Preparation And Polymeric Modificaion Of Graphene

Graphene as a two-dimensional carbon crystal discovered in recent years, has outstanding performance and excellent thermal, mechanical and electrical properties, and its nano-structure is very unique. Since been found, grapheme has been fully demonstrated the infinite charm in the theoretical study and practical application, and has attracted many scholars to study it.Graphene has large surface area theorectically. With the addition of a small amount of polymer, the composite matrix can have a significant performance improvement. However, with inert state of the interface, graphene compatibility with other media is poor. And between graphene layers there is a strong Van der Waals force, which is leading single layer to aggregate with each other. So graphene is difficult to disperse in water and common organic media. This requires it's hydrophilic or hydrophobic improvement, in terms of reducing restrictions on their application. Then on this basis, characteristics of gaphene/polymer composite could be studied further.This article applied the modified Hummers method and ultrasonic exfoliation to prepare graphene oxide, and then prepared grapheme by chemical reduction method. During the process, polyacrylamide (PAM) was used on grafting of graphene oxide (GO), and then GO grafted by PAM was reduced to PAM/graphene to get the modified graphene. Gernerally, graphene dispersion in water took a certain improvement. By TEM, IR and Raman spectroscopy, the product structure and the dispersity in water had been made a more systematic characterization. Raman test showed the number of layers is less than 8 layers, and also It's proved that such a common graphene and hydrophilic graphene was successfully prepared.Meanwhile, during the chemical oxidation and reduction process of graphene preparation, the study had been done on the hydrophobic modification effect. A coupling agent, y-ether oxygen trimethoxysilane (KH-560) was applied on dealing graphene surface.Then modified graphene/epoxy resin composite was tested on the improvement of electrical performance. An appropriate matching between graphene and KH-560 was chosen accoding to sedimentation test result. TEM images showed the modified graphene in ethanol media obtained a better dispersion. So the compatibility between ethanol and modified graphene had been improved. Then IR spectra demonstrated that the KH-560 was successfully grafted to the graphene surface. All test results proved a stable modified graphene was achieved; In addition, modified graphene/epoxy composite was taken to test its electrical properties. As modified graphene increasing, the conductivity of the composite increased. And dielectric constant had also significantly increased. And the dielectric loss of the composite also increased with the addition of modified graphene.