and Ruland-Vonk methods. A comparative analysis of both methods
The theoretical principles of the Hindeleh-Johnson and Ruland-Vonk methods of the determination of the crystallinity degree of polymers were discussed in detail. It was demonstrated it was impossible to use the procedure adopted in the Hindeleh-Johnson method for approximating the amorphous component of scattered intensity in a wide range of measurements (namely 2 ) in respect to a majority of polymers. The adoption of this approximation procedure was probably the reason of large differences in the values of crystallinity degree of PE and PET obtained by Hindeleh- Johnson, and other authors. The crystallinity degrees of four samples of PA-6 fibres with various stretch ratios (up to 300%) were determined experimentally. The Hindeleh-Johnson procedure of approximating the amorphous component in scattered radiation was modified. This component was represented by a combination of a third-order polynomial and two composite functions describing the amorphous maxima. These composite functions were linear combinations of Gauss function and Cauchy function. The computations were carried out using of own computer program. The calculations according to the Ruland method were carried out with the FFCRYST computer program. Conforming results were obtained in these two methods. This proves the validity of reservations about the Hindeleh-Johnson method in its original version.
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