Rubber Surface Fluorination with Xenon Difluoride

RUBBER SURFACE FLUORINATION WITH XENON DIFLUORIDE 

Friction force measurements at Skega AB were carried out by the following procedure. A piston/cylinder type of test ring was used. The O-ring being tested was greatly stretched over the piston and fitted into the seal groove. The cylinder was carefully wiped and dried with a clean cloth before the piston was put into the 

It is very important to know how surface fluorination affects the stability of tribological characteristics. In the case of Russian-made rubbers we used a standard friction machine (SMT), where abrading was done with a stainless steel instead of a conventional brass grid so that the test would be more rigorous. The results obtained are shown in Table 15.3. 

To validate our idea that treating rubber products with gaseous XeF, causes them to become surface-fluorinated, i.e., that chemically bonded fluorine atoms are incorporated in the surface layer, we did ESCA analyses ofthe samples treated in various modes. The results are shown in Table 15.4. 

Although we made no attempt to elucidate the mechanism of friction decreases in rubbers after surface fluorination, it seems to us that apart from the substitution of H atoms to F in the polymer macromolecule, which forms a fluoropolymer on the surface, there is another phenomenon that makes a significant contribution to the friction decreases, i.e., fluorination of carbon black, which is used in rubber recipes for reinforcement. It appears that when the carbon black in the surface of the rubber is fluorinated it produces a lubricating effect, followed by blooming on the surface of the treated rubber while it is under a friction load. So, in our opinion, two effects contribute to friction decrease of carbon-filled rubbers fluorination of the rubber macromolecules and fluorination of the carbon black rubbers that do not contain carbon black show a much smaller decrease in friction after XeF2 treatment. 

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RUBBER SURFACE FLUORINATION WITH XENON DIFLUORIDE... 

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