Temperature-dependent storage modulus of polymer nanocomposites, blends and blend-based nanocomposites based on percolation and De Gennes's self-similar carpet theories

Temperature-dependent storage modulus of polymer nanocomposites, blends and blend-based nanocomposites was studied using both analytical and experimental approaches. The analytical strategy comprised modeling the thermomechanical property of the systems based on parameters affecting the conversion degree of polymer chains in state-to-state transitions and mechanical characteristics of the polymer/polymer interface. Accordingly, percolation theory was developed to define the order of conversion rate and conversion degree of polymer chains considering the thermomechanical characteristics of the neat polymer matrix, behavior of nanoparticles in the system and formation of polymer/particle interphase region. The effect of interphase on a temperature-dependent conversion of polymer molecules was estimated based on De Gennes's self-similar using the molecular characteristics of the adsorbed polymer chains and related scaling factor. To validate the model predictions, different neat, blend, nanocomposite and blend-based nanocomposite samples were prepared using high-density polyethylene, polyethylene terephthalate and hollow graphene oxide nanoparticles, where needed, and subjected to dynamic mechanical thermal analysis and other required tests. Besides providing acceptably accurate predictions in the case of all neat and nanocomposite samples, the model was proved to be independent of the system's morphological variation.