A fiber specimen of B-amylose was prepared from enzymatically synthesized amylose, which is a purely linear 1,4-linked poly-R-D-glucose. X-ray crystal structure analysis was carried out by using the newly collected intensity data, which was estimated by using imaging plate according to the new procedure. The molecule of B-amylose assumes a left-handed parallel strand double helix, and two double helices pass through a hexagonal unit cell with parameters a ) b ) 18.52 Å, c (fiber axis) ) 10.57 Å, γ ) 120°, and the space group P6 1sC6 2 . A total of 36 water molecules were contained in a unit cell. The conformation of the primary hydroxyl group is gg, and the conformation of the bonds linking two glucose residues, Φ and Ψ, are +84.3 and -135.2°, respectively.

Amylose triacetate was synthesized by using enzymatically synthesized amylose. The enzymatically synthesized amylose is a linear 1,4-linked poly-R-D-glucose, which does not contain a 1,6linkage. X-ray crystal structure analysis was carried out for amylose triacetate I. Two left-handed (14/3) helices pass through a unit cell with parameters a ) 10.92 Å, b ) 18.91 Å, and c (fiber axis) ) 53.91 Å and space group P212121. The molecule does not have 1411 symmetry but only has 21 symmetry in the crystal. The up-and down-pointing molecules statistically coexist at a crystal site with the ratio 0.87: 0.13. The conformation of the O6 atom is almost tg, but one gg and one gt conformations are included.

The α and β forms of poly(butylene terephthalate) transform reversibly by elongation and relaxation. The conformation change occurs in the tetramethylene glycol part, from GGTGG conformation to TSTS̄T conformation. In this study, by using a doubly oriented sample, we measured the positions, intensities, and half‐widths of the (100) and (010) reflections of the α and β forms of poly(butylene terephthalate) with a position‐sensitive proportional counter system. During the transformation, the molecules translate only slightly. These slight molecular translations, or distortions, accumulate, and the crystallite of the α form breaks into the small crystallites of the β form as the α–β transformation proceeds, and the crystallite of the α form grows with the relaxation of the distortion accumulated in the crystal and amorphous regions and on the crystallite surface as the β–α transformation proceeds. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 765–771, 2002