Abstract: A self-scuttling device can include a pressure hull that can define an internal void having an internal pressure PVOID. The device can be disposed in an underwater environment having a pressure PAMBIENT that is greater than PVOID. The pressure hull can be formed with a fill port, which can be selectively opened to flood the void. A reactive agent can be disposed within the void. The reactive agent can be chosen to mix with seawater and establish a solution that corrodes the pressure hull when the reactive agent is exposed to seawater by flooding the void. The reactive agent can be disposed within a watertight container, which maintains watertight integrity at PVOID, but loses watertight integrity at the greater PAMBIENT. When this occurs, the reactive agent becomes exposed to seawater to establish the solution within the void that corrodes the pressure hull.

Abstract: Syntactic foam, comprising a cured product obtained from a composition which comprises: at least one epoxy resin, a curing agent, and hollow microspheres, wherein the microspheres have a density less than 0.25 g/cc and wherein the cured syntactic epoxy foam has a density less than 0.7 g/cc. The foam may be used to repair composites in aircraft.