Breach foam
Breach foam is a term that refers to fast-acting sealing agents which can provide temporary mending to damaged hulls and armors of vehicles. Although there are some differences in the chemicals and mechanisms used between the factions that use it, all share the fundamentals of breach foam's functionality and composition.
Chemically, breach foam is composed of unique combinations of reactive chemicals, polymers, and fillers. The reactive monomers, when mixed, undergo chemical reactions that lead to the rapid formation of polymers. Catalysts in the foam speed up the reaction, allowing it to form quickly amidst pressing situations (namely combat). These catalysts are often either metal salts or organic compounds that facilitate rapid polymerization. Blowing agents are used to form the iconic foam-like structure; they are often incorporated into the breach foam formulation. When activated, these agents release gases that allow the polymer to expand rapidly, and often come in the form of hydrofluorocarbons. Fillers are added to the breach foam formula to enhance its mechanical properties, and can include carbon or aramid fibers which provide strength and structural integrity.
Breach foams can also include stabilizers and additives, which are added to improve the stability and performance of the foam. Due to the various environments that breach foam can be used in, these can range from flame retardants for hampering flammability to UV stabilizers for use in space.
The mechanism of deployment for breach foam is designed to be fast-acting and efficient due to its purpose in sealing armor and hull breaches. The technology usually involves a multi-compartment system that keeps the reactive chemicals separate until deployment: each constituent reactive chemical is hosted in their own compartment, with catalysts, additives, and blowing agents being stored in other compartments. When a breach is found, the foam can be applied through various apparata, such as through breach foam guns or integrated rapid foam deployers. The activation of the apparatus allows the reactive chemicals and catalysts to rapidly mix and be deployed in an exothermic reaction, immediately forming a polymer network over the target area expanded by the blowing agents and mixed with additives and stabilizers for longer field life.
As the foam is applied, it expands and adheres to the surrounding surfaces, filling the void caused by damage. The breach foam cures over time, achieving its desired mechanical properties as a rigid and lightweight temporary appliqué armor.