Abstract : The addition of active filler (silica, carbon black) in rubbers leads to unusual mechanical behaviors, whose modeling represents still a challenging task. In these materials, the reinforcement is given by a network of filler aggregates connected by confined polymer regions (the size of few nanometers), where the polymer is in its glassy state because of the filler-matrix interaction. In our work, we propose a continuum mechanics approach to reproduce the physics of reinforcement from the nanoscopic to the macroscopic level. Firstly, we perform an experimental investigation of silica filled PDMS rubbers. Secondly, we derive a constitutive equation for the behaviour of glassy polymer within confined regions. Then, we study the effect of a confinement region on the force transmission between a pair of aggregates. We deduce that the contribution of the confined polymer is well separated from the rubbery geometric contribution. Finally, we build a network representation for a distribution of confinement states within the polymer nanocomposite. As a result, the model reproduces complex modulus temperature dependence and strain amplitude non-linearity (Payne effect).
thesis defense D COLOMBO - MINES ParisTechCalendar - MINES ParisTech