The Influence of the Irradiation Temperature on the Ratio of Chain Scission to Branching Reactions in Electron Beam Irradiated Polytetrafluoroethylene (PTFE)

Abstract

Polytetrafluoroethylene (PTFE) films have been irradiated by electron beam in vacuum at various temperatures ranging from room temperature up to temperatures far above the melting temperature. Changes of the chemical structure have been analyzed by 19F solid‐state NMR and IR spectroscopy. The concentration of several structures generated by irradiation increases with increasing irradiation temperature up to the beginning of the thermal degradation. The molar ratio of >CF branching points to CF3 end groups changes with crossing of the melting temperature. The generation of >CF branching points is accelerated if the PTFE is irradiated in the molten state, where branching reactions become more important.magnified image

Grafting of styrene into pre-irradiated fluoropolymer films: Influence of base material and irradiation temperature

“…The results confirm the knowledge that degradation is the predominant process in PTFE, which is induced by irradiation in solid-state, i.e. below the melting temperature (Lappan et al, 2007).…”

Basic characterization and investigation of a fluorinated terpolymer in pure state and in mixtures with kaolinite at solid interphases of thin films prepared by facile solution cast and nonsolvent methods

“…The signals of the spectrum are assigned to the specific functional groups. [23][24][25] The peak at À184 ppm is assigned to -CF (HFP) while -CF 3 (HFP) appears around -75 ppm. The peaks in the region between -90 ppm and -95 ppm are assigned to -CF 2 of VDF, the ones between -100 ppm and -114 ppm to CF 2 of HFP, and the ones between -115 ppm and -125 ppm to CF 2 of TFE.…”

Tailoring of Mesenchymal Stem Cells Behavior on Plasma‐Modified Polytetrafluoroethylene

“…In general, both reactions occur simultaneously, but one of them tends to dominate depending on the polymer types and irradiation conditions. It has been reported that PTFE in the solid state mainly undergoes chain scission during ion irradiation 26–28. In particular, the C–F bonds of PTFE are high in energy and short in length and the adjacent F atoms are repulsive to each other due to Van der Waals force and steric effects.…”