Anyone Building Stocks with Graphene?

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Kelster

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Hello All,
If anyone is into building stocks with carbon fibre and would like to try using Graphene, send me a PM with your contact info.

1% graphene in an epoxy matrix can increase the strength modulus of carbon fibre by 25% and decrease weight by 10%.
 
Kelster said:
Hello All, If anyone is into building stocks with carbon fibre and would like to try using Graphene, send me a PM with your contact info.
1% graphene in an epoxy matrix can increase the strength modulus of carbon fibre by 25% and decrease weight by 10%.
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I don’t think that you are right. The strength and elastic modulus of any composite are governed by so-called “The Rule of Mixtures"
Sc (strength of composite)=Sm x Vm + Sr x Vr
where Sm-strength of matrix, Sr-strength of reinforcement, Vm-volume fraction of matrix
Ec (elastic modulus of composite)=Em x Vm + Er x Vr
Where Em-elastic modulus of matrix, Er-elastic modulus of reinforcement
From the properties of graphene (https://www.graphenea.com/pages/graphene-properties#.XhJcskdKiMo)
Sr=130000MPa, Er=0.5 TPa=500GPa, and roughly for a resin matrix Sm=50MPa and Em=3GPa and assuming 1% by volume of Vr then we have
Sc=50x0.99 + 0.01x130000=1349.5MPa
Ec=3x0.99+0.01x500=7.97GPa
The obtained values are not much better than those if a carbon (graphite) fiber would be used. Carbon (graphite) fibers are available with strength approaching 5000MPa and moduli 300-700GPa. On top of it, graphene is in general much more expensive than carbon (graphite) fibers and difficult to produce in large quantities in contrast to carbon (graphite) fibers that are produced in at least hundreds of kilograms.
In addition, the calculations are done assuming a ideally parallel orientation of graphene sheets along the loading axis. Any deviation from this arrangement introduces an “orientation factor” less than 1 which substantially reduces obtained values. The incorporation of graphene sheets into a epoxy resin is a pain in the a..s.
 
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