Fourier-transform infrared study of uniaxially oriented polytetrafluoroethylene

Infrared measurements of the dichroic ratio of polytetrafluoroethylene absorption bands provide a valuable method of determination of the orientation of chains as well in crystalline regions as in amorphous ones. The 1452 cm⁻¹, 1545 cm⁻¹, and 2362 cm⁻¹ combination bands are convenient for measuring crystalline orientation while the 703 cm⁻¹, 740 cm⁻¹, and 786 cm⁻¹ bands lead to amorphous orientation. The 1795 cm⁻¹ (crystalline), 720 cm⁻¹, and 774 cm⁻¹ (amorphous) absorption bands are shown to be complex ones and thereby unusable for measuring orientation.