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内容記述 |
The effect of temperature on the irradiation-induced decomposition of polytetrafluoroethylene (PTFE), a representative fluorocarbon polymer, was investigated to improve the energy efficiency of the recycling process. The weight loss of PTFE was 18%, 33%, 64%, and 91% by the irradiation with a dose of 7.5 MGy (dose rate:1.0 kGy/s) at 30°C, 120°C, 200°C, and 270°C, respectively. During the electron beam irradiation of PTFE powders under an oxygen atmosphere, a greater weight loss of PTFE was observed at higher irradiation temperatures. At 370°C, PTFE powder is completely converted to gaseous components with an absorbed dose of 5.0 MGy; the primary product was identified as an oxidized fluorocarbon (C?F??O?). A lower dose rate (0.1 kGy/s) reduced the required absorbed dose for PTFE decomposition to 80% level. Post-irradiation analyses of the PTFE residues using TGA, SEM-EDX, and FT-IR consistently showed that higher irradiation temperatures accelerated the production of oxidized fluorocarbons and further oxidized gaseous products evaporating from the PTFE residue. XRD analysis showed that high-temperature irradiation also increased the crystallite size to 37±5 nm after irradiation at 270°C, which is nearly double the size of non-irradiated PTFE (21±2 nm). High-temperature irradiation significantly accelerated the oxidation and weight loss of PTFE, offering a promising method for enhancing the energy efficiency of PTFE recycling. |
