Determination of bicomponent dye solutions by means of zero‐crossing‐point derivative spectrophotometry

In this study, a new spectrophotometric method was developed for the determination of some textile dyes with different types of overlapping spectra. The binary mixtures of five dyes with yellow, scarlet, red, blue, and navy blue colors were analyzed by zero‐crossing‐point first‐derivative spectrophotometry. The absorption spectra of the mixtures prepared in different ratios were recorded between 400 and 700 nm. First derivative amplitudes at appropriate zero‐crossing wavelengths were selected for the determination of dyes in the mixtures. The proposed method was successfully applied to the determination of dyes with overlapping spectra in their bicomponent mixtures. The proposed derivative method is simple, rapid, and suitable for quantitative analysis of bicomponent dye solutions. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 307–311, 2008.     

Colour matching by principal component analysis‐based spectrophotometric technique

One of the most important aspects of the physics of colour is colour matching and recipe prediction. In this work, a new method is presented to evaluate the concentration of dyes in textile fabrics. The algorithm of the new technique is based on principal component analysis and single constant spectrophotometric matching methods. Using the normal spectrophotometric matching method, match prediction is carried out at three and 16 wavelengths. With the new algorithm, 3, 6, 9, 12 and 16 principal components are used in spectral match prediction. The performance of the new method improves with increasing numbers of principal components. In addition, the recipe prediction accuracy of the new method with three principal components is better than spectrophotometric matching at three wavelengths. The accuracy of principal component analysis–spectrophotometry with 16 principal components is comparable with the normal spectrophotometric matching method at 16 wavelengths.     

Correlation and Prediction of Carbon Dioxide Solubility in n‐Paraffin Systems

This work discusses high‐pressure gas solubility. Reference state is the Henry's law and a two‐parameter corresponding states model is used for the liquid phase. Pure gas is used as the vapor phase for the high‐molecular paraffin's gas‐liquid equilibrium. The systems under study are mixtures of carbon dioxide and normal paraffin up to a chain length of 44 carbon atoms. Correlated liquid compositions are in the 1 % to 3 % average absolute relative deviation range, with a maximum error of about 7 %. Using a known system as reference, the model could be used to predict solubility. In this case average absolute relative deviations are below 6 % in most cases.     

Rapid FTIR method for quantification of styrene‐butadiene type copolymers in bitumen

The mid‐IR molar absorptivity for polystyrene (PS) and polybutadiene (PB) blocks were obtained for five styrene‐butadiene‐styrene (SBS) and SB copolymers, including linear, branched, and star copolymers, and their blends with bitumen. The average absorptivity for PS and PB blocks was 277 and 69 L mol⁻¹ cm⁻¹ and it was little affected by the S/B ratio or the copolymer architecture. In the presence of bitumen, Beer's law was obeyed but the respective PS and PB absorptivity was 242 and 68 L mol⁻¹ cm⁻¹, possibly because of weak interactions between the copolymer and bitumen. The absorptivity values were used to calculate the concentration of SB‐type copolymers in blends with bitumen with an accuracy of 10% or better. The method can be used to probe the stability of bitumen–copolymer blends in storage at 165°C, to determine the copolymer concentration in commercial polymer modified bitumen (PMB), and to assess the resistance of PMB to weathering. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1034–1041, 2001     

Spectrophotometric investigation of laser dye diffusion in styrene–acrylonitrile copolymer solutions

An ultraviolet spectrometer was used to measure the absorption kinetics of a laser dye, 1,4‐bis(5‐phenyloxazoyl‐2‐yl) benzene, at its maximum wavelength in solutions of styrene–acrylonitrile copolymer dissolved in 1,4‐dioxane. From the time‐dependent absorbance data, the dye diffusion coefficient was calculated by a combination of Fick's law of diffusion with the Beer–Lambert law of absorption. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1481–1484, 2005     

Novel N‐ethyl‐2‐styrylquinolinum iodides as sensitizers in photoinitiated free radical polymerization of trimethylolopropane triacrylate (TMPTA), part 3

Three‐component systems, which contain a light‐absorbing species (dye), an electron donor (n‐butyltriphenylborate salt), and a third component (N‐alkoxypyridinum salt or 1,3,5‐triazine derivative), have emerged as efficient, visible‐light sensitive photoinitiators of free radical polymerization. It was found that three‐component systems are more efficient than their two‐component counterparts. Kinetic studies based on microcalorimetry revealed a significant increase in polymerization rate with increasing concentration of N‐alkoxypyridinum salt. Such results were not obtained for photoinitiating systems possessing 1,3,5‐triazine derivative as a second coinitiator. Based on the experimental results we concluded that the primary photochemical reaction involves electron transfer from the borate anion to the excited dye followed by the reaction of resulting dye‐based radical with second coinitiator that regenerates the original dye and simultaneously produces the alkoxy radical or triazynyl radical which could start the polymerization chain reaction. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Textile colour matching using linear and exponential weighted principal component analysis

In this work, linear and exponential weighted principal component analysis techniques based on spectral similarity were employed for the prediction of dye concentration in coloured fabrics, which had been dyed with three component dye mixtures. The matching strategy was based on the equalisation of the first three principal component coordinates of the weighted reflectance curves of the predicted and target sample in a dynamic 3D eigenvector space. The performance of the proposed algorithm was evaluated by the root mean square differences of the reflectance curves and the relative error of the concentration prediction, as well as the metamerism index. The obtained results indicated that the developed exponential weighted principal component analysis method is more accurate than the spectrophotometric method and the simple principal component analysis matching strategy.     

Spectrophotometric Determination of Benzalkonium Bromide in Pharmaceutical Samples with Alizarin Green

A direct, extraction‐free spectrophotometric method was developed for the determination of benzalkonium bromide (BAK). The method is based on the formation of mixed dye–surfactant aggregates between alizarin green (AG) and BAK in alkaline medium by measuring the decrease in absorbance of AG at 460 and 700 nm. Beer's law was obeyed in the concentration range 3–40 μg mL^?1 with good precision and accuracy. The limits of detection were 0.4 μg mL^?1 at 460 nm and 0.3 μg mL^?1 at 700 nm, which reduced to 0.2 μg mL^?1 by combining the absorbance at the two wavelengths. The proposed method was successfully applied to the determination of BAK in disinfectant solution and eye drops. The analytical results of the real samples were in good agreement with those of an HPLC method.     

Spectrophotometric Determination of Molybdenum‐Containing Compounds in Aqueous Glucose Solutions

The spectrophotometric determination of molybdenum‐containing compounds in aqueous glucose solutions using pyrazine‐2,3‐dicarboxylic acid was investigated. Determination of the molybdenum complex with pyrazine‐2,3‐dicarboxylic acid was performed at λ_max = 550 nm. The light absorption of the deeply violet complex follows Lambert‐Beer's law and can be measured with a molar absorptivity in the range of 4414–9020 L mol^?1cm^?1. The presented method is very sensitive and shows good reproducibility for the extinction values.     

Single‐pack,self‐curable,aqueous‐based polyurethane dispersion containing a disperse dye

An organic‐solvent‐soluble disperse dye was introduced into an aqueous phase by a reaction with a self‐emulsified, aqueous‐based polyurethane (PU), and this resulted in the formation of a homogeneous, aqueous polymeric dye dispersion. This aqueous polymeric dye was stable in a water phase with excellent color extension upon application. It was formulated with a latent curing agent, polyaziridine (e.g., TMPTA‐AZ), as a single‐component, self‐curable, aqueous polymeric dye. The curing reaction took place between PU carboxylic acid and the latent curing agent upon drying. A self‐cured polymeric dye was obtained with excellent color extension and fastness and resistance to organic solvents and water after drying. This single‐component, self‐curable, aqueous‐based PU system containing a dye has potential for printing, writing, and dyeing applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2006 © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3741–3747, 2006     

Spectrophotometric Analysis of Multicomponent Dye Solutions which do not Obey Beer's Law

A method for computing the dye concentrations of a multidye solution from measured absorbances is described. This method is very effective for determining concentrations of dyes when the absorption of light does not follow Beer's law. It is based on an iterative procedure, using calibrated extinction functions to vary the extinction coefficients which are used for a least squares calculation. Examples are given for mixtures of basic dyes and acid dyes respectively.     

Two Spectrophotometric Methods for the Assay of Benzalkonium Chloride in Bandage Samples

Two rapid, direct, extraction‐free spectrophotometric procedures were developed for the determination of benzalkonium chloride. The procedures were based on the formation of mixed dye‐surfactant aggregates between eosine Y and benzalkonium chloride (Method A), or between eosine B and benzalkonium chloride (Method B) in Clark‐Lubs medium by measuring the increase in absorbance at 556 and 550 nm, respectively. Beer's law was obeyed in the concentration range of 0.5–12 and 0.5–12 μg mL^?1 for benzalkonium chloride with good precision and accuracy, whose limits of detection were 0.1 μg mL^?1 at 556 nm for Method A and 0.2 μg mL^?1 at 550 nm for Method B, respectively. The proposed procedures were successfully applied to the assay of benzalkonium chloride in bandages. The analytical results of the real samples were in good agreement with those by HPLC.     

Preparation and electrooptic study of reverse mode polymer dispersed liquid crystal: Performance augmentation with the doping of nanoparticles and dichroic dye

Reported herein, the preparation, morphological, and electrooptic (EO) characterization of reverse mode polymer dispersed liquid crystals (PDLCs) with nematic liquid crystal (LC) and UV curable polymer optical adhesive using polymerization induced phase separation method. The PDLCs are switchable between transparent and opaque states due to the homeotropic and planar alignment of LC in their OFF and ON states of applied voltage, respectively. Further, effect of doping of a fixed concentration of azo dye and silica nanoparticles (NPs) on morphological, EO and response characteristics of same PDLC sample was also analyzed. Experimental results showed that doped reverse mode PDLCs have the higher OFF state optical transmission and boost up in the scattering ON state compared with pristine reverse mode PDLC. The phenomenon is also supported by extinction coefficient and absorption study based on Beer's law. The threshold and operating voltages were found reduced ~1.56 and ~1.73 times for NPs and (NPs + dye) doped reverse mode PDLCs, respectively, along with better contrasts to the pristine reverse mode PDLC. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48745.     

三元复合驱用缔合聚合物浓度检测方法优选

考察了淀粉-碘化镉法、浊度法、紫外分光光度法对于三元复合驱中疏水缔合聚合物AP-C1进行浓度检测的现场适应性和有效性。结果显示,从准确度来看,测试三元复合驱体系中缔合聚合物浓度最优的方法是淀粉-碘化镉法,其次是浊度法,紫外光谱法相对误差较大。碱浓度对于淀粉-碘化镉法和浊度法的影响较大,表面活性剂浓度的影响较小。虽然淀粉-碘化镉法测定三元复合体系中缔合聚合物浓度相对误差小,应用广泛,但是此方法操作过程相对复杂,反应条件不易掌握,测量时容易引入人为误差,重复性较难以保证,考虑到浊度法操作简单方便,相对误差在可接受范围内,所以对于现场实际条件下,建议采用浊度法进行检测。     

Measuring number‐concentrations of nanoparticles and viruses in liquids on‐line

BACKGROUND: The surge of studies on artificial and natural nanoparticles has revealed a new world for engineering and life sciences, but in most instances, the small scale has made their number‐concentration determination in liquids a challenging problem. Former success has mostly been limited to special particles measured by indirect techniques. A new approach is required for this determination to facilitate the production and application of nanoparticles in different systems. RESULT: Here, an approach is described using a nanoparticle tracking system based on Brownian motion, which can be used to determine the number‐concentration of nanoparticles, including viruses, in liquids on‐line. Extensive analysis showed the influence of suspension concentration and particle size on the accuracy of measurements. Natural nanoparticles of Adenovirus and several types of artificial nanoparticles, including precision nanobeads, uniform inorganic silica microspheres, monodisperse gold metal colloids and aggregated Aerosil nanoparticles, were measured and compared by counting the monitored particle number obtained using light scattered from individual particles, from which the particle number‐concentration, the product yield and the aggregation could be evaluated. CONCLUSION: This approach was compared with the mathematical calculation method and the emission spectrophotometry technique used for practical applications. The results showed this new approach had improved accuracy for determination of the particle number‐concentration. Copyright © 2010 Society of Chemical Industry     

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.     

Thermo‐electric‐visco‐elastic material

In this work, we introduce the Seebeck effect in Ohm's law and Thomson heating effect in generalized Fourier's law, to the equations of the linear theory of electro‐magneto‐thermoviscoelasticity, allowing the second sound effects. A normal mode analysis is used. The resulting formulation is applied to a problem of a rotating thick plate subject to heat on parts of the upper and lower surfaces of the plate that varies exponentially with time. The exact formulas of temperature, displacement, stresses, electric field, magnetic field, and current density are obtained. The considered variables are presented graphically and discussions are made. Seebeck and Peltier effects on thermoelectric viscoelastic material are studied. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Comparison of methods of parameric correction for evaluating metamerism

In practice, most metameric pairs do not achieve colorimetric equality for a set of reference conditions. These parameric pairs are composed of a residual color difference and a metameric difference. Three techniques have been used to correct this residual color difference: an additive correction in L*a*b*, a multiplicative correction in XYZ (recommended by the CIE), and parameric decomposition where the batch's spectrum is adjusted. Parameric decomposition can be viewed as batch correction using three “colorants” (process primaries) where the color‐mixing model is linear in reflectance. Most often, Cohen and Kappauf's Matrix R technique is used where the primaries are color matching functions. Alternative primaries were derived from a Munsell Book of Color and an automotive paint system using principal component analysis (PCA) and independent component analysis (ICA). 1,152 parameric pairs about 24 color centers were synthesized using the paint system and Kubelka–Munk turbid‐media theory. Each parameric pair was corrected to a metameric pair using these methods. Spectral accuracy was evaluated by comparing the corrected spectra to metameric reference spectra calculated using Kubelka–Munk batch correction. The Matrix R technique had the worst spectral accuracy under the reference conditions while both PCA and ICA had similar and reasonable accuracy. The special index of metamerism, change in illuminant, was calculated for each parameric pair using these various correction techniques to achieve colorimetric equality. The Matrix R and CIE‐recommended multiplicative techniques were statistically significantly worse than parameric decomposition using Munsell Book of Color PCA and ICA and automotive ICA process primaries. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 293–303, 2007     

Silicon‐containing anionic water‐borne polyurethane with covalently bonded reactive dye

A silicon‐containing water‐borne polyurethane (PU) polymer with hydroxyl side groups was synthesized that was stable in basic conditions and also capable of reacting with a reactive dye to form a covalently bonded dye molecule. The silicon‐containing anionic water‐borne PU prepolymer was synthesized from H₁₂‐4,4′‐diphenylmethane diisocyanate (H₁₂‐MDI), polytetramethylene glycol, polydimethylsiloxane (PDMS), 2,2′‐bis(hydroxymethyl), propionic acid (anionic centers), and triethyleneamine using the prepolymer mixing method. Water was then added to emulsify and disperse the resin to form an anionic water‐borne PU prepolymer. N‐(2‐Hydroxyethyl ethylene diamine) (HEDA) was used to extend the prepolymer to form a water‐borne PU polymer with a side chain of hydroxyl groups, which can further react with the reactive dye to form a dyed PU. The reactive dye of chlorosulfuric acid esters of sulfatoethyl sulfones can react with the water‐borne PU polymer. Behaviors of alkali resistance and dyeing properties were observed. In consideration of thermal properties, the dye‐grafted PU polymers exhibited lower glass‐transition temperatures for soft segments and hard segments than those without dye. Concerning mechanical properties, it was found that the modulus and the strength of the dyed PU polymers decreased with grafting of the dye molecule, but elongation at break was increased. The alkali resistance increased with PDMS content. For dye‐uptake properties, the percentage of dye grafting was over 90%. Also, the dye‐grafted PU exhibited a lower percentage of dye migration than that of polymers with ethylene diamine instead of HEDA as a chain extender, and showed greater colorfastness to light. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2045–2052, 2003     

NIR‐laser based detection of the photopolymerization state of acrylate coatings suitable for in situ measurements

The present article describes a method for the determination of the radical photopolymerization conversion of acrylic coatings suitable for an in situ monitoring during the coating process. Acrylate based coatings are increasingly used in many kinds of industrial coating processes, because of advantages of the solvent‐free application process. The applied method is based on 1620 nm light absorption of the acrylate. To overcome the disadvantages of a common NIR spectrometer, only the diffuse reflection of the relevant discrete wavelength at 1620 nm and of a reference wavelength is measured. A sophisticated sensor setup including an optical spatial filter and lock‐in amplified signal processing is used to achieve a sufficient signal to noise ratio. The capability of the sensor to discriminate between polymerized and unpolymerized coatings on metal substrates down to a coating thickness of 16 μm is demonstrated. Furthermore, the information on polymerization from larger depth in TiO₂ pigmented coatings is investigated. The results can be analytically modeled in analogy to the Lambert–Beer's law, resulting in a detection limit of a maximum pigment concentration of 15 wt % with 100 μm coating thickness. The presented sensor design is suitable to be used in an industrial production environment for example in screen printing applications as a monitoring and quality control tool. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012