Polyoxymethylene

"Polyoxymethylene (POM), also known as acetal,^[1] polyacetal and polyformaldehyde is an engineering thermoplastic used in precision parts that require high stiffness, low friction and excellent dimensional stability. As with many other synthetic polymers, it is produced by different chemical firms with slightly different formulas and is therefore sold under various commercial names like Delrin, Celcon and Hostaform."

"It was discovered by Hermann Staudinger, a German chemist who received the 1953 Nobel Prize in Chemistry. He had studied the polymerization and structure of POM in the 1920s while researching macromolecules, which he characterized as polymers. Due to problems with thermal stability, POM was not commercialized at that time."

"POM is characterized by its high strength, hardness and rigidity to ~40 °C. POM is intrinsically opaque white, due to its high crystalline composition, but it is available in all colors. POM has a density of ρ = 1.410-1.420 g/cm^3"

"POM homopolymer is a semi-crystalline polymer (75-85% crystalline) with a melting point of 175° Celsius. The POM copolymer has a slightly lower melting point of 162 – 173° Celsius."