ABSTRACT
Elastomers and rubber are differentiated from polymers by the mechanical property of returning to their original shape after being stretched to several times their length. The rubber industry differentiates between the terms
elastomer
and
rubber
on the basis of how long a deformed material sample requires to return to its approximate original size after a deforming force is removed, and on its extent of recovery. The American Society for Testing and Materials (ASTM) defines an elastomer as “a polymeric material which at room temperature can be stretched to at least twice its original length and upon immediate release of the stress will return quickly to approximately its original length.” ASTM D1566 is more specific and quantitative in defining rubber as “a material that is capable of recovering from large deformations quickly and forcibly… (and which), in its modified state, free of diluents, retracts within one minute to less than 1.5 times its original length after being stretched at room temperature to twice its length and held for one minute before release.”
