The dispersion of the reinforcers within the matrix C20 and AG20 in the composites was analyzed by scanning electron microscopy. The comparison of micrographs of CP2 vs. CP4 and CP20 vs. CP22 under 100,000 magnifications are shown in Figure 4. The micrograph of CP2 shows an aggregation of well delimited sphere shapes particles that are bigger than 300 nm while the CP4 micrograph shows, for the same magnification, a more continuous surface of such aggregation of sphere-shaped particles containing the biggest one of 150 nm. This comparison enabled us to consider that using the same quality of reinforcer, NSi, the composite resulting is affected by applying solvent exchange method to the pure matrix. Such a reaction could result in improved embedding of the filler within CP4 matrix, strengthened by the enhanced filler matrix interactions due to the matrix surface modification. However, the particle size distribution of every composite must be measured in the near future in order to clarify how this treatment is affecting the composites. The comparison of CP20 and CP22 focuses the attention on the effect of particle size since ASi is the filler that shows nearly one-tenth of NSi size. The micrograph of CP20 enabled us to see a more homogeneous distribution of particle size with values of 24 and 55 nm (not shown in picture) while the CP22 micrograph shows an even more continuous surface indicating that again the modification of the matrix has affected the distribution of filler giving place to a nice continuous morphology. In sum, we can say that using the filler of ASi (12 nm size) is very convenient for producing homogeneous composites when the matrix has been modified by a solvent exchange method such as AG20. Comparing the four composites micrographs allows us to see a progressive plasticizing effect that is clear in CP22 where the matrix is AG20 and the filler is ASi in 50 wt % content. This effect is very important to notice since no agglutinating resin was added in these composites.