Effects of Hydrothermal Treatment on the Structure and Properties of Aviation Polysulfide Sealant

An aviation polysulfide sealant has been soaked in a water bath at 85 °C to study the effects of hydrothermal treatment on this material. The morphology, Shore A hardness, and mechanical properties of the sealant were measured before and after soaking. The glass transition temperature (Tg) and room temperature storage modulus (E') were measured by means of a dynamic mechanical analyzer (DMA). The results showed that the surface glossiness of the polysulfide disappeared, some bubble defects appeared on its surface, the Shore A hardness and the tensile strength increased, while the elongation at break fluctuated with aging. The Tg and E' of the sealant changed only slightly. The chemical structure of the sealant was not obviously changed, and its aggregation state was changed only slightly, thus indicating that this sealant is characterized by good hydrothermal resistance.