Investigation of odd-odd nylons based on undecanedioic acid. 2: Crystal structures

Abstract

The crystal structures of the odd–odd nylons X 11 (X = 3, 5, 7, 9, and 11) under different conditions, including solution-crystallized samples and melt-crystallized samples, were investigated by wide-angle X-ray diffraction (WAXD) and electron diffraction (ED). For the melt-crystallized samples of the odd–odd nylons under consideration, the strong diffraction at 0.42 nm, which is typical of the hexagonal lattice, was found in the WAXD patterns. As for the solution-crystallized samples, nylon 11 11 presents the monoclinic crystal structure characteristic of the two strong diffractions at about 0.42 and 0.40 nm of the WAXD and ED patterns, while nylons 9 11, 7 11, 5 11, and 3 11 show the hexagonal crystal ones typical of the same diffraction patterns as those of the melt-crystallized samples. The model of hydrogen bonds in crystal structures of the odd–odd nylons under study is discussed. POLYM. ENG. SCI., 45:1673–1679, 2005. © 2005 Society of Plastics Engineers