Radiation-Induced Changes in the Degree of Crystallinity of Powdered Polytetrafluoroethylene

Smolyanskiĭ, A. S.; Arsentyev, Mikhail Aleksandrovich; Rashkovskii, A. Yu.; Политова, Е. Д.

doi:10.1134/s1063774519040205

Cited by 6 publications

(14 citation statements)

References 7 publications

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“…The XRD curve of fiber C 2 -2S shows six diffraction peaks at 18.3, 20.4, 24.6, 26.1, 28.8, and 34.2°. The diffraction peak of the PTFE (100) lattice plane increases to 18.3°, which indicates that an interaction occurs between iron species and PTFE molecules during sintering and the interaction narrows the interlayer space of the PTFE (100) lattice plane [ 30 ]. The interaction between iron species and PTFE molecules is one of the reasons why fiber C 2 -2S shows low leaching out of iron ions during application.…”

Section: Resultsmentioning

confidence: 99%

Iron Species-Supporting Hydrophobic and Nonswellable Polytetrafluoroethylene/Poly(acrylic acid-co-hydroxyethyl methacrylate) Composite Fiber and Its Stable Catalytic Activity for Methylene Blue Oxidative Decolorization

Ren

2021

Polymers

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Polytetrafluoroethylene emulsion was ultrasonically mixed with an extremely spinnable poly(acrylic acid-co-hydroxyethyl methacrylate) solution to get a dispersion with good spinnability, and the obtained dispersion was then wet-spun into water-swellable fiber. Crosslinking agents and iron species were simultaneously introduced into the water-swellable fiber through simple impregnation and water swelling. A composite fiber with Fenton reaction-catalyzing function was then fabricated by sequentially conducting crosslinking and sintering treatment. Due to crosslinking-induced good resistance to water swelling and PTFE component-induced hydrophobicity, the composite fiber showed a highly stable activity to catalyze H2O2 to oxidatively decolorize methylene blue (MB). Within nine cycles, the composite fiber could decolorize more than 90% of MB within one minute in the presence of H2O2 and did not show any attenuation in MB decolorization efficiency. The composite fiber still could reduce the total organic carbon of MB aqueous solution from 18.3 to 10.3 mg/L when used for the ninth time. Therefore, it is believable that the prepared fiber has good and broad application prospects in the field of dye wastewater treatment.

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Section: Resultsmentioning

confidence: 99%

Iron Species-Supporting Hydrophobic and Nonswellable Polytetrafluoroethylene/Poly(acrylic acid-co-hydroxyethyl methacrylate) Composite Fiber and Its Stable Catalytic Activity for Methylene Blue Oxidative Decolorization

Ren

2021

Polymers

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“…47-2217 [17]) and the results previously obtained in [18][19][20]. The procedure for determining the degree of crystallinity X c of polymers was described earlier [11].…”

Section: Characterization Of X-ray Diffraction Patterns Registered For Initial and Thermal-radiation Modified Polytetrafluoroethylenementioning

confidence: 98%

“…The X-ray diffraction study of PTFE and TRM-PTFE crystal structure was carried out at room temperature using a DRON-3M diffractometer (Cu K α radiation with a characteristic wavelength of λ Cu = 1.5406 Å, the scanning interval of diffraction angles 2θ from 5 to 80°, the scanning step from 0.05 to 0.02°, exposure from 1 to 20 s). The degree of crystallinity of the studied PTFE samples was determined from the X-ray diffraction data, as well as by differential scanning calorimetry measurements according to [11].…”

Section: X-ray Diffraction Pattern Measurementsmentioning

confidence: 99%

“…It was shown that the diffraction maximum hkl = 100 consists of two components, which correspond to PTFE crystals belonging to the hexagonal system, but having different interplanar spacings [11]. By approximating the spectral shape of the diffraction maximum under study with two Gaussians, it was found that the maxima of the components of peak hkl = 100 are located at 2θ = 18.027° ± 0.003° and 18.087° ± 0.001° for the initial polymer and at 17.832° ± 0.006° and 18.007° ± 0.001° for TRM-PTFE.…”

Section: Characterization Of X-ray Diffraction Patterns Registered For Initial and Thermal-radiation Modified Polytetrafluoroethylenementioning

confidence: 99%

“…In the X-ray scattering spectra of PTFE, the amorphous phase is characterized by a diffuse diffraction maximum in the region of 10°-25° [11,18]. Gamma-radiationinduced modification of PTFE at high temperatures leads to an insignificant increase (~5%) in the integral intensity of the diffuse diffraction maximum I, and, consequently, in the content of the amorphous phase in the polymer (Table 3).…”

Section: Characterization Of X-ray Diffraction Patterns Registered For Initial and Thermal-radiation Modified Polytetrafluoroethylenementioning

confidence: 99%

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Structure of polytetrafluoroethylene modified by the combined action of γ-radiation and high temperatures

Smolyanskiĭ¹,

Политова²,

Koshkina³

et al. 2021

Preprint

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By means of X-ray computed microtomography (XCMT) the existence of a developed microporous structure having an average pore diameter of ~3.5 μm and pore content of ~1.1 vol.% has been revealed in unirradiated polytetrafluoroethylene (PTFE). It has been found that the combined action of gamma radiation (absorbed dose per PTFE of ~170 kGy) and high temperatures (327-350 °C) leads to the disappearance of the microporous structure and the formation of several large pores with sizes from 30 to 50 μm in the bulk of thermal-radiation modified PTFE (TRM-PTFE). It has been established by X-ray diffraction (XRD) analysis that the thermal-radiation modification of PTFE leads to an increase in the interplanar spacings, the degree of crystallinity and volume of the unit cell, as well as to a decrease in the size of crystals and the X-ray density of the crystalline phase in comparison with the initial polymer. It is assumed that the previously established effect of improving the deformation-strength and tribological properties of the TRM-PTFE can be due not only to the radiation cross-linking of polymer chains but also to the disappearance of the micropore system and to the ordering of the crystalline phase of PTFE.

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Methods of determining the degree of crystallinity of polymers with X-ray diffraction: a review

Uzun

2023

J Polym Res

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Radiation-Induced Changes in the Degree of Crystallinity of Powdered Polytetrafluoroethylene

Cited by 6 publications

References 7 publications

Iron Species-Supporting Hydrophobic and Nonswellable Polytetrafluoroethylene/Poly(acrylic acid-co-hydroxyethyl methacrylate) Composite Fiber and Its Stable Catalytic Activity for Methylene Blue Oxidative Decolorization

Iron Species-Supporting Hydrophobic and Nonswellable Polytetrafluoroethylene/Poly(acrylic acid-co-hydroxyethyl methacrylate) Composite Fiber and Its Stable Catalytic Activity for Methylene Blue Oxidative Decolorization

Structure of polytetrafluoroethylene modified by the combined action of γ-radiation and high temperatures

Methods of determining the degree of crystallinity of polymers with X-ray diffraction: a review

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