Processing and characterization of new thermoset nanocomposites based on cellulose whiskers

In the present study, the processing and the mechanical properties of new t hermoset nanocomposites prepared from aqueous suspensions of microcrystalli ne cellulose fillers and epoxy are described. The nature of cellulose fiber s, which display a large aspect ratio and the ability to associate by means of H-bonds implies that the processing method chosen in this study avoids the problem of a high level of viscosity of the epoxy reactive system-whisk ers mixture. The reinforcing effect of this type of natural fiber in an epo xy matrix is mainly shown from the dynamic mechanical properties in the rub bery state. This unusual reinforcement is due to (i) the strong interaction s existing between the cellulose whiskers and the epoxy network and, (ii) t he creation of a percolating network linked by H-bonds between cellulose fi bers. The existence of such a percolation effect is evidenced from the anal ysis of the rubbery shear modulus of nanocomposites based on various volume fractions of whiskers with mechanical modeling such as Halpin-Kardos and p ercolation approaches.