Digital filtering and shape identification in the analysis of WAXD patterns of semicrystalline polymers

Most frequently, the degree of crystallinity of polymers is determined using Wide Angle X-ray Diffraction (WAXD) technique. The method consists in the resolution of WAXD diffraction curve of a polymer into individual crystalline peaks and amorphous halo. This work presents a procedure, which was elaborated to help in a quick determination of the angular positions of crystalline peaks present in the diffraction curve of investigated polymer. The positions of peaks are determined using numerical differentiation. Using these data the computer program WAXSFIT identifies investigated polymer and prepares a set of starting parameters which are used in the calculations of the degree of crystallinity.