  When silica-filled rubber compounds are deformed, structural modifications in
the material's bulk lead to irreversible damage, the most significant of which
is cavitation appearing within the interfaces of interconnected polymer and
filler networks. This work introduces a new method to analyze cavitation in
industrial-grade rubbers based on Ultra Small-Angle X-ray Scattering. This
method employs a specially designed multi-sample stretching device for
high-throughput measurements with statistical relevance. The proposed data
reduction approach allows for early detection and quantification of cavitation
while providing at the same time information on the hierarchical filler
structures at length scales ranging from the primary particle size to large
silica agglomerates over four orders of magnitude. To validate the method, the
scattering of SSBR rubber compounds filled with highly dispersible silica at
different ratios was measured under quasi-static strain. The strain was applied
in incremental steps up to a maximum achievable elongation or breakage of the
sample. From the measurements performed in multiple repetitions, it was found
that the minimum strain necessary for cavity formation and the size evolution
of the cavities with increasing strain are comparable between these samples.
The sample with the highest polymer content showed the lowest rate of cavity
formation and higher durability of silica structures. The structural stability
of the compounds was determined by the evolution of the filler hierarchical
structures, obtained by fitting data across the available strain range.
