The properties of poly(tetrafluoroethylene) (PTFE) in compression

Samples of DuPont 7A and 7C Teflon (PTFE, poly(tetrafluoroethylene)) were tested in compression at strain-rates between 10−4 and 1 s−1 and temperatures between −198 and 200 °C. Additionally, using a Split-Hopkinson pressure bar, a temperature compression series was undertaken between −100 and 150 °C at a strain rate of 3200 s−1. To investigate the small-strain response, strain gauges were used to measure axial and transverse strain allowing the Poisson ratio to be quantified. As expected, the mechanical properties were found to be strongly affected by strain-rate and temperature. Moduli were found by several methods and the trend, with respect to temperature, lends weight to the suggestion that the glass-transition temperature of PTFE is ≈−100 °C. The physical properties of the sintered PTFE were measured and the crystallinities measured by several techniques.