Combining Carbon Fibers and Nanotubes Makes an Awesome Prepreg
Companies involved in the composites industry, like Utah-based Rock West Composites for example, are always on the lookout for new technologies that could shape the future of what they do. It is quite likely that all industry eyes are on carbon nanotubes right now, given the amazing properties they exhibit compared to metals, metal alloys, and even standard carbon fibers. Companies like Rock West are especially excited to see the development of carbon nanotube prepregs.
A prepreg is a carbon fiber material (usually a fabric) that comes from the factory already impregnated with resin. Prepregs are viewed as especially attractive to manual layups in which even distribution of resin is critical to creating the desired finished product. Carbon fiber prepregs are being used to create all sorts of complex parts for the automotive, maritime, and aerospace industries.
The thing that has everyone’s attention right now is a new kind of prepreg that combines both carbon fibers and nanotubes into a single product. With this hybrid design, manufacturers are able to create a very good carbon fiber fabric that can be the basis for a high-quality prepreg. Introducing nanotubes creates a tougher material that makes for a much stronger reinforced plastic.
An Explanation of Nanotubes
Carbon fibers exhibit an exceptional strength-to-weight ratio all on their own. But when you combine them with nanotubes in a prepreg, the results are extraordinary. It all boils down to what nanotubes bring to the table.
Carbon nanotubes were originally discovered back in the early 1990s. A single nanotube is a tube-like structure that is measured on the nanoscale, thus its name. A single nanotube is tens of thousands of times smaller than a human hair in circumference. And yet, these amazing tubes are 100 times stronger than steel.
In the simplest terms possible, a carbon nanotube is a ‘sheet’ of carbon molecules bound together and then rolled up to create a tube-like structure. The sheet itself is known as a graphene sheet. As for the nanotubes, they can be either single-wall or multi-wall structures, depending on design.
Some have likened a single-wall nanotube to a drinking straw. That being the case, a nanotube with multiple walls would be like taking numerous straws of slightly smaller diameters and inserting them one into another.
The Benefit of Nanotubes
Now that you better understand what a carbon nanotube is, you may begin to understand how they can be beneficial to a carbon fiber prepreg. Think of it in terms of rebar and concrete. That is essentially what we’re talking about here. Carbon nanotubes reinforce sheets of carbon fiber to make them stronger, more resilient, and more dense.
Concrete is an excellent substance all by itself. But large concentrations of straight concrete are subject to weather, vibrations, and other degrading forces. By embedding rebar in a mass of concrete, engineers create a much stronger finished product that resists all those negative forces.
Embedding carbon nanotubes into a carbon fiber prepreg does essentially the same thing. It reinforces the carbon fiber sheet so that it better withstands the environmental pressures that can cause it to break down. More importantly, the resin matrix used to bind together the fibers and nanotubes creates a single, strong product after curing. This only increases the tensile strength of the prepreg.
Technology is constantly making composite materials better and stronger. Hybrid carbon fiber and nanotube prepregs are just the latest example. Who knows where research and development will take us in the future, a future that looks to be ever more dependent on composites.