Here is a calibrated material model for a PTFE (fluoropolymer, Teflon) tested at Room temperature. The material contained a small amount of graphite and carbon fibers. To use this material model you will need to first install the MCalibration software, and then export the model to your favorite FE software. The calibrated material model is the PolyUMod Three Network (TN) model.
Tutorial on how to include adiabatic heating in your material model calibration using MCalibration.