X-ray determination of crystallinity and diffuse disorder scattering

Abstract

An X-ray method of crystallinity determination has been developed which takes into account the diffuse scattering due to thermal vibrations and lattice imperfections in the crystalline part of a substance. Application of the method to a series of polypropylene samples shows that this diffuse scattering is predominantly caused by thermal motions.The normalization of the scattering curve leads to special absorption corrections for Compton scattering and indicates a scattering effect attributed to the carbon-hydrogen bond orbital

Determining the Degree of Crystallinity in Semicrystalline Materials by means of the Rietveld Analysis

“…The Ruland (1961) method was the first X-ray diffraction internal method of crystallinity determination based on rigorous physical considerations and on absolute corrected intensities expressed in electron units (e.u.). It was subsequently computerized (and slightly modified) by Vonk (1973).…”

“…), occupied by the crystallites inside a semicrystalline material. Although many different techniques have been developed in order to determine this quantity, which is important for both scientific and technological reasons, X-ray powder diffraction is one of the most popular methods since, following Ruland's (1961) fundamental paper, it is based on a rigorous theory. In this respect, much progress has been made, and specific procedures have been developed, especially in the field of so-called internal methods, which require no standard samples for comparison, except for the wholly amorphous sample of the system under study.…”

Chemical modification of cobalt ferrite nanoparticles with possible application as asphaltene flocculant agent

“…The diffractogram of the unmodified nanoparticles shows diffraction peaks at values of 2θ equal to 30.3°, 35.6°, 53.3° and 62.9°, which correspond to crystal planes (220), (311), (422) and (440), respectively, in the spinel structure of an orthorhombic cell. Moreover, these nanoparticles have a crystallinity of (81 ± 1)%, calculated using the Ruland method 14 and size crystallite (Lc) of (16.9 ± 1.5) nm, determined by Scherer equation at (311). The diffractogram of the modified nanoparticles does not shows any changes in the nanoparticles structure, keeping the spinel structure of an orthorhombic cell, since there are no changes in diffraction peaks.…”

Spectroscopic studies of the inclusion compound of lisinopril withβ-cyclodextrin

“…4, the most important contributions are due to the O-H stretching vibrations of primary (3504 cm −1 [9]), secondary OH groups of the cyclodextrin and of water molecules present inside CD cavity, also. The different shape of this massif (corresponding to ICs' obtained with various preparation methods), especially in the higher frequency side reveal the important role of the intra-and intermolecular H-bridges [10] and of the water molecules' expulsion during the inclusion process, also.…”

“…By taking into consideration the thermal vibration and lattice imperfections Ruland [9] has shown that the fraction of crystallinity can be determined by using the formula:…”