Dislocations in glassy polymers do they exist? Are they useful?

This paper reviews a series of models which apply the concept of dislocation to the interpretation of yield phenomena in glassy polymers. The point is made on three different scales. At the macroscopic scale (≈1 mm) shear fronts are observed at the tips of deformation bands, their elastic singularity being modeled by the theory of spread dislocations. At the mesoscopic scale (≈1 μm) the development of localized sheared domains is readily predicted by micromechanical simulations. At the microscopic scale (≈1 nm), the existence of dislocations among chain distributions is more problematic, but is supported by the large Baushinger effect observed during plastic cycling.