Analyzing the microstructure and mechanical properties of polytetrafluoroethylene fabricated by field-assisted sintering

Abstract The results presented here exploits field-assisted sintering (also known as spark plasma sintering) to elaborate polytetrafluoroethylene (PTFE) dense polymer materials from PTFE powder. This technique is especially suitable for processing viscous polymer materials, e.g. PTFE, which is known to be difficult to melt-process via the usual methods including hot press sintering and hot isostatic pressing. A series of sintered PTFE is prepared at constant sintering temperature and various heating rate and the microstructures formed in this manner are characterized using differential scanning calorimetry, Raman and infrared spectroscopies. Stress-strain curves performed by using both three-point bending and tensile tests highlight a significant dependence of the heating rate on the PTFE microstructure. The stress-strain behavior under large deformations is discussed on the basis of the theory proposed by Haward and Thackray.