Internal plasticization: The effect of chemical structure

The elastic and plastic properties of high polymeric materials are functions of the forces holding the molecules together and the ability of small segments of the chains to move about, relative to other segments. Internal plasticization is accomplished by introducing structural features which reduce intermolecular and intramolecular forces and which, in general, decrease the order of the polymer. Physical techniques used to determine the effect of such structural features have been discussed. The results of numerous investigations into the relations between structure and properties have been considered in an attempt to present a simple and consistent physical picture of these relations.