Rubber‐Like Elasticity

Abstract

AbstractRubber‐like elasticity, which is a property to sustain very large deformations without rupture up to about 10 times from the original length followed by complete recovery, is manifested in polymeric materials with a three‐dimensional network structure consisting of long, flexible polymer chains. Rubber‐like elasticity originates from the decrease in entropy of the chains between cross‐linking points resulting from the elongation. In addition, there is an internal energetic component to the elasticity, which can be extracted from thermoelastic experiments. This is related to conformational energy changes of the polymer chains and, in polymer gels containing large amounts of solvent, to energy changes in solvent‐polymer interactions. Because the network structures of polymeric materials cannot be directly observed, the theoretical models for predicting the correlation between the structure and physical properties are uncertain. However, estimating structures by combining existing models with measured physical properties is important for guiding material design. This article overviews experimental and theoretical aspects of rubber‐like elasticity.