A high viscous polymer processed by conventional and unconventional techniques: evaluation of mechanical behaviour and physical characteristics

Abstract

The physical and mechanical properties of polytetrafluoroethylene (PTFE) processed by conventional and unconventional techniques are reported. Whereas, manufacturing PTFE is problematic due to its high melt viscosity, a new process namely Spark Plasma Sintering (SPS) is performed to elaborate PTFE samples from the particles powder. Thanks to this new sintering process the series of PTFE samples are easily obtained in a remarkably short time. The properties of PTFE-SPS samples are compared to those measured in commercial samples processed by two classical methods: the extrusion and moulding. The tensile mechanical properties carried out at room temperature are found to be superior for the first set of samples (PTFE-SPS). The difference in these macro-behaviours including stiffness, toughness is related to some physical properties of the three series of samples such as their density or crystallinity. The stress–strain curves are then confronted to the Mooney–Rivlin model in order to capture the physics of the large deformations observed in these materials. It is concluded that the SPS technique appears to be a promising way to elaborate the PTFE for various reasons: (i) resolving the high molecular weight problem, (ii) reducing the processing time and cost and (iii) without compromising their mechanical or physical properties.