Heat-treated molded graphite

PTFE is a crystalline polymer consisting of twisted zigzag spirals with at least 13 repeating units per turn. This nonpolar polymer has a solubility parameter of 6.2 H, a high (327 C), and a heat deflection temperature of 121 C PTFE is a tough, flexible polymer which retains its ductility at extremely low temperatures (-269 0. The coefficient of friction of ptfe is the lowest of any known solid material (see Table 13.4). Films of ptfe can be bonded by adhesives to other surfaces if the polymer surface is treated with sodium. It also bonds to diamonds and graphite whose surfaces have been fluorinated. Liquid sodium removes fluoride ions from the surface and leaves free radicals on the polymer surface, ptfe is resistant to almost all corrosives and solvents, but it can be dissolved in hot perfluorinated kerosene, ptfe is difficult to mold or extrude. 

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