**3. Thermodynamics of elasticity**

Elastomers extend and contract by conformational change from a compact random coil to extended chain. The random coil can have many possible conformations resulting in a high entropy. A fully extended chain can only have one conformation resulting in low entropy. The extended chain will spontaneously contract into a random coil since the entropy of the process is favourable. Enthalpy is not a contributor for an ideal elastomer since intermolecular forces are minimal. Entropy is overcome by a mechanical force deforming the elastomer. Thermodynamic equations are applied to elastomeric deformation and recovery. By analogy with an ideal gas, elastomers that conform to the thermodynamics are called ideal elastomers. As in the case of real gases, real elastomers deviate from ideality.

Deviations of elastomers are the result of:


The aim of this review is to compile the updated knowledge on thermoplastic elastomers in general, practically their structures, syntheses, processing methods, mechanical properties and applications.
