2005 Volume 33 Issue 5 Pages 223-237
Application of a rate analysis to post-yield plastic flow in glassy polymers has been carried out through a novel approach. The rate analysis verified that during the yield process the structure of fully annealed glass initially in quasi-equilibrium was isothermally changed into various non-equilibrium melt-like structures depending on deformation rates and temperatures. It was shown that this was the case also for the polymer glass at temperatures far below the glass transition point. Structural relaxation in such mechanically induced non-equilibrium structures was illustrated using data of time-dependent mechanical property, differential scanning calorimetry and thermally stimulated deformation recovery. It was found that the strain energy given to glassy polymers during their yielding process was locked in tightly due to structural relaxation of the non-equilibrium structure. Applicability of the non-equilibrium structure to cold working of glassy polymers was discussed.