Anionic dye adsorption characteristics of surfactant‐modified coir pith,a ‘waste’ lignocellulosic polymer

The surface of coir pith, an agricultural solid waste, was modified using a cationic surfactant hexadecyltrimethylammonium bromide. Adsorption of anionic dyes on surfactant‐modified coir pith was investigated in a series of batch adsorption experiments. Two anionic dyes, acid brilliant blue (acid dye) and procion orange (reactive dye), were used in the adsorption studies. The effect of process variables such as contact time, concentration of the dyes, adsorbent dose, temperature, and pH were studied in order to understand the kinetic and thermodynamic parameters of the process. The kinetics of adsorption obeyed the second‐order rate equation. The equilibrium adsorption data were fitted into the Langmuir and Freundlich isotherms. It was found that modified coir pith yielded adsorption capacities of 159 and 89 mg/g for acid brilliant blue and procion orange, respectively. Mechanisms involving ion exchange and chemisorption might be responsible for the uptake of dyes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1538–1546, 2006     

Application of a reactive cationic dye to wool

This is a study on the application of a new type of reactive cationic dye. Stripping agents and the influence of aftertreatment are discussed. The result shows this kind of dye is more suitable than conventional reactive dyes for wool and the urea-surfactant method is the best stripping method.     

Synthesis of novel highly reactive silicone-epoxy monomers for cationic photopolymerizations

A series of novel cationically photopolymerizable silicone-epoxide monomers bearing substituted benzyl ether groups were prepared. Monomers with methoxy groups on the aromatic ring of the benzyl ether group were synthesized by sequential hydrosylation reactions of 1,1,3,3-tetramethyl disiloxane. Kinetic studies using real-time infrared spectroscopy of the cationic photopolymerizations of these novel monomers showed that those monomers with methoxy groups exhibited elevated rates of photopolymerization. The acceleration effect was explained on the basis of synergistic effects of two mechanisms, namely, the normal ring opening polymerization catalyzed by a Brönstead acid, and the cationic photopolymerization induced by the redox interaction between the free radicals formed in the backbone of the monomer and the onium salt used as photoinitiator. The methoxy groups on the aromatic ring of the benzyl ether enhance the stabilization of the carbocation formed in the structure of the monomer. Silicone-epoxy monomer with 2,5-dimethoxybenzyl ether group exhibited the higher photopolymerization rate. The latter compound can also be used as accelerator of the cationic photopolymerization of commercial silicone-epoxy monomer when used in low concentrations.     

Imparting insect repellency to nylon 6 fibers by means of a novel MCT reactive dye

Insect repellency of fiber is a property which makes the fiber to be of interest in the field of military and health. The insect‐repellent substrate could be prepared using either functional finishing or applying an insect‐repellent dye. In this article, insect‐repellent nylon 6 is obtained using a novel insect‐repellent reactive dye containing N,N‐diethyl‐m‐toluamide. To do this, N,N‐diethyl‐m‐toluamide (DEET) was first nitrated at the p‐position relative to amide functionality. The nitrated product was reduced in the presence of C₂H₅OH, SnCl₂, and HCl. The produced amine was then condensed with 2,4,6‐trichloro‐1,3,5‐triazine (cyanuric chloride) as a reactive group in below 5°C. The resultant adduct was finally reacted with an amino group present in 6‐amino‐1‐hydroxy naphthalene‐3‐sulfonic acid (J‐acid) to produce 7‐(4‐chloro‐6‐(4‐(diethylcarbamoyl)‐2‐methylphenylamino)‐1,3,5‐triazin‐2‐ylamino)‐4‐hydroxynaphthalene‐2‐sulfonic acid. To synthesis azo dye, sulfanilic acid was diazotized using HCl and NaNO₂ and then coupled to the above prepared component to produce insect‐repellent reactive dye. An analog dye was prepared via the same route without insect‐repellent group making stage. The chemical structures of the novel dyes were characterized using FTIR and ¹H‐NMR spectroscopy. The spectroscopic properties of the dyes were determined in terms of λ_max and ε_max in aqueous solution. The novel dyes were then reacted with nylon 6 and bonded to it covalently to provide permanent insect‐repellent substrate. The insect‐repellent efficacy of the reacted nylon 6 was studied using standard methods for Anophele mosquito repellent. The insect‐repellent dye reacted nylon 6 showed insect‐repellent activity. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Hydrodynamic properties of a novel ‘open wall’ monolith reactor

The hydrodynamic behavior of high-porosity ceramic acicular mullite (ACM) monoliths operated in gas–liquid Taylor flow was investigated by cold-flow tracer residence time distribution (RTD) experiments and compared with the hydrodynamic behavior of classical cordierite monoliths in terms of static liquid fraction, maldistribution and mass exchange between the dynamic liquid zone and the static liquid zone. The piston-dispersion-exchange (PDE) model was successfully fitted to the experimental data. The multiphase fluid mechanics were indeed different for ACM and cordierite monoliths: in contrast to the classical cordierite system, the mass exchange between static liquid and dynamic liquid was much higher and the liquid phase could access the open volume of the permeable ACM monolith wall. On the other hand, the larger velocity maldistribution, larger static liquid fraction and the liquid interaction between adjacent ACM microchannels resulted in less plug flow behavior.     

Preparation of betaine‐modified cationic cellulose and its application in the treatment of reactive dye wastewater

Betaine‐modified cationic cellulose was prepared through the reaction of cellulose with betaine hydrochloride by an efficient one‐step dry method. Dicyandiamide was used as a dehydrating agent to promote the formation of ester bonds between the reactants. Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy were used to characterize the cellulose betainate. Experiments showed that at a molar ratio of the cellulose glucose unit, betaine hydrochloride to dicyandiamide, of 1:1:0.5 at 150°C for 3 h, the degree of substitution of the cationic group reached 0.80. The adsorption of simulated C. I. Reactive Red 24 and C. I. Reactive Red 195 wastewater on the cationic cellulose was carried out, and the effects of the adsorbent dose, initial dye concentration, and salt concentration on the dye removal efficiency were investigated. The equilibrium adsorption isotherm data of the cationic cellulose exhibited a better fit to the Langmuir isotherm model than the Freundlich one. The experimental results suggest that the prepared cationic cellulose materials show potential application for reactive dye wastewater treatment. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40522.     

Reaction and diffusion of reactive disperse dye in nylon 6

The 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 at 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 to 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 only 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 × 10^?10 cm²/s) at all the pH's. The product of the second-order rate constant, k₂, of reaction of the dye and the dissociation constant, K_a, of the amino end groups was constant (k₂K_a = 4.0 × 10^?9 s^?1) at pH 2.2–8.0. The k₂ values of the reaction with various substrates for vinylsulfonyl and monochlorotriazinyl-reactive dyes were compared and the practical dyeing conditions were discussed.     

Dyeing of nylon 6 fabric with a bifunctional sulphatoethylsulphone reactive disperse dye

A bifunctional reactive disperse dye containing two temporarily anionic sulphatoethylsulphone groups was synthesised and applied to nylon 6 fabric by exhaust dyeing at a variety of pH levels and temperatures. A monofunctional reactive disperse dye containing one temporarily anionic sulphatoethylsulphone group was also synthesised, and its dyeing behaviour was compared with the bifunctional dye. The bifunctional reactive disperse dye exhibited high exhaustion and total fixation yield under alkaline conditions. The results also indicate that the introduction of two temporarily anionic sulphatoethylsulphone groups of the bifunctional dye gave an enhancement in dyeing performance compared with that of the monofunctional dye. The dyes also showed very good levelling and fastness properties on nylon 6 fabric.     

Colour specifiers – a tool for ‘quick response’?

Colour selection is an important factor in the design of textile products and traditionally this has depended on a large number of laboratory matchings being prepared from which the final selection is made. Colour atlases as an aid to colour selection are not new and those available are reviewed in this paper. The design of an ideal colour specifier is considered and its role is outlined together with a discussion of the advantages gained from its use. Finally the use of the specifier by dyers and printers as a further aid to ‘quick response’ is demonstrated. It is shown that the laboratory matching tier in the product development process can be eliminated by the use of the specifier in conjunction with a dedicated sample dyeing facility backed by colour measurement technology.     

Synthesis of novel polyaniline/MgO composite for enhanced adsorption of reactive dye

In this investigation, the porous structure of polyaniline/MgO (PANI/MgO) composites has been successfully synthesized by in‐situ oxidative polymerization method. The as‐prepared materials were characterized by Ultraviolet–visible absorption spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. The obtained composites, for the first time, are used as an adsorbent for the removal of the sulfonated anionic dye reactive orange 16 (RO) from aqueous solution. The equilibrium adsorption isotherms of RO on the PANI/MgO composites were analyzed by Langmuir and Freundlich models, suggesting that the Langmuir model provides the better correlation of the experimental data and maximum adsorption capacity was found to be 558.4 mg g^?1. In addition, adsorption kinetics was followed by both pseudo‐first‐order and pseudo‐second‐order, but the latter model matches the results much better than the former one. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40210.     

Salt-free dyeing of cotton cellulose with a model cationic reactive dye

A model cationic reactive dye based on an anthraquinone chromophore was prepared. The synthesis of this dye was achieved by the modification of the a free amino group of an anthraquinone-based dye, reacting first with cyanuric chloride and then with N -(2-aminoethyl)pyridinium chloride. TLC analysis was employed to follow the chemical reactions. The application of the prepared dye to cotton fabric was carried out using the exhaustion method without the addition of electrolytes. The results showed that, despite no electrolytes being present in the dye bath, a high percentage of dye exhaustion could be obtained. The high percentage of dye exhaustion was attributed to the attractive force between positive charges on the dye molecule and the negatively charged fibre surface. A high degree of dye fixation with excellent wash fastness was also achievable. Advantageously, it was found that this cationic reactive dye showed promising fastness to light when compared with that of analogous conventional basic dye on cotton. It is believed that the pyridinium cationic moiety, which attached separately to the chromophore via aliphatic spacer groups, was later eliminated during the washing-off process, hence causing an insignificant effect on the photofading of the dyed fabric.     

Anodic oxidation of the dye materials methylene blue,acid blue 25, reactive blue 2 and reactive blue 15 and the characterisation of novel intermediate compounds in the anodic oxidation of methylene blue

Anodic oxidation of the dye molecules, methylene blue, acid blue 25, reactive blue 2 and reactive blue 15 in chloride solution leads to colour destruction but UV and TOC data show that the oxidation reactions do not lead to complete destruction of the organic molecules. Analysis of the anodic oxidation products of [3,7‐bis (dimethylamino) phenothiazinium] chloride (methylene blue) in a chloride solution provides evidence for formation of seven neutral and two charged intermediates. The main intermediate is identified by its X‐ray diffraction crystal structure and accurate mass spectrometry as the novel leuco dye 4,6‐dichloro‐7‐dimethylamino‐3H‐phenothiazin‐3‐one, C₁₄H₁₀Cl₂N₂OS (I) formed by replacement of one of the dimethylamino groups of methylene blue with oxygen accompanied by regiospecific chlorination of the carbocyclic systems. The mass spectra of other intermediates formed are interpreted in terms of the structure of I. © 2002 Society of Chemical Industry     

On the evaluation of a ‘time constant’ for studying the smoke-filling processes in atrium spaces

The time constant which has been previously proposed to characterize the smoke-filling time in an atrium space for design purposes is further evaluated in this paper using the CFAST, FAST and CCFM. VENTS zone models developed at the Building and Fire Research Laboratory, NIST, USA. A design fire of thermal power and area related to the volume of the atrium space is proposed in order to evaluate the time constant. Results of the zone-modelling simulation supported the fact that the time required to fill 80% of the atrium space with smoke is related to its time constant. Full-scale experimental results on smoke-filling processes in atria available in the literature are compared. Use of this quantity to specify the smoke-filling time for an atrium space is recommended for design purposes.     

Synthesis,stability and printing properties of a novel 2‐sulphophenoxy‐4‐chloro‐s‐triazine reactive dye for ink‐jet printing of wool

We report here the synthesis and characterisation of a new medium‐reactivity reactive dye containing 2‐sulphophenoxy‐4‐chloro‐s‐triazine, having enhanced the activity of the chlorine atom for further substitution by the functional groups carried by wool fibre. In addition, a dichloro‐s‐triazine dye was also synthesised for the purpose of comparison. The progress of synthesis reactions and purity of the dyes were determined using capillary electrophoresis and thin layer chromatography. The molecular structure and the chemical compositions of the synthesised dyes were confirmed using Fourier Transform–infrared spectral data and elemental analyses. The inks containing the synthesised dyes were formulated and ink‐jet‐printed onto wool fabrics and then the printed fabrics were steamed at 102°C. Compared with the dichloro‐s‐triazine dye, superior performance in terms of ink stability, K/S and dye fixation was observed for the new 2‐sulphophenoxy‐4‐chloro‐s‐triazine dye. In addition, the light fastness of the fabric printed with the inks containing the new dye was 0.5‐grade greater than that of the fabric printed with the inks containing the dichloro‐s‐triazine dye, and no changes in shade and staining were observed following wash fastness tests of the fabrics printed with the inks containing the new dye.     

Synthesis and characterization of the novel nylon 12 6 based on 1,12‐diaminododecane

Successful polymerization of nylon 12 6 was accomplished in two‐steps, the preparation of nylon salts and involvement of the salts with a pressure vessel followed by high temperature melt polymerization. Chemical composition, thermal properties, crystal structure, mechanical properties, and moisture absorption were characterized in detail. Melting temperature and glass transition temperature were recorded at 234°C and 75°C, respectively, while the β‐relaxation peak was determined to be ?64°C. The results indicated that nylon 12 6 could be used at a broad range of temperatures. Characterization of the mechanical properties showed that nylon 12 6 exhibited a better flexibility and elongation compared with other industrially important nylons. The moisture absorption of nylon 12 6 decreased by 36.7% compared with that of nylon 6 12, suggesting that nylon 12 6 will exhibit a better dimensional stability in the humid environment. Overall, in this research, the novel nylon, that is, the nylon 12 6, shows a relatively low water absorption and excellent toughness contributing to its potential technological application in the future. POLYM. ENG. SCI., 59:192–197, 2019. © 2018 Society of Plastics Engineers     

Dyeing of nylon 6 fabric with a new bifunctional vinyl sulphone reactive disperse dye

A new bifunctional reactive disperse dye containing a temporarily anionic sulphatoethylsulphone and a nonionic disulphide bis(ethylsulphone) groups was synthesised and applied to nylon 6 fabric by the exhaust dyeing at a variety of pH and temperature conditions. A monofunctional reactive disperse dye containing only nonionic disulphide bis(ethylsulphone) group was also synthesised and its dyeing behaviour was compared with the bifunctional dye. The bifunctional reactive disperse dye exhibited high exhaustion and fixation values at pH 6 and 120 °C. The results also indicate that the combination of temporarily anionic and nonionic reactive groups of the bifunctional dye provided great enhancement in dyeing performance compared to that of the monofunctional dye. The dyes also showed very good levelling and fastness properties on nylon 6 fabric.     

阳离子荧光染料的合成及其性能研究

合成了一种新型双阳离子型荧光染料—反,反-1,4-双{2-[4-(N-乙基)溴化吡啶基]乙烯基}苯(DPPB),采用红外光谱和核磁共振谱仪对其进行了结构表征,通过染色实验研究其在腈纶织物上的染色性能及色牢度,同时研究了其单光子荧光性能。结果表明,DPPB的荧光性能良好,在腈纶织物上有良好的染色性能,所染织物具有蓝绿色荧光效果。