On the neck‐like deformation in high‐speed spun polyamides

Haberkorn, H.; Hahn, Kendo; Breuer, H.; Dorrer, H.-D.; Matthies, P.

doi:10.1002/app.1993.070470905

Cited by 60 publications

(72 citation statements)

References 18 publications

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“…[4][5][6][7][8][9][10][11] Many of these studies concerned PET. Our research group has studied on the fiber structure development process in the continuous laser-drawing for PET and PTT fibers through on-line WAXD and SAXS measurements [9] with synchrotron radiation systems [10,11,12] .…”

Section: Introductionmentioning

confidence: 99%

Mesophase structure discovered through in-situ X-ray measurement in drawing process of poly(ethylene 2,6-naphthalene dicarboxylate) fiber

Kim

Aida

Kang

et al. 2009

Polymer

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The structure development in the continuous laser-heated drawing process of poly(ethylene 2,6-naphthalene dicarboxylate) (PEN) fiber was analyzed by in-situ X-ray diffraction measurement. Because of the rapid and uniform laser-heating, and the resultant steady-state nature of the necking-drawing, the structure development after the on-set of necking could be measured in the time resolution of several hundred microseconds. We found for the first time the temporal appearance of meridional (001') diffraction at several milliseconds after the on-set of necking indicating that the mesophase structure similar to the one reported for poly(ethylene terephthalate) was also formed in the initial stage of fiber structure development of PEN. The d-spacing of the (001') diffraction 1.230 ± 0.003 nm was shorter than the c-axis lengths of both Į and ȕ crystals. IntroductionPoly(ethylene 2,6-naphthalene dicarboxylate) (PEN), containing naphthalene ring in its backbone, possesses higher glass-transition temperature (T g ) and higher melting temperature (T m ) than those of poly(ethylene terephthalate) (PET). Due to the stiff molecular chain of PEN, it can be expected to give high-performance fibers having excellent physical properties for engineering uses.There have been studied on hot-drawing and cold-drawing processes in PEN fibers and films, [1,2] in which the drawability of amorphous PEN was reported to depend on molecular weight and strain rate. The structural changes in the neck-drawing of amorphous PEN films have been investigated through off-line measurement using synchrotron X-ray radiation, [1,3] which revealed the appearance of smectic order with a period of 1.25 nm corresponding to a chain repeat length associated with a sinusoidal conformation of the polymer chains. It was 5% shorter than the chain repeat length of a more extended Į-conformation. However, so far, there has been found no report about on-line characterization of structure development process with orientation-induced crystallization in PEN fiber and films.Several studies on the on-line characterization of the fiber structure development during the drawing have been conducted using simultaneous synchrotron radiation as well as laboratory X-ray generators for WAXD and SAXS. [4][5][6][7][8][9][10][11] Many of these studies concerned PET. Our research group has studied on the fiber structure development process in the continuous laser-drawing for PET and PTT fibers through on-line WAXD and SAXS measurements [9] with synchrotron radiation systems [10,11,12] . Quantitative analyses on the fiber structure development mechanism were accomplished by direct measurement in the vicinity of the neck-deformation point, in which drawing behavior, fiber temperature changes, and WAXD/SAXS were measured as a function of elapsed time after the neck-deformation. [9][10][11][12] The elapsed time, calculated from distance between measurement point and the neck-deformation point, is high accuracy because the neck point could be fixed within confined region by rapid and unifo...

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Section: Introductionmentioning

confidence: 99%

Mesophase structure discovered through in-situ X-ray measurement in drawing process of poly(ethylene 2,6-naphthalene dicarboxylate) fiber

Kim

Aida

Kang

et al. 2009

Polymer

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“…Online characterization of these processes using in-laboratory X-rays has been demonstrated (Chappel, Culpin, Gosden & Tranter, 1964;Katayama, Amano & Nakamura, 1968;Spruiell & White, 1975;Haberkorn, Hahn, Breuer, Dorrer & Matthies, 1993), although low intensity seriously limits the applicability. For example, a very long exposure time is needed for good signal resolution [2-4 h for wideangle X-ray diffraction (WAXD), 12-24 h for smallangle X-ray scattering (SAXS)].…”

Section: Introductionmentioning

confidence: 99%

Studies of Structure and Morphology Development During the Heat-Draw Process of Nylon 66 Fiber by Synchrotron X-ray Diffraction and Scattering Techniques

Hsiao¹,

Kennedy²,

Leach³

et al. 1997

J Appl Cryst

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Online studies of structure and morphology development during continuous drawing of a nylon 66 fiber at different temperatures were carried out using synchrotron wideangle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) techniques. From the two-dimensional (2D) WAXD measurement, unit-cell parameters were determined. The results confirm that the triclinic cell structure persists above the Brill transition temperature (about 443 K). With increasing temperature, the unit-cell dimension a (dominated by hydrogen bonding) remains almost unchanged, while b increases and c decreases (both show a step-change at 403 K, prior to the Brill transition). The constant value of a agrees with the argument that the hydrogen bonding is relatively immobile at high temperatures prior to melting. The step-changes in b and c suggest that a premelting process of small (or defective) crystals precedes the Brill transition. As a result, the anisotropic thermal expansion of the surviving larger crystals results in a step-change behavior. This hypothesis is consistent with the crystal density data as well as the morphology evaluation by SAXS. Several dimensions were extracted from the 2D SAXS data: lamellar crystal and amorphous thicknesses (along the fiber) determined by the correlation function method, and crystal fibril width (perpendicular to the fiber) determined by the Porod analysis. These results also indicate that drawing annihilates small crystals, but the strain effect is much less than the temperature effect.

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“…Several studies have been conducted for the on-line characterization of structure development for synthetic fibers during drawing using simultaneous synchrotron radiation as well as laboratory X-ray generators for WAXD and SAXS [10][11][12]. Schultz et al [8,9] reported that unit cell dimensions, crystallinity, and orientation were dependent on stretching temperature and strain.…”

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Initial structure development in the CO2 laser-heated drawing of poly(trimethylene terephthalate) fiber

Kim

Kang

Murata

et al. 2008

Polymer

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Because rapid and uniform laser heating can fix the neck-drawing point in continuous drawing of PTT fiber, we have successfully analyzed the fiber structure development in the continuous drawing process by in-situ measurement with a time resolution of less than 1 millisecond. In this study, we investigated fiber structure development for PTT around the neck point controlled with a CO 2 laser-heated apparatus during continuous drawing, through on-line measurements of WAXD, SAXS, and fiber temperature. Fiber temperature attained by laser radiation initiated a rise around -3 mm in relation to the neck point at 0 mm, and increased to about 90°C, which is past the 45°C T g for PTT. The instantaneous increase in fiber temperature continued with a vertical ascent, with plastic deformation around the neck point. The crystalline diffraction pattern was revealed initially at the elapsed time of 0.415 ms immediately after necking, and remained fairly constant with elapsed time. The ultimate crystalline diffraction pattern for a completely drawn fiber showed little difference from that at the initial stage. In PET a two-dimensionally ordered structure in the form of a mesophase was detected immediately after the necking, whereas in PTT the phenomenon was not observed. With elapsed time, the d-spacing of (002) plane decreased gradually due to transformation of the initial all-trans conformation into trans-gauche-gauche-trans conformation, and ultimately the PTT molecular chain could favorably adopt the trans-gauche-gauche-trans conformation. SAXS pattern immediately after the necking revealed an X-shape; the scattering intensity concentrated on meridian directions due to individual crystal development, and at 2 ms two-pointed scattering started to appear. Past 8 ms, the typical two-pointed scattering pattern was prominent and its intensity increased with elapsed time. Long period decreased with increasing elapsed time, but the crystallite size of meridian (002) plane hardly changed. The decrease in long period might be caused by chain relaxation in the amorphous region.

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On the neck‐like deformation in high‐speed spun polyamides

Cited by 60 publications

References 18 publications

Mesophase structure discovered through in-situ X-ray measurement in drawing process of poly(ethylene 2,6-naphthalene dicarboxylate) fiber

Mesophase structure discovered through in-situ X-ray measurement in drawing process of poly(ethylene 2,6-naphthalene dicarboxylate) fiber

Studies of Structure and Morphology Development During the Heat-Draw Process of Nylon 66 Fiber by Synchrotron X-ray Diffraction and Scattering Techniques

Initial structure development in the CO2 laser-heated drawing of poly(trimethylene terephthalate) fiber

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