Abstract
Stress of polypropylene (P. P) fibers kept at the constant length during heating was measured as the functions of time and temperature. The results were analyzed on the basis of viscoelastic theory. At first in order to investigate the decay of stress in the sudden heating, the drawn samples were soaked in the silicone oil bath maintained at high temperature predetermined, It was found that the results are explained satisfactorly by an Eyring's model and the temperaturedependent spring fe (Fig.5)
Apparent activation energy ΔH for the flow process was also calculated from the experimental results. Next, the model mentioned above was applied to the stress decay in the constant rate heating to find that the calculated values agrees well with the experimental sesults.
