Correlation between stiffness of sheets prepared from cellulose whiskers and nanoparticles dimensions

Impressive mechanical properties of cellulose nanocrystals or whiskers have generated great interest from the scientific community as shown by the huge amount of recent literature in this field. It makes them ideal candidates for the processing of polymer nanocomposites. Their outstanding reinforcing capability is classically ascribed to a mechanical percolation phenomenon. At sufficiently high temperature, the stiffness of the materials depends only on the volume fraction of the percolating rigid phase and stiffness of the percolating network. The effect of the first parameter has been well investigated in the literature but surprisingly no report is found about the latter. Tensile tests were performed on films prepared by water evaporation of a series of cellulose whiskers suspensions. Interestingly, our experimental data show that a correlation exists between the stiffness of the films and aspect ratio of the constituent rod-like nanoparticles.