Preparation and Application of Graphene/Polymer Nanocomposites

Polymer materials are the most widely used materials on the market. They have the characteristics of low density and good processability. The use of such materials can be seen everywhere in industry or in people's lives. Since the clay/polymer nanocomposites have been reported, nanocomposites have become the subject of research in the scientific and industrial fields due to their excellent mechanical properties. With the continuous research on nanocomposites, graphene has been successfully introduced into polymer matrix, such as epoxy resin, phenolic resin, polyurethane (PU), polymethyl methacrylate (PMMA), polyolefin, polystyrene (PS), nylon (PA), etc., to prepare a large number of high performance graphene/polymer nanocomposites. At present, there are mainly three methods for preparing graphene/polymer nanocomposites.

Preparation of graphene/polymer nanocomposites

1. in situ polymerization

In the in-situ polymerization method, graphene or modified graphene is first blended with a monomer or a prepolymer, a suitable initiator is dispersed, and then parameters such as temperature and time are adjusted, and polymerization is initiated by heat or radiation. A graphene/polymer nanocomposite is obtained.

In-situ polymerization has two advantages: (1) ensuring uniform dispersion of filler particles in the polymer matrix; (2) large interaction between filler particles and polymer in the prepared nanocomposite, which is beneficial to stress transfer. The researchers successfully prepared a variety of graphene/polymer nanocomposites using this method, such as: graphene/polyimide (PI), graphene/polyurethane (PU), graphene/polypyrrole, graphene/poly aniline, graphene/polymethyl methacrylate (PMMA), and so on. However, this method has a drawback in that the viscosity of the polymerization system after the introduction of graphene is increased, making the polymerization reaction complicated and the operation becomes difficult.

2. solution blending

The solution blending method requires first obtaining a graphene dispersion which can be stably dispersed in an organic solvent, and then dispersing the polymer in a solution to remove the solvent, thereby preparing a graphene/polymer nanocomposite.

Polymer nanocomposites such as graphene/PS, graphene/PU, graphene/polycarbonate (PC), graphene/PMMA, graphene/polyvinyl alcohol (PVA), graphene/epoxy resin (EP) can be prepared by solution blending. This method is the most direct way to prepare polymer-based nanocomposites. Stable dispersion of graphene in an organic solvent can effectively control the size and morphology of graphene, and it is easier to achieve uniform dispersion of graphene in the polymer matrix. However, this method often requires the use of an organic solvent, which can cause environmental pollution.

3. melt blending

When preparing graphene/polymer nanocomposites by melt blending, firstly, the mixture of polymer and graphene is heated to above the melting point of the polymer to make it in a molten state, and then the shearing action is used to promote graphene in the polymer. In the dispersion, a graphene/polymer nanocomposite can be obtained.

The melt blending method does not require a solvent and is more economical and environmentally friendly than the above two methods. However, graphene is not easily dispersed in the polymer matrix and has a poor interface with the polymer. Further, if the functional group in the chemically modified graphene is unstable in a molten state, it is not suitable to prepare a composite material by melt blending. Graphene/PU, graphene/PMMA, graphene/PC, etc. can be prepared by this method.

Applications of Graphene/Polymer Nanocomposite

Because graphene has scientific significance and application value, it has shown great application advantages in biomedicine, electrode materials, light and electric sensors. With the deepening of its research, the application of graphene and its derivatives in polymer matrix composites shows greater potential, mainly in enhancing mechanical properties, improving photoelectricity, electrical and thermal conductivity and improving thermal stability and mechanical stability, etc.

Edited by Suzhou Yacoo Science Co., Ltd.