We extend a model that has been proposed for describing mechanical properties of glassy polymers and that takes into account the heterogeneous nature of the dynamics. We describe their nonlinear mechanical properties, up to a few 10% deformation. We propose that the elastic energy stored in the volume ∼ ξ3 of dynamical heterogeneities effectively reduces the free energy barriers present for internal relaxation. It allows to calculate yield stresses of order a few 10 MPa, which are consistent as compared to experimental data without additional adjustable parameters than the scale ξ. The model is solved in 3D by numerical simulations with spatial resolution the scale of dynamical heterogeneities. We show that the prediction of our model as regards to yield behavior is consistent with the value of 3–5 nm for the scale for dynamical heterogeneities. Yield appears as the result of an acceleration of the dynamics of subunits with intermediate relaxation times which relax under stress before subunits with very long relaxation. Our simulations describe the onset of plastic behavior and the reorganization at the scale of dynamical heterogeneities. We predict the appearance of shear bands on a scale of a few tens of nanometers at yield and beyond.

A coarse-grained model has been proposed recently in order to describe plastic properties of glassy polymers with space resolution the scale ξ of dynamical heterogeneities. This model allows for describing plastic flow by assuming that the elastic energy stored at the scale of dynamical heterogeneities reduces by a similar amount the free energy barriers for αrelaxation. The aim of this article is to consider in more details the evolution of the distribution of relaxation times under plastic deformation. This is achieved by taking explicitly into account the so-called facilitation mechanism during plastic flow introduced by Merabia and Long [Eur.