Density, infrared absorption, and crystallinity in 66 and 610 nylons

The intensities of crystalline and amorphous infrared bands of 66 and 610 nylon films were plotted against density. The curves were extrapolated to zero intensity to give revised values for the amorphous and crystalline densities which are probably more accurate than those previously used. The amorphous density of 610 nylon was in agreement with the value previously measured on quenched films, but the amorphous density of 66 nylon was about 2% lower. The new values for the crystalline densities are somewhat lower than those calculated from x‐ray diffraction data.