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.