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Structural Phase Transitions of Aliphatic Nylons Viewed from the Simultaneous Measurements of WAXD and SAXS
Authors:Kohji Tashiro  Kazuhiro Takeuchi  Yasuaki Ohta  Makoto Hanesaka  Tomoko Hashida  Yayoi Yoshioka  Chellaswami Ramesh
Institution:1. Department of Future Industry-oriented Basic Science and Materials, Toyota Technological Institute, Tempaku, Nagoya 468-8511, Japan;2. Osaka Technology Research Institute of Osaka Prefecture, Izumi, Osaka 594-1157, Japan;3. Division of Polymer Science and Engineering, National Chemical Laboratory, Pune 411008, India
Abstract:Structural changes occurring in the high temperature region of doubly-oriented nylon 10/10 sample have been investigated through the temperature-dependent simultaneous measurements of wide-angle and small-angle X-ray scatterings, and the results were compared with the infrared spectral data as well as the molecular dynamics simulation results. In the Brill transition region of 150–180 °C the methylene segments are conformationally disordered with keeping the intermolecular hydrogen bonds. During this phase transition the stacked lamellar structure did not change very much: the lamellae are tilted by ca. 34° from the draw axis and the long period is almost 160 Å. In the temperature region immediately below the melting point the molecular chains were found to be contracted by ca. 10% the original repeating period and the intermolecular hydrogen bonds were almost broken, causing the violent rotational and translational motions of the chains around the chain axis. At the same time the long period increased remarkably from 160 Å to 410 Å and the originally tilted lamellae stood up in parallel to the draw axis.
Keywords:infrared spectra  nylon 10/10 brill transition  phase transition  small-angle X-ray scattering  wide-angle X-ray diffraction
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