TEMPERATURE DEPENDENCE OF DIFFUSION OF MONOAZO ACID DYES IN NYLON 6 FILM TREATED WITH TANNIC ACID

Abstract

The effect of the change in the fine structure of nylon 6 film treated with tannic acid on the diffusion of monoazo acid dyes was investigated. Orange II (C. I. Acid Orange 7) and Diacid Supra Red 3 B (C. I. Acid Red 35) were used.
The apparent diffusion coefficients of these dyes (D_app) in the nylon were measured by means of the steady diffusion method in the temperature range 40 to 85°C.
The activation energy of the dye diffusion (E) evaluated from the slope of Arrhenius plot of D_app showed a break at a temperature (T_α) characterized by nature of the dye and tannic acid content in nylon 6.
For both dyes, D_app decreased and E increased as the tannic acid content in the nylon 6 was increased. These results were associated with retardation of the dye diffusion. However, while the glass transition temperature, T_g, was elevated, T_α was lowered as the tannic acid content was increased. This phenomenon was discussed in terms of the change in the fine structure of the amorphous region in the nylon 6.