Modeling stress-strain of glassy polymers up to yield

摘要

Based on a picture of a polymeric glass as a mosaic of nanoscale clusters of differing viscoelastic characteristics, we propose a new model for glassy polymers that accurately captures the stress-strain dependence at different rates and temperatures from small strain up to yield for polycarbonate. The model allows one to mterpolate and extrapolate limited experimental data (it requires three stress-strain curves as input). The model also provides insight into the fundamental issue of glassformer "fragility" in the glassy state and a practical means to assess dynamic inhomogeneities within polymeric glasses.