X-ray study of structural parameters of some tetrafluoroethylene copolymers

Kostromina, S.V.; Kozlova, N. V.; Zubov, Yu.A.; Чвалун, С. Н.; Fedorovich, Ye.A.; Ryvkin, G.A.

doi:10.1016/0032-3950(86)90242-x

Cited by 7 publications

(10 citation statements)

References 12 publications

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“…Figure 4 shows XRay diffraction patterns at room temperature for neat FEP quenched from the melt and neat PTFE powders. A sharp peak is observed at a scattering angle (2) 16 , from the amorphous region. These characteristics are also seen for all FEP/PTFE blends.…”

Section: Resultsmentioning

confidence: 99%

“…, which originate in FEP and PTFE crystallites, respectively, and a broad amorphous peak appears around 16 . These three peaks are resolved as follows and are drawn as broken curves in the figure.…”

Section: Resultsmentioning

confidence: 99%

“…The spacing (d 100 ) of PFA crystallites is estimated to be 4.95 # A and thus, the hexagonal a axis, a, is 5.71 # A, which is consistent with the literature value (5.68 # A). 15,16 The amorphous halo peak is seen around 2 of 16…”

Section: Resultsmentioning

confidence: 99%

“…The samples were slowly cooled from the melt at 623 K to room temperature prior to the measurements. All patterns were resolved into two peaks around 16 and 18 using the curve fitting method described already. The 18 peak is assigned to the (100) reflection of PTFE-type crystallites, and the 16 peak is attributed to a halo from the amorphous region.…”

Section: Resultsmentioning

confidence: 99%

“…The half-width is almost independent of temperature, but increases with PFA, in contrast to FEP/PTFE blends ( Figure 8b): In FEP/PTFE blends, the half-width of the separately formed PTFE crystallites was 0.07 , almost independent of FEP content, but in PFA/PTFE blends, half-width changed from about 0.07 in the 25% PFA blend to 0. 16 in neat PFA. The -OCF 2 -CF 2 CF 3 side chain in PFA may be not incorporated in the PTFE crystallites and as the result, and may be located outside the crystallites.…”

Section: Resultsmentioning

confidence: 99%

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Crystallization in Binary Blends of Polytetrafluoroethylene with Perfluorinated Tetrafluoroethylene Copolymer

Endo

Ohnishi

Kutsumizu

et al. 2004

Polym J

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ABSTRACT:Miscibility and crystallization were studied for two binary blends of polytetrafluoroethylene (PTFE) with poly(tetrafluoroethylene-co-10 mol % hexafluoropropylene) (FEP) and poly(tetrafluoroethylene-co-2 mol % perfluoropropylvinyl ether) (PFA), using DSC and X-Ray diffractometry. In FEP/PTFE blends, FEP and PTFE components were separately crystallized to form their own crystallites, while in PFA/PTFE blends, PFA and PTFE components were cocrystallized to form PTFE-type crystallites incorporating tetrafluoroethylene segments of PFA and PTFE. The crystallization behavior in both blends is discussed in terms of chemical structure, molecular weight, crystallization rate, blending method (how the two components are blended) and comonomer concentration. [DOI 10.1295/polymj.36.716] KEY WORDS Polytetrafluoroethylene / Poly(tetrafluoroethylene-co-10 mol % hexafluoropropylene) / Poly(tetrafluoroethylene-co-2 mol % perfluoropropylvinyl ether) / Blends / Crystallization / Polytetrafluoroethylene (PTFE) is a polymer with good thermal stability up to 720 K, excellent chemical resistance to many solvents, low surface energy, and good electric insulation.1 However, PTFE used industrially is generally required to have high molecular weight (for example, Teflon 3170 has an average number molecular weight, M n , of about 3:6 Â 10 5 ) enough to avoid excess crystallization, but the high molecular weight results in the high melt viscosity, and hence special processing technology such as powder sintering and paste extrusion is required to reform PTFE powders, for example, into sheets. To overcome the above undesirable properties of PTFE, fluorinated copolymers of tetrafluoroethylene (TFE), such as poly-(tetrafluoroethylene-co-hexafluoropropylene) (FEP) and poly(tetrafluoroethylene-co-perfluoroalkylvinyl ether) (PFAVE), have been developed. These copolymers are semicrystalline polymers and their melt viscosities are in general lowered by the introduction of comonomer, compared with those of PTFE, allowing their molding by usual melting extrusion and injection molding technologies.Recently, scientific interest has been paid to miscibility and crystallization in binary polymer blends.2 In particular, it is important to clarify how and why miscibility and crystallization occur in semicrystalline polymer/semicrystalline polymer blends. Miscibility and crystallization behavior has been investigated for several binary blends of PTFE with perfluorinated TFE copolymers.3-7 Runt et al. 3 studied miscibility and crystallization for binary blends of PTFE (Teflon 3170) with poly(tetrafluoroethylene-co-perfluoropropylvinyl ether) (trade name Teflon PFA335, but simply called PFA in this paper), using dynamic mechanical (DM) spectroscopy and differential scanning calorimetry (DSC), where the perfluoropropylvinyl ether (PVE) content of the PFA was 1-2 mol %. DM spectra as a function of temperature showed two peaks labeled and , which were related to reorientational motion of long segments above the glass transition temperature (T g ) and r...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Crystallization in Binary Blends of Polytetrafluoroethylene with Perfluorinated Tetrafluoroethylene Copolymer

Endo

Ohnishi

Kutsumizu

et al. 2004

Polym J

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Miscibility and crystallization of polytetrafluoro-ethylene/poly(tetrafluoroethylene-co-perfluoropropylvinyl ether) blends

Endo¹,

Yamada²,

Tadano³

et al. 2000

Macromol. Rapid Commun.

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Controllable design of polytetrafluoroethylene chemical component using the “harmful” irradiation heat

Peng

Yao

Heng

et al. 2022

Polymers for Advanced Techs

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In this paper, an investigation was performed to study the influence of irradiation heat on the structure and thermal properties of PTFE samples. The tribological properties of POM/irradiated‐PTFE composites were also compared. The results revealed that shortening the interval time of irradiation could induce higher surface temperature and produce more carboxyl groups and trifluoromethyl groups. Additionally, these bulky groups were partly incorporated into the crystalline region of PTFE, which increased the lattice parameters. The decreased interval time accelerated chain scission reactions, causing the Tm and T5% of irradiated PTFE with interval time of 6 min dropped by 12.1 and 107.6°C, respectively, compared with the unirradiated PTFE. More importantly, the POM/A1600 (weight ratio of 90/10) composites were endowed with the lowest friction coefficient of about μ = 0.129 due to the highest transfer film content formed on the friction pair after sliding. The study of the influence of irradiation heat on the degradation of PTFE could provide some theoretical basis for optimizing the electron beam irradiation process and achieving the controllable design of high degradable PTFE. This research could provide a new idea for the utilizing of irradiation heat in the fields of material modification.

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X-ray study of structural parameters of some tetrafluoroethylene copolymers

Cited by 7 publications

References 12 publications

Crystallization in Binary Blends of Polytetrafluoroethylene with Perfluorinated Tetrafluoroethylene Copolymer

Crystallization in Binary Blends of Polytetrafluoroethylene with Perfluorinated Tetrafluoroethylene Copolymer

Miscibility and crystallization of polytetrafluoro-ethylene/poly(tetrafluoroethylene-co-perfluoropropylvinyl ether) blends

Controllable design of polytetrafluoroethylene chemical component using the “harmful” irradiation heat

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