On-line WAXD / SAXS Measurements of Fiber Structure Development in the CO_2 Laser-Hated-Drawing of Poly(ethylene terephthalate) Fiber

合成纤维的结构和性能主要是在纤维的二次拉伸过程中决定的，即所谓的颈状变形。为了观察光纤结构的发展，设计并构建了激光拉伸法原位x射线测量系统。利用该系统，通过CO_2激光局部照射，成功地固定了运行光纤的颈部拉伸点。拉颈点位置波动小于0.5mm，对应的时间分辨率为几百微秒。在SPring8上进行了聚对苯二甲酸乙酯（PET）纤维结构形成的现场测量，其中最强的x射线束可用于日本的散射实验。广角x射线衍射（WAXD）和小角x射线散射（SAXS）作为颈缩后时间的函数进行了测量。还考察了它们对拉伸量的依赖性。从颈点开始，出现了较长的周期。同时，WAXD模式的晶体反射出现在四点模式之后。在大尺度上，密度波动比结晶更早出现。PET晶体在5.4^<o__->附近的经向反射（001′）与赤道反射（001′）在时间演化上表现出不同的行为。（001’）衍射峰正好出现在缩颈点之后。然而，晶体衍射在颈缩后几毫秒就出来了。（001′）峰在初始阶段随着时间的流逝而增大，在晶体衍射峰变得清晰时消失。（001’）反射源于PET延伸单链的构象。因此，在纤维结构形成的初始阶段，PET分子被扩展并形成二维有序结构。在下一步，这种结构转变为晶体一。进一步的数据分析得出了新的纤维结构发展模型。少

The structures and properties of synthetic fibers are mainly determined during the secondary drawing process of fibers, so-called neck-like deformation. To observe the fiber structure development in-situ X-ray measurement system with the laser drawing process were designed and constructed. The neck drawing point on running fiber was successfully fixed by local irradiation of CO_2 laser using this new system. The positional fluctuation of neck-drawing point was less than 0.5mm, which was corresponding to the time resolution of several hundred micro seconds. In-situ measurements of fiber structure formation of poly(ethylene terephthalate) (PET) were performed at SPring8, where the strongest X-ray beam was available for scattering experiments in Japan. Wide angle X-ray Diffraction (WAXD) and Small angle X-ray Scattering (SAXS) were measured as a function of elapsed time after necking. Their dependence on the drawing ration also examined. Four-point SAXS patterns considering relative to lo … More ng period appeared from the necking point. Meanwhile crystal reflections in the WAXD pattern appeared after the four-point pattern. The density fluctuation in large scale came out earlier than crystallization. The meridional reflection (001') of around 5.4^<o__-> and the equatorial ones from PET crystal shows the different behavior in time evolution. The (001') diffraction peak appeared just after necking point. However the crystal diffractions came out at several milliseconds after necking. The peak of (001') grew up with the elapsed time at the initial stage and disappeared when the crystal diffraction peaks became clear. The (001') reflection originated with the conformation of the extended single chain of PET. Accordingly at the initial stage of fiber structure formation PET molecules were extended and constructed the two-dimensionally ordered structure. At the next step this structure transformed to crystal one. The further data analysis leaded to the new model of fiber structure development. Less