Automatic measurement of the creep behavior of linear polymers in the course of homogeneous drawing

An automatic device was built, enabling the creep behavior of fibers of linear semicrystalline polymers to be studied during various stages of homogeneous drawing. The device first deforms the sample at constant speed up to a certain draw ratio; then, without interrupting the stress, the character of deformation is changed from deformation at constant speed to that caused by constant load (creep). It was verified that the method described supplies more detailed information on the changes of the mechanical behavior of polymers at various stages of orientation than does the more conventional stress-strain curve.