Change in colour of dyed aramid fabrics by sputter etching

The aramid fabrics Technora and Conex, dyed with CI Disperse Yellow 54, CI Disperse Red 60 and CI Disperse Blue 56, were treated with sputter etching and argon low-temperature plasma. The colour depth of Technora was considerably increased by sputter etching, whereas that of Conex was not. Changes in colour were investigated by the L*, C*, h colour system. The increase in colour depth due to sputter etching was greatly dependent on the decrease of metric lightness L* and the increase of metric chroma C*.     

The effect of humidity, fabric surface geometry and dye type on the colour of cotton fabrics dyed with a select range of anionic dyes

Four C.I. Solubilised Sulphur dyes were applied to cultivated silk fabric using sodium thioglycolate at pH 7, for 30 min at 60 °C in the absence of electrolyte. Medium/deep shades were obtained that displayed good/excellent fastness to washing at 40 °C and little or no sensitivity to oxygen bleach fading. The dry rub fastness of the dyeings ranged from moderate to good whilst the wet rub fastness varied from poor to moderate; light fastness of the 10% omf dyeings varied from low to moderate. The mild application conditions used had little effect on the tensile strength of the fabric.     

The surface polymerising of fluoromonomer and the shade-darkening effect on dyed polyester microfibre fabric

The surface polymerising of fluoromonomer on dyed polyester microfibre fabric is investigated. The shade-darkening effect of perfluoropolyester acrylate polymer is discussed by colour yield, reflectance spectrum and the colour differences. The surface polymerising of fluoromonomer on dyed polyester microfibre fabric had an excellent shade-darkening effect. After surface polymerising, the dyed fabrics had no significant effect on washing and wet rubbing fastness.     

The viscoelastic properties of modified thermoplastic impregnated multiaxial aramid fabrics

This study reports the manufacture of new fabric forms from the preparation of hybrid laminated multiaxial composites with enhanced thermo‐mechanical properties. Thermal and dynamic mechanical analysis of polymer matrix films and fabricated hybrid composites were used to determine the optimal material composition and reinforcement content for composites with improved viscoelastic properties. The introduction of 5 wt% silica nanoparticles in a composite of p‐aramid–poly(vinyl butyral) led to significant improvements in the mechanical properties, and the addition of silane coupling agents yielded maximal values of the storage modulus for hybrid nanocomposites. The introduction of silane led to a better dispersion and deagglomeration of SiO₂ particles, and to the formation of chemical bonds between organic and inorganic constituents, or p‐aramid–poly(vinyl butyral) composites. In this way, the mobility of macromolecules was reduced, which can be seen from the decreasing value of damping factor for the p‐aramid–poly(vinyl butyral) composite. Analysis of the glass transition temperature of the composite with amino‐functionalized silica nanoparticles revealed improved thermal stability in addition to the aforementioned mechanical properties of the tested materials. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

A study on the effect of bulk water content and drying temperature on the colour of dyed cotton fabrics

In the present study, the effect of various levels of bulk and free water content and its distribution on the colour of cotton fabrics dyed with direct dyes and their combinations were analysed. Twill and plain structures with two different parameters of fabric construction were chosen. The dyed samples were adjusted to different levels of wet pick‐up, with water ranging from 50% to 125% on the bone dry weight of the fabric (odwf) to achieve various levels of bulk water content. Further, the residual moisture content of the samples was adjusted to 40–10% odwf by means of hot air drying at different temperatures to obtain different levels of free water content and its distribution. For the assessment of colour and its comparison, the parameters ΣK/S and values were used. In order to bring out the true effect of moisture distribution and fabric structure, normalisation of dye uptake in the fabric based on weight and area were considered, respectively. The plain structures show a higher increase in colour than the twill structures when the bulk water content increases. At the same time, the fabric structures do not play a significant role, with increase in colour attributable to change in drying temperature. The findings reveal that the bulk water content, drying temperature and fabric geometry affects the colour of the fabric significantly.     

Modelling the properties of pigment‐dyed polyester/cotton sheeting fabrics by response surface methodology

The aim of this study was to model the effect of pigment, binder and fixer concentrations on the rubbing fastness, crease recovery, tear strength and stiffness of pigment‐dyed polyester/cotton sheeting fabrics. The design and analysis of experiments were carried out using Minitab^® statistical software according to the central composite design of response surface methodology. It was found that an increase in the binder concentration significantly improves the dry rubbing fastness, crease recovery and stiffness of the fabric, with a corresponding decrease in fabric tear strength, without significantly affecting the wet rubbing fastness. An increase in the fixer concentration significantly improves both the dry and wet rubbing fastness and crease recovery, with a decrease in fabric tear strength and stiffness. The effect of binder and fixer concentrations on crease recovery was not linear and there was significant negative interaction between these factors for dry rubbing fastness. The effect of pigment concentration was not found to be statistically significant for the types and range of concentrations of pigment, binder and fixer used in this study.     

Color analysis of natural colorant‐dyed fabrics

Colors from naturally dyed fabrics recently have attracted both consumers and manufacturers in fashion markets. Even though color attributes of the fabrics have been partially observed in some literature, a data base of colors for natural colorants in fabrics needs to be established and the colors to be characterized according to systematic color notations and tones in order to relate the traditional natural colors to contemporary color communication systems. Therefore, a study was performed to investigate color characteristics for a given large set of natural colorants‐dyed fabrics based on the Munsell color notations, to analyze their tones with relation to the notation such as hue, value, and chroma, and finally to identify the effects of mordanting, an important coloring auxiliary, on the colorimetric properties of the fabrics. As a result, the dominant hue for a total of 350 naturally dyed fabrics was yellowish families followed by reddish and purplish ones in the Munsell notation owing to the use of leaves and plant as usual natural dyestuff, which confirms the limit of color hues of the fabrics. Color value for most of naturally dyed fabrics was generally higher whereas the chroma was lower, which means that most of colors for naturally dyed fabrics tended to be bright and weak shaded. Grayish, light grayish, and soft tones were the main tones of natural colorant‐dyed fabrics. All of hue, value, and chroma were found as being influenced by mordanting in that more particularly; iron mordanting was likely to cause the decrease of both value and chroma for most of naturally dyed fabrics. These results could provide a systematic color data for naturally dyed fashion fabrics and suggest a future direction of color development for them. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 148–157, 2008     

Improving the light fastness of dyed nylon fabrics using nickel arylsulphonates

Various nickel arylsulphonates were synthesised and their protecting effects on the photofading of CI Basic Violet 3, CI Acid Red 94, CI Acid Red 87 and CI Acid Blue 74 examined on nylon fabric. The rates of photofading of the dyes were remarkably suppressed in the presence of nickel salts, while the addition of ultraviolet absorbers and conventional stabilisers afforded little retardation of the rate of fading. The antimicrobial activity against two species bacteria of nickel salts was also examined. This aftertreatment technique was shown to be safe for the environment and human health.     

芳纶表面改性研究进展

简单回顾了芳纶的发展历史,阐述了表面涂层法、化学改性、物理改性等几种芳纶表面改性方法的研究现状,同时介绍了3种常用来表征纤维复合材料界面结合强度的方法,最后指出芳纶表面改性技术的发展方向。     

Topping of naturally dyed wool fabrics with different natural dye sources

Wool fabrics can be dyed with synthetic dyes and even with natural dyes. To present a different aspect to the coloration of wool, the current study was focused on a topping process (ie, the dyeing of wool that was already dyed) with different natural dye sources. For this purpose, the fabrics that were already dyed with a natural dye source were once again dyed with two different natural dyes. In bottom dyeing (bottoming), fabrics were dyed with hops (Humulus lupulus L.) in the presence of different mordanting agents. Then the dyed, washed and dried samples were once again dyed (topping) with two different natural dye sources. For topping, powdered madder and acorn were tested in direct dyeing of wool samples. Finally, the colour changes were analysed with the use of a spectrophotometer. The study demonstrates that such a process (ie, bottoming with hops in the presence of different mordanting agents and then topping with madder or acorn) can be a way of obtaining different shades and colours with sufficient/good fastness values by natural dyeing.     

表面处理对芳纶纤维粘合性能的影响

研究活化液组成、间苯二酚-甲醛-胶乳(RFL)改性剂品种及浸渍工艺对芳纶纤维粘合性能的影响.结果表明,以环氧树脂-己内酰胺封闭异氰酸酯(简称封闭异氰酸酯)混合溶液作为一浴活化液的二次浸渍工艺和以封闭异氰酸酯改性RFL为浸渍液的一次浸渍工艺更适合芳纶纤维表面处理;在浸渍液成分一定的条件下,一次浸渍工艺处理效果优于二次浸渍工艺,操作更简便.     

The effect of internal scattering on the color of fabrics

The effect of internal scattering on the color of dyed fabrics is calculated with the help of a highly simplified model. The predictions agree, at least qualitatively with observation. If an internally scattering fiber is ring-dyed then at lower values of the product of the coefficient of extinction and dye concentration (25–250) it is lighter than a homogenously dyed fiber but at higher values of that product it is darker.     

Modelling the properties of one‐step pigment‐dyed and finished polyester/cotton fabrics using response surface methodology

Dyeing of polyester/cotton blended fabrics with two different classes of dyes for polyester and cotton is a lengthy and expensive procedure owing to different fibre contents that need different auxiliaries, pH, and temperature conditions. The aim of this study was to investigate and model the properties of a combined pigment dyeing and hand‐building finishing system for polyester/cotton blended fabrics. The one‐step process was investigated using response surface methodology, taking concentrations of pigment, softener, and hand‐building finish as experimental variables. It was found that increase in hand‐building finish helps to improve colour fastness at higher pigment concentrations but results in deterioration in fabric tear strength. However, the decrease in tear strength can be minimised by increasing the softener concentration. For a 15 g l^?1 pigment concentration, optimum fabric tear strength, crease recovery angle, bending length, and dry and wet rubbing fastness properties were obtained using 60 g l^?1 of softener and 65 g l^?1 of hand‐building finish. The prediction equations developed in this study can be used to determine the required amounts of softener and hand‐building finish to achieve commercially acceptable results at different pigment concentrations.     

Transcrystalline morphology of nylon 6 on the surface of aramid fibers

In this paper, the isothermal crystallization of nylon 6 in the presence of Kevlar 129 fiber was investigated by polarized optical microscopy (POM). The formation of a transcrystalline domain was found to be mainly controlled by crystallization conditions, such as the temperature of the isothermal crystallization, residual time at melting temperature and the cooling rate of the melt. The nucleation rate of nylon 6 on the fibers was mainly affected by the crystallization temperature. The interfacial transcrystallinity of nylon 6 occurred on the surface of Kevlar 129 fiber in the temperature range 130–190 °C. The reason for the formation of interfacial transcrystalline morphology is discussed from the molecular level, based on the understanding of the packing mode of nylon 6 chains around fibers and the interaction between matrix and fibers. It was found that the lattice matching and hydrogen‐bonding between nylon 6 and poly(p‐phenylene terephthalamide) (PPTA) crystals play an important role in the epitaxial crystallization. Copyright © 2004 Society of Chemical Industry     

The colour fastness of dyed fabrics to activated oxygen bleach-containing detergents: an international interlaboratory trial

The UK-TO single wash test procedure, developed to be diagnostic of the oxidative bleach response of dyed articles to repeated washing in activated oxygen bleach-containing detergents, has been subjected to extensive interlaboratory trials. The results indicate that both its repeatability and reproducibility are fully acceptable for the purpose of interlaboratory comparisons.     

The role of surface tension on the residual water content of fabrics

Cotton has been shown to hold up to 80% of its initial weight in water due to strong capillary forces after washing. According to the LaPlace equation for capillary rise, the rise is proportional to the surface tension of the air-liquid interface. The use of a tailored rinse additive has the potential to alter the surface tension of solutions significantly, thus leading to a lower capillary rise. This lower rise can be related to the residual water content in fabrics. The reduction of surface tension lowers the force required to displace liquid inside the capillaries formed by fabric fibers. If the amount of residual water in fabrics can be significantly lowered, the drying time of the fabrics would be decreased as well. We have shown that by reducing the surface tension of solutions, the residual moisture content of fabrics also decreases.     

Stab resisting behavior of polymeric resin reinforced p‐aramid fabrics

The stab resistant performance of p‐aramid fabrics reinforced with thermoplastic LDPE resin and thermoset epoxy resin was investigated by quasi‐static or drop tower stab resistance testing, and the stab resistance behavior against different shapes of impactors was also evaluated. The destruction behavior of LDPE reinforced p‐aramid fabrics against a knife impactor shows three distinctive steps; the initial penetration step with maximum strength, the cutting step by knife edge, and the destruction step of accumulated fiber bundles. On the other hand, epoxy resin reinforced p‐aramid fabrics against a knife impactor exhibit just two steps without the accumulation of fiber bundles. In the case of a spike impactor, the maximum stab resistant strength is observed from the initial penetration step; however, the stab resistant strength after initial penetration drastically decreased regardless of the reinforcing resins. It is also found that, even if the LDPE reinforced fabrics are multilayered, the performance improvement by resin reinforcement is observed only from the initial penetration step and the stab resistant strengths of the cutting step and the fiber accumulation step are not improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The enhanced cationic dyeability of ultraviolet/ozone‐treated meta‐aramid fabrics

Aramid fabrics were photo‐oxidised by ultraviolet/ozone irradiation. The surface properties of the modified fabrics were characterised by reflectance, attenuated total reflectance, electron spectroscopy for chemical analysis and surface zeta potential. The ultraviolet irradiation caused the oxygen content of the aramid fabric surface to increase, with the appearance of carbonyl and hydroxyl groups, and reduced the surface zeta potential, coupled with improved water wettability. Moreover, the crystalline structure did not change after ultraviolet/ozone treatment according to X‐ray diffraction results. The modified aramid fabrics showed higher affinity to cationic dyes, which may have resulted from the newly introduced electrostatic interaction between cationic dyes and anionic dyeing sites on the photo‐oxidised surface layers. Although colour fastness to both staining and rubbing were good to excellent, colour fastness to shade change was moderate. Furthermore, the ultraviolet/ozone pretreatment and cationic dyeing of aramid fabrics may overcome the loss in the mechanical properties associated with previously recommended dyeing methods for aramid fabrics.     

Non-formaldehyde durable press finishing of dyed fabrics: evaluation of cotton-bound polycarboxylic acids

The polycarboxylic acids 1,2,3,4-butanetetracarboxylic acid and citric acid are used as nonformaldehyde durable press finishing agents instead of formaldehyde-releasing N -methylol compounds. In this study, isocratic HPLC is applied in an attempt to quantify the polycarboxylic acids that react with cellulosic material dyed with CI Reactive Red 195, CI Reactive Yellow 145 and CI Reactive Blue 221. Subsequently, the fabrics are cured with formulations containing butanetetracarboxylic acid and citric acid or a combination of both. The chromatographic determination reveals that an increase in the depth of shade results in a decrease of the amount of butanetetracarboxylic acid, except in the case when the cotton is dyed with CI Reactive Blue 221, a copper formazan complex-based dyestuff. Colour measurements indicate that the Δ E * values decrease in the order CI Reactive Yellow 145, CI Reactive Red 195 and CI Reactive Blue 221.     

Interfacial studies on the surface modified aramid fiber reinforced epoxy composites

In this work, solutions of rare earth modifier (RES) and epoxy chloropropane (ECP) grafting modification method were used for the surface treatment of aramid fiber. The effect of chemical treatment on aramid fiber has been studied in a composite system. The surface characteristics of aramid fibers were characterized by Fourier transform infrared spectroscopy (FTIR). The interfacial properties of aramid/epoxy composites were investigated by means of the single fiber pull‐out tests. The mechanical properties of the aramid/epoxy composites were studied by interlaminar shear strength (ILSS). As a result, it was found that RES surface treatment is superior to ECP grafting treatment in promoting the interfacial adhesion between aramid fiber and epoxy matrix, resulting in the improved mechanical properties of the composites. Meanwhile, the tensile strengths of single fibers were almost not affected by RES treatment. This was probably due to the presence of reactive functional groups on the aramid fiber surface, leading to an increment of interfacial binding force between fibers and matrix in a composite system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4165–4170, 2006