Studies on the mechanism of the instability of polymers in tensile testing

This study deals with the mechanism of the instability of tensile force occurring in tensile testing for polymer materials. It was found that through a proper transformation of inertia coordinates, a tensile test can be described in the same governing differential equations with the same boundary conditions as those employed in melt spinning. This fact suggests that the nature of the instability is simply due to draw resonance rather than any other cause. The effects of extension rate in tensile testing and the specimen dependence on the instability of tensile force were experimentally investigated by using specimens with various molecular orientations. The results are interpreted by applying the principles of draw resonance in melt spinning.