Characterization of fluoroelastomers by various analytical techniques including pyrolysis gas chromatography/mass spectrometry

Hiltz, John A.

doi:10.1016/j.jaap.2013.06.008

Cited by 35 publications

(21 citation statements)

References 5 publications

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“…As regards FPM, absorptions at 2,923 and 2,853 cm −1 can be ascribed to the stretching of methylene C─H bonds in vinylidene units. The most intense broad absorption with a peak at 1,208 cm −1 , associated with the stretching of C─F in ─CF 2 ─ and ─CF 3 groups, is present in several FPM elastomers, but the two absorptions at 1,353 and 832 cm −1 appear together only in the spectrum of Viton A . Viton A is a copolymer of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) commercialized by DuPont and typically containing about 80 mol% VDF and 20 mol% HFP.…”

Section: Resultsmentioning

confidence: 99%

Degradation of EPDM and FPM elastomers irradiated at very high dose rates in mixed gamma and neutron fields

Ferrari

Pandini

Zenoni

et al. 2019

Polymer Engineering & Sci

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Elastomers are widely used in radioactive environments, where ionizing radiations induce a deterioration of their properties due to degradative phenomena occurring in the polymer structure. Their radiation resistance is usually assessed using γ‐rays and relatively low dose rates, but in actual applications, they are often exposed to mixed radiation fields and higher dose rates. Ethylene propylene diene monomer (EPDM) is known for its excellent resistance to γ‐rays but absorbs a larger dose by neutron interactions than fluoroelastomer (FPM). In this work, EPDM and FPM were irradiated in mixed neutron and gamma fields, using high dose rates (from 22 to 700 kGy h−1) and total absorbed doses between 0.2 and 3.5 MGy. The effects of irradiation were assessed by swelling tests, differential scanning calorimetry analysis and dynamic mechanical thermal analysis, and tensile tests. The results show that, even if irradiations were carried out in air, degradation took place under nonoxidative conditions owing to the high dose rates employed. Under such conditions, crosslinking is the dominant radiation‐induced reaction in both elastomers. Moreover, material degradation seems to be influenced mostly by the total absorbed dose and not by the type of radiation. Contrary to what observed at the lower dose rates employed with γ‐rays, major dose rate effects are not observed. POLYM. ENG. SCI., 59:2522–2532, 2019. © 2019 Society of Plastics Engineers

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Section: Resultsmentioning

confidence: 99%

Degradation of EPDM and FPM elastomers irradiated at very high dose rates in mixed gamma and neutron fields

Ferrari

Pandini

Zenoni

et al. 2019

Polymer Engineering & Sci

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“…Py‐GC/MS is considered the best technique for the characterization of polymeric materials and understanding variations in their composition . By using pyrolysis coupled with GC‐MS, even minor differences can become apparent.…”

Section: Resultsmentioning

confidence: 99%

“…Numerous reports are available regarding the application of this technique in the study of polymers . Fluoropolymers and the mechanisms of their pyrolysis are widely discussed in the literature . Therefore, due to the high sensitivity and selectivity, the Py‐GC/MS technique was selected for our studies, and a method for the evaluation of explanted samples of XIENCE stents was subsequently developed.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of chemical stability of polymers of XIENCE everolimus‐eluting coronary stents in vivo by pyrolysis‐gas chromatography/mass spectrometry

et al. 2017

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The polymers poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and poly(n-butyl methacrylate) (PBMA) are employed in manufacturing the XIENCE family of coronary stents. PBMA serves as a primer and adheres to both the stent and the drug coating. PVDF-HFP is employed in the drug matrix layer to hold the drug everolimus on the stent and control its release. Chemical stability of the polymers of XIENCE stents in the in-vivo environment was evaluated by pyrolysis-gas chromatography with mass spectrometry (Py-GC/MS) detection. For this evaluation, XIENCE stents explanted from porcine coronary arteries and from human coronary artery specimens at autopsy after 2-4 and 5-7 years of implantation, respectively, were compared to freshly manufactured XIENCE stents (controls). The comparison of pyrograms of explanted stent samples and controls showed identical fragmentation fingerprints of polymers, indicating that PVDF-HFP and PBMA maintained their chemical integrity after multiple years of XIENCE coronary stent implantation. The findings of the present study demonstrate the chemical stability of PVDF-HFP and PBMA polymers of the XIENCE family of coronary stents in the in-vivo environment, and constitute a further proof of the suitability of PVDF-HFP as a drug carrier for the drug eluting stent applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1721-1729, 2018.

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“…The results show that the crosslinking of the O-ring gasket increased a little after the failure, which coincides with the shore hardness results. It's implied that the O-ring gasket may have gone through aging and led to changes in the structure of a polymer [27] . The increase of the crosslinking may improve the brittle of the O-ring gasket and increase the possibilities of the fracture of the O-ring gasket.…”

Section: Dsc Analysis Of the O-ring Gasketsmentioning

confidence: 99%

Failure analysis of O-ring gaskets of the electric hydraulic system in the nuclear power plant

Yang

Ding

2017

Engineering Failure Analysis

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Characterization of fluoroelastomers by various analytical techniques including pyrolysis gas chromatography/mass spectrometry

Cited by 35 publications

References 5 publications

Degradation of EPDM and FPM elastomers irradiated at very high dose rates in mixed gamma and neutron fields

Degradation of EPDM and FPM elastomers irradiated at very high dose rates in mixed gamma and neutron fields

Evaluation of chemical stability of polymers of XIENCE everolimus‐eluting coronary stents in vivo by pyrolysis‐gas chromatography/mass spectrometry

Failure analysis of O-ring gaskets of the electric hydraulic system in the nuclear power plant

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