Epoxy-amine composites with ultralow concentrations of single-layer carbon nanotubes

Description of the degree of reinforcement of polymer/carbon nanotube nanocomposites in the framework of percolation models

“…The functionalization of car bon nanotubes does not change the general picture: above the percolation threshold of carbon nanotubes, a sharp decrease in the elastic moduli of both the func tionalized [1] and not functionalized [2,3] nanofiller is observed. A similar effect was also observed in the case of preliminary ultrasound treatment of poly mer/carbon nanotube nanocomposites [17].…”

“…As is known [2,3], up to the percolation threshold of carbon nanotubes in the polymer matrix, the rein forcing (reinforcement) elements of the structure of nanocomposite are the interphase densely packed regions [10], whose size can exceed D CNT by an order of magnitude and more and, for ϕ n > ϕ c (where ϕ c is the percolation threshold), such an element is the per colation skeleton of carbon nanotubes. This means that, according to the classification presented above [7], for ϕ n < ϕ c , the reinforcing element is the first sub set (n = 1) and, for ϕ n > ϕ c , the third subset (n = 4).…”

“…At present, there are sufficiently many works (e.g., [1][2][3]) in which an extremal dependence of the elastic modulus of polymer/carbon nanotube nanocompos ites on the content of the nanofiller at its very low con centrations (<0.01 wt %) is revealed. This effect is usu ally explained by the aggregation of carbon nanotubes and attainment by them of the percolation threshold [2,3].…”

“…This effect is usu ally explained by the aggregation of carbon nanotubes and attainment by them of the percolation threshold [2,3]. However, these explanations are only qualitative and disregard the specific features of aggregation of carbon nanotubes.…”

The effect of interaction between carbon nanotubes (nanofibers) on interphase adhesion in polymeric nanocomposites

“…It was thus assumed in [2] that ring like carbon nanotubes can be considered macromolecular tangles in semidilute solutions. In the case of rod like macromolecules, the Flory formula has been used for determination of the percolation threshold percola tion in carbon nanotubes in polymeric nanocompos ites [3].…”