Orientation of nano-crystallites and anisotropy of uniaxially drawn α-polyamide 6 films: XRD, FTIR, and microwave measurements

Abstract

We have used various techniques such as X-ray diffraction, Fourier transform infrared spectroscopy as well as dielectric measurements with a 4 GHz Microwave resonator to investigate the structure of uniaxially drawn α-polyamide 6 films. The influence of uniaxial drawing on several parameters such as degree of crystallinity, orientation and size of crystallites, permittivity and anisotropy was studied as a function of the drawing ratio. The main axis (b-axis) of the polyamide 6 nano-crystals is aligned in the direction of drawing, while the hydrogen bonds (a-axis) are oriented transverse to the drawing direction. Increasing the drawing ratio yields a higher crystallinity, a better orientation of the crystallites, and a stronger dielectric anisotropy of the films. The good agreement of the results demonstrates that all the three experimental techniques are well suited to characterize the microstructure of polyamide films.