Effects of heat and gamma radiation on the degradation behaviour of fluoroelastomer in a simulated severe accident environment

Song, Inyoung; Lee, Tae Hyun; Ryu, Kyungha; Kim, Yong Jin; Kim, Myung-Sung; Park, Jong Won; Kim, Ji Hyun

doi:10.1016/j.net.2022.08.006

Cited by 7 publications

(2 citation statements)

References 17 publications

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“…Nonetheless, the most recent research on radiation-induced rubber degradation concentrates on how it affects material performance. Recent research on radiation-induced rubber degradation mainly focuses on its impact on material performance. − However, comprehensive investigations on the MW-assisted oxidative degradation of fluoroelastomers and their degradation processes are lacking. Our research team has been extensively studied the mechanisms of degradation of LTCFs made with CH-assisted oxidative degradation.…”

Section: Introductionmentioning

confidence: 99%

Microwave-Assisted Oxidative Degradation of Poly(vinylidene fluoride-co-hexafluoropropylene) Copolymers: Preparation, Characterization, and Reaction Mechanism

Qi,

Gao,

Gan

et al. 2024

Macromolecules

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This study focuses on the synthesizing of liquidterminated carboxyl fluoropolymers (LTCFs) from poly-(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) through microwave (MW)-assisted oxidative degradation. An indepth analysis was conducted on the preparation process, the duration of MW irradiation, and the resulting changes in LTCFs. Chemical titration and gel permeation chromatography (GPC) revealed that the MW-assisted oxidative degradation was achieved in 150−240 s, which is several orders of magnitude shorter than heat (CH) oxidative degradation. The modifications in the structure of C�C and C�O bonds within LTCFs were investigated over a time range of 0 to 900 s using Fourier transform infrared spectroscopy (FTIR), ultraviolet−visible spectrophotometry (UV−vis), and 19 F nuclear magnetic resonance ( 19 F-NMR). The analysis reveals that the dehydrofluorination reaction primarily occurs on the HFP-VDF-HFP sequence, resulting in two sequence structures: C�C Zaitsev and C�C Hofmann . The dehydrofluorination of the P(VDF-HFP) copolymer followed Zaitsev's rule mainly and Hofmann's rule slightly. Furthermore, it was observed that the processes of C�C bond formation (K HF reaction) and conversion (K C−C reaction) are in competition. When H 2 O 2 is enough, the degradation of the P(VDF-HFP) copolymer predominantly follows the K C−C reaction and partially the K HF reaction. The opposite is true for low H 2 O 2 concentrations. To conclude, this study suggests a mechanism for the synthesis of LTCFs using MW-assisted oxidative degradation of P(VDF-HFP). Under MW, the C atom adjacent to a C�C bond readily undergoes autocatalytic K HF reactions, creating conjugated polyene sequences of certain lengths. Meanwhile, the rapid degradation of H 2 O 2 expedites C�C oxidative breaking, producing the COOH functional groups.

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Section: Introductionmentioning

confidence: 99%

Microwave-Assisted Oxidative Degradation of Poly(vinylidene fluoride-co-hexafluoropropylene) Copolymers: Preparation, Characterization, and Reaction Mechanism

Qi,

Gao,

Gan

et al. 2024

Macromolecules

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“…Sugama et al 2015 96 Geothermal (water/oxygen)The presence of oxygen disturbs the C-F bond, through a three-stage oxidation mechanism, impacting the thermal stability of FKM. Song et al 202297 Gamma radiation and heatDecrease in C-H bonds and formation of the functional group containing oxygen and double bonds such as C-O, CQO, and CQC by auto-oxidation. The auto-oxidation process forms cross links with oxygen and reduces mobility, causing fluoroelastomer hardening.…”

mentioning

confidence: 99%

Encapsulating and inkjet-printing flexible conductive patterns on a fluoroelastomer for harsh hydrocarbon fluid environments

Wankhede

Alshehri

2023

J. Mater. Chem. C

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Influence of γ‐irradiation dose on the mechanical and tribological properties of fluoroelastomer

Xiao,

Zhang,

Wei

et al. 2024

Polymer Engineering & Sci

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Fluoroelastomer (FKM) undergo various degrees of degradation in a gamma‐irradiated environment, leading to changes in their mechanical and tribological properties. In this paper, changes in the properties of FKM were investigated for six different doses. Fourier transform infrared‐atomic absorption spectroscopy (FTIR‐ATR) results show that FKM samples undergo dehydrofluorination and oxidation reactions during irradiation, resulting in the formation of C=C, C=O, and ‐OH functional groups. The results of the swelling test showed that the degree of cross‐linking of the FKM specimens increased with increasing irradiation dose. Mechanical test results show that the fracture mechanism of FKM specimens gradually evolves from ductile fracture to brittle fracture with the increase of irradiation dose. Its tensile strength reaches its maximum at an irradiation dose of 1000 kGy, and the modulus of elasticity becomes larger with increasing irradiation dose. The results of wear tests show that the average coefficient of friction of FKM specimens first decreases, reaches a minimum at 500 kGy, and then gradually increases. The amount of wear increases with increasing irradiation dose. The wear mechanism of FKM specimens is abrasive wear at 0–500 kGy, adhesive wear at 1000 and 2000 kGy, and fatigue wear at 3000 kGy.Highlights FKM was irradiated by gamma‐ray with a total dose of 3000 kGy. Dehydrofluorination and oxidation reactions occur during irradiation. Increased cross‐linking leads to changes in mechanical properties. The wear mechanism of FKM with different doses has been investigated.

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Effects of heat and gamma radiation on the degradation behaviour of fluoroelastomer in a simulated severe accident environment

Cited by 7 publications

References 17 publications

Microwave-Assisted Oxidative Degradation of Poly(vinylidene fluoride-co-hexafluoropropylene) Copolymers: Preparation, Characterization, and Reaction Mechanism

Microwave-Assisted Oxidative Degradation of Poly(vinylidene fluoride-co-hexafluoropropylene) Copolymers: Preparation, Characterization, and Reaction Mechanism

Encapsulating and inkjet-printing flexible conductive patterns on a fluoroelastomer for harsh hydrocarbon fluid environments

Influence of γ‐irradiation dose on the mechanical and tribological properties of fluoroelastomer

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