The Chemistry Stuff – Graphene and Graphene Oxide
Hello everyone!
This week, most of my time is going into learning as much as I can about dispersion methods for graphene oxide (GO) and composites so I will be ready once I head up to ERAU. I promised I would go into more detail about GO, so I’ll do that today.
Monolayer graphene, initially observed in 2004, can be produced through various methods, each resulting in different quantities and qualities. Only pure graphene exhibits the impressive characteristics I mentioned last week. Right now, it is difficult and expensive to produce a large amount of high quality graphene. Additionally, pure graphene is hydrophobic due to its carbon structure, making it difficult to mix it with other substances. By contrast, GO has many different functional groups (like =O, -OH, -COOH, or -O-) attached to its structure, causing it to be hydrophilic. Since GO can be chemically produced from graphite, it is also generally cheaper than graphene.
There are several ways to make GO, but the GO I will be using is made via the Hummers’ method. In this process, graphite and sodium nitrate are added to a solution of concentrated sulfuric acid. Then, potassium permanganate is added to the solution. After this process, products must be cleaned. This reaction technically yields graphite oxide, which has layers of unseparated GO. To get individual layers of GO, the material is usually placed in a sonicator, where sound energy agitates and separates each layer. Hummers’ method is a good way to make a lot of GO quickly. Researchers often reference this method when working with GO.
There are different ways I can use GO to try and strengthen the composite I will be making. One method is to add the GO directly to the epoxy. Based on information from ACT, the GO must be added before the hardener, otherwise the GO tends to clump up, which can have negative effects. Another interesting method I found is to bond the GO directly to the glass fibers, creating a much stronger interaction between the fibers and the epoxy matrix. However, this process is more complicated and requires more equipment and materials.
This subject has a lot of fascinating information, and I’m looking forward to getting to work hands-on.
Here are some of the papers I have been reading if you want to look further:
Modifying glass fibers with graphene oxide: Towards high-performance polymer composites
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