Investigation of non-ideal two-phase polymer structures by small-angle X-ray scattering

作者：Chris G. Vonk · 发表于：Journal of Applied Crystallography · 年份：1973 · DOI：10.1107/s0021889873008204 · 被引用次数：361 · 研究领域：Electron and X-Ray Spectroscopy Techniques、Polymer crystallization and properties、High voltage insulation and dielectric phenomena

The mean square of the electron-density gradient, 〈|grad η|2〉 in isotropic structures is shown to be proportional to the fourth moment of the SAXS intensity distribution in reciprocal space ∫s4I(s)ds, as well as to the second derivative of the correlation function in the origin. In the case of two-phase structures with unsharp phase boundaries, these relations may be used to find the thickness E of the transition regions. As was shown by Ruland [J. Appl. Cryst. (1971). 4, 70–73] E can also be determined by analysis of the intensity in the tail of the SAXS pattern. This approach is used here to investigate the effect of E on the one-dimensional correlation function. In the application of both methods, separation of the SAXS intensity from the continuous background of liquid scattering constitutes a critical step. A procedure in which the background is represented by a curve of the type a + bsn, where n is an even number, is found to work well for a number of polymers.