A microscopic look at the reinforcement of silica-filled rubbers

The deformed structure of silica-filled elastomers under uniaxial strain has been investigated using a combination of both small angle x-ray scattering and small angle neutron scattering methods. Using an extraction procedure and taking into account the two-phase nature of these polymer-based composites, the single chain scattering behavior as well as filler properties could be obtained uniquely on identical samples. For the first time the deformation of the rubbery matrix on the length scale of the network chain in a filled rubber could be determined and therewith the importance of matrix overstrain for the mechanical properties was estimated. Additionally, the determination of filler deformation and filler destruction presents microscopic details of the mechanisms of filler networking and the stress-softening Mullins effect.