Neutron crystal structure analysis of polyethylene‐d₄: The application of a neutron imaging plate

Abstract

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

c(4 × 2) Structures of Alkanethiol Monolayers on Au (111) Compatible with the Constraint of Dense Packing

“…The accuracy of MM calculations was tested on the most stable packing structure of polyethylene (orthorhombic unit cell). Obtained distances and angles between the alkane chains are within 1% error from the most recent experiments . The DFT geometry optimization and total energy calculations were performed for butanethiol and pentanethiol SAMs (hereafter, C4 and C5) using the SIESTA code within the generalized gradient approximation (GGA) with Perdew−Burke−Ernzerhof (PBE) functional .…”

Investigations of the Intermolecular Forces between RDX and Polyethylene by Force–Distance Spectroscopy and Molecular Dynamics Simulations

“…PE crystals consist of macromolecules in the trans conformation, as this configuration possesses the lowest potential energy. X-ray crystallography reveals that PE crystals are orthorhombic cuboids with cell dimensions of a = 7.417 Å, b = 4.939 Å, and c = 2.534 Å. , Each cell comprises two C 2 H 4 units, one unit from one chain segment and four other shared with adjoining cells at the corners. A molecular weight of 56.0 g/mol for the unit cell, together with its unit-cell volume, yields a calculated density of 1.00 g/cm 3 at 298 K. In contrast, the RDX molecule consists of three alternating N–NO 2 and CH 2 groups arranged in a six-membered C–N ring.…”

Toward a new polyethylene scattering law determined using inelastic neutron scattering

“…This result is shared by experiments involving electron diffraction on PE [45] and neutron diffraction experiments on deuterated PE [46]. The unit cell is a¼7.64Å, b ¼4.48Å, and c ¼2.54Å, with the backbone of the molecule extending along the c-axis.…”

“…The intensities measured by Ref. [46] for deuterated-PE, but using the unit cell dimensions for hydrogenated-PE [44], were employed to calculate the Q values for the diffraction peaks. Several possible HDPE diffraction peaks are seen despite the strong incoherent scattering.…”

“…The residual shows the HDPE lattice [110] peak at Q ¼ 1:5Å À1 , which is clearly distinct from the sample frame background. Other expected peak locations are shown as the red vertical lines, with height proportional to intensity relative to the [110] peak[44,46] (For interpretation of the references to color in this figure caption, the reader is referred to the web version of this article.) .…”