Thermoset Elastomers

Publisher Summary Elastomers are defined by their very large deformability with essentially complete recoverability. In order for a material to exhibit this type of elasticity, three molecular requirements must be met: the material must consist of polymeric chains, the chains must have a high degree of flexibility and mobility, and the chains must be joined into a network structure. The first requirement arises from the fact that the molecules in a rubber or elastomeric material must be able to alter their arrangements and extensions in space dramatically in response to an imposed stress, and only a long-chain molecule has the required very large number of spatial arrangements of very different extensions. The second characteristic required for rubberlike elasticity specifies that the different spatial arrangements be accessible. The last characteristic cited is required in order to obtain the elastomeric recoverability. Typical nonbiological applications are tires, gaskets, conveyor belts, drive belts, rubber bands, stretch clothing, hoses, balloons and other inflatable devices, membranes, insulators, and encapsulants. Biological applications include parts of living organisms, and various biomedical devices.