抄録
The fold content (Cf) of polyethylene, which varies with drawing and/or annealing, was evaluated by IR method described in the previous report.
Polyethylene film having a-axis orientation was drawn to various draw ratios, draw directions and at various temperatures. In the drawing processes, Cf decreases abruptly in the region of draw ratio of 2-3 and gradually decreases with further drawing when drawn along the machine direction. The contents of remaining folds are quite different between the specimens drawn along the machine direction and those drawn transversely to this direction. Cf also decreases with increasing draw temperature when the film is drawn at constant draw ratio. These facts suggest the difference between the deformation processes of the slipping or rotation of lamellae and those of direct unfolding of chains from the lamellae.
In the annealing process, Cf reflects the content of refolding and indicates the differences in the microstructures of the drawn specimen before and after heat treatment.
