Strain-Induced Molecular Orientation in Sheared Polycarbonate

Adolfo Jesus R. Gopez


Characterization of molecular orientation was done on polycarbonate samples previously deformed in plane simple shear. Birefringence and extinction angle values and x-ray data indicated the presence of molecular orientation. Measurements done on underperformed samples showed no evidence of orientation indicating that the orientation in the deformed sample is strain-induced. A theoretical expression giving birefringence as a function of draw ratio was derived using the pseudo-affine hypothesis. Good agreement was found with the birefringence data. Comparison with samples deformed in uniaxial tension showed that for the same draw ratio, samples deformed in simple shear had higher birefringence.

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