Biaxially oriented polyamide‐6 (BOPA) film has been widely used in many packaging applications. However, the BOPA film with excellent toughness is still required when utilizing in the field of soft‐packaged lithium‐ion batteries, pharmaceutical blister packaging, or frozen food packaging especially for vacuum packaging of irregular‐shaped food products. The purpose of this study was to improve the toughness of BOPA films by toughening with poly(ether block amide) (PEBA) (BOPA/PEBA films) based on the simultaneous biaxial stretching technology. The crystal structure, morphology, optical properties, barrier, and mechanical properties of BOPA/PEBA films were investigated. The results showed that the incorporation of PEBA into BOPA films slightly decreased the melting temperature and crystallinity of PA6, and the BOPA/PEBA films exhibited only α‐form crystals and no preferential orientation in the machine direction (MD) and transition direction (TD). The morphological observation showed that higher addition of PEBA led to the formation of microvoids due to the poor compatibility between PA6 and PEBA. As a result, the transmittance and oxygen barrier properties of the BOPA/PEBA films decreased. In addition, mechanical analysis suggested that the addition of PEBA could effectively improve the toughness of BOPA film.

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In this study, biaxially oriented polyamide 6/polyketone/graphene oxide (PA6/PK/GO) films were prepared by melt blending then simultaneously biaxially stretched process, with the aim of obtaining high barrier properties films and improvements in their mechanical properties. The oxygen transmission rate of biaxially oriented PA6/PK/GO film significantly decreased with addition of polyketone and GO. It is surprising that the biaxially oriented process can excellently improve the barrier properties of biaxially oriented PA6/PK/ GO film. For example, there was 94.7% OTR reduction of the film containing 20 wt% PK and 0.08 wt% GO compared with PA6 film at a stretching ratio of

The main purpose of this work was to investigate the linear tearing properties of PA6/MXD6 films prepared by simultaneous biaxial stretching. The compatibility between PA6 and MXD6 and the thermal properties of the PA6/MXD6 composites were also investigated. The results showed that the tearing deviation of the blending films decreased from 100 to 3.8% when the MXD6 blend ratio increased from 0 to 25%, but the deviation increased when the MXD6 blend ratio continue to increase. It means that the PA6/MXD6 films with addition of 25 wt% MXD6 exhibited the best linear tearing properties. The differential scanning calorimetry results revealed that the addition of MXD6 reduced the melting temperature from 227.5 to 224.8°C and crystallization temperature of PA6 from 179.3 to 175°C due to the benzene ring structure of MXD6. The dynamic mechanical analysis results indicated that MXD6 exhibits favorable compatibility with PA6. In addition, it was found that the barrier properties of the biaxially oriented PA6/MXD6 films were extremely improved with the increase of MXD6 content.

A new bio-based polyamide 56/512 (PA56/512) has been synthesized with a higher bio-based composition compared to industrialized bio-based PA56, which is considered a lower carbon emission bio-based nylon. In this paper, the one-step approach of copolymerizing PA56 units with PA512 units using melt polymerization has been investigated. The structure of the copolymer PA56/512 was characterized using Fourier-transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance (1H NMR). Other measurement methods, including relative viscosity tests, amine end group measurement, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), were used to analyze the physical and thermal properties of the PA56/512. Furthermore, the non-isothermal crystallization behaviors of PA56/512 have been investigated with the analytical model of Mo’s method and the Kissinger method. The melting point of copolymer PA56/512 exhibited a eutectic point at 60 mol% of 512 corresponding to the typical isodimorphism behavior, and the crystallization ability of PA56/512 also displayed a similar tendency.