Hi there, my names Noel Craig, I'm from Belfast in Northern Ireland and would like to ask the community here
about their experience with graphene as a potential additive in lightweight high strength composite 
materials. Alternatively perhaps you have heard about the material but have been driven away by the
shocking cost of it.

I ask because it has been the subject of personal research along with nano materials  for around two years now
and I have developed my own top down environmentally friendly and highly scale-able approach to it's production.
I am not here to sell my material but just to get an idea as to how common in usage the material has become.

Thanks
Noel

It's all part of the matrix (and no, you havent taken the blue pill). The theory is that the fillers are in the entire matrix, handling and transferring loads the same as a fibre reinforcement is. Anything that improves the strength of the matrix for a certain application is beneficial - resin ratios are relative. A straight carbon/epoxy matrix may be at its strongest at a specific ratio to each other. But if you are adding another type of reinforcement to the matrix then there's no saying that the addition of that reinforcement doesn't allow that specific ratio of carbon:epoxy to change without hurting the mechanical performance, and in fact it may even improve it.

Realistically, it's quite complicated. As Oekmont said, the resin part of the matrix doesnt account for terribly much of the mechanical strength of a well made composite laminate. Certain fillers do slightly improve the mechanical performance in terms of tensile strength, compressive strength, yield strength, etc. But in a lot of cases, you improve one and hurt another. You can also change certain properties that the resin is associated with; such as conductivity, lubricity, density, shrinkage, thixotropy, etc. So generally with fillers you know what properties it can add, you know what properties it can take away, and you use the ones that give your laminate the properties that you desire. 

The problem with nanotubes and graphene and other additives like these is that they are SUPER expensive, and their benefits in composite applications aren't really a direct correlation to that price, so why use them? They may improve things a tiny bit, and if they were super cheap then people might use them. But they are just too expensive to be useful.