What is POM？
Like ABS and PC, POM is a standard universal abbreviation in the polymer materials field, referring essentially to polyoxymethylene—a thermoplastic engineering plastic whose molecular main chain is composed of repeating oxymethylene (-CH₂O-) units. It is divided into two major categories: homopolyoxymethylene (POM-H) and copolymerized polyoxymethylene (POM-C). Renowned as "super steel" or "acetal resin" for its excellent wear resistance, fatigue resistance and dimensional stability, it is one of the most widely used engineering plastics.
Core Properties and Production Process of POM
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Raw Material Sources
The core raw materials are formaldehyde (for homopolymer POM) or formaldehyde and dioxolane (for copolymer POM). Formaldehyde is mainly derived from methanol oxidation (methanol can be produced from natural gas or coal), making POM a petroleum-based/fossil-based plastic. Currently, bio-based formaldehyde technology is still in the R&D phase, and large-scale production of bio-based POM has not yet been realized.
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Production Process
The mainstream industrial process is a combined
polymerization + post-treatment technology. Homopolyoxymethylene is produced via cationic polymerization of formaldehyde; after polymerization,
end-capping treatment (removal of unstable hydroxyl groups) is required to enhance the material’s thermal stability. Copolymerized polyoxymethylene is prepared through ring-opening polymerization using formaldehyde and dioxolane as comonomers; it does not require complex end-capping treatment and has better thermal stability than homopolyoxymethylene. The polymerization products of both processes undergo secondary processing including pelletizing, extrusion, injection molding and rotational molding to be made into various finished products.
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Key Properties
Its core advantages lie in
high wear resistance, excellent fatigue resistance and outstanding dimensional stability: it features a low friction coefficient and good self-lubricating performance, enabling long-term operation without lubrication with minimal wear; it has strong resistance to repeated impact and alternating loads, and is not prone to fatigue fracture; it has extremely low water absorption (<0.2%), maintaining precise dimensional accuracy even in humid environments; its heat deflection temperature is approximately 110–124°C, allowing stable performance over a wide temperature range from -40°C to 100°C. Its main drawbacks are poor weather resistance (prone to aging and degradation upon prolonged exposure to sunlight) and weak resistance to strong oxidizing media (e.g., concentrated nitric acid, hydrogen peroxide), which can be improved by adding antioxidants, ultraviolet absorbers or through blending modification.
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Application Scenarios
POM is concentrated in scenarios requiring high wear resistance, fatigue resistance and dimensional precision, covering the automotive, electronics and electrical appliances, machinery manufacturing and daily necessities industries. Typical applications include automotive transmission components (gears, racks, bearings, universal joints), precision parts of electronic devices (keyboard brackets, switch housings), mechanical engineering accessories (sliders, guide rails, nuts, bolts) and daily necessities (zipper teeth, faucet valve cores, toy gears). It is particularly suitable for manufacturing mechanical structural parts subject to high-frequency movement.
