Dynamic mechanical properties of enhanced filler dispersion polyethylene-glycol/q-SiO₂ composites

In this work, polyethylene-glycol (PEG)/q-SiO₂, (silica quartz) composites were prepared by dispersing q-SiO₂, in various fractions, i.e., 0, 20, and 40 wt.%. We elaborated the silica dispersion in the polymer matrix from the previously reported solid method (reported in [1]) and a liquid method. In the latter, the dispersion of q-SiO₂, in the matrix was done by a stirring process in the liquefied polyethylene glycol with temperature control. The filler content and mixing method were selected to optimize the dynamic mechanical properties of composites, especially, the shear moduli (G' from the Dynamic Mechanical Analyzer (DMA) instrument. The maximum shear modulus value was found with 40 wt.% q-SiO₂, by the liquid method, which showed 46% increment as compared to 40 wt.% q-SiO₂, by the solid method. We showed in this work that the dynamic mechanical properties are tightly related with the dispersion of the filler in the matrix. The quantitative analysis of filler dispersion was done using PixelProfile software and dispersibility characterization from SEM-EdX images. We analyzed each image in three regions by RGB (Red-Green-Blue spectrum). The lower the dispersibility index (I_{dispersibility} ), the better the filler dispersion. By applying the liquid method, the dispersibility indices were 0.357 for 20 wt.% and 0.705 for 40 wt.%, better than solid method.