**6. Conclusions**

Generally, the high energy of the gamma-rays and the formation of radicals led to the chain scissioning, resulting in a decrease in molecular weight of the polymer. The produced alkyl free radicals react with oxygen to form peroxyl free radicals through the abstraction of hydrogen led to the cleavage of the C-H, C-C, and C-F chains.

When aromatic fluorinated polymers are irradiated, the observed yield of breaks obtained by splitting C-F and C-C bonds is often lower than those from the C-H and C-C bonds in aliphatic hydrocarbon polymers. Namely, the fluorine atoms are not readily abstracted from fluorinated polymer by general molecules and radicals such as H, CH3, CF3, and C2F5. This is because of radiation resistance due to the combination of C-F binding force and aromatic resonance structure. Actually, the aromatic hydrocarbon biphenyl and terphenyl are reported to be sufficiently resistant to radiation, the fluorine atoms of aromatic fluorocarbon (i.e., 1F-PS and 5F-PS) are also expected to be resistant to radiation. The more fluorine content in the benzene, the highly ordered π-stacking of fluorinated benzene increases charge carrier mobilities, suggesting stabilization against bond rupture by the radiation. So, it seems reasonable to conclude that the fluorine will be hardly abstracted from 5-F rather than 1-F based on simulation and measurement results [28].

**Author Contributions:** Conceptualization, Y.-H.Y., J.-H.P. and H.-J.G.; methodology, Y.-H.Y., H.-E.S. and N.-H.L.; software, Y.-H.Y., J.-H.P., M.-S.C., J.-H.M. and J.-Y.P.; validation, M.-S.C., J.-H.M. and J.-H.L.; formal analysis, Y.-H.Y., J.-H.L. and H.-E.S.; investigation, Y.-H.Y. and H.-E.S.; resources, Y.-H.Y. and H.-E.S.; data curation, Y.-H.Y. and H.-E.S.; writing—original draft preparation, Y.-H.Y. and H.-E.S.; writing—review and editing, Y.-H.Y., H.-E.S. and H.-J.G.; visualization, Y.-H.Y., H.-E.S. and H.-J.G.; supervision, H.-J.G. and N.-H.L.; project administration, N.-H.L.; funding acquisition, N.-H.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the Nuclear R&D program of the Ministry of Science and ICT.

**Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.
