The role of anelasticity in high stress mechanical response and physical properties of glassy polymers

Non‐elastic deformation of amorphous polymers is studied from strain recovery tests. In particular, a strain recovery master curve is built. It allows one to estimate recovery times necessary to recover the whole non‐elastic deformation. On such a curve, two non‐elastic deformations, namely anelastic (nonlinear) and plastic deformations, are distinguished by their range of recovery times. The evolution of these two components is followed during a constant strain rate test. This clearly shows the importance of the anelastic deformation for the understanding of the nonlinear response of glassy polymers. Moreover, the structural modifications induced by non‐elastic strain of glassy polymers were studied by mechanical spectroscopy, differential scanning calorimetry and density measurements. These modifications appear to result from the anelastic part of the strain. Lastly, a consistent description of the mechanical response of amorphous solid polymers, and subsequent recovery processes, is proposed. The polymers tested were poly(methyl methacrylate). atactic polystyrene, and polycarbonate.