Azo dye adsorption effect induced by elliptically polarized light in azo dye-doped liquid crystals

This study elucidates the azo dye adsorption effect induced by elliptically polarized light in azo dye-doped liquid crystals (ADDLCs). Experimental results reveal that the light-induced molecular reorientation that is caused by the adsorbed azo dyes declines as the absolute value of the ellipticity of the pumping beam, having a proper selectively fixed light intensity or a proper selectively fixed light component along the direction of major axis, increases. The long axes of the adsorbed dyes are found to be independent of the sign of the light ellipticity, but they do depend on the direction of the major or minor axis of the elliptically polarized light. Notably, the tilt angle in LC alignment is not observed in this experiment. Additionally, neither twist angles nor tilt angles can be induced using a circularly polarized pumping beam.     

Electrochemical and UV–Vis/ESR spectroelectrochemical properties of thienylenevinylenes substituted by a 4-cyanostyryl group

The π-electron delocalisation in conjugated thienylenevinylenes bearing arylethenyl chromophores, makes those materials interesting candidates for electro-optic applications. In this study, we report the results of electrochemical and UV–Vis/ESR spectroelectrochemical studies of a pair of thienylenevinylenes substituted by the 4-cyanostyryl group, bearing either a hydrogen, or methyl group terminated α carbons at the peripheral thiophene rings. The reactivity of various functional segments of investigated molecules was assessed by comparing the reactivity of the protected and unprotected counterparts and the behaviour of their electrooxidation products. For the capped derivative, two irreversible anodic redox processes giving electrochemically inactive products were observed, while the uncapped molecule yields electroactive materials already upon its first oxidation step.     

NR–EPDM covulcanization: A novel approach

Bis(diisopropyl)thiophosphoryl disulfide (DIPDIS) was used successfully as a novel coupling agent cum accelerator to co‐vulcanize the elastomer blend comprising highly unsaturated natural rubber (NR) and ethylene propylene diene rubber (EPDM) of low unsaturation content. The blend vulcanizates produced exhibit improved physical properties that can be further enhanced by implementing a two‐stage vulcanization technique, as well as by judicious selection of the NR‐to‐EPDM ratio. The results indicate coherency and homogeneity in the blend composition of two‐stage vulcanizates. The cure‐rate mismatch problem could thus be solved through the formation of rubber‐bound intermediates with a multifunctional rubber additive (i.e., DIPDIS), thereby restricting the curative migration from lower to highly unsaturated rubber. The blend morphology as revealed by SEM studies accounts for significant improvement in physical properties, particularly in two‐stage vulcanizates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 800–808, 2001     

Mass transfer in rolling rotary kilns: a novel approach

A novel approach to modeling mass transfer in rotary kilns or rotating cylinders is explored. The movement of gas in the interparticle voids in the bed of the kiln is considered, where particles move concentrically with the geometry of the kiln and gas is entrained by these particles. The approach considers a differential section along the length of a rotary kiln where the gas concentration in the freeboard is assumed to be uniform in that section. A reactor modelling approach has been used to derive effectiveness factors for the bed as a function of bed fill, reaction kinetics and rotation speed. In many cases, the entrained gas becomes depleted within the bed, leading to a simplified model for the bed effectiveness factor. Experimental data confirms the validity of this model for slower rates. At faster rates, mass transfer can be much higher than the model predicts, indicating that other mechanisms, such as dispersion or diffusion are also important in these conditions.     

UV enhanced gas-solid synthesis of chlorinated poly vinyl chloride characterized by a UV-Vis online analysis method☆

Dynamic characteristics of UV enhanced gas–solid PVC chlorination process were revealed by a UV–Vis spectral online analysis method. Experimental results showed an instantaneous increase of the chlorination rate as soon as UV lightwas affiliated, which demonstrated the intensified effect of UV radiation on PVC chlorination directly. Different affiliationmethods of UV light were then studied, proving that continuous UV radiation could enhance the chlorination process significantly while intermittent UV radiation was able to initiate the chlorination reaction once it was conducted. Besides, experiments were carried out to study the influences of parameters on the chlorination process such as UV wavelength, chlorination temperature, partial pressure of chlorine gas and PVC raw materials. Among all the parameters, chlorination temperature and partial pressure of chlorine gas were testified as two key factors to determine the chlorination performance. Thermal analysis of CPVC products showed that their corresponding properties such as the glass transition temperature (T_g) and the homogeneity of chlorine distribution in polymer phase were improved with the increase of chlorine content.     

一种新型双发色团罗丹明荧光染料的合成与结构表征

基于双发色团荧光染料的优良光学性能,设计以水合肼、二硫化碳及罗丹明B为起始原料,经反应分别得到1,3-二氨基硫脲与罗丹明B酰肼。通过分子间缩合反应以1,3-二氨基硫脲两端的氨基分别连接两分子罗丹明B,合成了一种新型双发色团罗丹明荧光染料。利用~1H NMR、HRMS-ESI对所合成目标物分子结构进行表征,优化反应物配比以提高缩合反应产率,为双发色团荧光染料的合成提供新思路。     

Synthesis and dyeing performance of a novel yellow crosslinking polymeric dye

A polymeric dye was synthesised via the reaction of 2,4-dinitrochlorobenzene and polyallylamine prepared from the homopolymerisation of monoallylammonium chloride. The polymeric dye was fixed to cotton and silk via a crosslinking agent [2-chloro-4,6-di(aminobenzene-4'-β-sulphatoethylsulphone)-1,3,5- s -triazine]. The fixation of this polymeric dye reached 99% and the dyeing was fast to dimethylformamide at the boil, indicating that the dye fixation was through covalent bonding with the crosslinking agent, which acted as a bridge between the fibre polymer and the dye molecule. The dyed samples showed excellent fastness to washing and rubbing.     

Synthesis and application of a novel,triphendioxazine‐based,phosphorus‐containing acid dye for wool

A novel phosphorus‐containing acid dye based on triphendioxazine was designed and synthesised from diphenylamine through a series of reactions. The dye has a navy‐blue colour, high molar extinction coefficient of 5.32 × 10⁴ l/mol·cm, and high substantivity for dyeing wool in a salt‐free, aqueous dyebath. A high exhaustion value of 98.2% on wool fabrics was recorded at 3% omf and a liquor ratio of 1:20. The wash fastness values of the acid dye, including colour change and staining on cotton and wool, were grades 5, 4 and 4–5, respectively. The dry and wet fastness are grades 4–5 and 4, respectively. In addition, light fastness reaches grades 6–7 at 3% omf dye concentration. These dye properties are better than those of commercial triphendioxazine dyes, for example, CI Direct Blue 106 and CI Reactive Blue 198, under analogous dyeing conditions.     

Prediction of dye concentrations in a three‐component dye mixture solution by a PCA‐derivative spectrophotometry technique

Derivative spectrophotometry is one of the most important techniques that can be used to determine the dye concentration. In addition, principal component analysis (PCA) is a linear method to condense the dimensionality of large numbers of absorbance spectra. In this work, PCA and derivative spectrophotometry techniques are used to improve the accuracy of Beer's law prediction of the concentrations in three‐component dye mixtures. The performance of the new method is compared with the normal Beer's law by calculation absolute error, relative error, and ternary relative error of prediction. As obtained results indicate, the prediction accuracy of dye concentration prediction in PCA‐derivative spectrophotometry method is higher than normal Beer's law method. © 2009 Wiley Periodicals, Inc., Col Res Appl, 2010.     

Composite natural rubber based latex particles: a novel approach

The oil resistance of natural rubber (NR) film could be effectively improved by using the heterocoagulation of large NR particle with small polychloroprene (CR) particles. In the preparation of NR/CR composite particle with a core-shell structure, a nonionic surfactant whose molecule bears poly(ethylene oxide) (PEO) was adsorbed on CR particles and allowed to form complexes between PEO and indigenous surfactant (protein-lipid) on the NR particle surface. Composite latex particle obtained was characterised by particle size, zeta potential and glass transition temperature measurements and the data indicated the presence of CR on the outer layer of composite particle. Better oil resistance of film casted from heterocoagulated latex when compared to that of NR film confirmed the NR/CR core-shell structure. The epoxidised natural rubber (ENR), crosslinked ENR and/or skim latex particles were investigated in order to replace the use of CR in the heterocoagulation process.     

A novel multi-channel reactor system combined with operando UV/vis diffuse reflectance spectroscopy: Proof of principle

A 36 channel reactor system combining high-throughput experimentation (HTE) with operando UV/vis diffuse reflectance (UV/vis-DR) spectroscopy is introduced and applied for the oxidative dehydrogenation of propane (ODP) to propene at 500 °C over polycrystalline V₂O₃, VO₂, and V₂O₅. This set-up enabled to monitor reaction-induced reduction of V₂O₅ to V₂O₃, and VO₂ during the ODP reaction. The operando UV/vis-DR spectroscopic analysis along the catalyst bed demonstrated that the vanadium oxidation state at the reactor inlet is higher than at the reactor outlet. This is due to the depletion of oxygen and the enrichment of propene down stream along the catalyst bed.     

A novel nonchemical approach to the expansion of halloysite nanotubes and their uses in chitosan composite hydrogels for broad‐spectrum dye adsorption capacity

A novel method based on cryoscopic expansion of halloysite nanotubes via frozen water molecules entrapped in their lumens and subsequent lyophilization was described. Detailed analyses confirmed that the inner and outer diameters as well as the surface area of the nanotubes could be efficiently increased without disturbing the inherent tubular structure. The benefits of cryo‐expanded nanotubes for the enhancement of chitosan hydrogel performances were discussed. The composite hydrogels, depending on their compositions and morphologies, exhibited significantly enhanced swelling and mechanical properties compared with neat chitosan hydrogel. This effect was even more pronounced in the hydrogels containing cryo‐expanded halloysite nanotubes. Although neat chitosan is a selectively good adsorbent for anionic dyes, in the presence of a small amount of cryo‐expanded halloysite, the resultant composite hydrogel can establish a relatively high adsorption capacity for anionic and cationic dyes as a broad‐spectrum dye adsorbent. POLYM. COMPOS., 37:2770–2781, 2016. © 2015 Society of Plastics Engineers     

Synthesis and evaluation of a novel blue cationic reactive dye for modified nylon 6.6 ‘Tactel Coloursafe’

A novel blue cationic reactive dye (dye 1 ) based on an azo benzothiazole derivative and possessing an acrylamido reactive group, was synthesised and evaluated on dyeing Coloursafe modified nylon 6.6 at optimum pH. Benzothiazole quaternary dye was chosen as a target as this is known to be very strong chromophically. Evaluation of the technical properties of dye 1 showed that it fixed efficiently to nylon under acidic dyeing conditions. As it was necessary to prove that fixation occurs via a covalent bond, the dyeing properties of a non‐reactive cationic dye, (CI Basic Blue 41), on dyeing nylon 6.6 at optimum pH were evaluated. CI Basic Blue 41 was similar in structure to dye 1 and would be capable of forming an ion–ion bond with the fibre. Evaluation of the technical properties of dye 1 proved that, in all cases, its fixation efficiency and build‐up properties were far better than that of CI Basic Blue 41.     

Synthesis and characterization of branched polymers by a free radical approach using a novel ‘macroiniferter’

Free radical bulk polymerization of styrene and methyl methacrylate (MMA) was carried out using a novel ‘macroiniferter’ which resulted in branched polymers with relatively narrow molecular weight distribution. This approach involving the novel macroiniferter; poly[3-(t-butylperoxy)propyl disulfide] (PBPPDS) that has side chain peroxide groups and main chain disulfide linkages was developed to prepare soluble branched polymers as well as to control the extent of branching in vinyl polymers synthesized via a free radical route. The synthesis, characterization and thermal degradation studies of PBPPDS are reported here for the first time. The resulting polystyrene (PS) and poly(methyl methacrylate) (PMMA) polymers were characterized using gel permeation chromatography (GPC), intrinsic viscosity [η] measurements and the degree of branching was studied by the determination of g′ factor.     

Synthesis of a novel water-soluble crosslinking polymeric dye with good dyeing properties

A novel yellow polymeric dye was synthesized by the reaction of 2,4-dinitrochlorobenzene with polyallylamine prepared from the homopolymerization of monoallylammonium chloride. The structure of the polymeric dye was characterized by using IR, UV–visible, TLC and ¹H NMR analysis, and the λ_max of this polymeric dye in water is 361 nm. The effects of the concentration of amino group, the mole ratio of Na₂CO₃ to amino group, the reaction temperature, and the reaction time of the reaction are discussed in detail. Furthermore, the silk and cotton dyed with this polymeric dye were fixed by the use of crosslinking agent, 2-chloro-4,6-di(aminobenzene-4′-β-sulphatoethylsulphone)-1,3,5-s-triazine, they have high fixation and the polymeric dye shows very good fastness to washing and rubbing.     

Effective removal of a cobalt‐tetrasulfonated phthalocyanine dye from an aqueous solution with a novel modified chitosan‐based superabsorbent hydrogel

Industrial wastewaters from the Merox process are heavily polluted by toxic cobalt‐tetrasulfonated phthalocyanine (CoTsPc) dye catalyst, and in this article, we describe the synthesis of novel chitosan hydrogels and their adsorption capabilities against CoTsPc as biosorbents. In this study, novel chitosan hydrogels were crosslinked by 3,3′,4,4′‐tetracarboxybenzophenone dianhydride and used for the first time. The adsorption capacities of the hydrogels were significantly improved, and they exhibited excellent sorption behavior with ammonium sulfate modification. The adsorption behavior was observed to be pH dependent, and the optimum pH was found to be 8. Moreover, the swelling studies indicated that the hydrogels are superabsorbent. The reusability of these dye‐adsorbent hydrogels was also evaluated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46167.     

Preparation of novel hybrid inorganic–organic hollow microspheres via a self‐template approach

BACKGROUND: Hollow microspheres, especially biodegradable polymeric microspheres, have attracted considerable attention due to their particular characteristics. Up to now, microspheres have been prepared via various strategies, for instance the template synthesis method and the self‐assembly process. However, economic, novel and simple methods to prepare hollow microspheres are still being sought. RESULTS: Phosphazene‐containing microspheres, which contain self‐assembled core‐shell structures, were prepared at high colloid contents using an ultrasonic bath via a self‐template approach. Along with the controlled self‐degradation of the internal core, the corresponding hybrid inorganic–organic hollow microspheres appeared. The mechanism was evidenced by means of transmission and scanning electron microscopy, cross‐polarization with magic angle spinning NMR, Fourier transform infrared spectroscopy, X‐ray diffraction and thermogravimetric analysis. CONCLUSION: It was clarified that the phosphazene‐containing microspheres could be formed and stably dispersed without aggregation even at high colloid contents using the ultrasonic bath method and the microspheres contain self‐assembled core–shell structures. Along with the controlled self‐degradation of the internal core, the corresponding hollow microspheres appeared. The mechanism of this preparation is of great significance because it is completely different from the conventional template synthesis method and the self‐assembly process. The absence of any stabilizing agent and special templates might inspire creative imagination in the design of new morphologies of micro‐ and nanostructures. Copyright © 2007 Society of Chemical Industry     

微通道反应器中偶氮染料连续化制备技术研究

对微通道反应器中偶氮染料连续化制备技术进行研究,以C.I.酸性红54为模型底物,考察微通道反应器中反应物流速、停留时间、管道内径和反应温度对反应的影响,得较优工艺条件为:重氮组份、偶合组份的摩尔比为1∶1,反应物流速ν=0.18 m/s,停留时间τ=11.11 s,管道内径D=1.0 mm,室温下进行(20℃),产率为96.80%。以C.I.酸性红54较优工艺条件为基础,固定反应物流速ν=0.18 m/s,管道内径D=1.0mm,对不同色系的酸性偶氮染料和活性偶氮染料在微通道反应器中的反应情况进行初步研究,产率均大于80%。该工艺具有连续化、高效、条件温和等优点,具有很好的广泛实用性。