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.

The crystal structure of natural rubber has been studied by many researchers including Bunn and Nyburg. However, the accepted crystal structure has not been reported. In the present study, the X-ray crystal structure analysis was carried out by using an imaging plate at −50 °C. Four molecular chains with STS̄cisS̄TScis conformation pass through a unit cell with a = 12.41 Å, b = 8.81 Å, c = 8.23 Å, β = 94.6°, and P21/a-C 2 h 5. In the crystal lattices, two molecular chains related by the mirror symmetry statistically occupy a crystal site with the ratio 0.67:0.33.

Neutron diffraction provides a more detailed structure than X‐ray diffraction. In this study, a neutron crystal structure analysis of polyethylene‐d4 was carried out with a neutron imaging plate. This was the first crystal analysis of the crystalline polymer with the neutron fiber pattern. The procedure was almost the same as that in a previous work, in which the neutron structure analysis was carried out on the basis of the equatorial reflections. The azimuthal angle of the molecule with respect to the a axis was estimated to be 46.3°. This corresponded well to the value of 45° estimated in the previous work within the accuracy of the standard deviations. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3836–3839, 2004

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