Polysulfide Rubber is valued as a sealant because it is what?

• A. A good sealant
• B. A good conductor
• C. A poor adhesive
• D. A rigid polymer

Answer: (A)

Polysulfide rubber is valued as a sealant because it combines elasticity, chemical resistance, and strong adhesion, which are all crucial for effective sealing. Its flexibility lets joints move with expansion and contraction without cracking, maintaining a tight barrier across a wide temperature range and under vibration. It also forms a near-impermeable seal to liquids and gases, preventing leaks. In addition, it adheres well to common substrates like metal and plastic and resists fuels, solvents, and weathering, making it durable for automotive, aerospace, and construction use. It wouldn’t be chosen for conductivity since it’s an excellent insulator, nor would a rigid or poorly adherent material provide reliable seals.