graphene powder and preparing modified asphalt thereof, which comprises the following specific implementation steps:

(1) adding 40 ml of 99.5% dimethyl sulfoxide into a beaker, slowly adding a certain amount of graphene powder, fully and uniformly stirring by adopting a glass rod to prepare a dispersion solution of the graphene powder, and fully soaking for 2 hours at room temperature;

(2) carrying out suction filtration on the soaked graphene powder dispersion liquid by adopting a circulating water type vacuum pump, soaking and uniformly stirring the filtered paste graphene by using distilled water, standing for 1 hour, pouring out the supernatant, carrying out suction filtration on the lower graphene turbid liquid by using the vacuum pump again, drying the obtained paste graphene in an oven at 170 ℃ for 4 hours, naturally cooling to room temperature, and fully grinding the dried blocky graphene to obtain the dispersed graphene powder;

(3) putting No. 70 matrix asphalt into an oven with the temperature of 163 ℃ for heat preservation for 1 hour to enable the asphalt to be in a flowing state, and pouring 500 g of No. 70 matrix asphalt into a beaker;

(4) placing the asphalt in a flowing state on a heating furnace, keeping the temperature of the asphalt at 163 ℃, stirring for 10 minutes by using a glass rod, adding the prepared graphene powder into the asphalt, and continuing stirring by using the glass rod until the graphene powder is completely immersed in the asphalt;

(5) starting a high-speed shearing stirrer, placing a shearing head in the asphalt, adjusting the shearing and stirring speed to 5000 revolutions per minute, and keeping high-speed shearing for 40 minutes to obtain graphene modified asphalt;

(6) the dispersion degree of the graphene powder in the asphalt is analyzed by using a scanning electron microscope, a fluorescence microscope and a tomography scanner, and the doping amount of the graphene powder is adjusted to determine the doping amount of the graphene powder with the optimal dispersion in the asphalt, so that the modification effect of the graphene on the asphalt is further improved.

Claims

1. A method for improving the dispersion degree of graphene powder and preparing modified asphalt thereof is characterized by comprising the following specific steps: