Suzhou duotema: Polyoxymethylene (POM), also known as acetal resin, polyoxymethylene and polyacetal, is a thermoplastic crystalline polymer, known as “super steel” or “saigang”.
Adding conductive carbon black is a common method for manufacturing conductive POM. The so-called conductive carbon black refers to a kind of carbon black with small particle size, large surface area and many lock structures. Carbon black is generally made of various organic hydrocarbons by incomplete combustion or thermal decomposition. It is insoluble and immiscible microsphere particles. In addition to lone pair electrons and aromatic rings, its surface also has polar functional groups such as quinone carbonyl and phenolic hydroxyl. The addition amount of conductive carbon black is generally 0.5% – 20%. If the conductivity of carbon black is good, the surface resistivity or volume resistivity of POM can be reduced to 1 × 102 quantity level.
However, due to the role of superior functional groups on the surface of carbon black, the thermal stability of POM is often reduced, resulting in the reduction of physical and mechanical properties. In order to overcome this disadvantage, the method of combining conductive carbon black and hydrophilic polymer compounds (such as PEG) can be adopted to reduce the use of carbon black, or the method of adding heat stabilizer based on formaldehyde capture agent can be adopted to improve the thermal stability of the system. In contrast, the use of carbon fiber can not only greatly improve the various properties of POM (including self lubrication), but also achieve good antistatic property. If 20% carbon fiber with good conductivity is added, the surface resistivity and volume resistivity of POM can reach 1 × 102 orders of magnitude.
