Polytetrafluoroethylene (PTFE) is a fluorocarbon-based polymer which has the appearance of a white powder but the particle size varies from micron to sub-micron; final particle size depends on the milling process. The polymerisation process controls the molecular weight of PTFE and the density is approximately 2.2 g/ml.
PTFE has a small surface area which makes it an inefficient thickener, meaning a relatively high percentage (compared to other thickener types) is required for a grease to be formed when added to a base oil. Morphology of the PTFE particles also plays an important role in the thickening efficiency. Electron beam irradiation will also alter the physical and chemical properties of PTFE.
PTFE is a common thickener but there are many sizes and grades of PTFE on the market, the quality of which varies widely and can have a big effect on performance.
Melting point of PTFE is approximately 325°C.