Structural factors in deformation of crystalline polymers
Title:
Structural factors in deformation of crystalline polymers
Author:
Takayanagi, Motowo Kajiyama, Tisato
Appeared in:
Journal of macromolecular science. Part B, Physics
Paging:
Volume 8 (1973) nr. 1-2 pages 1-27
Year:
1973-10-01
Contents:
The multiple α absorption of bulk-crystallized polyethylene (PE) was separated into the α1 and the α2 absorptions on the assumption that this α2 absorption is associated with shear deformation of lamellar crystals, i.e., has the same characteristics as in single crystal mats. The separated α1 mechanism is related to the molecular motions in the intermosaic block region. The α1 process is very sensitive to static and dynamic deformation, whereas the α2 process is not affected. Plastic deformation of bulk crystallized PE was analyzed in terms of true stress and true strain. The temperature dependence of the critical yield stress below 60°C showed the same magnitude of activation energy (26 kcal/mole) as that of α1. The leading mechanism of deformation at lower temperatures is the breakdown of lamellar crystals into mosaic blocks. Compressive deformation of solid-state extrudates along the molecular axis, giving rise to kink bands, was analyzed with X-ray goniometry and in terms of the strain-rate dependence of the yield stress. The deformation of the crystals in the kink bands occurred by superposition of intercrystallite slip (α1) and uniform shear deformation (α2). It was concluded that consideration of intermosaic slip mechanisms (α1), in addition to the shear deformation (α2) and the interlamellar deformation (β), is effective and helpful to understand the deformation process of crystalline polymers.
Journal description