Oriented Structure of Uniaxially Rolled Poly(ethylene terephthalate) Film

Kim

et al. 2017

Polymer

The effects of spinning conditions on fiber properties are not well explained by the fiber structures because the birefringence, crystallinity, and SAXS patterns are often similar. In this study, the effects on the fiber structure development of polyethylene terephthalate after necking was analyzed by simultaneous WAXD/SAXS measurements. An X-shaped SAXS pattern was observed for all fibers drawn at the minimum draw ratio. In contrast, by drawing under a drawing stress of 100 MPa, the strong diffraction of the smectic phase and an obviously larger long period less than 1 ms after necking were observed for fibers spun at 500-1500 m/min, while almost no smectic phase was observed for fibers spun at 2000 m/min. A higher crystallization rate and clear draw ratio dependence of crystallization rate were also observed for the fiber spun at 2000 m/min. The clear differences in structure development can explain their differences in tensile strength and thermal shrinkage.

Section: Saxs Patternsmentioning

confidence: 66%

Effect of melt spinning conditions on the fiber structure development of polyethylene terephthalate

Tomisawa

Kim

et al. 2017

Polymer

“…The layer-lined USAXS streak of PET can be explained by the fibrillar-shaped smectic phase formed less than 1.0 ms after necking, and its growing to microfibril [12]. This smectic phase is a metastable structure, first reported by Bonart [22], and has been formed during batch drawing [11] and heat treatment of oriented amorphous PET [23]. The smectic phase has also been observed for PEN [24] and PBT [25], although it has not been observed for PPS [20].…”

Section: Fibril-size Structure Development Of Pet and Ppsmentioning

confidence: 84%

“…Mahendrasingam et al [9] and Kawakami et al [10] studied the structural change during the batch drawing of a PET film. More recently, Okada et al [11] obtained X-ray images in the through and edge directions of a uniaxially drawn PET film, and investigated the differences in the structural changes in each direction. In the edge image, shear deformation was observed as a shear band-like structure formed by stacking benzene rings.…”

Section: Introductionmentioning

confidence: 99%

Ultra-SAXS observation of fibril-sized structure formation after the necking of poly(ethylene terephthalate) and poly(phenylene sulfide) fibers

Tomisawa

Ando

et al. 2018

Polym J

Self Cite

“…The x-shaped pattern was obvious at the lower draw ratio, and was particularly distinct for S-PET, whereas the x-shaped pattern was observed for a longer elapsed time, 0.58 ms, with the higher draw ratio and for H-PET. The x-shaped pattern was also observed for the high-speed spun fiber 32,33 and the edge image of a PET film drawn at 100 o C. 34 Funai et al 35 proposed the zig-zag fibril to explain this pattern, but the structuralorigin of the pattern remains unclear. Figure 12 shows an intensity profile parallel to the equator passing through the 4-point peak.…”

Section: Saxs Patternmentioning

confidence: 88%

Fiber structure development in PS/PET sea-island conjugated fiber during continuous laser drawing

Sugawara

Kim

et al. 2015

Polymer

The effect of draw ratio, molecular weight, and sea-island conjugated spinning with a polystyrene component on the fiber structure development of PET during laser drawing was analyzed by in-situ measurements with a 0.1 ms time resolution using an ultra-high luminance X-ray beam generated from a synchrotron equipped with an undulator. The fiber temperature increased from 120 o C to 160-220 o C during the structure development process. By drawing the higher molecular weight PET to a higher draw ratio, a larger amount of fibrillar smectic mesophase formed just after the onset of necking, and a more highly oriented crystal formed after the extinction of the smectic mesophase. Accordingly, fibers with higher strength and higher thermal shrinkage stress were obtained. On the other hand, by conjugated spinning with a PS component, the fiber temperature increased along with an increase in the drawing stress, but the stress applied to the PET component should have decreased.The amount of smectic mesophase formed by the conjugated-spinning process was drastically decreased, and no crystallization induction time was observed, unlike the other cases. Crystallization, particularly the growth of a lamellar crystal, was also promoted. Moreover, a higher Young's modulus, a higher yield stress, and a higher shrinkage stress were observed for the conjugated-spun and drawn fibers. Therefore, the fibrillar smectic mesophase seems to block the formation of the lamellar crystal. Furthermore, the resultant fibrillar structure tends to result in a higher strength, but a relatively lower modulus and yield strength of the fiber.