Influences of the Nanoparticles Related Parameters on the Tensile Strength of Polymer Nanocomposites

In this study, a comprehensive model has been proposed in order to predict the tensile strength of nanocomposites considering the effects of the random orientation of nanoparticles, the properties of the polymer/particle interphase region and also the inevitable aggregation/agglomeration phenomenon. The model was structured based on the nanoparticle shape (e. g. platelet, cylindrical and spherical) so it could perfectly demonstrate the random orientation. It was revealed that neglecting the aggregation/agglomeration of the nanoparticles (χ = 0) increased the prediction error to about 12 % while the χ = 0.07 % decreased the error to about 7-9 % for samples with low contents of nanoparticles (< 0.5 Vol.). The model was also applicable to the case of nanocomposites containing high contents of nanoparticles (> 1 % Vol.) which demonstrated its advantage, compared to other similar models, to predict the tensile strength in a wide range of nanoparticle contents (prediction error < 10 %). Moreover, the model was completely capable of characterizing the polymer/particle interphase regardless of the polymer type and the shape of the nanoparticles. The model verification was accomplished by comparing its predictions with the tensile test results for the prepared nanocomposite samples of different compositions (Polystyrene/Silica, Polystyrene/Graphene Oxide and Polystyrene/Carbon nano-tubes) and data from the literature. Also, the samples were subjected to TEM in order to qualitatively evaluate the behavior of the Nanoparticles with different shapes in the polystyrene matrix.