A

Abrasion Resistance

The ability of a rubber compound to resist surface wearing by mechanical action.

Accelerator

A chemical compound that speeds up the vulcanization of natural or synthetic rubbers.

Air Checks / Traps

Surface markings or depressions resulting from the trapping of air between the rubber surfaces being cured and the mold or press surface.

Ambient Temperature

The temperature of the environment surrounding a particular object.

Aliphatic

A major group of organic compounds characterized by the presence of straight chain arrangements of carbon atoms. The three subgroups that comprise aliphatic hydrocarbons are

paraffins (alkanes), olefins (alkenes), and acetylenes (alkynes).

AMS

Aerospace Material Specification.

AN

Abbreviation for Air Force-Navy (specifications).

Aniline Point

The lowest temperature at which equal parts of aniline and a test liquid (such as oil) will uniformly mix or blend. The aniline point of oil is a measure of aromaticity (the amount of unsaturated hydrocarbons present). The lower the aniline point, the more unsaturants are present and the higher the potential for swelling certain rubber compounds.

Antioxidant

Any organic compound that slows the process of oxidation.

Antiozonant

Any substance that slows the severe oxidizing effect of ozone on elastomers. Exposure to ozone typically causes surface cracking in many rubbers.

Aromatic

A major group of unsaturated cyclic hydrocarbons containing one or more rings. A typical aromatic compound is benzene, which has a six carbon ring, containing three double bonds.

AS568*

Aerospace Standard Uniform Dash Numbering System for O-rings. All military standard (MS) drawings currently use this system. Supersedes ARP-568. *Note: The current revision of the standard is C but it changes periodically.

ASTM

American Society for Testing and Materials.

Axial Seal

Squeezed, like a gasket, on both the top and bottom surfaces of the seal's cross section. A face seal.