Easier and Safer to Use Carbon Nanotubes in Polymer Nanocomposite

A research team from Skoltech, Aalto University, and Kurnakov Institute has recently developed a new, versatile and simple approach to using carbon nanotubes for manufacturing carbon nanotube-polymer nanocomposites. The method is reported in Carbon and involves making briquettes — dense packages of carbon nanotube powders. Nanocomposites made with briquettes perform equally well as those made from the more expensive masterbatches, which are also polymer-specific — that is, less versatile.

“We believe the use of dense briquettes of carbon nanotubes can significantly facilitate the development of the carbon nanotube composite industry. This technique is cheap and applicable to a broad variety of polymer matrices, without sacrificing any of the electrical and thermal properties of the final material,” the lead author of the study, Skoltech PhD student Hassaan Butt, stated.

In the last decades, carbon nanotubes have been intensively investigated by researchers from academia and the industry because of their unique combination of electrical, thermal, and mechanical properties. Meanwhile, polymer-based nanocomposites have come to be the largest carbon nanotube application and the one closest to widespread integration into everyday life. It is easy to understand why: The smallest amounts of nanotubes added to a polymer endow the material with fundamentally new properties, such as electrical conductivity and piezoresistivity, as well as crucially enhancing its thermal and mechanical properties.

The recent study in Carbon began as an attempt to address the challenge of achieving sufficient carbon nanotube dispersion within a host polymer to attain optimal composite properties. To this end, Skoltech researchers and their collaborators from Kurnakov Institute investigated the method for rapid expansion of supercritical solution (RESS) of nanotubes, which leads to their deagglomeration. However, it did not yield any improvements in the ultimate properties of polymer nanocomposites. The team decided to explore the implications of this from the opposite perspective.

Study co-author and one of the main contributors, Skoltech PhD student Ilya Novikov, explained: “Having realized that rapid expansion produces a tenfold decrease in the bulk density of the nanotubes but does not improve composite properties, we thought, why don’t we do the opposite thing and compress the powders instead. What if compression does not impair the material’s performance?” The reason this would be exciting, he added, is that higher density means greater convenience and fewer safety hazards in manufacture due to unwanted nanotube aerosolization.