CHEMICAL INTERACTION OF METALS WITH POLYTETRAFLUOROETHYLENE

Chemical reactions of cadmium, indium and tin with PTFE have been found to occur when mixtures of the metal and polymer were heated in a differential scanning calorimeter to 773 K. Analysis of the residues by X-ray photoelectron spectroscopy (XPS) showed the presence of fluoride ions. The evaporation of a metal film on to the clean polymer surface has also been found by XPS to produce metal fluoride for nickel, cadmium, tin, indium and lead but not silver or gold. The rubbing of aluminium on to PTFE also produces reaction to give fluoride. The PTFE polymer molecules have been found to diffuse to the surface of metal/polymer composites at a significant rate. This latter process may be important in the use of this polymer in bearing materials. © 1979 Chapman and Hall Ltd.