Reaction of Dichlorotriazinyl Reactive Dyes With Cellulose and Simultaneous Diffusion in Cellulose

Morita, Zenzo; Nishikawa, Isao; Motomura, Hiromi

doi:10.2115/fiber.39.11_t485

Cited by 13 publications

(5 citation statements)

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“…Owing to repulsion of the cellulosate ions and the dye anions, an increase in pH will also lead to a decrease in K. In summarizing the expected influence of the pH on the efficiency, we can say that an increase in pH should decrease E and E as well as E*. This prediction has recently been verified experimentally by Morita [4,5,6].…”

Section: Discussionmentioning

confidence: 69%

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Efficiency of Monofunctional Reactive Dyeing : A Mathematical Analysis

Rys

Sperb

1989

Textile Research Journal

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We present a mathematical model for the diffusion-reaction process, describing the dyeing of textile fibers with monofunctional reactive dyes. In particular, we have studied the behavior of the fixation efficiency for various dyeing conditions. The behavior of a reactive dye moving from the dyebath into the interior of the textile substrate depends primarily on four processes: the convectional diffusion in the dyebath to the fiber surface, the molecular diffusion through the hydrodynamic boundary layer and within the fiber, the adsorption, and the chemical reaction. The latter two processes cause immobilization of the diffusing species on the polymer chains of the fibers. The overall effect of these four steps determines the levelness of the dyeing, the spatial distribution of the fixed dye throughout the fiber cross section, and also the efficiency of the dyeing. The efficiency is given by the ratio of the total amount of dye that has reacted with the substrate versus the total amount of the dye that has hydrolysed in the external (= dyebath) and internal (= pore liquid) solutions.Up to now, various expressions for efficiency have been suggested and discussed [ 8,9,13 ] . Our contribution derives the efficiency by rigorous mathematical analysis of the interplay between diffusive transport phenomena within a textile substrate and the competitive chemical rate processes encountered in reactive dyeing. The question as to whether or not hydrodynamic effects in the dyebath can also influence the efficiency will be the subject of a subsequent study.The overall rate of reactive dyeing with textile fibers can be expressed by F'ick's second equation in its original meaning of a material balance:In this equation, Dreai is the real, concentration-independent diffusion coefficient' of the dye in solution, b is a factor that takes into account the random configuration of the pores (tortuosity factor = lr3 for an anisotropic medium), and 72 denotes the Laplacian. The right-hand side of Equation t represents the difference between flux into and out of a volume element and is therefore concerned only with the concentration of the mobile reactive dye [D,*] in the pore liquid of the textile fibers ( ~ ), whereas the left-hand side represents the total amount of molecules accumulated in that volume element: Here, [Do.] and [D,°j are the concentrations of adsorbed and covalent-bonded dye, respectively; [Dh,,.*] is the concentration of dye hydrolyzed in the pore liquid ; and Pdenotes the porosity. Combining Equations I and 2 gives Equation 3:Because the hydrolyzed dye must be washed off very easily, reactive dyes have to possess low affinity. Thus, a linear adsorption isotherm can be assumed:where K is the inner adsorption equilibrium constant. Because the adsorption of the reactive dye on the pore surface within the fiber is much faster than the diffusion and the chemical reaction with the functional groups of the textile substrate, the approximation (Equation 4) reduces Equation 3 to Equation 5:As a first approximation, we can ass...

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Section: Discussionmentioning

confidence: 69%

“…Because the adsorption of the reactive dye on the pore surface within the fiber is much faster than the diffusion and the chemical reaction with the functional groups of the textile substrate, the approximation (Equation 4) reduces Equation 3 to Equation 5:…”

Section: Competitive Processes In Reactive Dyeingsmentioning

confidence: 99%

Efficiency of Monofunctional Reactive Dyeing : A Mathematical Analysis

Rys

Sperb

1989

Textile Research Journal

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“…From the perspective of cellulosic fibre dyeing and the role of added NaCl or Na 2 SO 4 in dye uptake, the vast majority of kinetic studies have focussed on direct dyes, as demonstrated by the results presented in Figure 6 and, to a lesser extent, reactive dyes, 36,38,39,[55][56][57][58][59][60][61][62][63] though the kinetics of vat dye adsorption have received attention, as illustrated by the findings shown in Figure 7.…”

Section: Kinetic Analysismentioning

confidence: 99%

The role of inorganic electrolyte (salt) in cellulosic fibre dyeing: Part 2 theories of how inorganic electrolyte promotes dye uptake

Burkinshaw

2021

Coloration Technology

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This review concerns the application of vat dyes, sulphur dyes, azoic colorants, direct dyes and reactive dyes to both natural and man-made cellulosic fibres from aqueous dyebaths using exhaust dyeing processes and the role of added inorganic electrolyte in such dyeing processes. In this part of the paper, the various theories/hypotheses/ concepts which have been proposed to account for the promotional effect exerted by added inorganic electrolyte on dye uptake are reviewed and scrutinised, from the viewpoints of the essential physico-chemical properties of the five classes of dye used and the fundamental aspects of their application.How to cite this article: Burkinshaw SM. The role of inorganic electrolyte (salt) in cellulosic fibre dyeing: Part 2 theories of how inorganic electrolyte promotes dye uptake.

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“…[16][17][18] In the present paper, a reactive disperse dye with a vinylsulfonyl group is applied to nylon 6 which has only one kind of functional group. The terminal amino group undergoes an acid-base equilibrium and only the free base is expected to react with the dye.12~13y15 As this reactive dye is adsorbed by nylon 6 as a disperse dye, there is no salt formation between dye and terminal amino groups.…”

Section: Introductionmentioning

confidence: 99%

Reaction and diffusion of reactive disperse dye in nylon 6

Morita

Saito

Motomura

1986

J of Applied Polymer Sci

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SynopsisThe diffusion of a reactive disperse dye with a vinylsulfonyl group accompanied by simultaneous reaction with the amino end groups in nylon 6 was examined by the method of cylindrical film roll a t 70°C and pH 2.2-8.0. The experimental diffusion profiles of the active and fixed species of the dye in nylon 6 were confirmed t o be described by the diffusion equation accompanied by the chemical reaction with substrate taking the limited amount of the end groups into account, where the active species of dye were assumed to react oniy with the free base of amino end groups. The completion of the reaction with the amino end groups was observed in the first layer from the surface at pH 6.0-8.0. The value of diffusion coefficient was constant (8.0 X lo-'' cm2/s) a t all the pH's. The product of the second-order rate constant, k , , of reaction of the dye and the dissociation constant, K,, of the amino end groups was constant ( k , K , = 4.0 X lo-' s ~ ' ) at pH 2.2-8.0. The k , values of the reaction with various substrates for vinylsulfonyl and monochlorotriazinyl-reactive dyes were compared and the practical dyeing conditions were discussed.

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Reaction of Dichlorotriazinyl Reactive Dyes With Cellulose and Simultaneous Diffusion in Cellulose

Cited by 13 publications

References 4 publications

Efficiency of Monofunctional Reactive Dyeing : A Mathematical Analysis

Efficiency of Monofunctional Reactive Dyeing : A Mathematical Analysis

The role of inorganic electrolyte (salt) in cellulosic fibre dyeing: Part 2 theories of how inorganic electrolyte promotes dye uptake

Reaction and diffusion of reactive disperse dye in nylon 6

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