ASTM D1566 defines elastomers as "macromolecular materials that rapidly return to the initial dimensions and shapes after substantial deformation by a weak tension followed by release of tension." The standard also makes a comparison with rubber, defining it as "material that is capable of recovering from large deformations rapidly and forcefully, and may be, or is already, modified to a state in which it is essentially insoluble (but may increase by volume) in a solvent such as benzene, methyl ethyl ketone or ethanol toluene azeotrope. These definitions apply to natural rubber (derived from latex) and to synthetic elastomers, respectively.
Put simply, rubber is considered to be that material which, when stretched to twice its length and held for 1 minute, is about 1.5 times its original length after being released. In the case of elastomers, the length recovery would be closer to the original.
Elastomers, when compared to other engineering materials, are characterized by high deformability, very low rigidity, and high energy storage capacity. Certain elastomeric materials have specific characteristics such as resistance to corrosive chemicals, oil resistance, ozone, temperature and other environmental conditions.
HARPER, Charles A.; PETRIE, Edward M. Plastics Materials and Process: A Concise Encyclopedia. Hoboken: John Wiley & Sons, Inc., 2003.
WIEBECK, Hélio; HARADA, Júlio. Plásticos de Engenharia: Tecnologia e Aplicações. São Paulo: Artliber Editora, 2005.
About the author: Daniel Tietz Roda is Plastics Technologist graduated from the FATEC/ZL and Mechanical Design Technician from ETEC Aprígio Gonzaga, in São Paulo, Brazil. Roda worked 5 years with technical assistance and development of plastics in industries and nowadays is the publisher of this website.