The dyeing of cellulose with direct dyes. Part II. The absorption of chrysophenine by cellulose sheet

Changes in the pore structure of cotton cellulose resulting from the steps of the wet-fixation process were assessed by measurement of moisture regain, water of imbibition, and dye sorption. These measurements reveal the relative proportions of pore surfaces in the nonswollen state, the pore volumes in the swollen state, and the pore surfaces in the swollen state, respectively. The uniformity of deposition of the methylolated melamine resin was established by both light and scanning electron microscopy; the resin is deposited on fiber surfaces as well as in the internal pores of the fibers. The increases in pore surfaces and volumes in the fixation step, as well as the decreases effected by curing, were determined in relation to the structure of unmodified cotton and cotton treated by a pad-dry-cure process employing both "resinforming" highly methylated hexamethylolmelamine and "crosslinking" dimethyloldihydroxyethyleneurea reagents.

Section: Resin Deposition An~i Compositionmentioning

confidence: 98%

Alteration of the Pore Structure of Cotton by the Wet-Fixation Durable-Press Process

Bertoniere

Martin

Blouin

et al. 1972

“…When the data of Figure 4 are replotted inFigure 5for these assumptions, a rather consistentEtc 4 The sorption of C. I. Direct Yellow 12 by regenerated cellulose sheets at 60°C[39].The value of (KI)p used for calculation is given at the head of each section A, B. The upper, heavy lines are calculated for a carboxyl dissociation coefficient of 1.…”

mentioning

confidence: 98%

Ionizable Groups in Fibers and Their Role in Dyeing. An Examination of the Sorption of Anionic Dyes by Cellulosic Fibers and Films

McGregor

1972

The development of a simple but general approach to equilibrium dyeing has stimulated a re-examination of existing data on the sorption of anionic dyes by, cellulosic fibeis. New data are also analyzed.The volume term V of the conventional theories has been replaced by the concept of an average practical ionic distribution coethcient ( K 1 ) P for the inorganic ions in the system. ( K 1 ) P can be measured independently of the dye sorption data.The conventional theories ignore the acidic groups in cellulosic fibers and appear to use incorrect values for V. For these reasons the conventional theories appear to be seriously in error. A direct experimental test of these conclusions is proposed.

“…Willis et al [34] reP9rt -åH values ranging from 9.3 to 15.9 kcal/mole,for the adsorption of Chrysophenine G on cellopnane sheet in the presence of sodium chloride of concentrations up to 4 g/liter. Graham and Fromm [ 14 ] , f rom calculations of -OH° using the data of Willis et al, point out that -aH° increases with increasing salt concentration for a fixed value of the dye adsorption.…”

Section: Influence Of Electrolytes On the Adsorption Processmentioning

confidence: 99%

The Influence of Different Electrolytes on the Interaction of Chlorazol Sky Blue FF with the Cotton Fiber Surface in Aqueous Solutions

Iyer

Сринивасан

Baddi

1968

Investigations were carried out to study the adsorption of Chlorazol Sky Blue FF on cotton fiber from aqueous solutions of 0.1 N LiCl, NaCl, KCl, RbCl, and CsCl. The dye uptake both at 50° and 60° increased markedly with increasing size of the alkali metal cation. The equilibrium dye adsorption could be described by a Langmuir-type equation. The calculated standard affinity of dye adsorption showed a fairly constant value, but the exothermic heat of dyeing and the entropy of dyeing, calculated from the individual isotherms, increased as the dye adsorption increased in the presence of either higher electrolyte concentrations or equivalent concentrations of alkali metal cations of larger size. Possible changes in the orientation of adsorbed dye ions on the cellulose surface can account for the increased -Δ H ° and -ΔS ° values. It is pointed out that, apart from the usual well known effects of electrolyte cations, an ,important contributory factor to the adsorption process arises from the disturbance caused by the cations to the structure of water hydrogen-bonded to the cellulose surface and "iceberg" water around the hydrophobic parts of dye molecules. This effect, which will increase with the size of the alkali metal cation, explains the results adequately.