Effects of acid dyes on crystallization and mechanical properties of melt-reprocessed nylon 66

Abstract

Nylon fibers dyed with different types of acid dyes were melt reprocessed using a compression-molding machine. The crystalline structure and mechanical properties of the melt-reprocessed nylon were experimentally evaluated. It was found that metal complex acid dyes showed much more distinct effects on the structure and mechanical properties of melt-reprocessed nylon than nonmetallized acid dyes. They decreased the crystallization rate of the molten nylon and reduced its crystallinity. They also reduced the imperfect form I structure in the crystalline region. Compressionmolded nylon samples showed inferior mechanical properties in the presence of metal complex acid dyes. The coordinate bonds between the Cr 3ϩ ions and amide groups are possibly formed in melt-reprocessed nylon, which could be the reason for the changes in the structure and properties of melt-reprocessed nylon.

Reinforcement of nylon 6 with functionalized silica nanoparticles for enhanced tensile strength and modulus

“…With the addition of functionalized silica particles crystallinity increased to 29%. We have also noticed a corresponding shift in the crystalline temperature from 189 to 196 • C. Similar changes in crystalline temperature have been reported for nylon 66 when acid dyes were added [15]. Since changes in per cent crystallinity in our case were small, their effect on the mechanical properties was modest.…”