- Abrasion Resistance
- The ability of a rubber compound to resist surface wear 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. This standard periodically changes so check for the latest revision.
- 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.