Effects of dimensions and regularity on the mechanical properties of the smectic phase formed during orientation-induced crystallization of poly(ethylene terephthalate)

Tomisawa, Ren; Oneda, Shun; Ikaga, Toshifumi; Kim, KyoungHou; Ohkoshi, Yutaka; Okada, Kazuyuki; Masunaga, Hiroyasu; Kanaya, Toshiji; Katsuta, Hiroo; Funatsu, Yoshitsugu

doi:10.1016/j.polymer.2019.01.002

Cited by 11 publications

(7 citation statements)

References 23 publications

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“…[14][15][16] Furthermore, the apparent modulus was obtained from the change in smectic d-spacing with drawing stress. 9 This indicates that the extension of the molecular chains can be quantitatively estimated from the smectic d-spacing. Therefore, the d-spacing can be used to estimate the fraction of molecular chains that can bear the tensile force applied to the ber, and it can be used to examine relationship with the tensile strength more precisely than the amount of smectic phase.…”

Section: Introductionmentioning

confidence: 93%

“…7 The smectic phase has a brillar-shape with an aspect ratio of ~ 10 and is thought to be transformed into micro brils in the resultant ber by orientationinduced crystallization. 8 Because the smectic phase comprises bundles of oriented molecular chains, this phase mainly bears the tensile force during the ber-drawing process prior to orientation-induced crystallization, 9 and these bundles of oriented molecular chains also bear the tensile force applied to the resultant ber at breakage. High-molecular-weight polymer is generally used for obtaining high-tensile-strength PET ber, 10 but excessively high molecular weights negatively affect molecular orientation along the ber axis because of molecular chain entanglement.…”

Section: Introductionmentioning

confidence: 99%

“…The amount, d-spacing (d), and persistence length (L) of the smectic phase were evaluated from the integrated intensity along the meridian (I), peak position, and widths of the diffraction peak. 9 The integrated intensity (I) was normalized by the X-ray irradiation volume. The peak position and width along the meridian were obtained by tting of the Gaussian )].…”

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confidence: 99%

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Tensile strength of polyester fiber estimated by molecular-chain extension prior to structure formation

Ohkoshi

Tomisawa

Nagata

et al. 2023

Preprint

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The combination of laser irradiation heating and synchrotron X-ray sources has made it possible to observe the fiber-structure development that occurs at sub-millisecond timescales after necking during continuous drawing. Through wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) analysis of poly(ethylene terephthalate) fibers of three different molecular weights drawn under equivalent stresses, a good correlation was observed between the d-spacing of smectic (001') diffraction extrapolated to the necking point and the strength of the drawn fiber. This indicates that the molecular chains that bear the drawing stress also bear most of the applied stress during tensile testing of the resultant fiber. In addition, considering the drawing-stress dependence of the d-spacing and the molecular weight distribution of the fiber revealed that molecular chains with molecular weights over 23,000 g/mol bear the majority of tensile force applied to the fiber.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Tensile strength of polyester fiber estimated by molecular-chain extension prior to structure formation

Ohkoshi

Tomisawa

Nagata

et al. 2023

Preprint

Self Cite

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“…To estimate limiting tensile properties, we concentrated on the relationship between the drawing-stress dependance of d 0 and the molecular weight distribution of the fiber. In a previous study, an apparent modulus of 40 GPa was calculated by plotting d 0 against drawing stress 9 . Following this approach, we calculated the apparent modulus of the H-polymer.…”

Section: Relationships Between the Smectic D-spacing And Tensile Prop...mentioning

confidence: 99%

“…Accordingly, good correlation between the amount of smectic phase and the tensile strength of drawn fibers has been observed [14][15][16] . Furthermore, the apparent modulus was obtained from the change in smectic d-spacing with drawing stress 9 . This indicates that the extension of the molecular chains can be quantitatively estimated from the smectic d-spacing.…”

mentioning

confidence: 99%

Tensile strength of polyester fiber estimated by molecular-chain extension prior to structure formation

Tomisawa

Nagata

Otsuka

et al. 2023

Sci Rep

Self Cite

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The combination of laser irradiation heating and synchrotron X-ray sources has made it possible to observe the fiber-structure development that occurs at sub-millisecond timescales after necking during continuous drawing. Through wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) analysis of poly(ethylene terephthalate) fibers of three different molecular weights drawn under equivalent stresses, a good correlation was observed between the d-spacing of smectic (001ʹ) diffraction extrapolated to the necking point and the strength of the drawn fiber. This indicates that the molecular chains that bear the drawing stress also bear most of the applied stress during tensile testing of the resultant fiber. In addition, considering the drawing-stress dependence of the d-spacing and the molecular weight distribution of the fiber revealed that molecular chains with molecular weights over 23,000 g/mol bear the majority of tensile force applied to the fiber.

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Twist springback and microstructure analysis of PEEK sheets in ultrasonic-assisted thermal incremental forming

Liao

Zhou

Xue

2022

Int J Adv Manuf Technol

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With a view to reducing the springback and twist of PEEK during the incremental forming process, the ultrasonic vibration is introduced into polymer thermal SPIF. In this study, the effects of temperature and ultrasonic vibration on twist and springback of formed parts are investigated. Several modi ed tool trajectories are developed, and the in uence of tool trajectory on twist and springback are also studied.Finally, the microstructures of PEEK parts are analyzed by XRD. The results show that the increase of temperature is helpful to reduce the twist and springback. The ultrasonic vibration is bene cial to the improvement of geometric accuracy, while the side wall bulge aggravates at 140 ℃ after the ultrasonic vibration is applied. The optimized tool trajectory can effectively eliminate twist and reduce the springback of PEEK parts. The XRD result shows that the ultrasonic vibration is helpful to increase the molecular chain orientation, improve crystallinity and re ne crystallite at 60 ℃ and 100 ℃. However, the opposite trend occurs at 140 ℃ due to the disorientation effect of molecular chain.

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Effects of dimensions and regularity on the mechanical properties of the smectic phase formed during orientation-induced crystallization of poly(ethylene terephthalate)

Cited by 11 publications

References 23 publications

Tensile strength of polyester fiber estimated by molecular-chain extension prior to structure formation

Tensile strength of polyester fiber estimated by molecular-chain extension prior to structure formation

Tensile strength of polyester fiber estimated by molecular-chain extension prior to structure formation

Twist springback and microstructure analysis of PEEK sheets in ultrasonic-assisted thermal incremental forming

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