Heat Tolerance

Vespel® is a polyimide made by DuPont®. It is a high performance plastic used to make custom parts as well as standard screws, hex nuts, bolts, bearing, washers, etc. It is used in extreme and hostile environmental conditions. Vespel® will perform well in a very wide range of temperatures from cryogenic to 550° F (288° C). Also it can tolerate occasional extreme heat up to 900° F or 482° C without losing its mechanical properties.

Excellent Combined Attributes

Vespel® does not outgas at high temperatures and performs well in vacuum applications even at cryogenic temperatures. But it has a down side in that it will absorb a small amount of water so pump times may be longer. Additionally, Vespel® is a creep resistant material. Also along with these characteristics it combines lubricity, dimensional stability, chemical resistance and radiation resistance. While other materials may surpass Vespel® in each of the above mentioned categories, none can compare when these attributes are combined.

What is Vespel®?

Vespel® is a high-performance polyimide resin. It can be recognized by its ring-shaped molecular structure containing nitrogen. As it is light weight, it is often used as an alternative to metals. Also, it combines the best properties of ceramics, metals and plastics and is often used in high-heat environments where other thermoplastic materials lose their mechanical properties. Vespel®’s properties include:

  • Excellent Temperature Performance Vespel® has a continuous service temperature from cryogenic temperatures up to 550ºF (288° C) with occasional exposure up to 900° F or 482° C. No other plastic has a temperature range as wide as Vespel®.
  • Low coefficient of friction
  • Does not become brittle: Even at cryogenic temperatures as low as -400° F.
  • Chemical Resistant: Is not affected by solvents, industrial hydraulic fluids, fuels and many other chemicals.
  • Flight Approved: Both NASA and the US Air Force have approved Vespel® for flight in our skies and in outer space.
  • Exceptionally clean: Extremely high purity, virtually no particulate shedding in plasma, and very low trace metal content.
  • Excellent dielectric properties: This polymer displays minimal electrical and thermal conductivity
  • High mechanical strength and stiffness: Vespel® can handle repeated cleaning cycles, mechanical abuse, frequent handling, etc.

Grades of Vespel®

SP-1 is the base polyimide resin that is not filled. Its operating temperature ranges from cryogenic to 550° F ( 300° C.) It has the best electrical and thermal insulation values. Also, this resin grade exhibits physical strength and maximum elongation. Additionally, it has high resistance to plasma.

SP-21 is15% graphite filled which reduces friction in wear applications. Although of all the graphite-filled resins this has the best mechanical properties, they are still lower than those for SP-1.

SP-22 is 40% graphite filled. SP-22 displaces lower friction, improved dimensional stability (low coefficient of thermal expansion), wear resistance and low oxidation.

SP-211 is 10% PTFE and 15% graphite filled. So it has the lowest coefficient of friction of all the grades over a wide range of operating conditions as well as excellent wear resistance up to 149° C or 300° F. Thus it is often used in sliding or linear bearings applications.

SP-3 This grade is 15% molybdenum disulfide solid lubricant filled. SP-3 is intended for wear and friction resistance in vacuum and other moisture-free environments. So it is commonly used for seals, plain bearings, gears, and other wear surfaces in outer space or in ultra-high vacuum as well as dry gas environments.

What is Vespel® Used for?

Vespel® parts are commonly found in semiconductors, automobiles, jet engines, heavy-duty off-road equipment and military equipment. Indeed almost every jet engine made in the West has Vespel® parts in it. Hence this material is one of the most commonly used high performance plastics in the aerospace industry. NASA and the US Air Force have flight approved it. Indeed Vespel® parts can endure the most extreme environments including from deep space to reactor chambers.

  • Washers
  • Bearings
  • Bushings
  • Screws
  • Gaskets
  • Insulators
  • Thrust washers
  • Seal Rings