Preparation and characterization of a two-component silicone gel sealant

The effect of different nSi-H/nSi-Vi ratio on the thermal stability, tensile strength and elongation at break of unfilled silicone gel sealants were studied. Two types of fillers were dispersed in the silicone matrix with different content and the composition and mechanical properties of filled composites were studied for establishing a new type of sealants materials. Expandable microspheres improved the elongation at break of the composites to 205% but degraded tensile strength. Fumed silica (SiO2) increased the composites´ breaking elongation from 64% to 394% and also degraded the tensile strength. The proper addition of fillers should be 0.75phr for expandable microspheres and 3phr for fumed silica (SiO2) to obtain both good tensile strength and high breaking elongation.