Infrared spectroscopy polytetrafluoroethylene

The melting of a semierystalline or crystalline pol mier exhibits itself as an endothermic peak. The peak temperature is correspondent to the actual melting point of the pol mier. As in DSC, the area under the peak is proportional to the crystalline fraction of the sample. Mixtures of polymers can be characterized by DTA because the melting points of individual pol miers are, for the most part, unaffected by the mixture. Similar pol miers, such as high and low density, are distinguishable by DTA while infrared spectroscopy would not be able to easily resolve such subtle differences. Figure 10.29 shows a thermogram of a mixture of polytetrafluoroethylene (PTFE) and perfluoroalkoxy polymer (PFA). 

Torsional Damping - One of the methods to measure the crystallinity of polytetrafluoroethylene is torsional damping. Other methods include infrared spectroscopy, x-ray diffraction, and ultrasonics. 

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