Effect of carbon black nanoparticles on reflective behavior of printed cotton/nylon fabrics in visible/near infrared regions

Tuning the level of visible and near infrared (NIR) reflectance of textile surfaces is crucial for making them undetected in each environment. In this regard, samples of cotton/nylon fabrics were printed using a mixture of some special pigments and carbon black (CB) nanoparticles to produce brown, olive green and khaki shades which are present in concealment patterns of textiles employed in deserts. The effect of CB nanoparticles on Vis/NIR reflectance, air permeability, perspiration, light, wash fastnesses, and colorimetric values of each printed sample were evaluated. The presence of CB nanoparticles in printing formulations was found to cause significant decline in Near Infrared (NIR) reflectance of samples. The results showed that air permeability of samples printed containing CB nanoparticles are higher than samples printed with no CB particles. Absorbing phenomenon imposed by CB nanoparticles was fast against washing and perspiration, although printed samples indicated high to moderate light fastness. Furthermore, detectable change in visible appearance of the printed patterns was the main point of concern even at concentrations as low as 0.05 g/kg CB in printing formulation.     

Predicting the air permeability of polyester/cotton blended woven fabrics

The aim of this study was to model the air permeability of polyester cotton blended woven fabrics. Fabrics of varying construction parameters i.e. yarn linear densities and thread densities were selected and tested for air permeability, fabric areal density and fabric thickness. A total of 135 different fabric constructions were tested among which 117 were allocated for development of prediction model while the remaining were utilized for its validation. Four variables were selected as input parameters on basis of statistical analysis i.e. warp yarn linear density, weft yarn linear density, ends per 25 mm and picks per 25 mm. Response surface regression was applied on the collected data set in order to develop the prediction model of the selected variables. The model showed satisfactory predictability when applied on unseen data and yielded an absolute average error of 5.1 %. The developed model can be effectively used for prediction of air permeability of the woven fabrics.     

Influence of low temperature plasma treatment on the properties of ink-jet printed cotton fabric

The aim of this paper is to study the possibility and effectiveness of applying LTP treatment to enhance the performance of pre-treatment paste containing sodium alginate so as to improve the properties of the ink-jet printed cotton fabric. Experimental results revealed that the LTP pre-treatment in couple with the ink-jet printing technique could improve the final printed properties of cotton fabric.     

The effect of etching on low-stress mechanical properties of polypropylene fabrics under helium/oxygen atmospheric pressure plasma

Polypropylene nonwoven fabrics were exposed to He/O₂ atmospheric pressure glow discharge plasma. Surface chemical analysis and contact angle measurement revealed the surface oxidation by formation of new functional groups after plasma treatment. Weight loss (%) measurement and scanning electron microscopy analysis showed a significant plasma etching effect. It was investigated in low-stress mechanical properties of the fabrics using Kawabata Evaluation System (KES-FB). The surface morphology change by plasma treatment increased surface friction due to an enhancement of fiber-to-fiber friction, resulting in change of other low-stress mechanical properties of fabric.     

Investigation on the effect of titanium dioxide nano particles on camouflage properties of cotton fabrics

Cotton fabrics were dyed with three commercial vat dyes in order to provide camouflage in Vis-NIR regions and imitate reflectance profile of greenish leaves. To investigate the effect of nano particles on camouflage properties of dyed fabric, nano particles of TiO₂ were applied on dyed fabrics using pad-dry-cure method. The nano TiO₂ padded dyed fabrics were investigated using scanning electron microscopy (SEM). Reflectance curves of coated dyed samples with different concentrations of nano TiO₂ were measured. Results showed that in both of the standard shades, nano TiO₂ increases the reflectance value in NIR region and with increasing the concentration of nano TiO₂, the reflectance curves of samples tend to show the maximum reflection of greenish leaves (deciduous leaves) in NIR region. Chromatic values (CIE1976 L*, a*, and b*) and color difference (according to CIECMC color difference ΔE*cmc (2:1)) of each of the coated samples were measured using the reflection spectrophotometer. By considering the influence of white color of nano TiO₂ on green shade of dyed cotton fabrics and increasing the color difference (between coated samples and the standard shades of the 1948 U.S army pattern) in visible range, optimum concentrations of nano TiO₂ for development of camouflage properties on cotton fabrics in both NIR and visible region were determined. These values for NATO and forest green shades were 0.75 % and 0.5 %, respectively. Fastness results showed that both of the samples have acceptable color fastness. The effect of washing and exposure to light on camouflage properties of coated dyed fabrics in visible (in term of chromatic values) and NIR region (in term of spectral reflectance) was investigated when those were coated in optimum concentrations of nano TiO₂. The results showed that the effect of after treatments (washing and exposure to light) on surface color spectral characteristics and camouflage properties was inconsiderable.     

Natural dyeing with black cowpea seed coat. I. Dyeing properties of cotton and silk fabrics

A new trial to determine the dyeing properties of cotton and silk fabrics with a black cowpea seed coat as crop waste was investigated. The natural dye anthocyanins were extracted from a black cowpea seed coat in an aqueous solution and used to dye silk and cotton. The optimal conditions for colorant extraction were an aqueous solution of a dried seed coat of black cowpea in a 1:10 liquor ratio at 70 °C for 4 hours with pH of 4. The best dye-uptake of silk and cotton fabric were obtained when the pH was 3.5 and 3.0 respectively, the temperature was 80 °C for 1 hour and the liquor ratio of black cowpea was 1:20. Different colors as dusky brown, brown, faint yellow, light green, reddish brown, cyan and green could be obtained using a various kind of mordants. The depth and brightness of color tones were affected by different dyeing and mordanting pH conditions. The colors of the fabrics were examined using a computer color matching system in terms of the K/S values and CIELAB color-difference values. The dyeing was evaluated using standard light, wash and heat fastness tests. Good wash and heat fastness were obtained but the poor light fastness indicated the need for improvement to fulfill the requirement for textile applications.     

Study on the aging and yellowing properties of sebum-soiled cotton fabrics

The accumulation and autoxidation of residual oily soil from human sebum is regarded as a major reason for the aging and yellowing of clothing and household textiles. In this study, the yellowing degree of cotton fabrics soiled with human sebum components and aged under various environmental conditions (various temperatures, humidities and light intensities etc.) were investigated. The representative sebum components including olive oil, squalene, oleic acid and cottonseed oil were selected and their chemical changes were studied by FTIR analysis. The results showed that, olive oil, squalene, oleic acid and cottonseed oil could caused more significant fabric-yellowing than other components in human sebum, and the yellowing degree could become higher with increasing temperatures, humidities and/or light intensities of aging environments. The chemical structures of olive oil, squalene and oleic acid changed remarkably after aging treatment. The aging products contained hydroxyl groups and carbonyl groups, and the conjugated C=O group was considered to be the chemical species leading to the yellowing of sebum-soiled fabrics.     

The influence of corona discharge treatment on the properties of cotton and polyester-cotton knitted fabrics

In this study, the effect of corona discharge treatment on the physical and mechanical properties of bleached cotton and polyester-cotton fabrics were investigated. For this purpose, the samples were treated by corona discharge at two levels of voltage 5 and 10 kV, and at various duration times of plasma, ca. 1.4, 2.1 and 3.5 min. The corona discharge treatment was applied on the fabric samples before and after bleaching treatment. The results show that the corona influences on the surface morphology, breaking strength, air permeability, abrasion resistance, and pilling of cotton and polyester-cotton fabrics. Moreover, the levels of voltage and duration of plasma have a different effect on the properties of fabrics.     

Investigation of the effect of cupric chloride on thermal stabilization of polyamide 6 as carbon fiber precursor

An investigation on the role of cupric (Cu²⁺) ion incorporation during the thermal stabilization of polyamide 6 fibers was carried out using a combination of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) measurements. Cupric chloride pretreated and thermally stabilized polyamide 6 (PA6) fibers was characterized by a reduction in fiber diameter and linear density values together with color changes from light brown to black with increasing stabilization time. PA6 fibers were properly stabilized after 8 h of stabilization time prior to carbonization. The results obtained from DSC and TGA measurements indicated that there was an improvement in the thermal stability when cupric (Cu²⁺) ions were incorporated into the polymer structure. TGA thermograms showed the relative improvement in thermal stability as indicated by increasing char yield with progressing time. Char yield reached a maximum value of 33.6 % at 1000 °C for the cupric chloride pretreated PA6 fibers stabilized for 12 h at 180 °C. Experimental results obtained from DSC and X-ray diffraction methods suggested the loss of crystallinity as a result of perturbation of hydrogen bonds with progressing time. The formation of cupric ion-amide coordination bonds improved the thermal stabilization by encouraging the development of ladder-like structures. The investigation resulted in a new method of evaluation of X-ray stabilization index specifically intended for the thermally stabilized PA6 fiber.     

Objective measurement of hand properties of plasma pre-treated cotton fabrics subjected to flame-retardant finishing catalyzed by zinc oxide

In the present paper, flame resistance property is imparted to cotton fabrics by N-methylol dimethylphos-phonopropionamide (Pyrovatex CP New, FR), melamine resin (Knittex CHN, CL), phosphoric acid catalyst (PA), and ZnO/nano-ZnO co-catalyst. The study shows that effectiveness of the FR-CL-PA reaction to form a crosslinked structure is enhanced by the co-catalytic reaction, resulting in enhancement of fabric’s compressional recovering ability. However, the low pH reaction weakened the fabrics, resulting in poor tensile strength and toughness, stiffer hand feel, brittle and tendered polymer layers, a less spongy fabric structure, and a roughened fabric surface with fuzzy fibrils. In addition, atmospheric pressure plasma jet (APPJ) was used to enhance materials properties by sputtering or etching effect. The roughening effect of plasma treatment enhances tensile properties of treated specimens. Nevertheless, the positive effect is negligible after post-treatment with flame-retardant agents. Moreover, the increased inter-yarn friction enhances the subjective stiffness of fabric and the rigid effect is even worse for plasma pre-treated cotton specimens subjected to flame-retardant treatment. However, plasma pre-treated specimens have a compressible structure after post-treatment with flame-retardant agents. Moreover, neutralization of flame-retardant-treated specimens helps minimize side effects of acidic finishing, irrespective of tensile and compression properties. The process also minimizes shear and bending rigid effect by removing unattached metal oxides from the fabrics.     

The study of coloration and antibacterial efficiency of corona activated dyed polyamide and polyester fabrics loaded with Ag nanoparticles

The aim of this study was to examine the influence of dyeing on antibacterial efficiency of corona activated polyamide and polyester fabrics loaded with colloidal Ag nanoparticles as well as the influence of the presence of Ag nanoparticles on the color change of dyed fabrics. C.I. Acid Green 25 and C.I. Disperse Blue 3 were used for dyeing of polyamide fabrics and C.I. disperse violet 8 for polyester fabrics. The color change of polyamide fabrics depends on the dye type, which was generally lower compared to polyester fabrics. Antibacterial efficiency of Ag loaded fabrics was tested against Gram-positive bacterium Staphylococcus aureus and Gram-negative bacterium Escherichia coli. Corona activated polyester and polyamide fabrics showed excellent antibacterial efficiency independently of order of dyeing and Ag loading. The morphology of fibers loaded with Ag nanoparticles was assessed by SEM and atomic absorption spectroscopy for elemental analysis.     

Synthesis of ZnO nanoparticles by PNP and its application on the functional finishing of cotton fabrics

This paper presents a facile and novel approach for the synthesis of ZnO nanoparticles in aqueous solution based on a one-step reaction between a modified hyperbranched polymer (PNP) and zinc nitrate. The prepared ZnO nanoparticles polymeric hybrid was characterized and its antibacterial activity was investigated. The results indicated that the ZnO nanoparticles have an average size about 6 nm and well dispersed in aqueous medium. The minimum inhibitory concentration (MIC) of them was 20 ppm and 60 ppm against S. aureus and E. coli, respectively. For the functional finishing of cotton fabrics by these ZnO nanoparticles, a microwave assisted in situ fabrication method was employed. Scanning electron microscope (SEM), energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) measurements confirmed that the ZnO nanoparticles in situ generated in cotton fabrics successfully. Fourier transform infrared (FT-IR) spectroscopic investigation demonstrated that the ZnO nanoparticles were fixed on the cotton fibers by PNP. The treated cotton fabrics exhibited excellent UV protective properties and antibacterial activities. When ZnO content of cotton fabric was 1.49 %, the UPF value of treated cotton fabric exceeded 125 and the bacterial reduction rate against S. aureus and E. coli reached 99.97 % and 98.40 %, respectively.     

The effect of the pretreatment print paste contents on colour yield of an ink-jet printed cotton fabric

Optimum condition concerning the content of pretreatment print paste and steaming time for ink-jet printing was newly developed through the orthogonal analysis. The cotton fabric treated under the newly developed optimum condition could achieve a high level of colour yield similar to that of the commercially pretreated cotton fabric available in the market for ink-jet printing. The results were discussed thoroughly in this paper.     

Dimensional and physical properties of plain knitted fabrics made from 50/50 bamboo/cotton blended yarns

In this study, the dimensional and some physical properties of plain knitted fabrics made from 50/50 bamboo/cotton blended yarns are investigated. In order to see the differences and similarities, the results are then compared with those for similar fabrics knitted from 50/50 conventional viscose/cotton and 50/50 modal/cotton blended yarns. Each fabric type was produced with three different stitch lengths. After all fabrics were dyed under identical dyeing conditions, they were subjected to dry and full relaxation treatments. For dimensional properties of fabrics, course, wale and stitch densities were measured. Then, by calculating statistically best-fit lines passing both through the experimental points and the origin, dimensional constants i.e. k values were predicted in terms of the fiber types. The result show that each fabric type knitted from bamboo/cotton, viscose/cotton and modal/cotton blended yarns behaves in a similar manner. However, in both dry and fully relaxed states, the modal/cotton knitted fabrics tend to have slightly higher k values than the bamboo/cotton and viscose/cotton knitted fabrics. For physical properties, fabric weight per unit area, thickness, bursting strength, air permeability and pilling were evaluated. The results show that the weight, thickness and air permeability values are independent of the fiber type. Plain knitted fabrics from modal/cotton blended yarns have the highest bursting strength values. Plain knitted fabrics from bamboo/cotton blended yarns tend to pill less.     

Effect of using cold plasma on dyeing properties of polypropylene fabrics

The low temperature plasma (LTP) technique is used widely to modify polymer and textile materials. This paper describes the development of a plasma system for textile treatment. Polypropylene (PP) has a very low value of the surface free energy (approximately 20–25 mJ/m²). Due to low surface energy, Polypropylene has very weak hydrophilic properties. By controlling the plasma variables, such as the nature of gas, the discharge power, the pressure and the exposure time, a great variety of surface effects can be generated. In this paper, we report the effect of cold plasma of O₂ and N₂ gases at various time of exposure on the dyeing and physical properties of PP fabrics. The results show a significant increase in the color depth upon dyeing after treating PP fabrics with low temperature plasma of O₂ and N₂. For comparing the amount of fabrics dye exhaustion, we have used reflective spectrophotometer. The morphology of the modified surfaces has also been investigated using scanning electron microscopy (SEM). And also FTIR was used to examine the functional groups of the corresponding samples.     

The reinforcement effect of carbon fiber on the friction and wear properties of carbon fiber reinforced PA6 composites

The tribological performance of PA6 and carbon fiber reinforced polyamide 6 (CF/PA6) under dry sliding condition was examined. Different contents of carbon fibers were employed as reinforcement. All filled and unfilled polyamide 6 composites were tested against CGr15 ball and representative testing was performed. The effects of carbon fiber content on tribological properties of the composites were investigated. The worn surface morphologies of neat PA6 and its composites were examined by scanning electron microscopy (SEM) and the wear mechanisms were discussed. Moreover, all filled polyamide 6 have superior tribological characteristics to unfilled polyamides 6. The optimum wear reduction was obtained when the content of carbon fiber is 20 vol%.     

The effect of alkali pre-treatment on formation and adsorption of silver nanoparticles on cotton surface

This study is an attempt to investigate the feasibility of alkali pre-treatment to activate surface hydroxyl groups of cellulose fibers in order to enhance the deposition efficiency of silver nanoparticles (AgNPs) onto cotton fabrics. Cotton samples were pre-treated with various alkali solutions containing different earth metal hydroxides (LiOH, NaOH, and KOH). The as-prepared samples were then treated with aqueous silver nitrate followed by reduction treatment with aqueous ascorbic acid, which caused in situ formation of AgNPs on fiber surfaces. The surface structure of the fabrics was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis, and colorimetric data. The amount of silver was measured by using inductively coupled plasma-optical emission spectrometer (ICP-OES). Antimicrobial activity was measured against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. It was established that alkali pre-treatment had a substantial effect on the formation and adsorption of AgNPs on the fibers. Alkali pre-treated samples were homogeneously coated by AgNPs with high surface coverage. Alkali type had significant effect not only on the amount of AgNPs on the surface but also on its size. High antibacterial activity against both Gram-positive and Gram-negative strains was also demonstrated, even after 10 cycles washing.     

The effect of different connections in double layered woven fabrics on comfort properties

With the increasing demand of fabrics for special usage areas, more complex woven structures are designed and from the structural point of view, especially the parameters which affect the comfort properties become more important. This paper reports the effect of structural parameters of double layered woven fabrics, such as number of interlacing picks, period of interlacing and number of weft skips on the basic comfort properties of the fabrics (thickness, air permeability and wicking properties) produced according to Taguchi orthogonal array design. The investigated parameters were determined before and after finishing treatment. According to the results, it is found that period of interlacing has an important effect on the thickness and air permeability of both untreated and treated fabrics whereas in terms of drying coefficient, the effect of the investigated parameters is not statistically important.     

An investigation of continuous finishing and dyeing on the mechanical properties and handle of cotton fabrics

In this paper, the effect of continuous finishing-desizing, scouring, bleaching and dyeing of woven cotton fabrics on the low stress mechanical and surface properties has been studied. The cotton fabric properties were measured by the famous KES-FB system. The handle of the finished fabrics were calculated by the handle evaluation programme. The results showed that the mechanical properties changed significantly by the desizing and gradually by the scouring, bleaching and dyeing processes.     

Silver containing sol-gel coatings on polyamide fabrics as antimicrobial finish-description of a technical application process for wash permanent antimicrobial effect

This paper reports on an antimicrobial finishing for polyamide with high washfastness. As antimicrobial agent modified silica sols containing silver components are used as coating agent and are applied to the polyamide fabric by using a semi-industrial procedure. The antimicrobial properties of coated polyamide fabrics are determined against the bacteria E. coli. Significant antimicrobial effects are observed even after 40 washing cycles. The amount of silver on the polyamide fabrics was measured by using ICP-OES. Besides this, samples are investigated by means of UV/Vis-spectroscopy and scanning electron microscopy. Furthermore textile properties as, e.g., air permeability and mechanical properties were measured. Due to high antimicrobial effect and the strong washfastness of this finishing, this reported method could be of high interest for industrial production processes.