Remnant morphologies in highly-drawn polyethylene after annealing

Specimens of the polyethylene Sclair 2907, full of large banded spherulites, have been drawn to high extensions, and parts of these annealed close to their melting points under constraint. Etching with permanganic reagents and examination under the scanning electron microscope revealed that in transverse sections of the unannealed specimens, the legacy of the banded spherulitic morphology is seen at draw ratio 10 × but appears to have been overwritten by subsequent developments at 20 × and 33 ×. However, after annealing, the specimens show recrystallized regions which follow the pattern of the original banded spherulites drawn affinely. This is so even for 33 × drawn specimens where the unannealed longitudinal morphology has been overwritten by a new structure of density-deficient regions arranged in parallel bands. It is inferred that different deformation mechanisms operate on bundles of lamellae oriented differently in the original material, and that legacies of the original morphology may be retained at much higher deformations than previously assumed, but they may require appropriate treatments to make them visible.