Interfacial factors affecting the strengthening efficacy of nanoclay in nanocomposites

Polymeric media are strengthened by nanoparticles when the critical interfacial shear strength between the polymer and the nanoparticles, tau(c), is greater than the interfacial shear strength, tau, because stress is carried through the interphase region, improving the sample strength. Starting from this assumption, tau(c), tau, clay size, and interphase thickness are used to formulate the operating levels for interphase depth, interphase volume, and clay volume in nanocomposites. Moreover, the interphase factor A in the Kolarik model is developed for calculations of the tensile strength of nanocomposites, taking into consideration the orientation factor, tau(c), tau, the operating interphase depth, the clay thickness, and the operating clay concentration. All factors' impacts on A and the nanocomposite strength are examined, and empirical results for various samples are used to validate the advanced model. A ranges from 0 to 80 for different parameter values, and varying the parameters can result in improvements up to 500% in the nanocomposite strength. A dense interphase region, low tau(c), high tau, and reedy clays of large size are found to improve A and the nanocomposite strength. Using the reediest clay at maximum concentration yields the highest tensile strength, while high tau(c) very short clays, and thick clays diminish the strengthening character of clay in the specimens. (C) 2020 Elsevier Ltd. All rights reserved.