VISCOELASTICITY OF POROUS COMPOSITE-MATERIALS - EXPERIMENTALS AND THEORY

The viscoelasticity of latex/PS beads composites, having the same volu me content of latex and PS beads, but various porosity ratios and spec ific surfaces of particles has been investigated in the glass temperat ure range of the latex matrix. In order to give evidence for the main factors governing the viscoelastic properties, data were compared to n umerical simulations based on the Christensen and Lo model and Skorokh od's approach. Such modelings were performed by considering either the latex matrix or the PS beads as the continuous phase. It was conclude d that the glassy modulus is mainly governed by the volume fraction of porosity, while the rubbery modulus is controlled by both the interac tions between phases and the void volume content. The location of the mechanical relaxation seems to be governed by the mechanical coupling between phases, which implies some local phase inversion. The magnitud e of the mechanical relaxation depends not only on the chemical coupli ng induced by the interactions between phases, but also on the mechani cal coupling.