Polyoxymethylene
Polyoxymethylene (POM), also known as acetal, polyacetal, and polyformaldehyde, is an engineering thermoplastic used in precision parts requiring 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 sold variously by such names as Delrin, Kocetal, Ultraform, Celcon, Ramtal, Duracon, Kepital, Polypenco, Tenac and Hostaform.
| Names | |
|---|---|
| Other names
Poly(oxymethylene) glycol; polymethylene glycol | |
| Identifiers | |
| ChemSpider |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| (CH2O)n | |
| Molar mass | Variable |
| Appearance | Colorless solid |
| Density | 1.41–1.42 g/cm3 |
| Melting point | 165 °C (329 °F) |
| Electrical resistivity | 14×1015 Ω⋅cm |
| −9.36×10−6 (SI, at 22 °C) | |
| Thermochemistry | |
Heat capacity (C) |
1500 J/kg·K |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |
POM is characterized by its high strength, hardness and rigidity to −40 °C. POM is intrinsically opaque white because of its high crystalline composition but can be produced in a variety of colors. POM has a density of 1.410–1.420 g/cm3.
Typical applications for injection-molded POM include high-performance engineering components such as small gear wheels, eyeglass frames, ball bearings, ski bindings, fasteners, gun parts, knife handles, and lock systems. The material is widely used in the automotive and consumer electronics industry. POM's electrical resistivity is 14×1015 Ω⋅cm making it a dielectric with a 19.5MV/m breakdown voltage.