DEFORMATION PROCESSES OF POLYETHYLENE IN THE STRETCHING TO THE DIRECTION PERPENDICULAR OF FILM INTERPRETED IN TERMS OF CRYSTAL ORIENTATION

Orientation behavior of crystalline phase in the uniaxial stretching of tubular extruded polyethylene film in the direction prerpendicular to the machine direction is discussed quantitatively in terms of the X-ray pole figure and the degree of biaxial orientation functions.In the stretching the following deformation processes are recognized:(1) The screw axis of lamellar texture shifts to the stretching direction. The order of orientation distribution of b-axis about the screw axis is still kept up at the displacement of the screw axis.(2) The shifting of screw axis is attended by a-, c-axes rotation about b-axis. And the value of biaxial orientation functions _??_ and _??_ is recognized to increase gradually.The crystal c-axis becomes, finally, almost parallel to the stretching axis and a-, and b-axes take optionally rotating orientation in the perpendicular direction to c-axis.