Abstract
A new method for studying the anisotropy in mechanical relaxations of oriented polymers is proposed. The method consists of measuring velocicty and attenuation of ultrasonic shear waves propagating in the normal direction to the film as a function of the angle between draw direction and wave polarization. This method can separate the orientation of crystalline phase, amorphous phase and others in the polymer, because multiple relaxations in the temperature dispersion curve are ascribed to related phases, respectively. Preliminary results for low density polyethylene and polytetrafluoroethylene at 3 and 10 MHz in temperature -60° to 40°C are presented and the deformation mechanism of polyethylene is suggested.
Published Version
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