1) What is the main reason behind GO having weak mechanical properties?
2) If GO is mechanically weak, how come some lit. report GO being used as a reinforcer to enhance mechanical properties?
I am quite new to this topic and I was particularly confused by how quite a lot of lit. reports using GO as a reinforcer, mostly with cellulose.
Hi Fatima Ahmad,
It depends purely on what kind of application it is.
And it is all about relative properties of the materials.
So, do not confused.
This is a rough copy and paste from the highly cited paper by Yanwu Zhu , Shanthi Murali, Weiwei Cai , Xuesong Li , Ji Won Suk , Jeffrey R. Potts, and Rodney S. Ruoff:
"Polymer nanocomposites with GO-derived graphene materials as filler have shown dramatic improvements in properties such as elastic modulus, tensile strength, electrical conductivity, and thermal stability. Moreover, these improvements are often observed at low loadings of filler evidently due to the large interfacial area and high aspect ratio of these materials, requiring small amounts of filler to achieve percolation. At 0.7 wt% loading, a solution-mixed PVA-graphene oxide nanocomposite showed a 76% increase in tensile strength and a 62% increase in Young’s modulus; the results were attributed to effective load transfer to the graphene oxide filler via interfacial hydrogen bonding".
Besides, Polymer-nanocopmposites with GO-derived graphene materials can be designed to conduct electricity (or to retain their insulant properties)...
Please take care of the fact that GO is used as a cheap primary precursor for synthesing graphene, the mechanical properties of which are far better (young modulus = 1 TPa, and so on), than those of GO.
http://docenti.unicam.it/tmp/2303.pdf
Thanx freour, i am aware of the superior mechanical properties of graphene, but am not too sure about GO......
Actually, GO is an oxide, thus, a ceramic material, ceramics usually exhibit higher stiffness and ultimate strengths (expressed in stress levels) than polymers. Consequently, GO can be used as reinforcements in polymers.
If I remember well, graphene oxide monolayers have a Young modulus of 38 GPa, whereas most polymers have a Young modulus weaker than 4.5 GPa. Edit : it was 40 GPa (see the second attached paper).
Some examples and explanations are given in the linked papers.
http://digital.csic.es/bitstream/10261/61165/1/Improving%20the%20mechanical.pdf
http://web.mit.edu/mbuehler/www/papers/ACS_Nano_2012.pdf
Actually, GO is not as weak as you might think. But just have a look at the attched paper.
Article Space-Resolved In-Plane Moduli of Graphene Oxide and Chemica...
Dear Fatima
Actually, it depend on the preparation method
I used the solution method and it gave me poor mechanical properties..
Haia Aldosari, you are right. have a look here:
Article Systematic evaluation of different types of graphene oxide i...
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