Determination of crystallinity in polyester fibers by x-ray methods

The methods of Hermans and Weidinger and of Wakelin et al. (the correlation and integral methods) were used to determine the degree of crystallinity in poly(ethylene terephthalate) (PET) fibers. A standarization of cutting of the amorphous background scattering in PET fibers, indispensable for the method of Hermans and Weidinger, is put forward. On using a partial standardization of the intensity diffracted and scattered in the fiber, namely, on taking into account the x‐ray density of the specimen, variability in the intensity due to differences in absorption in the specimen at different angles 2 θ and variability in the specimen mass reflecting x‐rays in the function of the diffraction angle, good agreement of the PET fiber crystallinity values is observed.