Chemical and Radiation Cross-Linking of Polytetrafluoroethylene by Containing Fluorinated Compound

摘要

The thermo-chemical-induced crosslinking of polytetrafluoroethylene (PTFE) has been demonstrated by using fluorinated-compound without any other catalyst materials. The heat-treatment for PTFE containing the various amount of fluorinated-compound was carried out at 350 ℃ ± 5 ℃ for 30 minutes. After treatment, the various measurements and analysis were performed. By the solid-state ~(19)F-NMR spectroscopy, the new signal appeared at -188 ppm, which is assigned to the fluorine signal of >CF- group (Y-type crosslinking site). The obtained materials showed good mechanical properties and lower crystallinity, which were confirmed by tensile and flexural tests, and DSC analysis, compared with PTFE. Hence, the obtained material is confirmed to be crosslinked through thermal chemical reaction with decomposion of fluorinated-compound. The chemical-radiation synergetic crosslinking of PTFE (SX-PTFE) was carried out. By ~(19)F-NMR spectroscopy, several new peaks were appeared at - 85 ppm, - 89 ppm, - 110 ppm, - 114 ppm and - 188 ppm, respectively. The peaks at - 83 ppm and - 89 ppm correspond to -CF_3 were assigned to the fluorine signals of chain end group in amorphous and branching chain end group, respectively. The peaks at -110 ppm and -114 ppm were assigned to the fluorine signals of Y-type crosslinking site and hexafluoropropylene, respectively. The signal at -188 ppm is assigned to the fluorine signal of >CF- group. The peak intensity was higher than chemical-crosslinking and radiation-crosslinking. The mechanical properties of the SX-PTFE composite were much improved. The wettability of the obtained materials was the same as that of PTFE. That is, wettability of obtained materials hold the original property.