Properties of polyamide 6,10/poly(vinyl alcohol) blends and impact on oxygen barrier performance

The oxygen transmission rate, average volume of free‐volume cavities ( V f ) and fractional free volume ( F v ) of polyamide 6,10 (PA610)/poly(vinyl alcohol) (PVA) (i.e. PA610 x PVA 05 y , PA610 x PVA 08 y and PA610 x PVA 14 y ) blend films reduced to minimum values when their PVA contents reached corresponding optimal values. Oxygen transmission rate, V f and F v values obtained for optimal PA610 x PVA z y blown films were reduced considerably with decreasing PVA degrees of polymerization. The oxygen transmission rate of the optimal bio‐based PA610 80 PVA 05 20 blown film was only 2.4 cm 3 (m 2 ·day·atm) −1 , which is about the same as that of the most often used high‐barrier polymer, ethylene–vinyl alcohol copolymer. Experimental findings from dynamic mechanical analysis, differential scanning calorimetry, wide‐angle X‐ray diffraction and Fourier transform infrared spectroscopy of the PA610 x PVA z y blends indicate that PA610 and PVA in the blends are miscible to some extent at the molecular level when the PVA contents are less than or equal to the corresponding optimal values. The considerably enhanced oxygen barrier properties of the PA610 x PVA z y blend films with optimized compositions are attributed to the significantly reduced local free‐volume characteristics.