Only a very small quantity of graphene would need to be added to some plastics to make a very big difference. (Versarian) 

Graphene: living in a stronger material world?

The word “revolutionary” has often found its way onto the automotive industry’s descriptive list of new technologies – sometimes more in hope than conviction.

However, provided it is joined by the qualification “potentially,” it just could be applied to an emerging advanced material: graphene. At the moment only a "teenage" material—first isolated in 2004 by researchers at the University of Manchester in the north of England—graphene still is growing steadily towards mature production. But within a decade it could bring advantages across the design and manufacturing spectrum, including to EV and autonomous-vehicle efficiency.

Dr. Andrew Deakin is Chief Technical Engineer of the advanced materials engineering group Versarien, which plans to take graphene from the laboratory to the production line as a significant weight-saving, material-strengthening and battery-improving solution: “I believe it is revolutionary because used effectively, it may be able to reduce vehicle plastics’ weight by up to 20%. It also has huge potential for use in batteries, thanks to its excellent conduction properties, which would provide much longer battery life.”

Graphene, an allotrope, is a derivative of graphite, commonly used for pencils and as a dry lubricant. Its manufacture in automotive-industry high-volume terms will demand intensive development programs. But Deakin is an enthusiastic advocate of graphene’s future supporting role in both vehicle design and manufacture. He also is pragmatic: “It could be a couple of years away for some applications, 10 years for others. It is very difficult to judge—but I am confident of its promise.”

By 2020, predictions show that some 36,000,000 t of plastics may be used annually by the global auto industry, but that figure could vary; if integrated with graphene to create stronger, lighter plastics, the end result might be more plastics being used as other heavier materials are replaced. So assessing the net environmental effect/gain may be complex. However, weight saving,  good for cutting energy consumption, would be a plus, as would the ability to meet or enhance crashworthiness capability: “The challenge at present is making sufficient graphene to be used in a variety of plastics to enable us to understand fully what its benefits really are. At present, we are just getting to the stage where we can make large-scale tests with applications to many materials and different types of components.”

Enhancing plastics

Deakin and his team are aiming to make plastics more than 30% stronger to reduce the amount needed to achieve similar—or better—levels of strength. But a test program would necessarily have to be applied to every type of plastic used in a car: a number typically pegged at around 13.

“It is necessary to decide how it should be mixed with plastic and how much would be needed—say anything from 1% to 5%,” said Deakin. “Then there is the matter of refining various processes and techniques needed. After that will come the optimization of thorough testing to facilitate production on an industrial scale.” 

So Deakin’s full application list now embraces tires, as well as composite body panels, CFRP and batteries. “All could be made to perform very much better. Initially, we must decide which one makes the most sense, so we are working with many people in the industry to determine that. For example, tire life could be 1.5 and even twice as long than at present and also reduce the need for microplastics. One recent report stated that more than 28% of all primary microplastics that enter the oceans (they would probably be less than 1mm long) come from tires.”

Batteries would be lighter and smaller, helping to increase driving range to a practical figure. Potentially, they would also charge more quickly.    

Another initial area of interest is the use of graphene in plastic panels or bumpers to improve impact strength. Again, there is a need to optimize the percentage of graphene for required crashworthiness. The chassis may also get similar treatment if plastic forms part of it.  Graphene cannot generally be used to strengthen aluminum or steel, but when combined with plastic could be a metal alternative, explained Deakin: “If metal can be replaced by plastic components greatly stiffened by graphene, torsional stiffness would be maintained or improved, as would crashworthiness. So we would see far more scope to change to lighter plastics, CFPR (linking carbon fibers more effectively) and GRP.”

Versarien bought the specialist company 2D in 2014, which at that time was making only one gram of graphene a day. Now, with the use of new machinery soon to come on stream, Versarien expects to increase that to 1 kg  (2.2 lb) a day later this year. Deakin likes to describe this increase—correctly if a little cheekily—as a production-factor increase of 1000. However, it is very significant because that rate could be scaled to 10 kg (22 lb) per machine, the installation of 100 machines taking  total production to one ton per day. “And it is necessary to put only a very small quantity of graphene into some plastics (perhaps as little as 1% or less) to make a very big difference," he added.

Deakin is coy about detailing the machines and precisely how they operate, but says they could be easily installed on a plastics’ producer’s existing manufacturing site.

What Deakin terms “real” graphene comprises a single layer of carbon atoms one atom thick. However, Versarien is now achieving a majority of flakes <=5 layers and 90% <=10 layers; average lateral dimension is 2 microns.

Recyclability is a significant aspect germane to the introduction of any new material. Deakin believes the addition of graphene will enable a used plastic’s potential (such as when it has been degraded by UV light) to be brought back into the supply chain with its original characteristics or performance.

But what of the ever-present question of reaching a convincing cost-benefit ratio in reducing the amount of plastic in a car by adding in graphene? Said Deakin: “We can see, by using our techniques, that looks to be feasible in the next few years—maybe five.”

So could a material of a single atom’s thickness really support an increase in technology revolutions?  We’ll have to see if it registers on the global auto industry’s “rev” counter.

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