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 a-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 (baxis) 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.

Influence of Melt-Draw Ratio on the Crystalline Structure and Properties of Polypropylene Cast Film and Stretched Microporous Membrane

“…The crystallinity and crystal size were both increased. 30,31 The mechanical properties, such as elastic modulus, yield strength, and stress-hardening, of the oriented polymer increased synchronizedly with increasing MDR. 17,32 For the stretched microporous membrane, Lee 33 et al reported that the higher the MDR was, the higher the elastic recovery of cast film, and the better the air permeability of stretched microporous membrane.…”

Preparation of Ag nanoparticles-reinforced polyamide 6 nanocomposites by in situ polymerization and investigation of its properties

“…Furthermore, the α phase is predominant in nano-Ag/PA6 composites, but is obviously reduced in the PA6 matrix. This is due to the heterogeneous nucleation effect of silver nanoparticles in PA6 matrix, which play an important role in forming the perfect crystal structure 16, 17 . Figure 3 shows the crystallization and melting behaviors of PA6 and nano-Ag/PA6 composites containing 0.1% to 0.9% silver nanoparticles (Fig.…”

Effect of external field on the lamellar crystalline structure and properties of poly(4‐methyl‐1‐pentene) casting film

“…If the MDR was increased to 200, long period, crystalline phase thickness, crystallinity, and lamellae cluster size remained constant; however, the orientation was improved with MDR, it was one of the key factors that had a great influence on performances of membrane. Carreau and other groups also indicated that the increase in draw ratio led to the improvement of crystal orientation . Processing conditions, such as die temperature of extruder, MDR, and the air knife play an important role in MEAUS and it makes a great difference on the crystal morphologies.…”

“…Carreau and other groups also indicated that the increase in draw ratio led to the improvement of crystal orientation. [8][9][10][11] Processing conditions, such as die temperature of extruder, 12 MDR, 13,14 and the air knife 15 play an important role in MEAUS and it makes a great difference on the crystal morphologies. In addition, processing condition also influences properties of stretched membranes.…”