Characterization of structural modifications in poly-tetra-fluoroethylene induced by electron beam irradiation

Abdou, Saleh M.; Mohamed, R. I.

doi:10.1016/s0022-3697(01)00131-7

Cited by 31 publications

(19 citation statements)

References 4 publications

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“…In our studies, the crystallinity of PTFE increases from original 0.81 to 0.85 at 20 kGy, but keeps almost constant at higher dose level. The observed increasing of crystallinity with dose is generally consistent with the finding [12] in the electron beam irradiation of PTFE sheet, although in which the crystallinity is higher than 90% at 150 kGy.…”

Section: Radiation Effect On Crystallinity and Chemical Structuresupporting

confidence: 88%

Study on polytetrafluoroethylene aqueous dispersion irradiated by gamma ray

Wang

Liu

et al. 2006

Journal of Fluorine Chemistry

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Section: Radiation Effect On Crystallinity and Chemical Structuresupporting

confidence: 88%

Study on polytetrafluoroethylene aqueous dispersion irradiated by gamma ray

Wang

Liu

et al. 2006

Journal of Fluorine Chemistry

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“…2. These features can be attributed to wagging and rocking modes of CF 2 groups that are located within amorphous regions of the PTFE solid [7,25]. The intensity of these modes decreases upon exposure of PTFE to a-radiation, as observed in spectra of the 10 5 and 10 6 Gy samples shown in Fig.…”

Section: Ftirmentioning

confidence: 96%

“…Table 1 Assignments of spectral features observed in FTIR data of virgin and a-irradiated PTFE. Previously determined assignments and corresponding observed energies in FTIR spectra are included [7,16,25,28,29,31]. The virgin PTFE spectrum shows several modes between 800 and 700 cm À1 , as seen in Fig.…”

Section: Ftirmentioning

confidence: 99%

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Cross-linking of polytetrafluoroethylene during room-temperature irradiation

Pugmire

Wetteland

Duncan

et al. 2009

Polymer Degradation and Stability

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a b s t r a c tExposure of polytetrafluoroethylene (PTFE) to a-radiation was investigated to determine the physical and chemical effects, as well as to compare and contrast the damage mechanisms with other radiation types (b, g, or thermal neutron). A number of techniques were used to investigate the chemical and physical changes in PTFE after exposure to a-radiation. These techniques include: Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and fluorescence spectroscopy. Similar to other radiation types at low doses, the primary damage mechanism for the exposure of PTFE to a-radiation appears to be chain scission. Increased doses result in a change-over of the damage mechanism to cross-linking. This result is not observed for any radiation type other than a when irradiation is performed at room temperature. Finally, at high doses, PTFE undergoes mass-loss (via small-fluorocarbon species evolution) and defluorination. The amount and type of damage versus sample depth was also investigated. Other types of radiation yield damage at depths on the order of mm to cm into PTFE due to low linear energy transfer (LET) and the correspondingly large penetration depths. By contrast, the a-radiation employed in this study was shown to only induce damage to a depth of approximately 26 mm, except at very high doses.

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“…[8] Therefore, the simple and rapid method described by Suwa et al [5] is still used to estimate the molecular weight of PTFE. [9][10][11][12][13] Admittedly, some published results are doubtful, because the calculated molecular weights are low and outside the limits of Equation (2a), [9,11] or the equation was applied for PTFE which was assumed to be cross-linked by irradiation. [12] In a previous study, number-average molecular weight of radiation-degraded PTFE with M n < 10 5 g/mol was calculated using end-group concentration determined by IR spectroscopy and 19 F solid-state NMR.…”

Section: Introductionmentioning

confidence: 99%

The Estimation of the Molecular Weight of Polytetrafluoroethylene Based on the Heat of Crystallisation. A Comment on Suwa's Equation

Lappan

Geißler

Häußler

et al. 2004

Macro Materials & Eng

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Summary: The influence of number‐average molecular weight $\overline M _{\rm n}$ ranging from 1.4 · 104 to 1.2 · 106 g/mol on the thermal behaviour of polytetrafluoroethylene (PTFE) has been studied. Samples have been prepared by radiation‐induced degradation of commercial PTFE. The molecular weight $\overline M _{\rm n}$ has been calculated using end‐group concentration determined by infrared (IR) spectroscopy and 19F solid‐state nuclear magnetic resonance (NMR) spectroscopy. Melting and crystallisation heats were investigated by differential scanning calorimetry (DSC). The results have been discussed with respect to quantitative relationships between number‐average molecular weight and heat of crystallisation of PTFE described in the literature. The molecular weight calculated from Suwa's equation, which is often used in the literature, has been found to be too low.

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Characterization of structural modifications in poly-tetra-fluoroethylene induced by electron beam irradiation

Cited by 31 publications

References 4 publications

Study on polytetrafluoroethylene aqueous dispersion irradiated by gamma ray

Study on polytetrafluoroethylene aqueous dispersion irradiated by gamma ray

Cross-linking of polytetrafluoroethylene during room-temperature irradiation

The Estimation of the Molecular Weight of Polytetrafluoroethylene Based on the Heat of Crystallisation. A Comment on Suwa's Equation

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