Non-Gaussian Model for Rubber Elasticity: (I) Finite Chain Extensibility and Tube Concept

摘要

A simple, useful model for an elastic network is developed in terms of finite chain extensibility and entanglement constraints. For the former, each chain that constitutes the network is treated as a specific non-Gaussian one and for the latter is confined within a tube that represents entanglement constraints. The model is built within the framework of the classical phantom network theory. In addition, it considers fluctuations of diameter of the tube. While the extent of suppression of junction fluctuation is also incorporated through the well-known empirical factor h, the tube diameter is assumed to be deformed under a power law including its exponent (γ) that describes the strain-dependence of spatial constraints. Two free energies due to deformations of the network and tube diameter are calculated.