Structure and properties of hygroscopic PA6 - Inorganic salt blend

Blends of nylon-6 and inorganic salt (composition range 0-10% by weight) were prepared by melt processing at 230degreesC, forming an intimate blend of the two components. The structure of the blend was investigated by using FTIR and WAXD techniques. The formation of a nitrogen atom-metal ion coordination bond is seen in the FTIR spectrum. X-ray analysis showed the decrease of the nylon-6 crystallinity due to the existence of the coordination bond. The hygroscopicity of the nylon-6 blend increases sharply with the increase in salt addition. The coordination interaction can hinder the internal rotation of nylon-6 molecular chain leading to the increase in the rigidity of the nylon-6 blend and to the decrease in the toughness.