Procedure for evaluating the crystallinity from X-ray diffraction scans of high and low density polyethylene/SiO2 composites

The separation of amorphous and crystalline contributions in diffraction data is a necessary step in the study of the structure of the less-ordered regions and in the calculation of the crystallinity of a HDPE and LDPE/SiO₂ nanocomposites. The nanocomposites have been prepared by melt compounding using a twin screw extruder. We suggest here that the diffraction pattern of a nanocomposite with a high degree of crystalline order may be fitted with easily resolvable crystalline peaks, and that the intensity not attributable to the crystalline peaks may be regarded as the amorphous scattering. This amorphous halo can be used as a template in analysing the diffraction patterns of crystalline samples.