Acid scavengers
Neutralise acidic residues to protect processing equipment from corrosion.

Activity
is a measure which indicates how much polymer a certain amount of catalyst produces in a specified time. For a full definition the polymerisation conditions (mode, temperature, pressure etc.) have to be defined.

Additive
Additives are added to the polymer to protect it from degradation and to give the material desired properties. Normally the additives are mixed with the powder before the extruder.

Active site
The site on the catalyst at which the polymerisation takes place.

Anti-blocking and slip agents
Surface-modifying additives to reduce friction and tackiness of polyolefin films.

Antioxidants
A group of substances being able to inhibit radical reactions in the polymer and thus prevent degradation processes. Different types are available: sterically hindered phenols and phosphites as base for polyolefins,sulphur based heat stabilisers and C-radical scavengers for special applications.

Antistatic agents
Surface-modifying additives to reduce surface resistance of polyolefins, eliminating charge build-up and dust collection; an example of a widely used antistatic agent is glycerine-monostearate (GMS).Different types of antistatic agents are used in polymerisation reactors to prevent the formed polymer powder from adhering to the reactor wall.
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