RELATIONSHIP BETWEEN THE APPLIED STRESS TRANSFER AND THE NANOFILLER AGGREGATION LEVEL FOR POLYMER/ CARBON NANOTUBES NANOCOMPOSITES

Abstract

The relationship was studied between the parameter important for the formation of the properties of polymer nanocomposites, namely, the transfer efficiency of the mechanical stress applied to the sample from the polymer matrix to the nanofiller, and the structure of carbon nanotubes formed in this matrix. It has been found that the indicated efficiency, controlled by the level of interfacial adhesion of the nanofiller-polymer matrix, critically depends on the main negative process for all nanocomposites, that is, aggregation of the nanofiller, an increase in the degree which reduces the efficiency of stress transfer. For the nanocomposites under consideration, the process of carbon nanotubes aggregation takes place in the form of emergence of their annular formations that are fractal objects, which has been confirmed experimentally. This fact allows characterization of the carbon nanotubes structure in a polymer matrix using a fractal dimensionality. It has been found that an increase in the fractal dimensionality of the annular formations of carbon nanotubes, reflecting an upgrowth in the degree of their aggregation unambiguously reduces the efficiency of mechanical stress transfer as well as the nanofiller ability to generate interfacial regions.