Abstract

Polytetrafluoroethylene (PTFE) has a unique position in the plastics industry because of its chemical inertness, heat resistance, excellent electrical insulation properties, and low coefficient of friction in a wide temperature range. This white to translucent solid polymer has an extremely high molecular weight in the 10⁶–10⁷ range. It is a highly crystalline polymer and has a crystalline melting point, and its high thermal stability is due to the strong carbon-fluorine bond, making PTFE a very useful high temperature polymer.

Commercial PTFE is manufactured by two different polymerization processes that result in two different types of chemically identical polymers. Suspension polymerization produces a granular resin, and emulsion polymerization is used to produce coagulated dispersion or stabilized dispersion. Because of its high molecular weight, PTFE melt does not flow and cannot be fabricated by conventional techniques. The suspension polymerized PTFE is usually fabricated by modified metallurgy techniques. Emulsion polymerized, coagulated PTFE is processed by a cold extrusion process; the stabilized dispersions are processed according to latex processing techniques.