Rubber elasticity and wheat gluten proteins

Many materials exhibit elastic behaviour when a stress is applied, the material returning to its original dimensions after the stress has been removed. In crystalline and glasslike solids the elastic limits rarely exceed 1%. In contrast, true elastomers are able to undergo large elastic deformations, that is, to stretch and return to their original state in a reversible way and without breaking. Such elastomeric materials are polymers consisting of long flexible chainlike molecules These chains are capable of undergoing considerable molecular motion, unlike in crystalline solids where only limited atomic movement is permitted. The energy involved in the deformation of elastomers is stored and on removal of the stress this energy is recovered. This latter stage is therefore passive in that it does not require energy input. The degree to which an elastomer is ideal is determined by how much of the stored energy is recovered, with some systems being more efficient than others.