Influence of different fillers on the properties of an experimental vinyl polysiloxane

The aim of the study was to evaluate the effect of the incorporation of different fillers on an experimental vinyl polysiloxane (VPS) at two different concentrations, 20% and 40%. Different fillers were added to an experimental VPS. The study was developed in two stages: (i) incorporation of fillers in different concentrations: (a) 20 wt% fillers, and (b) 40 wt%. The fillers were added to experimental VPS and mixed with a speed mixer; (ii) characterization of experimental VPS; after the base paste and catalyst paste were mixed, the experimental VPS was used to make specimens specifically for each test, which were stored at 23 degrees C for 24 hours. The tests were designed according to the specific standardization for the analysis of tensile strength, detail reproduction, Shore A hardness, and elastic recovery. For analysis of filler size pattern, scanning electron microscopy at 1500x magnification was used. The aerosil OX-50 40% (AE), and pure aluminum hydroxide 40% (PAH) groups presented the highest tensile strength and Shore A hardness values. However, those were the only groups that did not present continuous detail reproduction of an intersection of 20 mu m line. The elastic recovery was not statistically significant. The undesirable characteristics of VPS (lowest Shore A hardness and tensile strength) were observed when it was added to the composition of acrylic polymer (AP) and fiberglass (FG) in both concentrations, 20% and 40%. In groups AE and PAH, agglomerates of nanofillers were shown in SEM micrography, while the other groups presented different shapes and fillers sizes.