Synchrotron X-ray diffraction of a single filament and a bundle of poly (p-phenylene terephthalamide) filaments

Chu, Benjamin; Wu, Chi Hao; Li, Yingjie; Harbison, Gerard S.; Roche, E. J.; Allen, Steven R.; McNulty, Thomas F.; Phillips, J. C.

doi:10.1002/pol.1989.140280703

Cited by 8 publications

(3 citation statements)

References 10 publications

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“…The use of synchrotron radiation microbeam of a high brightness has enabled WAXD characterization of individual fibers with sufficient diffraction intensity. For instance, Chu et al employed this method to investigate the lattice deformation of single PPTA fibers under tensile stress . Li et al studied the structural evolution of PPTA fibers during stretching and found that the amorphous phase can transform into a crystalline phase at high strains .…”

Section: Introductionmentioning

confidence: 99%

“…The use of synchrotron radiation microbeam of a high brightness has enabled WAXD characterization of individual fibers with employed this method to investigate the lattice deformation of single PPTA fibers under tensile stress. 9 Li et al studied the structural evolution of PPTA fibers during stretching and found that the amorphous phase can transform into a crystalline phase at high strains. 10 However, such experiments require a high-energy light source provided by a synchrotron facility and are not suitable for routine research.…”

Section: ■ Introductionmentioning

confidence: 99%

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Quantifying Crystallinity in Poly(p-phenylene terephthalamide) by Raman Spectroscopy

Sun,

Meng,

Luo

et al. 2024

Macromolecules

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Poly(p-phenylene terephthalamide) (PPTA) forms high performance fibers, and their mechanical properties are critically dependent on the degree of crystallinity. Here we report a new method for quantifying the crystallinity in PPTA by Raman spectroscopy. The Amide I band at ∼1650 cm −1 in the Raman spectrum of PPTA was deconvoluted into three components associated with cis and different trans conformers respectively, and the assignments were supported by spectral calculation results. Then, the crystalline contribution to this band was isolated, from which the degree of crystallinity was derived. The measurement results were highly reproducible and in excellent agreement with that obtained by wide-angle X-ray diffraction over a wide range, showing good precision and accuracy. This method was then applied to analyze a defect of ∼5 μm size observed in a commercial PPTA fiber, and a much larger zone of lower crystallinity than the normal fiber section was revealed centered around the defect.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Quantifying Crystallinity in Poly(p-phenylene terephthalamide) by Raman Spectroscopy

Sun,

Meng,

Luo

et al. 2024

Macromolecules

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“…Chu et al detected the lattice deformation of PPTA single fiber under tensile stress using a synchrotron wide-angle X-ray diffraction method. [18][19][20] However, they reported only equatorial 200 and 110 reflection shifts, which correspond to the lattice deformation in the direction perpendicular to the chain axis and tensile stress. Davies et al measured the lattice deformation from meridional layer lines of PPTA single fiber using a microfocus X-ray diffraction technique.…”

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confidence: 99%

Elastic Modulus of the Crystalline Regions of Poly (p-phenylene terephthalamide) Single Fiber Using SPring-8 Synchrotron Radiation

Kotera

Nakai

Saito

et al. 2007

Polym J

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ABSTRACT:The elastic modulus, E l , of the crystalline regions of poly (p-phenylene terephthalamide) (PPTA) single fiber in the direction parallel to the chain axis was measured by X-ray diffraction using synchrotron radiation at beamline BL46XU of SPring-8. The E l value of the PPTA single fiber was obtained as 156 GPa at room temperature from the initial slope of the stress-strain curve of the crystal lattice. However, the inclination of the stress-strain curve changed at a tensile stress of around 1000 MPa, which produced an E l 0 value of 199 GPa in a higher stress region. This indicates that the deformation mechanism in the crystal lattice at higher tensile stress was different from that in the initial stage of the tensile deformation. Stress hardening of PPTA was also observed macroscopically during the tensile deformation process. Stress hardening in the crystal lattice was found to directly affect macroscopic stress hardening of the PPTA fiber. Poly (p-phenylene terephthalamide) (PPTA) fiber is one of the most popular high performance polymer fibers. Well known by its commercial names, Kevlar Ò , and Twaron Ò , it has excellent thermal stability and good mechanical properties. PPTA fiber is widely used in industrial materials, reinforcement fibers for advanced composite materials, and so on.1,2 The mechanical properties of PPTA fiber are affected by the microstructures formed during liquid-crystalline spinning. In the last few decades, the relationship between the microstructures and the mechanical properties of PPTA fibers has been extensively studied. Black reported that a possible explanation for the extraordinary mechanical properties of PPTA fiber is its extended chain orientation rather than its high crystallinity. 3PPTA fiber is said to possess microscopically radially oriented pleated sheet structures, in which the microfibrils are misoriented with a long (300-500 nm) zigzag structure along the fiber axis. [4][5][6] Northolt et al. reported that the macroscopic deformation of PPTA fiber is governed by the orientational change in the PPTA micro-fibrils along the fiber axis in the initial tensile stress region. 7,8 Therefore, after the micro-fibril orientation has been completed, stress hardening due to the elongation of the molecular chains themselves is observed in the high tensile stress region. The structural changes during the fiber tensile deformation process have also been investigated in several studies using a variety of methods, such as Raman spectroscopy, 9-11 an X-ray diffraction method, 7,8,[12][13][14][15][16][17][18][19][20][21] and a combined microfocus Raman/microfocus X-ray diffraction technique. 22The elastic modulus, E l , of the crystalline regions of polymers in the direction parallel to the chain axis provides important information on the molecular conformation, its deformation process, and its relations to mechanical properties. The E l value also plays an important role in attempts to obtain high modulus polymer materials because the E l value is equal to the maximum attain...

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Synchrotron wide‐angle x‐ray diffraction of single‐filament PPTA fibers under stress

Chu

1991

J Polym Sci B Polym Phys

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Synchrotron X-ray diffraction of a single filament and a bundle of poly (p-phenylene terephthalamide) filaments

Cited by 8 publications

References 10 publications

Quantifying Crystallinity in Poly(p-phenylene terephthalamide) by Raman Spectroscopy

Quantifying Crystallinity in Poly(p-phenylene terephthalamide) by Raman Spectroscopy

Elastic Modulus of the Crystalline Regions of Poly (p-phenylene terephthalamide) Single Fiber Using SPring-8 Synchrotron Radiation

Synchrotron wide‐angle x‐ray diffraction of single‐filament PPTA fibers under stress

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