The Effect of Stretching on the Crystal Structure and Crystal Orientation of PA510/SiO₂ Films

• Main Authors: Lingna Cui, Yu Dong, Yuejun Liu, Shuhong Fan
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: Materials
• Subjects: polyamide 510; X-ray diffraction; orientation; mechanical properties; optical properties; barrier properties
• Online Access: https://www.mdpi.com/1996-1944/14/4/705

In order to explore the relationship between the microstructure and macroscopic properties of PA510/SiO₂ films, the effect of the stretching on the crystal structure and crystal orientation of stretched PA510/SiO₂ films was studied. It could be seen from the transmission electron microscopy (TEM) graphs that the layered SiO₂ molecules were mainly oriented toward the machine direction (MD) and the dispersion could be improved by stretching. Through wide-angle X-ray scattering (WAXS) analysis, PA510/SiO₂ stretched films only contained a γ crystal form. During uniaxial stretching, especially for 1 × 3 film, the γ₁(100) crystal form was obviously oriented in the equatorial direction, and the orientation of γ₂(004) and γ₃(006) crystal forms could be observed in the meridian direction. According to the Herman orientation function, the orientation of the <i>b</i>-axis in the MD increased with the increase of the stretching ratio. It was worth noting that the orientation of the crystal region was more obvious. The addition of SiO₂ and the orientation of the crystalline and amorphous regions could improve the barrier properties of the films. The changes in the optical properties of stretched films were affected by the dispersion state of SiO₂ and the surface roughness.