Study on chemical structures of poly (tetrafluoroethylene-co-perfluoroalkylvinylether) by soft-EB irradiation in solid and molten state

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• 作者：Tomoyuki Kakigi ; Akihiro Oshima ; Nozomi Miyoshi ; Katsuyoshi Murata ; Kazuki Fujii ; Naohiro Mitani ; Tatsuya Urakawa ; Yukiko Sato ; Akio Matsuura ; Jingye Li ; Takaharu Miura ; Etsuko Katoh ; Masakazu Washio
• 关键词：PFA ; Soft-EB ; DSC ; ¹⁹F MAS NMR ; Y-type crosslinking ; Tertiary carbon
• 刊名：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
• 出版年：2007
• 出版时间：December 2007
• 年：2007
• 卷：265
• 期：1
• 页码：118-124
• 全文大小：427 K

文摘

Poly (tetrafluoroethylene-co-perfluoroalkylvinylether) (PFA) was irradiated by soft electron beam (soft-EB) under nitrogen gas atmosphere in solid-state and its molten state, respectively. The changes of thermal property and chemical structures of irradiated PFA in solid-state and molten state were studied by differential scanning calorimetric analysis (DSC) and solid-state ¹⁹F magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. By DSC analysis, the melting temperature shifted to lower temperatures, and crystallinity decreased with increasing soft-EB dose. By solid-state ¹⁹F MAS NMR spectroscopy, the new signals was observed and the detected new signals in irradiated PFA at 315 °C and at 30 °C were due to the tertiary carbon group with branching site (Y-type crosslinking site), perfluoro-propylene site and chain end methylene groups, respectively.

Moreover, the molar ratio of perfluoroalkylvinylether (FAVE) structure to –CF₂– units decreased with increasing dose.