Diffusion of monoanionic dyes in nylon

Abstract

The diffusion of three monoanionic dyes [Orange II (C.I. Acid Red 7) and two chromium complex dyes] in nylon 6 is discussed on the basis of dye distribution obtained by the film‐roll method. Variations of the diffusion coefficients with dye concentration depend characteristically on the dye species and in one case show a maximum near the dye concentration stoichiometric to the amino endgroup concentration in the nylon. These concentration dependences are interpreted on the assumption of two thermodynamically distinct dye populations in equilibrium.

Studies on the Sorption of Azo Dyes Containing Fluorine Atoms by a Nylon 6 Film. Part 1. Effects of fluorine atoms on the sorption of azo dyes by a nylon 6 film.

“…The sorption and diffusion behavior of acid dyes by nylon 6 is a matter of interest from scientific and practical point of view, and has been interpreted by a dual sorption mechanism, in which two kinds of sites to interact with the dyes electrostatically and nonelectro statically are taken into account (12)(13)(14).…”

Dual Mode Diffusion and Sorption of Sodium Chloride in Pre-Cooked Potato (Solanum tuberosum L.)

“…This assumption was supported by the fact that the dual mode parameters obtained from the sorption isotherm can explain the variation of D with the dye concentration (Komiyama & Iijima, 1974;Petropoulos, 1985). Generally in cooked foodstuffs, the total weight of discrete liquid water droplets is considerable as compared with the weight of water in the swollen substrates.…”

“…Equation (2) in the literature (Komiyama & Iijima, 1974) gives a relation between C p + C L and θ as,…”

“…In our previous three studies, we have applied a dual mode diffusion and sorption theory originally developed for dye diffusion in nylon (Komiyama & Iijima, 1974). Generally foodstuffs under cooking conditions contain 60-95% water, which are much more than the water content, 6% of a polymer substrate like nylon.…”

“…The variations were successfully explained with the dual mode diffusion and sorption theory, which has been successfully applied to the diffusion of NaCl in cooked Japanese radish, solidified egg white, and pork meats. The original theory (Komiyama & Iijima, 1974) was revised by changing the definitions of the parameters for the presence of liquid water droplets in the foodstuffs. The sorption isotherms, being found to be almost linear with very slight concave upward curvatures, were explained by invoking the presence of the droplets.…”