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Non-Linear Behavior of Filled Elastomers by Molecular Dissipative Dynamics

Wednesday, September 29, 2004 - 2:45pm - 3:35pm
Keller 3-180
Didier Long (Université de Paris XI (Paris-Sud))
Whereas non-reinforced rubbers have a low resistance to tear and wear, reinforced elastomers can be used under very demanding conditions. The corresponding effects are very important since the energy of tearing can be hundred of times larger than that for the non-reinforced material. Recent progress regarding the glass transition mechanisms in the vicinity of interfaces have allowed for understanding some aspects of the reinforcement, such as the high shear modulus and some dissipative properties. By implementing this picture in dissipative molecular dynamics simulations, we show here how one can account for some of the striking non-linear properties of these systems, such as the Payne effect (strong drop of the shear modulus at a few percents deformation) and the Mullins effect (hysteresis of mechanical properties, partially recoverable after waiting or thermal treatment of the system). We show also that the associated mechanisms lead to some specific plastic properties.