Etude rheologique de suspensions de poudres d'aluminium nanometriques enrobees de polyethylene

The rheology of viscous suspensions of nanoparticles still remains poorly understood and the effect of the coating of these powders on the flow behavior is even more difficult to assess. We have studied the rheology of ultrafine aluminum suspensions prepared from two low molecular weight polymers of different viscosities: a hydroxy-terminated polybutadiene and a polypropylene glycol. The nanosize aluminum powders had previously been coated by a thin layer of high density polyethylene using an in-situ polymerization process. The rheological characterization of the suspensions was conducted by the means of steady and oscillatory shear flow measurements for similar concentrations of non-coated and coated particles. The effect of the coating process on the steady shear viscosity of the suspensions is discussed in terms of the interactions between the particles and the suspending fluids.;Our principal objective is to understand the effect of coating on the rheology of suspensions of aluminum powder by calculating the adhesions parameters and relating them to the rheological properties of our suspensions. (Abstract shortened by UMI.).