Two-dimensional Infrared Spectroscopy Study on Polytetrafluoroethylene F-C-F Stretching Vibration

The temperature effect of the F-C-F stretching vibration mode of polytetrafluoroethylene was studied by one-dimensional infrared spectroscopy in the temperature range from 303 Kto 393K.The polytetrafluoroethylene F-C-F asymmetrical stretching vibration mode(νasCF2)and symmetrical stretching vibration mode(νsCF2)occurred respectively near 1220cm-1and 1150cm-1.Second derivative infrared spectra and fourth derivative infrared spectra of polytetrafluoroethylene were investigated also.The band resulting from theνasCF2appeared near 1210cm-1and 1260cm-1,but the band resulting from theνaCF2appeared near 1145cm-1,1155cm-1and 1175cm-1.Two-dimensional infrared spectra of polytetrafluoroethylene were studied to determine the sequence ofνCF2intensity changes.It had been found that the sequence of polytetrafluoroethylene intensity changes was 1145cm-11210cm-11155cm-11175cm-11260cm-1.The study demonstrated the key roles of infrared spectroscopy in the analysis of thermal denaturation of the polytetrafluoroethylene.