Analysis of deformation of the filled elastomer in mesoscopic scale was investigated with 3-D FEM (Finite Element Analysis). Combination of 3-D TEMT (Transmission Electron Micro Tomography) and Voxel-FEM enables us to reconstruct mesoscopic scale 3-D image and calculate 3-D strain distribution. To the first approximation, the calculated stress-strain behavior shows a good agreement with the experimental results. The strain concentration over 200% can be seen between carbon black aggregates, even if the overall strain is only 15%. The rubber occluded by carbon black aggregates can also be observed. The virtual rubber model constructed with perfectly dispersed fillers was also calculated. This shows less overall stress than that of the actual filled model reconstructed with 3-D TEMT image. It is found that the occluded rubber can behave as a hard domain and is an important factor of the filler reinforcement effect on rubber.

The three-dimensional (3D) morphology of particulate fillers embedded in a rubbery matrix was examined by transmission electron microtomography (TEMT). Two types of nanofillers, i.e., carbon black (CB) and silica (Si) nanoparticles, were used as the nanofillers. Although the CB and Si nanoparticles were difficult to distinguish by conventional transmission electron microscopy (TEM), they appeared different by TEMT; the CB and Si nanoparticles appeared to be hollow and solid particles in the cross-sectional images of the TEMT 3D reconstruction, respectively, demonstrating that TEMT itself provided a unique particle-discriminative function. The nanoparticles were found to form aggregates in the matrix. It is intriguing that each aggregate was made of only one species; not a single aggregate contained both the CB and Si nanoparticles. A particle-packing algorithm was developed to estimate the positions of each primary nanoparticle inside the aggregates.

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