Structural Phase Transitions of Aliphatic Nylons Viewed from the Simultaneous Measurements of WAXD and SAXS

• Published in: Macromolecular symposia 2006-10, Vol.242 (1), p.250-256
• Main Authors: Tashiro, Kohji, Takeuchi, Kazuhiro, Ohta, Yasuaki, Hanesaka, Makoto, Hashida, Tomoko, Yoshioka, Yayoi, Ramesh, Chellaswami
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Hydrogen bonds; Infrared; infrared spectra; Lamellar structure; nylon 10/10 brill transition; Nylons; Organic polymers; Phase transformations; phase transition; Physicochemistry of polymers; Properties and characterization; Segments; small-angle X-ray scattering; Spectra; Structure, morphology and analysis; Translational motion; wide-angle X-ray diffraction
• ISSN: 1022-1360; 1521-3900
• DOI: 10.1002/masy.200651034

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.