Elastomer Terms and Definitions

Plastic Deformation: A Change in dimension of an object under load that is NOT recovered when the load is removed (putty and tensile bar examples).

Elastic Deformation: When the dimensions return to their original values, when the load is removed (rubber band example).

Abrasion Resistance: Ability of a material to withstand surface loss due to frictional forces such as rubbing, scraping, grinding, sanding, etc.

Hardness:  The Resistance of a material to abrasion, compression, indentation, and scratching. (ASTM D2240)  The measurement of force required for a needle or point to penetrate the surface of a test specimen.

Tear Strength:  The force or stress required to begin/continue a tear.

Compression Set: (ASTM D395)  Ability of a material to return to its original thickness after being under a compressive load and temperature. Measures % deformation or decrease in thickness (the lower the number, the better the result).

Permanent Tension Set: (ASTM D412) Ability of a material to return to its original length after being under tension.