Micromechanism of the deformation process of macromolecular systems

The mechanism of cold drawing is described by a model of inhomogeneous deformation. The fundamental assumption of the model is that a random polymer coil subjected to an external stress forms a highly oriented strand and a residual rest coil that remains isotropic after a phase of elastic deformation. In this coil-strand transition model, the strand is growing during deformation by reduction of the volume part of the rest coil. In the volume-creating model, the constant orientation difference between rest coil and strand gives rise to a linear energy and entropy law and thus to a constant tensile stress. In the volume-conserving model, a decreasing power law for the stress-strain relationship is found, which is able to explain certain features of the cold drawing process.