Influence of the Fillers Aspect Ratio and Dispersion

Compared to microcomposites, where the mechanical behavior is mainly a function of the characteristics of filler and matrix and their respective concentrations, generally speaking, two major characteristics define the mechanical performance of polymer nanocomposites (8) the nanoscale size and geometry of the fillers (aspect ratio) and their dispersion into the polymer matrix, and the interaction between the polymer chains and said nanofillers (interphase). This section highlights the influence of these two factors on the mechanical behavior of polymer nanocomposites. 

Although polymer nanocomposites display a stiffness enhancement that as with more conventional composites tends to be linear with increasing filler volume fraction, this may not be fully linear and may also more conventionally exhibit a critical volume fraction, beyond which stiffness starts to decrease due to nanofiller accumulation and thus efficiency loss [26], 

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