Graphene has Come of Age

#composites, #graphene, #iso, #standards, #sustainability

I have seen some interesting things about graphene lately published in places like Composites World, and in some advertisements in the various news feeds I get about composites.  It appears that graphene has actually come of age and is being included as part of a few composite material suppliers’ product mixes.  It is even available on AZOM which is one of the global materials commodity marketplaces where all sorts of things are available for sale, commonly at discount prices. 

The thing that finally peeked my interest and curiosity is an upcoming webinar organized by Composites World and presented by the Executive VP of MITO Material Solutions (https://www.compositesworld.com/events/details/an-overview-into-the-new-iso-ts-for-graphene-related-2d-materials?first_name=Ned&last_name=Patton&email=ned%40nedpatton.com&custom_field_company=&utm_bmcr_source=CW+Today+5%2F2%2F2025).  MITO Material Solutions has apparently been involved in the development of the new ISO standards for 2D graphene materials.

SEM image of MITO 2D Graphene (Composites World 10/12/2022)

There are actually several ISO standards relating to graphene.  The first, released in 2017 (ISO/TS 80004-13:2017) provided a framework for users and manufacturers of 2D graphene and graphene related products to have a common vocabulary for how to talk about their products so that all interested parties could communicate in a common vernacular.

This standard has since been withdrawn and replaced with a new ISO standard, released in 2021 (ISO/TS 21356-1:2021) that includes this common vocabulary and also outlines methods for characterization and classification of 2D graphene materials.  It turns out that the main classification means that ISO adopted for pure graphene flakes has to do mostly with the size of the flakes and how many carbon layers there are in the flakes.  This goes from very few layer graphene (vFLG) which is 1-3 layers, few layer graphene (FLG) which is 2-5 layers of carbon, multi-layer graphene (MLG) which is 2-10 layers of carbon, and graphene nanoplatelets (GNP) which is stacks of graphene that can contain many layers and still be called graphene.

Since then, there have been at least 4 more ISO standards for graphene that have been either adopted or introduced, including for products that have been released that are specific to industries that are adopting graphene-based materials for their products, for standard means of characterizing graphene so that the tests can be used to certify a graphene to ISO/TS 21356, as well as having graphene included in the list of potential nanoparticle inhalation risks.   

I do need to step back a little bit and remind everyone of the structure of graphene.  I have talked in this space about this before, but those of you that remember that I talk about the benzene ring a lot and aromatic organic compounds and how important this 6-sided structure is to the structural part of our natural world as well as increasingly our engineering

This ball and stick model pretty much tells the entire story about graphene.  Each ball is a carbon atom and each stick connecting the balls together is a carbon-carbon bond.  This is the most stable carbon structure that exists and is the backbone of one of the most ubiquitous compounds on earth – cellulose.  It is also the basic structure of carbon fibers of all types.  In other words, it is this basic 6-carbon ring structure that keeps your Boeing 787 or Airbus A350 flying from LA to London at 40,000 feet.  In real life, graphene flakes look a lot like the following pic.  These are flakes of graphene that are in the MLG category where there are on the order of 10 carbon layers in each flake, and this is a picture of the alcohol suspension that they are in.  If you look at the little scale in the bottom left of this pic, it looks like the average dimension in the plane of the flakes is 1-2 microns.  So these things are really tiny.      

Interestingly, until 2004 pure graphene in flake or sheet form was a laboratory curiosity because the smart chemists and material scientists in the major laboratories, both government and industry, had not figured out how to make this stuff in high enough quantities that it could be commercialized.  A lot has changed in the last 20 years, and now there are, at least according to Wikipedia, at least 9 manufacturers of graphene both in raw material form and in products that are made using graphene that they produce.  These companies are in the US, Canada, the UK, the EU, and even in Australia.  In addition to these companies, there are at least three companies using graphene to make batteries, predominantly for the transportation industry. 

Because of the high in-plane electrical conductivity of this stable carbon structure, graphene is used not only as a structural material but at the same time as a better conductor than copper at about at a fraction of the weight of carbon.  With the advent of EVs, the new graphene batteries, once they are in full production, will lower the cost and increase the range of the EV battery.  Already EVs are cost competitive with gasoline burning vehicles, and it appears that graphene based composite materials for anodes in these batteries has the opportunity to help make that cost trade even more in favor of the EV.

That is why the push to develop ISO standards for different grades of graphene material is being pursued by the graphene industry.  The folks that make this stuff want to be able to grade their products and provide certification that their products meet international standards in order to sell them into a highly regulated industry.  In other words, not having these standards in place puts up berries to adoption of them in industries that could put them to good use, like the aviation and automotive industries.

This is especially true of the use of graphene in composites as these materials are increasingly being sought after and used in aviation and automotive applications because of the light weight and high strength of composites.  Graphene has shown its potential to make not only highly electrically conductive composites, but also flexible membrane composites that not only can take considerable load for their weight, they can at the same time conduct electricity at very low resistance or electrical signals.  And these materials are completely bio-compatible because after all we are just big bags of water being held together with lots of carbon, with some other stuff added in of course.  Adding a bit more carbon to the mix is basically in the noise.  And since the 6-sided structure of carbon is the one that is favored in our planet’s biology, graphene is basically a natural substance.

So, this is another industry that is very tightly regulated where graphene and composites made using graphene have the potential to have a significant impact.  Small graphene particles are very easily absorbed into the body and are being studied for drug and gene delivery.  Little carbon nanotubes (graphene rolled up into a tube structure) are extremely well tolerated by the body and they are being studied for use in drug and gene therapy delivery.  There are also graphene composite biosensors being developed for use in detecting harmful biomolecules like viruses, chemistries given off by cancer cells, and even the biomarkers for diseases like diabetes. 

And, of course, since the medical care industry and medical products industry is even more regulated than the automotive or aviation industries, the importance of having standards and accepted grading standards for graphene flakes, sheets, nanotubes, nanofibers, and particles allows for these industries to begin to gain acceptance of their products for use when human safety and health is on the line. 

There are in fact several companies in the throes right now of getting their products through the FDA and NIH here in the US and also the respective health agencies in the UK, EU, and other countries that have these controls in place for their graphene based biomedical devices and treatments. 

There are also several companies in the aviation industry that are working toward the use of these new ISO standard graphene materials in commercial transport aircraft.  Even Airbus is involved in this, as well as a number of suppliers to Boeing.  And of course graphene has already been applied in both military aviation and spacecraft.  Graphene makes an excellent choice as a re-entry heat shield since the little graphene sheets or flakes can be aligned parallel to the base of the re-entering capsule.  This last application is still being developed because we still do not have the technology to make a competent heat shield where all of the graphene flakes are aligned properly and all touch each other so they conduct heat flake to flake.  Once that technology has been perfected and proven, NASA, SpaceX, and the ESA will be sure to adopt it for all of their reusable spacecraft. 

One more thing that I need to mention here, because sustainability is such an important facet to the development of all new materials and technologies, is that since this 6-sided carbon ring is the preferred form of carbon for structural applications in our biology, as well as being the backbone of a majority of the organic compounds that our biology uses, sourcing the precursors for making graphene from bio-sources rather than petroleum will be crucial to the sustainability of this industry.  Forest products waste is the thing that comes to my mind since cellulose is one of the most ubiquitous organic compounds on earth and those of you that have been reading these posts already know that cellulose is merely a long chain of these 6-sided carbon rings with some oxygen and hydrogen attached where they need to be to make this long chain sugar molecule. 

That’s about it for this week.  As always, I hope everyone that reads these posts enjoys them as much as I enjoy writing them.  I will post this first on my website – www.nedpatton.com – and then on LinkedIn.  And if anyone wants to provide comments to this, I welcome them with open arms.  Comments, criticisms, etc. are all quite welcome.  I really do want to engage in a conversation with all of you about composites because we can learn so much from each other as long as we share our own perspectives.  And that is especially true of the companies and research institutions that I mention in these posts.  The more we communicate the message the better we will be able to effect the changes in the industry that are needed. 

My second book, which should be out in the fall, is a roadmap to a circular and sustainable business model for the industry which I hope that at least at some level the industry will follow.  Only time will tell.  Since my publisher and I have finally come to agreement about the title for my next book, our daughter has been kind enough to put together a draft of the cover of the book for them to use to come up with a final version.  So, my publisher has finalized the cover of the book, and I’ve included that at the end of this post as promised.  Let me know whether or not you like the cover.  Hopefully people will like it enough and will be interested enough in composites sustainability that they will buy it.  And of course I hope that they read it and get engaged.  We need all the help we can get. 

Last but not least, I still need to plug my first book, so here’s the plug.  The book pretty much covers the watershed in composites, starting with a brief history of composites, then introducing the Periodic Table and why Carbon is such an important and interesting element.  The book was published and made available last August and is available both on Amazon and from McFarland Books – my publisher.  However, the best place to get one is to go to my website and buy one.  I will send you a signed copy for the same price you would get charged on Amazon for an unsigned one, except that I have to charge for shipping.  Anyway, here’s the link to get your signed copy:  https://www.nedpatton.com/product-page/the-string-and-glue-of-our-world-signed-copy.  And as usual, here are pictures of the covers of both books.