FORMATION OF CARBON NANOTUBE ROPES AND THEIR EFFECT ON THE PROPERTIES OF POLYMER NANOCOMPOSITES

摘要

Carbon nanotubes represent a unique nanofiller with exceptional mechanical properties and a high degree of anisotropy. These characteristics determine the presence of two types of aggregation for such a nanofiller, namely, the formation of ropes (bundles) of individual nanotubes and formation of their annular structures. Estimates made within the percolation model have shown that each rope of carbon nanotubes in polyamide-6-based nanocomposites consists of several hundred individual nanotubes. In turn, the formation of such ropes has a critical effect on formation of annular structures of carbon nanotubes, since an increase in the diameter of ropes results in an increase in the radius of these annular structures. This effect determines both the level of in-terfacial adhesion in polymer nanocomposites and their final mechanical characteristics. It has been shown that an increase in the number of carbon nanotubes per one rope reduces its specific surface and the fractal dimensionality of the surface of ropes, which ultimately determines the decrease in the reinforcement degree of polymer/carbon nanotubes nanocomposites. The thermody-namic analysis of carbon nanotubes interactions has shown that these interactions are significantly higher than similar interactions between polymer macromolecules. This effect determines the formation of carbon nanotube ropes already at the stage of their production. The obtained results suggest that individual carbon nanotubes with a large radius of their annular structures can produce the greatest effect in reinforcement of polymer nanocomposites.