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Classification And Function Of Antistatic Agents
- Sep 04, 2018 -

Antistatic agents are classified according to different usage methods. Antistatic agents can be divided into external antistatic agents and internal antistatic punishment.

According to the ionization of hydrophilic groups in antistatic agents, antistatic agents can be divided into ionic and non-ionic types.

If the hydrophilic group can be ionized in water, then the negative charge will be anionic, whereas the positive charge will be cationic: if the antistatic agent has more than two hydrophilic groups in the molecule, and the ionized antistatic agent has different positive and negative charges, it will be amphoteric antistatic agent.

If the hydrophilic group does not ionize the hydroxyl, ether, ester bonds and so on after encountering water, such antistatic agents are non-ionic antistatic agents.

According to the different chemical structure, antistatic agents can be divided into sulfuric acid derivatives, phosphoric acid derivatives, amines, ammonium salts, imidazoline and ethylene oxide derivatives and so on.

The mechanism of antistatic agents:

Charge leakage and neutralization occur in the process of friction. Charge leakage is mainly through volume conduction, surface conduction and radiation to the air. Generally, the volume resistance of solids is 2 to 3 orders of magnitude higher than the surface resistance (100 to 1000 times higher). How is the surface resistivity of polymer materials dominated the charge prevention effect? That is, surface leakage is the main factor in charge leakage. Therefore, by reducing the surface resistance and improving the surface electric conduction, the effect of preventing static electricity can be achieved.

External antistatic agents generally use water, alcohol or other organic solvents as solvents or dispersants (usually formulated as a solution of Q5% - 20%). Antistatic agents are coated on the surface of plastics, and the lipophilic groups of antistatic agents molecules are adsorbed on the surface of plastics, which are easily adsorbed on the surface of plastics because of the presence of hydrophilic groups. A conductive layer of a single molecule, such as an ionic antistatic agent, can also act as an ionic conductive layer, thereby reducing the surface resistance and accelerating the leakage of charges.

On the other hand, the dielectric constant of the friction gap is obviously higher than that of the air because of the molecular layer of the antistatic agent and the absorbed water on the surface of the plastic.