How are polysulfides used in lubricants and rocket propellants?

Polysulfides are utilized in lubricants and rocket propellants due to their distinct chemical properties:

• Lubricants: Polysulfides with four or more sulfur atoms are employed as industrial lubricants. Additionally, sulfurized olefins are specifically used for extreme-pressure lubrication. Phosphorus sulfides, such as $P_4{S}_{10}$, are also utilized in the preparation of industrial lubricant additives.12
• Rocket Propellants: Certain synthetic organic polysulfides, known as Thiokols, serve as binders in solid rocket propellants. These materials are valued for their high sulfur content and density, as well as their resistance to chemical and physical attack.314

It is important to note that while these compounds are highly effective in industrial applications, their use requires careful handling due to the specific chemical reactivity of sulfur-sulfur bonds.4