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.     

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.     

One-bath one-dye class dyeing of PES/cotton blends after corona and chitosan treatment

In this work, the effects of corona discharge (CD) and chitosan treatment on the dyeability of polyester/cotton blends with direct and reactive dyes were studied. The surface chemical changes of polyester and cotton were analyzed using X-ray Photoelectron Spectroscopy (XPS). The correlation between chemical changes, wettability, and dyeability after CD and/or chitosan treatment has been established. Color intensity of both single components and PES/cotton blend increased proportionally with increasing chitosan concentration. The results obtained open the possibility for a new method for dyeing of polyester/cotton blends in a single bath using one dye-class that is commonly used for dyeing of textile material of cellulosic origin.     

Improvements of surface functionality of cotton fibers by atmospheric plasma treatment

This study aims to investigate the viability of atmospheric plasma treatment over raw cotton fabric surfaces as an alternative method for superseding the wet textile pre-treatment processes. For this purpose, the fabric samples were treated with air plasma and argon atmospheric plasma. Thereafter, the hydrophilicity and the wickability of plasma treated samples increased, and also the contact angles decreased significantly. Chemical changes were analyzed by FTIR-ATR and XPS. Morphological changes were observed by SEM. The results were inspected for assessing to what extent the replacement might be achieved by inducing this surface modification method.     

Influence of oxygen plasma pre-treatment on the water repellency of cotton fibers coated with perfluoroalkyl-functionalized polysilsesquioxane

Oxygen plasma pre-treatment was applied to cotton fabric with the aim of improving the water repellency performance of an inorganic-organic hybrid sol-gel perfluoroalkyl-functionalized polysilsesquioxane coating. Cotton fabric was pre-treated with low-pressure oxygen plasma for different treatment times and operating powers. Afterward, 1H,1H,2H,2H-perfluorooctyltriethoxysilane (SiF) was applied to the cotton fabric samples using the pad-dry-cure method. The surfaces of the untreated and modified cotton fibers were characterised using Fourier transform infrared spectroscopy, Xray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The water repellency of the SiF-coated fabric samples was evaluated using static and sliding contact angle measurements with water. The results show that the plasma treatment with the shortest treatment time (10 s) and the lowest operating current (0.3 A) increased the atomic oxygen/carbon ratio of the cotton fiber surface from 0.6 to 0.8 and induced the formation of a nano-sized grainy surface. Increasing the plasma treatment time and/or operating current did not intensify the surface changes of the cotton fibers. Such saturation effects were explained by the large influence of reactive oxygen atoms during the plasma treatment. The measured static water contact angles on the surface of the untreated and plasma pre-treated and SiF-coated cotton fabrics showed that the oxygen plasma pre-treatment enabled the increase of the water contact angle from 135° to ≈150°, regardless of the applied plasma treatment time and discharge power. This improvement in the hydrophobicity of the SiF coating was followed by a decrease in the sliding angle of water droplets by more than 10° compared to the plasma untreated and SiF-coated sample characterized by a water sliding angle of 45°. Additionally, measurements of the water sliding angle revealed that the increase of the static contact angle from 149° to 150° corresponded to a drop of the water sliding angle from 33 to 24°, which suggests that the plasma pre-treatment of 20 s at an operating current of 0.3 A produced the best water-repellent performance of the SiF-coated cotton fabric.     

Enzymatic treatment on cotton fibers: degradation kinetics of pectin and influence of shape change on adsorption

Alkaline pectinase was one of the most effective enzymes to treat cotton as alternative agent to replace the conventional alkaline method. Removal of pectin and cutin was considered the explanation for improvement of wettability as well as water adsorption on cotton fiber. However, degradation kinetics of pectin is unclear, and the influence of fiber shape on property changes after enzymatic treatment was ignored. The main objective of this work was to reveal interactions between pectinase and cotton fiber for mechanism study. A heterogeneous catalysis kinetic equation, which is associated with Langmuir adsorption model and enzyme deactivation, was used to describe the heterogeneous catalysis. The enzymatic process conditions were optimized. Raw cotton fibers, pectinase-treated and alkali-treated fibers were characterized by impurities content determination, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Mechanism of water adsorption enhancement on treated fibers was discussed. In addition to elimination of the outer impurities, flat fibers with less twist and shape changes of lumen were also obtained to ensure better accessibility and water adsorption after enzymatic treatment.     

X-ray diffraction analysis of Yemeni cotton fibers

The lowland and coastal regions are the areas where cotton is cultivated in Yemen. The land used for this purpose exceeds 120 acres and expandable in the upcoming seasons. We have selected the earlier two varieties of cotton fibers cultivated in two different areas Abyan and Zabid. Wide Angle X-ray Scattering (WAXS) data from these fibers have been recorded and analysed to obtain the micro-structural parameters with the application of Line Profile Analysis (LPA). Linked Atom Least Squares (LALS) program has been used to obtain molecular structure and packing in these fibers. For the first time micro-structural parameters of these cotton fibers cultivated in Yemen are computed and reported. This study will be of help to understand the structure-property relation in these cotton fibers.     

Influence of alkali treatment on the structure and properties of hemp fibers

Alkali treatment may change the structures and properties of cellulosic fibers. The aim of this work was to study the mechanism of structural changes of hemp fibers treated with different alkali concentrations and time by SEM, FTIR, tensile and bending tests. The results showed that the alkali treatment removed some of non-cellulosic materials from the surface of fibers and caused many cracks along the axis of fibers. The crystalline order index increased firstly followed by decreased with the increase of concentration. The deconvolution spectra in OH stretching region showed that the alkali treatment decreased the amount of hydrogen bonding firstly and then increased. The S/G ratio results also support the removal of non-cellulosic materials. The tensile strength of the fibers increased with the alkali concentration. Furthermore, the suitable chemical treatment not only slenderized the hemp fibers, but also softened the fibers dramatically.     

Investigation of antibacterial properties of nano-ZnO assembled cotton fibers

Nano-ZnO assembled cotton fibers (NZCF) with excellent antibacterial properties were fabricated using microwave synthesis method. The effects of ZnO size, ZnO content, assembly times, microwave power and Zn²⁺ concentration of the synthesis solution on the antibacterial activity of the NZCF were studied using bacteriological tests such as Petri dish and agar diffusion method. The results show that NZCF has the antibacterial circle width (ACW) of about 1.5–2.3 mm and 2.3–3.4 mm against Escherichia coli (E. coli, gram-positive organism) and Staphylococcus aureus (S. aureus, gram-negative organism), respectively. It is also found that the antibacterial activity of NZCF increases with decreasing ZnO size, increasing ZnO content in NZCF and increasing Zn²⁺ concentration in synthesis solution.     

Controlling supermolecular structures and improving colorfastness in cotton fibers

A new discovery was made in which commercially available triethanolamine could reduce the lattice volume of the supermolecular structure of cotton from the periphery of the lattice by moving cellulose chains on the surface of the crystallites to the amorphous regions, thereby decreasing the close-packed crystallization volume and leading to an increased free volume of the amorphous regions. Subsequently, several supermolecular structures for cotton fibers were successfully controlled to improve the colorfastness in cotton fibers at the molecular level. With the decrease in the degree of crystallinity, more unfixed dyes could be removed by washing reagents, whereas the remaining dyes were mostly fixed to the cotton by covalent bonds, causing a stronger colorfastness, with the best wet rubbing fastness reaching a relatively permanent grade 4. Moreover, the effect mechanism revealed that the unfixed dyes were detached from the cotton fibers according to the reverse process of the adsorption models and that there were additional methods for the unfixed dyes in the fibers to be removed in the presence of triethanolamine than when using pure water. In addition, the binding forces of dye adsorption in the cotton fibers decreased, while the entropy of dye adsorption was higher than that measured when using pure water. Thus, the results suggested that controlling the supermolecular structures of the cotton fibers promoted the removal of unfixed dyes from the fibers and achieved improved colorfastness.     

Nanofibrillation of cotton fibers by disc refiner and its characterization

Nanofibrils of cellulose were prepared from short staple cotton by refining process using a lab disc refiner that exerts a combination of shear and frictional forces. The nanofibrils were characterized by scanning electron microscope (SEM), atomic force microscope (AFM), X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). From SEM and AFM, it was found that starting average diameter of the cotton fiber (∼25 μm) was reduced to 242 nm after 30 passes of refining. FTIR analysis revealed the increase in amorphous nature of cotton cellulose due to refining process. Supportively, XRD analysis showed a steady decline in percent crystallinity of the cotton fibers as the cotton fibres were passed through the refiner for more number of passes. Similarly, degree of polymerization (DP) was reduced from 2720 to 740 due to the refining process. Nanofibrils of cellulose from short staple cotton have a huge potential for application in nanofilters and as biodegradable fillers in nanocomposites.     

Effect of temperature and durations of heating on coir fibers

Biocomposites derived from polymeric resin and lignocellulosic fibers may be processed at temperatures ranging from 100 °C to 230 °C for durations of up to 30 min. These processing parameters normally lead to the degradation of the fiber's mechanical properties such as Young's modulus (E), ultimate tensile strength (UTS) and percentage elongation at break (%EB). In this study, the effect of processing temperature and duration of heating on the mechanical properties of coir fibers were examined by heating the fibers in an oven at 150 °C and 200 °C for 10, 20 and 30 min to simulate processing conditions. Degradation of mechanical properties was evaluated based on the tensile properties. It was observed that the UTS and %EB of heat treated fibers decreased by 1.17-44.00% and 15.28-81.93%, respectively, compared to untreated fibers. However, the stiffness or E of the fibers increased by 6.3-25.0%. Infra red spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to elucidate further the influence of chemical, thermal and microstructural degradation on the resulting tensile properties of the fibers. The main chemical changes observed at 2922, 2851, 1733, 1651, 1460, 1421 and1370 cm⁻¹ absorption bands were attributed to oxidation, dehydration and depolymerization as well as volatization of the fiber components. These phenomena were also attributed to in the TGA, and in addition the TGA showed increased thermal stability of the heat treated coir fibers with reference to the untreated counterparts which was most probably due to increased recrystallization and cross linking. The microstructural features including microcracks, micropores, collapsed microfibrils and sort of cooled molten liquid observed on the surface of heat treated coir fibers from the scanning electron microscope (SEM) could not directly be linked to the effect of temperature and durations of heating although such features may have largely account for the lower tensile properties of heat treated coir fibers with reference to untreated ones.     

Effect of color changes of naturally colored organic cotton fibers on human sensory perception

This study aims to investigate the color changes of Naturally Colored Organic Cotton (NaCOC) fibers after scouring, and to evaluate the human sensory perception for the fibers. Furthermore, it tries to observe the relationship between the color coordinates and the sensory perception. Three colors (ivory, coyote-brown, green) of NaCOC fibers were scoured under four different treatments (boiling water, enzyme, sodium carbonate, sodium hydroxide). The color coordinates (L, a, b) were measured in CIELAB using spectrophotometer (SP62, X-Rite), and color differences (ΔL, Δa, Δb, ΔE) were calculated. Human sensory perception for the NaCOCs was evaluated by 27 female participants. The questionnaire consisted of nine pairs of bipolar visual sensory adjectives using the SDS. The values of L and b fell, while the value of a arose after scouring in general. The value of ΔE was the highest when treated with alkali solutions among all treatments. Human sensory perception such as brightness, clearness, lightness and freshness generally decreased, while vividness and strength increased. The meaningful color factors to predict brightness, lightness were L and ΔL, and those to predict vividness and strength sensory were ΔL.     

Application of analytic hierarchy process for the selection of cotton fibers

In many engineering applications, the final decision is based on the evaluation of a number of alternatives in terms of a number of criteria. This problem may become very intricate when the selection criteria are expressed in terms of different units or the pertinent data are difficult to be quantified. The Analytic Hierarchy Process (AHP) is an effective way in dealing with such kind of complicated problems. Cotton fiber is selected or graded, in the spinning industries, based on several quality criteria. However, the existing selection or grading method based on Fiber quality Index (FqI) is rather crude and ambiguous. This paper presents a novel approach of cotton fiber selection using the AHP methodology of Multi Criteria Decision Making.     

Cutinase treatment of cotton fabrics

Our study proposes an enzymatic scouring method for cotton fabrics using the enzyme cutinase. We established cutinase treatment conditions for cotton fabrics from their relative activity at different pH levels, temperatures, enzyme concentrations, and treatment times. Weight loss, moisture regain, K/S value, tensile strength, and SEM micrographs of cotton fabrics were analyzed. We determined the optimum cutinase treatment conditions to be as follows: pH of 9.0, temperature of 50°C, cutinase concentration of 100 %, and a treatment duration time of 60 min. We discovered that this cutinase treatment hydrolyzed the cuticle of cotton fabrics. The cutinase treatment did not decrease the moisture regain and the K/S value. The optimum concentrations of Triton X-100 and calcium chloride, which were used as auxiliaries for cutinase treatment, were found to be 0.5 % (v/v) and 70 mM, respectively. Some cracks were observed on the surface of the cotton fibers; however, the tensile strength did not decrease.     

Influence of chitosan on the effects of proteases on wool fibers

Textile processes generally produce a large amount of wastewater and cause a negative environmental impact. The use of proteases in wool finishing could be an appropriate alternative to classical finishing methods. However, the enzymatic treatment could cause excessive fiber damage. The application of biopolymer chitosan on wool fabrics prior to proteases treatment in attempt to overcome the damage promoted by the enzymes has been studied. The treatments based on chitosan application followed by enzymatic treatment reduce felting shrinkage, enhance whiteness degree, and improve dyeability of wool. Moreover, it plays an important role in minimizing the wool fiber damage.     

Waste cotton fibers based activated carbon: Optimization of process and product characterization

Waste cotton fibers were used to produce activated carbon fiber (ACF) via chemical activation method with phosphoric acid. The effect of different operational parameters on the adsorption capacity and yield of activated carbon fibers was studied by Taguchi experimental design. Optimized conditions were: Activation temperature of 450 °C, activation time of 0.5 h, impregnation ratio of 2, and the rate of temperature rising of 10 °C min^?1. The activated carbon fiber produced under optimized conditions was characterized by pore structure analysis, scanning electron microscopy (SEM), X-ray energy-dispersion spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction analysis (XRD). The obtained results showed that the produced activated carbon has developed porous structure, fibrous shape, predominantly amorphous structure, large number of oxygen functional groups, and acidic nature.     

新疆机采棉加工工艺对棉花质量的影响

为了研究新疆机采棉加工工艺在清理杂质的同时对棉花品质的影响,围绕典型的新疆机采棉加工工艺,从4道籽棉清理前后、轧花前后、3道皮棉清理前后等环节取样、测试,探讨棉花品质指标(含杂率、上半部平均长度、长度整齐度指数、断裂比强度)在新疆机采棉加工过程中的变化规律,分析含杂率与棉纤维上半部平均长度、长度整齐度指数、断裂比强度之...     

Water and oil-repellent coatings of perfluoro-polyacrylate resins on cotton fibers: UV curing in comparison with thermal polymerization

UV curing of perfluoro-alkyl-polyacrylate resins able to impart water as well as oil-repellency to cotton fabrics was studied in comparison with conventional thermal polymerization. The process was assessed through weight gain and gel content measurements while the properties conferred to cotton fabrics were determined in terms of water and oil contact angles, moisture adsorption, and water vapor permeability. The polymerization yields were of the same order (>80 %) of those obtained with thermal curing as well as the high contact angles with water (>127°) and oil (>118°) even at low resin add-on (3 %). UV cured resins yielded oil contact angles mostly higher than 120° denoting super oil-repellent surfaces. Moreover the water and oil-repellency was adequately maintained after washing. The moisture adsorption of finished fabrics was lower than that of untreated cotton, but slightly higher for UV cured than thermally treated fabrics. Water vapor transmission rate showed that the finish treatment, thermal as well as by UV curing, does not reduce the breathability of the original cotton. DSC analysis demonstrated that the fiber pyrolysis is affected by the polymer add-on, while FTIR-ATR spectra of all finished fabrics showed typical peaks of ester and C-F groups. XPS analysis showed small differences between thermal and UV curing coatings with each resin, while coatings with the lowest percentage of fluorine groups did not affect the water and oil-repellency.