Physical,chemical, and dyeing properties of Bombyx mori silks grafted by 2‐hydroxyethyl methacrylate and methyl methacrylate

To obtain silk weight gain and to improve silk properties, Bombyx mori silks were grafted with either 2‐hydroxyethyl methacrylate (HEMA) or methyl methacrylate (MMA). The moisture regain of the HEMA‐grafted and MMA‐grafted silks depended on the hydrophilicity of the used monomers. The acid and alkaline resistances of the HEMA‐grafted and MMA‐grafted silks were clearly improved. Both commercial synthetic dyes, that is, acid and reactive dyes, and a natural dye extracted from turmeric, with potassium aluminum sulfate as a mordant, were used in this study. The results suggested that the dye uptake increased in the presence of poly(2‐hydroxyethyl methacrylate) or poly(methyl methacrylate) in the silk fibroin structures when acid and curcumin dyes were used. The washfastness level of the HEMA‐grafted silk dyed by acid and reactive dyes was similar to that of the degummed silk. However, the colorfastness to washing of the MMA‐grafted silk dyed by an acid dye was improved when the polymer add‐on concentration was 65%. In addition, the washfastness for both grafted silks was improved when they were dyed with natural curcumin dyestuff. The acid and alkaline perspiration fastness properties remained unchanged for the HEMA‐grafted and MMA‐grafted silks when acid, reactive, and curcumin dyes were applied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of postreatment on the corrosion behaviour of tartaric-sulphuric anodic films

Unclad and clad AA2024 T3 specimens were anodised in a chromium-free tartaric-sulphuric acid bath (TSA) and subsequently postreated by different processes including impregnation in a cold, concentrated chromate solution, Cr-free hot-water sealing, and dichromate hot-water sealing. The purpose of this work is to evaluate the effectiveness of the classical postreatments used in the aircraft industry on the TSA-anodic films and their corrosion resistance behaviour. TSA-anodic films were characterised by scanning electron microscopy (SEM) and their thicknesses were measured by SEM and the eddy current method. Electrochemical impedance spectroscopy (EIS) was used to characterise the barrier and porous layers, and jointly with potentiodynamic polarisation allowed the evaluation of corrosion resistance parameters with immersion time in NaCl solution for anodised and postreated specimens. In all cases the postreatments increased the resistance of the barrier layer against degradation. However, the NaCl electrolyte easily penetrated TSA-anodised porous layers when they were not postreated, while penetration was slightly more difficult in cold-postreated specimens. The effective pore plugging was observed in the sealed TSA specimens resulting in an improved corrosion resistance. On the other hand, unsealed clad AA2024 specimens showed a self-sealing process of the TSA-anodic layer, which was slower for the cold chromate solution-postreated specimens.     

Prediction of Dimensionless Cutsize for Size‐Fractionated Measurements of Particles that Impact on a Sintered Stainless‐Steel Filter

Abstract

This investigation experimentally studied the penetration curve of particles that impact on a sintered stainless‐steel filter with various pore sizes, sampling flow rates and jet diameters. The penetration curves were compared to those with an aluminum foil substrate. Test data reveal that when the sintered stainless‐steel filter has larger pore sizes (100 µm or 40 µm), the particle penetration, P(%), is lower and the curve is less steep than that obtained from the aluminum foil substrate. The penetration curve of the sintered stainless‐steel filter with smaller pore size (5 µm) is close to that of the aluminum foil substrate. The dimensionless cutsize‐shift (the ratio of the dimensionless cutsize of sintered stainless‐steel filter to that of aluminum foil) falls as the pore sizes and the Reynolds number increase. Experimental data were then compared with theoretical results, and theory over‐predicted the dimensionless cutsize‐shift. Hence, a regression equation for the dimensionless cutsize‐shift is proposed by fitting the experimental data. The discrepancy between the experimental data and the regression prediction is within 4%. The regression equation can be used to predict the dimensionless cutsize for the size‐fractionated measurements of particles that impact on a sintered stainless‐steel filter with various sized pores and Reynolds numbers.     

Reactive‐Injecting Follow‐Through Shaped Charges from Sequent‐Material Conical Liners

Shaped charges using reactive‐metal liners have the potential for beyond‐penetration effects, e.g. thermodynamic events that increase pressure in a volume adjacent to the penetration. Shaped charge liners made from a copper penetrating‐ and an aluminum reactive‐component in a sequent‐material configuration were compared in tests to baseline homogeneous copper liners. Copper lined shaped charges had greater mild steel penetration performance, but lacked beyond‐penetration pressurization effects exhibited by the sequent‐material lined units. Jet capture experiments, beyond‐penetration constant‐volume tests, and thermochemical equilibrium calculations provide evidence supporting the aluminum slug comminution into unoxidized reactive fuel, augmenting beyond‐penetration effects.     

Direct coloration of textiles with photochromic dyes. Part 3: dyeing of wool with photochromic acid dyes

Wool dyed with two isomeric water‐soluble spirooxazine‐based photochromic acid dyes, which were specifically designed and synthesised for direct application to protein and polyamide substrates, showed reversible change from a pale yellowish colour to blue when exposed to sunlight or UV light. With the first dye, significantly higher photochromic colour change was obtained when the wool was bleached, a feature attributed to a more open fibre structure which may facilitate penetration of the non‐planar dye anion and also the photocoloration reaction which requires a change in molecular geometry. Experimentation demonstrated that the optimum conditions for application of this dye to wool was from an aqueous dyebath at neutral pH and a temperature of 60 °C. An investigation using HPLC demonstrated that the dye was susceptible to decomposition in aqueous solution at higher temperatures and at lower pH values. The second dye was also applied to wool fabric to give a fabric with similar photochromic properties. The technical performance of the dyed fabrics, in terms of washfastness and photostability, was assessed.     

Ink‐jet printing process for lyocell and cotton fibres. Part 2: The relationship of colour strength and dye fixation to ink penetration

The colour appearance on ink‐jet printed textiles is influenced by a range of factors, including the chemical and physical nature of the fibre, dye–fibre affinity, pretreatment and fabric structure. Regression analyses were conducted to study the correlation between colour strength, fixation and ink penetration obtained by ink‐jet printing lyocell fibres (standard Tencel and Tencel A100) and cotton with an ink based on a monofunctional reactive red dye. The fixation was highest on Tencel A100, followed by standard Tencel and then cotton, while colour strength was highest on standard Tencel followed by cotton and Tencel A100. A linear relationship between colour strength and ink penetration was found with cotton, indicating greater dependence of depth of shade on ink penetration than on standard Tencel and Tencel A100 fabrics, where the interrelationships were more complex, but of low statistical significance. A schematic representation is proposed illustrating the mechanism of ink penetration into pretreated fibres, which provides a reasonable interpretation of the events occurring as dye penetrates into and fixes onto the fibres.     

Bonding properties between nitrile–butadiene rubber and aluminum alloy treated by anodizing methods

In this work, the bonding properties between the LD7 aluminum alloy anodized by sulfuric acid or phosphoric acid and nitrile–butadiene rubber (NBR) were investigated. The bonding properties between the anodized aluminum alloys and NBR were compared with those between aluminum alloys treated by burnishing or sandblasting and NBR. The results revealed that, in comparison with sulfuric acid anodized samples, samples anodized in phosphoric acid solutions showed higher 90° peel strength. Under the same conditions, an increase in the anodic film thickness in the studied range may improve the adhesion property between rubber and an aluminum alloy. In comparison with aluminum alloys treated by burnishing or sandblasting, the surface of the anodized aluminum alloy showed homogeneously dispersed pores, which resulted in better and homogeneous bonding properties. A vacuum‐drying process on the anodized aluminum alloys after they were coated with adhesives facilitated penetration of the adhesive molecules into the pores on the oxide layer, which considerably improved the bonding properties. In addition, rubber macromolecules could also penetrate the pores in the aluminum oxide layer, leading to a strong physical anchor–hold interaction after a long time of soaking and diffusion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Application of polycarboxylic acid sodium salt in the dyeing of cotton fabric with reactive dyes

In this study, the effects of polycarboxylic acid sodium salt on the dyeing of cotton with reactive dyes were evaluated by measuring and comparing the K/S values and dyeing fastnesses of the dyed cotton fabric samples. Results showed that the K/S value and dyeing fastness of cotton fabrics dyed with polycarboxylic acid sodium salt, substituting inorganic salts as exhausting agent were close to that of with sodium chloride when dip‐dyeing process was used. While, in pad‐dry dyeing, the K/S value of cotton fabric samples dyed with polyacid salts as exhausting agent was higher than that of with sodium sulfate, and the dyeing fastnesses of these samples were nearly the same. The dyeing mechanism of cotton fabric with reactive dye, using polycarboxylic acid sodium salt as exhausting agent was analyzed. The dyeing exhausting mechanism of reactive dye seems different when the inorganic salt and polycarboxylic acid sodium salt were used as exhausting agent in the dyeing of cotton fabric with reactive dye. The polycarboxylic acid sodium salt, as weak electrolyte, increased the dye‐uptake of reactive dye on cotton fabric not only by screening negative charges on cotton surface, but also by the effect of salting‐out or hydrophobic combination. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Dyeing Kinetics of an Acid Dye in a Nylon Film

The dyeing kinetics of an acid dye (C. I. Acid Blue 182) in a nylon 6 substrate was investigated using partition–cell and film–roil methods. The concentration dependence of the diffusion coefficient of acid dye in the nylon film was derived from both methods and compared with a prediction based on diffusion together with adsorption equilibrium established instantaneously between mobile and immobilised dye molecules in pores. These two sets of experimental results were found to be incompatible with each other. It was deduced that two kinds of region exist in the nylon, one being a region available for rapid penetration and the other, connected to it and formed by slow relaxation, a region of poor penetration.     

Dye Fixation Using Radio—frequency Heating

Radio-frequency (r.f.) heating has been used to achieve the fixation of acid dyes on nylon fibres. This permitted rapid heating to the fixation temperature, and some enhancement in the degree of dye penetration was observed. Success was also obtained in fixing disperse dyes on polyester and reactive dyes on cotton using r. f. techniques. The experiments clearly demonstrate that r.f. heating offers a versatile method for enhancing dye fixation.     

Reduced angle sensitivity of structural coloration on an industrial aluminium platform

Existing structural coloration methods using thin films, commonly implemented in high‐purity aluminium, produce colours which are highly dependent on the viewing angle because of the inherent angular dependence of thin film interference. Adapting the thin film coloration mechanism to anodisation of industrial‐quality aluminium alloys, which scatter light more efficiently than their high‐purity counterparts, reduces angle dependence in the colour produced. This reduction of angle dependence, as well as the wide use of anodised aluminium in consumer products, suggests that structural colour based on anodised aluminium could potentially be scaled up for commercial scale production.     

Biomordanting willow bark dye on cellulosic materials

A semi‐quantitative study of willow bark dye adsorption on two different cellulose materials using biomordants was carried out. The studied celluloses were microcrystalline cellulose (MCC) AaltoCell and regenerated Ioncell‐F (IC) fibres. The dye was a hot water extract of willow bark and the adsorption to cellulose was carried out using carboxylic acid‐containing biomordants, namely, oxalic acid, citric acid and tannic acid. Alum was employed as the reference mordant. A semi‐quantitative estimation of the dye uptake was conducted using high‐performance liquid chromatography equipped with a diode array detector and also by visual inspection, as well as an evaluation of the coloration using CIELab parameters. The mechanism of the dye adsorption on the cellulose surfaces was studied via Fourier Transform–infrared spectroscopy. According to the results, MCC had a higher affinity for polyphenolic dye than the regenerated cellulose fibres. Dye uptake on MCC was 50%‐80% and 44%‐57% on IC. For MCC, the biomordants improved the dye uptake more effectively than the control mordant, alum, whereas for IC the biomordants were less effective than alum.     

Dyeing properties of Bombyx mori silks grafted with methyl methacrylate and methacrylamide

To improve their dyeing and colorfastness properties, degummed Bombyx mori silks were chemically modified by a grafting technique with either methyl methacrylate (MMA) monomer or methacrylamide (MAA) monomer. Both commercial synthetic dyes, that is, acid and basic dyes, and natural dyes extracted from turmeric, without and with potassium aluminum sulfate mordant, were used in this study. Percentage dye uptake increased with the presence of poly(methyl methacrylate) or polymethacrylamide in the silk fibroin structure regardless of the types of the dyestuffs. Furthermore, compared to the degummed silk, the colorfastness to washing of the MMA‐grafted and MAA‐grafted silks dyed with acid, basic, and curcumin dyestuffs were greatly improved. Colorfastness to both acid and basic perspirations with acid and basic dyestuffs was slightly improved, whereas perspiration fastness remained unchanged for curcumin dyeing without and with the presence of the mordant. Also, the low‐light resistances of the degummed and grafted silks dyed by curcumin dyestuff were notably improved by the MMA and MAA grafting technique. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:1169–1175, 2006     

The correlation between the interference colour and growth procedure of anodic titanium dioxide nanotube arrays

Titanium dioxide nanotube arrays were anodised from titanium foils in an aqueous electrolyte solution of hydrofluoric acid. The formed oxide showed visually different colours owing to light interference in the titanium dioxide layer. The behaviour of interference colour in anodic titanium dioxide film was investigated by varying anodisation parameters such as the applied voltage and the anodisation time. The morphologies and the crystalline phases of anodised samples were studied on a field emission scanning electron microscope and X‐ray diffractometer. The correlation between the interference colour and growth procedure of anodic titanium dioxide nanotube arrays was studied. The anodic films prepared under different conditions consisted of a compact oxide film with a nanoporous/tubular structure upon/beneath it. The crystalline phase of the anodic oxide layer was amorphous. The optical properties of the oxide film were investigated on a spectrophotometer. Optical interference could be detected in compact oxide layers when the thickness of the titanium dioxide was as small as 70 nm. In general, the interferences of the nanoporous/tubular structures were lower than those for compact structures. The empirical colour properties were estimated by the L*a*b* system. The relationships between the interference colour of anodic titanium dioxide film and its thickness and morphology are discussed.     

Mechanism involved in the dyeing of wool with an oil‐in‐water microemulsion system

This article investigates the influence of oil‐in‐water (o/w) microemulsions, used as media for both dye solubilization and dye baths, on the dye uptake on fiber surfaces. An acetic acid solution/Synperonic L7/benzyl alcohol microemulsion system was used to solubilize a water‐insoluble antimicrobial natural dye (C.I. Natural Orange 2) and to dye wool fabric at an acidic pH. The results clearly show that the dye exhaustion on the fabric took place mainly when the temperature of the dye bath promoted a change in the molecular organization of the microemulsions with the liberation of the dye solubilized in the oil droplets of the microemulsions. Although uniformly and evenly dyed fabrics were obtained, they showed very low wash fastness. To confirm the mechanism involved and to achieve dyed fabrics with good wash‐fastness properties, two different dyeing methods were also studied. The first method was dyeing at a constant low temperature, at which the o/w microemulsion remained a monophase system; the second one was dyeing at a high temperature, at which it was transformed into a multiphase system. Both the dye exhaustion and wash fastness improved considerably for the fabrics dyed at a high temperature. Moreover, uniform and even dyeing was achieved. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Use of boron oxide and boric acid to improve flame retardancy of an organophosphorus compound in neat and fiber reinforced polyamide‐6

The aim of this study was to investigate the usability of boron oxide and boric acid to enhance flame retardancy of (aluminum diethyl phosphinate)‐type organophosphorus compound in polyamide‐6 and its 15 wt% of short (glass fiber)‐reinforced composite. Materials were compounded by melt‐mixing method via a twin‐screw extruder, and the specimens for testing and analyses were shaped by injection and compression‐molding. For the neat polyamide‐6 specimens, mass loss cone calorimetry analyses indicated that replacement of a certain amount of aluminum diethyl phosphinate with boron oxide or boric acid could result in significant improvements in many flame‐retardancy parameters. For instance, the suppression in peak heat release rate value of polyamide‐6 could be as much as 84% or 86% for boron oxide and boric acid, respectively, whereas it was only 32% when aluminum diethyl phosphinate was used alone. Char microscopy, thermogravimetric analyses, X‐ray diffraction, and evolved gas analyses revealed that the main contribution of boron oxide and boric acid to the barrier mechanism of aluminum diethyl phosphinate was the formation of additional glassy boron oxide layers and boron phosphate layers. J. VINYL ADDIT. TECHNOL., 22:300–310, 2016. © 2014 Society of Plastics Engineers     

A new method to visualize and characterize the pore structure of TENCEL® (Lyocell) and other man‐made cellulosic fibres using a fluorescent dye molecular probe

The internal porous structures of the man‐made cellulosic fibers Lyocell (TENCEL®), Modal, and Viscose fibers were visualized by applying fluorescence microscopy on fiber cross sections. The fiber pore structure was probed by the optical brightener Uvitex BHT, and the dye penetration depth was measured. The main differences in the pore structures of these three fiber types could be visualized. Only TENCEL shows a significant difference between dried and never‐dried fibers. A fiber structure model of TENCEL was obtained, which discriminates three different porous zones with respect to dye diffusion kinetics. The results are discussed in relationship with the fiber physical and chemical properties. The dye penetration depth and kinetics in TENCEL fibers was found to be sensitive to the production and treatment conditions, in particular to changes in the pore system by drying, and following alkali swelling processes. The performance of surface‐specific enzymatic peeling could also be observed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Modified 2,4‐difluoro‐5‐chloro‐pyrimidine dyes and their application in ink‐jet printing on wool fabrics

This paper describes the modification of three commercially available 2,4‐difluoro‐5‐chloropyrimidine dyes (Drimarene Brilliant Red K‐4BL, Drimarene Brilliant Blue K‐BL and Drimarene Golden Yellow K‐2R) by the reaction of the parent dye with 4‐hydroxybenzensulphonic acid sodium salt. Capillary electrophoresis was used to monitor both the course of the above reaction and to ascertain the dye stability of the dyes in an ink formulation. Inks prepared from the modified dyes showed much higher storage stability compared with the parent dye‐containing inks; this was confirmed by capillary electrophoresis analysis. Inks containing the modified dyes were printed on wool fabrics and diffusion/fixation achieved by ‘batching’ the prints at 25 °C; high fixation values were obtained for all three modified dyes. These prints exhibited excellent colour fastness to washing, rubbing and light, the former test confirming a high degree of dye–fibre covalent bonding.     

Dye Impregnation Method for Revealing Machining Crack Geometry

The palladium nitrate dye penetrant method for revealing surface microcracks was investigated and applied to display the geometry of machining cracks in silicon nitride flexure test specimens. This method used elemental mapping with an electron probe microanalyzer to detect the presence of the dye and, thereby, display the crack geometry. A previously used bending method and a method developed in this study in which the specimen surface is exposed to the dye under pressure were used to facilitate dye penetration. Prior to applying the method to study machining cracks, carefully controlled Knoop indentation cracks introduced into flexure specimens were used to verify penetration of the dye to the crack tip. During these experiments it was found that the palladium nitrate dye resulted in a reduction in flexure strength, which, on further study, was attributed to the dilute nitric acid solution used to formulate the dye. Exposure to carbon tetrafluoride plasma etching prior to applying the pressurized dye method also resulted in a detectable decrease in flexure strength. Although there was clear evidence that exposure to dye and plasma etching resulted in a small but measurable decrease in flexure strength for the silicon nitride material studied, there was no detectable change in observed crack geometry. The reduction in flexure strength was apparently caused by a decrease in resistance to initiate crack propagation. It was concluded that the palladium nitrate dye method is an accurate and useful means for determining the geometry of small, otherwise difficult to observe surface microcracks. Nevertheless, caution should be exercised with the use of this method during strength measurements. When applied to machining cracks, the complex nature of these shallow, elongated, sometimes joining cracks was unambiguously revealed.     

Dyeing behaviour of Japanese oak silk fibres treated with methacrylamide

Japanese oak silk fibres have been treated with methacrylamide, and the dyeing behaviour when using levelling acid and milling acid dyes has been investigated. Infra-red spectroscopy indicated that a methacrylamide polymer skin was produced on the fibre surface at high levels of polymer add-on. The methacrylamide polymer skin was dyed with the milling acid dye, although not dyed with the levelling acid type. The penetration of the levelling acid dye into the fibres was not interrupted by the polymer skin.