Modeling of the elastic stiffness of biobased polymer nanocomposites

The increment of the elastic modulus of two series of biobased polymer nanocomposites with increasing nanofiller volume fraction was simulated with a micromechanical model developed in previous works. The model assumes an effective interphase between the matrix and the nanoparticles, with different elastic properties. This model has been modified, by assuming that the ratio of particle radius over the interphase thickness follows a normal distribution. Simulating the experimental data of tensile modulus, an average value of the ratio of interphase thickness over particle radius was estimated, for all nanocomposites examined. The simulations were in accordance with the nanofillers quality dispersion, as provided by scanning electron microscopy. It was found that the interphase thickness (over particle radius) increment is correlated with the enhanced compatibility of polymeric matrix with silica nanofillers. Furthermore, a finite element analysis has been performed, and its results were compared to the analytical calculations.