You own a carbon fiber tennis racket or laptop computer. The carbon fiber itself is a composite material made by combining carbon fiber fabric with an epoxy resin. It is a composite material currently made at standard scale. What if you could make a composite at nanoscale? Would you have a better product?
Researchers at Texas A&M University are looking to answer that question. They are currently researching a process that combines carbon fibers, carbon nanotubes, and cellulose nanocrystals. They have achieved good results thus far. If they manage to perfect the process and make it cost-effective on a larger scale, the way we produce carbon-based composites could be altered forever.
A Definition of Composites
The engineers at Salt Lake City’s Rock West Composites explained that a composite material is any material made up of two or more substances with the necessary properties to meet the finished product’s specifications. The key thing to understand about composites is that the combined properties of the ‘ingredients’ are that which make the resulting material so desirable.
Concrete is an excellent example. Concrete is a mixture of cement, water, and aggregate – usually sand. Both cement and sand have properties that make them desirable for plenty of applications. But you cannot build a skyscraper with either one on its own. Combine the two materials and throw in a little water, and now you have a material you can build with.
Taking it one step further, concrete is porous and brittle. So building a skyscraper with concrete alone would not be wise. Instead, contractors combine concrete with rebar to create an entirely new composite that stands up to a world of punishment.
Carbon Fiber As a Composite
Moving on to carbon fiber, your tennis racket or laptop computer is made with a material that combines carbon fibers and resin. Carbon fiber fabric alone would be unusable as a material for your tennis racket or laptop. It is simply not rigid enough. But combine it with resin and you’re good to go.
The Texas A&M researchers are looking to make that carbon fiber better. Their research is centered around the concept of making carbon fibers even stronger by attaching carbon nanotubes to them. Carbon nanotube research has been ongoing for a few years now.
Carbon Nanotubes and Strength
Carbon nanotubes definitely add strength to fibers. The problem is that they are difficult to attach consistently across the entire surface of a carbon fiber tow or fabric. This lack of consistency prohibits achieving the kind of strength engineers want.
The researchers have discovered they can introduce cellulose nanocrystals and improve consistency at the same time. The nanocrystals work in conjunction with the carbon nanotubes to distribute them and attach them to carbon fibers more consistently.
In a paper outlining their study, the researchers show how their process increases carbon fiber’s strength and rigidity. But that’s not all. They say the added cellulose nanocrystals and carbon nanotubes also increase electrical and thermal conductivity. That means the resulting material transfers heat better and conducts electricity more efficiently.
The implications here are pretty significant. For example, a carbon-based composite with exceptional electrical conductivity could be used to increase the efficiency of electric vehicle power storage systems. Essentially, it makes it easier to turn an electric car’s carbon fiber body into a power storage unit.
Composites are wonderful materials. Every time researchers figure out how to make them better by adding a new ingredient, they open the doors to using composites in entirely new ways. It is a great time to be in the composites industry, that’s for sure.