Structural evolution and properties of polyamide‐6/poly(ether block amide) films during the simultaneous biaxial stretching

Abstract

The purpose of this study was to investigate the structural evolution and properties of simultaneously biaxially stretched polyamide-6/poly(ether block amide) copolymer (PA6/PEBA) films. The results showed the melting temperature of PA6 increased from 220.02 C to 225.56 C when the stretching ratios increased from 1 Â 1 to 3.5 Â 3.5, suggesting the occurrence of β ! α crystal transformation. Meanwhile, the increase of stretching ratios increased the crystallinity of the films due to the molecular orientation, which could create a more tortuous path for the diffusion of oxygen molecules through the films. As a result, the oxygen barrier performance of the stretched PA6/PEBA film was increased after biaxial stretching. The morphological observation showed that spherical or slightly ellipsoidal PEBA particles were dispersed in the PA6 matrix. The thermal shrinkage of the stretched film increased as the stretching ratios increased, and no significant difference of the shrinkage between machine direction (MD) and transition direction (TD) was observed in the stretched films. It was also found that the tensile strength of the stretched films in MD and TD exhibited the highest value at a stretching ratio of 3.5 Â 3.5, which was about 1.7 times and 2.1 times higher than that of the unstretched PA6/PEBA film, respectively.

Structure evolution and properties enhancement of polyamide‐6/polyamide‐1010 films under uniaxial and biaxial stretching

“…Similar behavior was observed in the investigation of the polyamide-6/poly(ether block amide) films during the biaxial stretching. 19…”

“…However, as for the toughness of BOPA film, only sporadic attention has been paid to the toughening of BOPA film. 18,19 In our previous study, 18 we found that the toughness of BOPA film was improved by the addition of poly(ether-block-amide) (PEBA) copolymer, but with greatly reduced strength at higher PEBA content. Therefore, a more extensive study on BOPA film with high toughness has to be still carried out to meet the high-performance demands for s-LIB packaging.…”

“…In our previous works, the effect of biaxial stretching on the PA6/PEBA films was investigated. 19 However, to the best of our knowledge, no work has been found to investigate the effect of stretch orientation on the mechanical properties of stretched polyamide-6/PA1010 films with excellent toughness, especially the change of microstructure during the stretching process and the relationship between the microstructure and mechanical properties.…”

Poly(vinyl alcohol)/Kaolin Barrier Films with Superior Dispersion Fabricated by Solid-State Shear Milling and Biaxial Stretching

“…Apparently, with the help of biaxial stretching, both the strength and modulus of the stretched films were dramatically improved owing to the in-plane orientation of microstructures (Figure 6d,e). For example, unstretched PVA/K5 exhibited a tensile strength of 25.7 MPa and a modulus of 29.3 MPa, while for BO-PVA/K5, its tensile strength reached 146.4 MPa with a Young's modulus of 5.5 GPa, even beyond some engineering plastics such as nylon, 36,37 fully meeting the requirements of high-performance packaging materials for mechanical properties. It was worth noting that the superdispersed kaolin reduced the interaction between PVA molecules to some degree because of its physical blocking effect, resulting in the decrease of the elongation at break.…”