Understanding the viscoelastic behavior of silica filled rubber

This thesis focuses on the understanding the viscoelastic behavior of silica filled Nitrile Butadiene Rubber (NBR) using different sizes/surface areas in three different regions of deformation that will be developed in 3 chapters. The characterization of the samples used in this work is described in Chapter 2. Then, chapters 3, 4 and 5 will describe the viscoelastic behavior as follows:
Chapter 3: We perform oscillatory measurements at small deformation (linear region) to show, for the first time, a rescaling of the reinforcement as a function of volume fraction and particle size.
Chapter 4: We apply Large Amplitude Oscillatory Shear (LAOS) in order to study the nonlinear behavior of filled rubbers. We compare the elastic response observed in strain sweep measurements with the response analyzed within a single cycle oscillation (described by Lissajous curves).
Chapter 5: We apply very large deformations (until the break point) in our rubber systems. We use a modified Griffith theory to predict the stress at break of rubber compounds, knowing the fracture energy and elastic modulus of the material that can be measured separately.
Chapter 6: We show partial results that deserve more research, such as the SAXS experiments under tensile stress done in Grenoble, France, and spectroscopy measurements under stress done at the Max Planck Institute for Polymer Research in Mainz, Germany. In addition, we suggest the implementation of coupling agents in our rubber compounds to better understand and control the interactions between filler particle and polymer matrix.