What is Vespel®?

Vespel® is a family of durable, high-performance, composite plastic materials developed, patented, and manufactured by DuPont. These specialized polymers are formulated to provide heat resistance, lubricity, dimensional stability, and chemical and creep resistance, and are specially engineered for service in harsh or severe working environments.

Vespel composites exhibit high reproducibility and very consistent thermophysical properties. It can be heated to 300°C (572°F) repeatedly without any change to its thermal or mechanical properties. This makes Vespel a popular thermal conductivity reference material in thermal insulator testing. Vespel’s volume magnetic susceptibility is very close to that of water at room temperature (-9.02 ± 0.25x10^-6 at 21.8°C for Vespel vs. -9.03x10^-6 at 20°C for water.) Both substances are diamagnetic—i.e., they are repelled by a magnetic field. Thanks to these similarities, Vespel is often used in high-resolution probes for NMR (nuclear magnetic resonance) spectroscopy. Vespel plastics do not outgas, even at elevated temperatures, unlike most other plastic materials. This makes Vespel well-suited for use as lightweight heat shields and similar applications. Due to its unique molecular makeup, Vespel performs well in vacuum applications, even at cryogenic temperatures.

Several variations of Vespel exist, each specially formulated for specific applications. Vespel materials can be molded or direct-formed into machine parts and components of all shapes and sizes. Vespel SP-1 is the “original” Vespel, offering high plasma resistance and very low electrical and thermal conductivity, with high strength and elongation. Vespel SP-21 adds 15% graphite to increase wear resistance and reduce friction. Vespel SP-22 adds 40% graphite for even greater wear resistance, even lower friction, and improved dimensional stability. Vespel SP-211 adds 10% PTFE to the SP-21 formula and provides the lowest coefficient of friction of any Vespel material, as well as excellent wear resistance. Vespel SP-3 adds 15% molybdenum disulfide lubricant to the SP-1 formula for improved wear resistance and friction resistance in vacuum and other moistureless applications. Vespel CR-6100 adds carbon fiber materials for improved machinability, allowing the material to be precision-machined into complex high-wear parts.