Two-dimensional wide-angle X-ray

The lamellar reflections are not flat, but are curved i.e., there is a continuous shift in the z-position of the maxima (z ) in the lamellar peaks as a function of x (Figure 1) Because of this curvature, the two-dimensional (2-D) data could not be fitted in Cartesian coordinates. But they are not curved enough to be a circle, hence the polar coordinates ordinarily used in analyzing the wide-angle x-ray diffraction patterns cannot be used either. It appears that the description in elliptical coordinates provides the best fit to the data. This feature of the scattering curve will be analyzed in detail in this paper. 

The time required to collect wide-angle X-ray diffraetion patterns varies greatly with the thiekness of the sample, the intensity of the radiation, and the sensitivity of the deteetor. Position-sensitive detectors may provide suffieient information within a few seconds, while photographic film may require an exposure of many hours (or even days) to record the seattering pattern Irom a thin film or fiber. Scintillation counters typically scan at speeds on the order of 0.5-5°/min. When highly intense sources such as synchrotron radiation are eombined with two-dimensional electronic detectors, data can be collected suffieiently fast that it is possible to obtain information regarding X-ray diffraction during real-time erystallization. 

A wide- and small angle X-ray diffraction study of crosslinked (134) has shown the presence of two phases, viz. an amorphous phase and a two-dimensional ordered phase. Changes of the ordered structure depend on the ion-exchange capacity of the polymer and extent of water swelling. Pervaporation membranes have been prepared by thermally crosslinking of polyphosphazenes bearing p-methoxyphenoxy, methoxyethoxyethoxy and o-allylphenoxy groups in the presence of a radical initiator. ... 

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