THE EFFECT OF TWISTING ON THE DYE DIFFUSION IN NYLON 6 MONOFILAMENT

Abstract

Twisted nylon 6 monofilaments were dyed in an aqueous solution of an acid dye, C. I. Acid Red 88, at 60_??_96°C. Before dyeing, the filaments were twisted by 0_??_10T/cm and fixed at both ends. The apparent diffusion coefficient D of this dye in the nylon 6 filament was obtained from the linear relationship between the dye penetration distance and the square root of diffusion time. The diffusion coefficient decreased monotonically with increasing the twist, while it increased with increasing the dying temperature. The Arrhenius plot of D gave an activation energy of about 33kcal/mol irrespective of the twisting.
For comparison with twisting, the filaments were extended and then dyed under a fixed extension. D for the extended sample decreased with increasing the extension but showed a little variance at the large elongation range. The reason for such a difference between the twist and extension may be due to the particular mode of the deformation of the crystallites during twisting.