Determination of kinetic and thermodynamic aspects of cellulose triacetate dyeing using matching‐index‐of‐refraction absorption spectroscopy

A simple method of analysis is described in which ordinary absorption spectroscopy is employed to measure dye content within cellulose triacetate fibres in order to determine the rate of dyeing for triacetate fabric immersed in infinite dyebaths at various temperatures. The results are analysed to yield values for the activation energy and enthalpy change associated with the transfer of a dye, Disperse Red 13, from a saturated dyebath to the interior of triacetate fibres immersed in that bath.     

Fading characteristics of a disperse dye on cellulose triacetate, polyester and nylon under monochromatic light radiation

Light fastness of CI Disperse Blue 165 dye on cellulose triacetate, polyester and nylon fabric substrates exposed to monochromatic light was examined on a radiant energy basis. The action spectra indicated a strong effect on the substrate-fading characteristics: nylon exhibited poorer light fastness in the visible and ultraviolet light range than polyester and cellulose triacetate. Two specific fading peaks were found for the nylon substrate, which were different to those found for the polyester and cellulose substrates. It was shown that polyester exhibited the best light fastness properties overall. The colour changes in the fading process suggested that the fading products of the dye on nylon (where reduction occurred) were different from those on the polyester and cellulose triacetate substrates (where oxidation occurred).     

Control of the crystal structure of microbial cellulose during nascent stage

The structure of the product, from an Acetobacter culture in the presence of Fluorescent Brightener, Direct Red 28, and Direct Blue 1, 14, 15 and 53, characterized by an X‐ray diffractormeter is a crystalline complex. On the other hand, solid‐state ¹³C‐NMR spectroscopy reveals that the product is noncrystalline. However, the X‐ray result of the product sample suggests that the dye molecule is included in the form of a monolayer between the cellulose sheets in the complex corresponding to the (11¯0) plane of microbial cellulose. But the celluloses regenerated from the Fluorescent Brightener product, the Direct Red 28 product, and the rest of the dye products are celluloses I, IV, and II, respectively. More specifically, the ¹³C‐NMR spectra revealed that the crystal types of cellulose from the Fluorescent Brightener and Direct Red 28 products are I_β and IV_I, respectively. Thus, the crystal structure of the product and the regenerated cellulose depends mainly on the position and number of the sulfonate groups in a direct dye and the interactions of the dye with the noncrystalline microbial cellulose in the nascent stage. The conformation and arrangement of the nascent cellulose chain changes when a direct dye adheres to it. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1726–1734, 2001     

Crystal structures of C.I. Disperse Red 65 and C.I. Disperse Red 73

Single crystals of C.I. Disperse Red 65 and C.I. Disperse Red 73 were grown from ethyl acetate and acetonitrile/toluene solutions, respectively, and their crystal structures were determined using single-crystal X-ray diffraction analysis. In each dye molecule, the aminoazobenzene framework is almost planar due to intramolecular H-bonding. In the case of C.I. Disperse Red 65, intermolecular associations occur by π–π stacking and intermolecular H-bonding, resulting in a herringbone-type arrangement; for C.I. Disperse Red 73, toluene molecules stabilize the crystal structure via π–π stacking.     

分散黄棕SE-2RLM增效效应的研究

本文研究了C. I. 分散橙30与C. I. 分散橙76相混合(分散黄棕SE-2RLM)的增效效应。通过熔点图、上染量和提升力的测定,确证了分散黄棕SE-2RLM存在增效效应。分散黄棕SE-2RLM为一具有最低共熔点的共熔物。最低共熔组成的分散黄棕在聚酯纤维上具有最大的上染量,该组成的分散黄棕在原染料强度、提升力、热熔曲线、pH依存性和升华牢度等。方面明显地优于两组份染料。或两组份染料之一。     

利用计算机配色拼混的分散黑染料

根据计算机配色软件对一黑色色样进行了测试,确定了一种了该分散黑染料的组成为C.I.分散橙73、C.I.分散橙44、C.I.分散紫93、C.I.分散蓝291∶1,用量比为1∶2.74∶2.51∶1.95。该复配分散黑具有稳定的色光,良好的染色提升性,各项色牢度均达到要求。     

Pad dyeing of cellulose acetate nanofibres with disperse dyes

In addition to a number of applications of nanofibres in technical fields such as medical, filtration and biosensing, nanofibres are recently being widely explored in terms of apparel use. Past work has focused on the functional properties of nanofibres for apparel use. Coloured nanofibres were produced to investigate their aesthetic properties for the potential application to apparel. Webs of cellulose acetate nanofibre were electrospun and dyed with a high energy level CI Disperse Red 167:1 dye and a low energy level CI Disperse Blue 56 dye using the continuous pad–dry–bake method. Results revealed that the high energy level dye produced better colour yield than the lower energy level dye. The dyed cellulose acetate nanofibres produced acceptable colorimetric values, colour yield and colour fastness. Young’s modulus of dyed nanofibres increased by threefold in comparison to the undyed cellulose acetate nanofibres. Scanning electron microscopy images showed good morphology with the smooth surface of the dyed cellulose acetate nanofibres.     

Dichroism of poly(ethylene terephthalate)-disperse dye system

As an approach to the basic study on the orientation behavior of amorphous region, the dichroic orientation factor, D, of poly(ethylene terephthalate), PET, fiber or film dyed with disperse dyes was investigated in relation to Δn, birefringence of the crystalline and amorphous regions, and Δn_a, birefringence of the amorphous region. It was found that D versus Δn plot belonged to a linear relationship passing through the origin but breaking slightly toward the D axis at Δn ? 0.14, while D versus Δn_a plot was expressed by a straight line passing similarly through the origin but with no break. D₀, the value of D at the ideal parallel orientation, was obtained by extrapolating the latter plot of the samples stretched with no relaxation: 1.00 and 0.73 for the PET–C.I. Disperse Yellow 7 and PET–C.I. Disperse Red 17 systems respectively. When the sample had been relaxed, the D versus Δn_a was also linear; however, D₀'s obtained were smaller than the above mentioned respective values. Even in these cases D for Disperse Yellow 7 versus the corresponding D for Disperse Red 17 belonged to a linear relationship with the slop 1:0.73. As the result it was concluded that the transition moment of molecule of C.I. Disperse Yellow 7 coincided with the molecular axis and the dye molecule combined parallel to PET chain, while as to C.I. Disperse Red 17 any definite conclusion could not be determined. However, in the both cases the mode of combination of dye molecules with PET is definite and kept unchanged during stretching and heating.     

VIS absorption spectrophotometry of disperse dyes

In the investigations of the dyeing processes, the low solubility of disperse dyes in water represents a practical problem for the determination of dye concentration in dyebaths and waste waters. Therefore the use of an organic solvent which, dissolves disperse dyes, is recommended in visible spectrophotometry of disperse dyes. Three organic solvents (ethanol, N,N-dimethylformamide, acetone) and two disperse dyes, the disazo dye C.I. Disperse Orange 29 and the anthraquinone dye C.I. Disperse Blue 56, were used for spectroscopic analysis in this present work. The absorbance of aqueous dye dispersions and various organic solvent dye solutions was measured to evaluate the effect of the solvent on the shape and intensity of the absorption spectra and on the wavelength shift of maximum absorption. The validity of Beer–Lambert’s law in each system was ascertained. A suggestion is made how VIS absorption spectrophotometry can be used to determine the dye concentration in disperse dyebaths. The addition of organic solvent to the dyebath leads to dye dissolution, and the Beer-Lambert’s law is then fulfilled. The optimum ratio between the dyebath dispersion and the organic solvents for the dyes investigated is also determined.     

C．I．分散蓝284对聚乳酸纤维的染色性能研究

使用C.I.分散蓝284对聚乳酸纤维进行了染色实验,研究了不同乳酸光学异构体单体含量的聚乳酸纤维的染色性能,结果表明纤维中右旋乳酸单体含量的提高有利于纤维对染料吸附量的提高.同时发现染料在纤维上的吸附等温线不属于Nemst型吸附,这可能与染料分子产生聚集有关.染色纤维的颜色产量随着染色温度的提高而提高.     

Preparation of Aqueous Nanodispersions of Disperse Dye by High-Gravity Technology and Spray Drying

Disperse dyes are poorly water-soluble and difficult to stably disperse in an aqueous medium, which greatly limits their application in dyeing synthetic fibers. Micronization can solve this problem. Herein, a facile way to prepare stable aqueous nanodispersions of disperse dye (C.I. disperse yellow 54) is presented by combining high-gravity antisolvent precipitation in a rotating packed bed (RPB) with spray drying. The as-prepared product had an average particle size of 120 nm, which could be readily redispersed in water. Compared with raw dye, the wettability and dispersibility of disperse dye nanoparticles were remarkably improved. Furthermore, the dyeing properties of the nanodispersions were obviously better than those of the commercial dye, which was micronized by ball milling.     

Effects of Gaseous Diffusion in the Substrate on Light Fastness of Dyes

Various disperse dyes in cellulose triacetate (cta) film and some dyes in Cellophane regenerated-cellulose film, sealed in envelopes of undyed hydrophobic films, viz. polytetrafluoroethylene (ptfe), polyacrylonitrile (pan), polyethylene terephthalate) (pet) and cta, have been exposed to light from a 400-W mercury lamp. Fading is retarded by the undyed films. The order of effectiveness is ptfe> pan > pet > cta. The permeability of water vapour (except for pan) or oxygen through these films decreases in the above order. The retardation is similar in magnitude to the corresponding differences in light fastness of the disperse dyes on textile fibres. It is suggested that the action, except possibly in pan, is caused by retardation of the diffusion of an oxygen molecule towards contact with a dye molecule during the short life-time of the excited state of the dye; calculation shows that there is only a very small chance of such contact. An expression is derived which shows that the rate of fading depends on both the life-time of the excited dye molecule and the rate of diffusion of oxygen in the substrate. The retardation effect, termed ‘diffusion-restriction’ (dr) effect, probably operates to some extent in all fading of colorants in fibres or films.     

Synthesis of cellulose triacetate-I from microfibrillated date seeds cellulose (<Emphasis Type="Italic">Phoenix dactylifera L.</Emphasis>)

Cellulose triacetate (CTA) has successfully been synthesized from microfibrillated date seeds cellulose. The cellulosic material under study constituted 84.9% amorphous phase with a degree of polymerization of 950. Acetylation was conducted at 50 °C under optimized heterogeneous conditions by acetic anhydride as acetyl donor, acetic acid as solvent and sulfuric acid as catalyst. In this process, cellulose was acetylated without dissolving the material throughout. The acetylated cellulose chains on the surface were dissolved gradually in acetic acid, which created new accessible zones. The yield of cellulose triacetate was studied varying acetic acid, acetic anhydride and catalyst concentrations, as well as reaction times. The ratio between the intensity of the acetyl C=O stretching band at around 1740 cm^?1 and the intensity of C–O stretching vibration of the cellulose backbone at 1020–1040 cm^?1 was used to optimize the reaction time. The optimal reaction conditions of 8% concentration of sulfuric acid, acetic anhydride/cellulose weight ratio of 3:1, acetic acid/cellulose weight ratio of 7:1, reaction time of 3 h and reaction temperature of 50 °C have given highest yield of cellulose triacetate, of about 79%. The obtained date seeds-based cellulose triacetate was characterized thoroughly by Fourier transform infrared (FTIR), X-ray diffraction (XRD), nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The synthesized product was identified as cellulose triacetate-I (CTA-I) characterized by a melting temperature of 217 °C and a decomposition temperature of 372 °C. These results demonstrated that date seeds can be used as potential source of microfibrillated cellulose which can be easily functionalized.     

Lattice Conversion of Cellulose in Wood

When peracetylated wood, prepared in an acetic anhydride-pyridine medium, was saponified and recrystallized, almost no conversion of cellulose I to cellulose II took place. Neither was conversion detected, when thirteen species of wood, differing in density from 0.17 to 0.71, as well as in lignin content from 18.1 to 38.8 %, were treated with 17.5 % aqueous NaOH, followed by recrystallization. The corresponding treatments for cellulose triacetate or cellulose resulted in complete conversion to cellulose II. Partial delignification of wood preceding the alkali-induced mercerization was found to cause partial lattice conversion to cellulose II, and the ratio of lattice conversion (L.C.R.) increased with the degree of delignification. The L.C.R. value reaches slightly more than 50 %, when one third of the lignin is removed, and the removal of about two third of the lignin from wood results in an almost complete conversion. The effect of lignin removal on lattice conversion was similar among the wood species, irrespective of their density and lignin content, Introduction of acyl groups larger than caproyl into wood, followed by saponification and mercerization resulted in a high conversion of cellulose in wood from cellulose I to cellulose II.     

Mutagenic activity removal of selected disperse dye by photoeletrocatalytic treatment

The degradation of black dye commercial product (BDCP) composed of C.I. Disperse Blue 373, C.I. Disperse Orange 37, C.I. Disperse Violet 93 dyes was investigated by photoelectrocatalysis process. The dyes have shown high mutagenic activity with Salmonella strain YG1041 and TA98 with and without S9. Samples of BCPD dye submitted to conventional chlorination and photoelectrocatalytic oxidation were compared monitoring its products by HPLC using a diode array detector, spectrophotometry UV–vis, TOC removal, and mutagenicity potency. The photoelectrocatalytic method operating with Ti/TiO₂ as anode at +1.0 V and UV illumination presented fast oxidation of test solutions containing 10 mg L⁻¹ of dye in 0.1 mol L⁻¹ NaCl pH 4.0 leading to 100% of discoloration, 67% of mineralization, and negative response to all tested Salmonella strains. The formation of Cl^•, CL₂ ^• on photoelectrocatalytic medium improved the efficiency of the method in relation to conventional chlorination method that promoted 100% of discoloration, but only 8% of TOC removal and more mutagenic product.     

分散红73和分散蓝183及其混合物在超临界二氧化碳中溶解度的测定与关联(英文)

The solubility of disperse dyes and their mixture in supercritical carbon dioxide is an important property in study and development of supercritical fluid dyeing technology. In this study, solubilities of C.I. Disperse Red 73, C.I. Disperse Blue 183 and their mixture in supercritical CO2 are measured at temperatures from 343.2 to 383.2 K and pressures from 12 to 28 MPa with a static recirculation method. Under the experimental conditions for the binary (C.I. Disperse Red 73 + CO2 or C.I. Disperse Blue 183 + CO2) and ternary (C.I. Disperse Red 73 + C.I. Disperse Blue 183 + CO2) systems, the solubilities increase with pressure. The solubility of C.I. Disperse Blue 183 decreases with the increase of temperature when the pressure is lower than 16 MPa, and the trend is opposite when the pressure is higher than 16 MPa. However, there is no crossover pressure for C.I. Disperse Red 73. The solubilities are also affected by molecular polarity of dyes. The co-solvent effect exhibited in the dissolving process of mixed dyes promotes their disso-lution in supercritical CO2. The experimental data of solubilities of C.I. Disperse Red 73, C.I. Disperse Blue 183, and their mixture are correlated with the Chrastil model and Mendez-Santiago/Teja model. The former is more accurate.     

A new dye‐modified poly(ethylene oxide)–poly(propylene oxide) polymer used as a dispersant for CI Disperse Red 60

A new dye‐modified poly(ethylene oxide)–poly(propylene oxide) polymer, in which the dye molecule (CI Disperse Red 60) is bonded onto polyether monoamine via a triazine ring, was synthesised for the preparation of dye aqueous dispersions and was characterised by Fourier Transform‐infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy and elemental analysis. This polymer exhibits unique dispersing performance for CI Disperse Red 60. The mechanism behind the improved performance is briefly discussed with the help of adsorption isotherms. The results indicated that the hydrophobic dye group of this polymer can strongly adsorb onto the dye particle surface through π–π interaction while its long hydrophilic poly(ethylene oxide) chains allow the formation of a thick layer around the dye particles. It was speculated that the adsorbed polymer molecule on the dye surface would form a brush‐like monolayer conformation. The dyeing performance of the prepared dye dispersions on polyester fabrics was also investigated. It was found that this polymer can effectively increase the apparent solubility of disperse dye. The dyed fabrics showed very good to excellent fastness to washing and rubbing, while the dyeing effluent was colourless.     

Correlation of solubility data of azo disperse dyes with the dye uptake of poly(ethylene terephthalate) fibres in supercritical carbon dioxide

Solubility data of disperse azo dyes in supercritical carbon dioxide are presented for dyeings of poly(ethylene terephthalate) fibres with CI Disperse Red 167:1, carried out at 200–300 bar and 80–120 °C, with varying amounts of adulterants. The same dyeings were also carried out in water for comparison. Scanning electron micrographs were taken of the dyes which show a growth of dye crystals during treatment in supercritical carbon dioxide. The paper reports that at 120 °C, melting of the pure dye CI Disperse Red 167:1 is observed. The presence of adulterants in the dye formulations help prevent agglomeration by acting as spacers between the dye molecules. Dyeings of PETP carried out under conditions of the highest solubility of the dye in supercritical carbon dioxide do not necessarily result in a very high dye uptake. This was shown by pressure- and temperature-dependent dyeing experiments of PETP in supercritical carbon dioxide.     

The Influence of Different Substitution Levels of Guar on the Quality of Viscose Prints with VS Monoreactive Dye

Abstract

The basic problem of reactive printing on viscose with polysaccharide guar thickeners is the capability of dye molecule to react with the hydroxyl groups of cellulose (binding of the dye) as well as with the hydroxyl groups of water (the dye hydrolyzes) or the thickener (binding of the dye) (1, 2]. This latter is most clearly expressed in combination of the polysaccharide unmodified guar thickener and the bifunctional reactive dye where the bifunctional dye forms, due to the presence of two reactive groups, a bridge between the cellulose fibre and the guar thickener (3). The unmodified guar has a large number of free hydroxyl groups which cause crosslinking with cellulose and hinder the thickener to wash off, thus increasing the stiffness of the printing fabric. The further investigation has shown that this undesireous reaction with the guar molecules can be partly diminished by the suitable selection of chemically modified guar thickener or by lowering the dry substance content [4, 5].

In this paper the influence of nonsubstituted and different substitutited guar thickeners with monoreactive (vinylsulphone) dyes on the changing of fabric stiffness will be shown.