Effect of the Fractal Nature of the Surface of Carbon Nanotubes on the Properties of Polymer Nanocomposites

• Published in: Surface investigation, x-ray, synchrotron and neutron techniques Vol. 17; no. 1; pp. 159 - 162
• Main Authors: Kozlov, G. V., Dolbin, I. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-02-2023; Springer Nature B.V
• Subjects: Aggregates; Anisotropy; Carbon; Carbon nanotubes; Chemistry and Materials Science; Fillers; Formations; Fractal geometry; Fractals; Macromolecules; Materials Science; Nanocomposites; Polymers; Reinforcement; Surface structure; Surfaces and Interfaces; Thin Films; fractal dimension; nanocomposite; aggregation; carbon nanotubes; surface; degree of reinforcement
• ISSN: 1027-4510; 1819-7094
• DOI: 10.1134/S1027451023010147

We study the effect of the surface structure of aggregates (annular formations) of carbon nanotubes in the polymer matrix of a nanocomposite on the degree of reinforcement of the latter. The specific properties of carbon nanotubes (high degree of anisotropy, high longitudinal and low transverse moduli of elasticity) lead to the formation of aggregates typical for them, namely, ring-shaped formations. A decrease in the radius of these formations means intensification of the aggregation process. The variation in the curvature of the initial nanotubes implemented in this process (their deviation from straightness) determines a change in the structure of the surface of annular formations or a decrease in the effective (real) fractal dimension of the surface of these formations, which characterizes the degree of irregularity of such a surface. This change in the surface structure of carbon-nanotube aggregates causes the effect of “forcing out” macromolecules of the matrix polymer (or their fragments) from the indicated surface, which causes a decrease in the number of contacts between the polymer matrix and the filler and a decrease in the level of interfacial adhesion between the indicated structural components of the polymer/carbon-nanotube nanocomposites. The forcing out effect, which means the absence of contacts between the polymer matrix and the filler, is fully implemented when closed annular nanotubes appear, leading to a sharp decrease in the potential for reinforcement of polymer nanocomposites by this nanofiller. For such formations, an increase in the content of carbon nanotubes barely has an effect on the degree of reinforcement.