Diffraction pattern and structure of amorphous and crystalline regions in semicrystalline nylon 6.6

Abstract

X-ray diffraction data on two nylon 6.6 samples of different crystallinity are analysed to yield separate scattering functions for the amorphous and crystalline regions. The amorphous pattern is found to be quite different from the smooth background usually assumed in the determination of polymer crystallinity. Radial distribution functions derived from the data are qualitatively different beyond the nearest neighbour distance regions. The curves for the crystalline regions show discrete distance distributions to very large separations. In contrast, the positional correlation between atom pairs in the amorphous regions are short-range and much less well defined, and the degree of hydrogen bonding in the amorphous regions appears to be lower than in the crystalline regions.