Determination of the Degree of Crystallite Orientation in Cotton Fibers by Means of the Recording X-Ray Diffraction Spectrometer

Abstract

An improved technique is described for the quantitative determination of the degree of crystallite orientation of cellulose in cotton and related cellulosic fibers, using the X-ray diffraction spectrometer with potentiometer recording and a rotating specimen mount. The method is based on the angular dispersion of the 002 diffraction arc of cellulose but employs the somewhat more conveniently determined angle at half-maximum in tensity instead of the photographically determined "40% angle," used by Berkley. It is shown that the angle of half-maximum intensity (50% angle by analogy) is less than Berkley's "40% angle" by a constant value of 3.3°. The effects upon the precision of the results of sample preparation and instrumental variations are described. Under the conditions proposed, the precision of the half- maximum angle is about 0.65°. This compares with a precision of about 1.0° for results obtained by photographic recording and photometering of the X-ray patterns [2]. Using the improved X-ray spectrometer technique described, the dark room required for photographic determination of orientation, with its rigid processing control, can be dispensed with, and a determination can be made in about one-fourth of the time.