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

Lingna Cui,Yu Dong,Yuejun Liu,Shuhong Fan

doi:10.3390/ma14040705

Abstract

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 b-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.

Highlights

Key Laboratory of Advanced Packaging Materials and Technology of Hunan Province, School of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007, China; Abstract: 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 has been shown that the thermal properties, impact strength and tensile strength of bio-based long-carbon-chain polyamides can be effectively improved by adding a nanofiller such as nano-clay, nano-cellulose or graphene
The macro-properties of polyamides are the concrete presentation of a microstructure, and changes in polyamide chain orientation, crystal structure and morphology can affect the macro-properties of polyamides

Summary

Materials

Polyamide 510 resin in pellet form was supplied by Cathay Industrial Biotech (Shanghai, China). The PA510/SiO2 film was prepared by extrusion casting (FDHU-35, Guangzhou Putong Instrument, Guangzhou, China). Where the x is the content of the SiO2 , ∆Hm is the melting crystallization enthalpy obtained from the first heating scan and ∆H0 is the heat of fusion for 100% crystalline polyamide. Three parallel tests were performed on each specimen Tensile tests of both the MD and TD were carried out using a universal material testing machine (CMT 2202) (Sansi aspect technology, Shenzhen, China). The elongation at break and tensile strength of the PA510/SiO2 films were measured according to ASTM standard. The transmittance and haze of the PA510/SiO2 films were measured using a transmittance haze tester (WGT-S) (Precision Scientific Instruments, Shanghai, China) with GB/T. 48 N/m, 330 kHz and 0.5~2.0 Hz, respectively

Results and Discussion

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Conclusions