Isodimorphism in\nPolyamide 56/Polyamide 66 Blends\nwith Controllable Thermal and Mechanical Properties

Abstract

The crystallization behaviors of polyamide 56/polyamide\n66 (PA56/PA66)\nblends are investigated. Isodimorphism is first found in PA56/PA66\nblends. The melting point, crystallization temperature, and crystallinity\nof the blends first decrease and then increase with the increase of\nPA66 content in the blends at the pseudo-eutectic point with ϕ₆₆ = 0.5. The crystalline structure follows the dominant component\nin the blends. That is, PA56 phase and PA66 phase are obtained in\nthe PA56-rich and PA66-rich blends, respectively, upon cooling the\nblends from the melting state. Both PA56 phase and PA66 phase are\nformed in PA56/PA66 blends at the pseudo-eutectic point upon cooling\nfrom the melting state. Fourier transformation infrared spectroscopy\nresults indicate that the isodimorphic behavior is attributed to the\nhydrogen bonding interactions between PA56 and PA66 chains in the\nblends. Mechanical properties of the blends indicate that the elongation\nat break of the blends is tremendously enhanced without scarifying\nthe strength and modulus of the materials. The isodimorphism of PA56\nand PA66 provides a simple and promising approach for fabricating\npolymeric materials with versatile applications.