Partially miscible EVOH/copolyamide-6/6.9 blends: The effect of stretching on the structure

✍ Scribed by Y. Nir; M. Narkis; A. Siegmann

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 163 KB
• Volume: 38
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(20000315)38:6<813::aid-polb1>3.0.co;2-z

✦ Synopsis

Binary blends of random copolymers, ethylene-vinyl-alcohol (EVOH) consisting of 38 mol % ethylene and Copolyamide-6/6.9 with an approximate 1 : 1 comonomer ratio, were prepared via blown-film extrusion and uniaxial stretching. The anisotropy induced by the uniaxial deformation of the polymer blends was characterized by X-ray diffraction and birefringence measurements. The stretched films also were investigated via oxygen permeability. The results showed a sharp decrease in the apparent crystallite size throughout the entire composition range in comparison to the blown films. However, the order perceived within the amorphous phase in the EVOH-rich blends increased (decrease in oxygen permeability), whereas in the copolyamide-rich blends, orientation resulted in a decrease in the amorphous phase order (increase in permeability). Apparently, orientation destroyed the amorphous interpolymer complex.