THE DYEING OF CELLULOSE TRIACETATE WITH DISPERSE DYES

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Abstract
The diffusion coefficient of disperse dyes into cellulose triacetate was determined in the vicinity of glass transition temperature, (Tg.) by the film-roll method. In the original cellulose triacetate sample, the crystallinity determined by X-ray method was 12.5%, and Tg determined dilatometrically was 105°C. The crystallinity increases in water above Tg. In order to avoid the change of crystallinity during the diffusion measurement, in some experiments the film was pretreated in water at 130°C for 25hrs. The crystallinity of the pretreated film was 24%.The diffusion coefficients increased with increasing crystallinity as in the case of polyamide.This is attributed to the loosening of amorphous structure by the pretreatment in hot water.Activation energy of diffusion, E, increased with increasing crystallinity below Tg. The values. changed at about 105°C. For example, on the diffusion of 1, 4-diamino-2-methoxyanthraquinone (II in this report), the activation energies above and below Tg were 43 and 30kcal/mol, respectively. The greater the molecular weight of penetrant, the greater the value of E both above and below Tg. This tendency is shown more clearly above Tg.The jump distance, λ, was calculated by the formula E=(c. e. d.)•S•N•λ, where S is effective cross-sectional area of penetrant. The values of λ for dye II were 21 Å above Tg and 14 A below Tg.Diffusion coefficients and activation energy of disperse dyes were compared with those for secondary acetate, polyester and polyamide.

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