Polyoxymethylene

Polyoxymethylene 3D spacefill

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. POM is characterized by its high strength, hardness, and rigidity over a broad temperature range.

Properties

Polyoxymethylene is a highly crystalline polymer with a density of 1.41 to 1.61 g/cm³. It has a melting point of approximately 175°C (347°F) and is known for its high mechanical strength and rigidity. POM exhibits good wear resistance, low coefficient of friction, and excellent dimensional stability. It is resistant to a wide range of solvents and has good electrical insulating properties.

Production

POM is produced by the polymerization of formaldehyde. The two main types of POM are homopolymer and copolymer. Homopolymer POM is produced by the polymerization of anhydrous formaldehyde, while copolymer POM is produced by the copolymerization of formaldehyde with other monomers such as ethylene oxide.

Applications

Polyoxymethylene is widely used in various industries due to its desirable properties. Common applications include:

• Automotive: gears, bushings, and fuel system components.
• Consumer electronics: connectors, switches, and housings.
• Medical devices: insulin pens, inhalers, and surgical instruments.
• Industrial machinery: conveyor belts, bearings, and pump components.

Advantages and Disadvantages

Advantages

• High mechanical strength and rigidity
• Excellent wear resistance and low friction
• Good dimensional stability
• Resistance to a wide range of chemicals and solvents
• Good electrical insulating properties

Disadvantages

• Susceptibility to UV degradation
• Limited resistance to strong acids and bases
• Potential for formaldehyde emission during processing

Safety and Handling

POM should be processed in well-ventilated areas to avoid the inhalation of formaldehyde fumes. Proper personal protective equipment (PPE) such as gloves and safety glasses should be worn to prevent skin and eye contact.

Related Pages

• Thermoplastic
• Polymer
• Engineering plastic
• Automotive industry
• Consumer electronics
• Medical devices
• Industrial machinery