Objective pilling evaluation of nonwoven fabrics

A pilled nonwoven fabric image consists of brightness variations caused by high frequency noise, randomly distributed fibers, fuzz and pills, fabric surface unevenness, and background illumination variance. They have different frequency and space distributions and thus can be separated by the two-dimensional dual-tree complex wavelet transform reconstructed detail and approximation images. The energies of the six direction detail sub-images, which capture brightness variation caused by fuzz and pills of different sizes, quantitatively characterize the pilling volume distribution at different directions and scales. They are used as pilling features and inputs of neural network supervised classifier. The initial results based on a nonwoven wool fabric standard pilling test image set, the Woolmark®, SM 50 Blanket set, suggest that this objective pilling evaluation method developed by the combination of pilling identification, characterization method and neural network supervised classifier is feasible.     

Optimization of the needle punching process for the nonwoven fabrics with multiple quality characteristics by grey-based taguchi method

This study is intended for finding out the optimal processing parameters for needle punching nonwoven fabrics in order to work out its maximal strength. Taguchi method together with grey relational analysis is employed to resolve the problem as regards multiple-quality optimization, and further discover the optimal combination of processing parameters for needle punching nonwoven fabrics. Firstly, orthogonal array L₁₈(2¹×3⁷) is used to deal with the processing parameters that may exert influence over the manufacturing of needle punching nonwoven fabrics. Then grey relational analysis is applied to resolve the deficiency of Taguchi method that focus on single quality characteristic. Next, the response table of grey relational analysis is used to obtain the optimal combination of processing parameters for multiple quality characteristics. In the current experiment quality characteristic refers to the tensile strength and tear strength of the nonwoven fabrics. Additionally, signal-to-noise ratio (SN ratio) calculation and analysis of variance (ANOVA) can be adopted to explore the experimental results. Through ANOVA, the significant factors that exert comparatively significant influence over the quality characteristic of the needle punching nonwoven fabrics, that is, the control factors are determined so that the quality characteristic of the needle punching nonwoven fabrics can be effectively controlled. Finally, confirmation experiment is conducted within 95 % confidence interval to verify the experimental reliability and reproducibility.     

Compressional fatigue behaviors of air and mechanical folding nonwoven fabrics

The perpendicular-laid nonwoven fabrics may show high loft performance because of the structure composition, which has much fiber oriented in the thickness direction. The ability to maintain the thickness after the cyclic loading is a basic requirement of good high lofts. When the perpendicular-laid nonwoven fabrics are put to practical use as a cushion material, the compressional properties of the cyclic loading should be significant. In this study, a compressional fatigue system has been developed and evaluated with two kinds of perpendicular-laid nonwoven fabrics with different manufacturing processes. The system equation developed provides a stress profile that can be used for analyzing the practical compressional fatigue. The fiber structure of the perpendicular-laid nonwoven fabrics was investigated by using the orientation distribution function (ODF).     

Drape behaviour of seamed fabrics

Clothe drape depends, on the one hand, on the mechanical and constructional properties of the textile materials and, on the other hand, on the form — construction of the cloth, and their connected positions at the seams. This article analyses the influence of seam types and directions on fabric drape. The drape coefficient together with the number and distribution of folds were determined using a Cusick Drape meter with a video camera and Drape Analyser. The results of our investigation showed that the number of folds on the samples with seams was greater, or in some cases, equal to samples without seams. The distribution and form of the folds also changed. Drape coefficient was, in most cases, greater on samples with seams than samples without seams. Furthermore it was discovered that by measurement repetition the angle values are similar even when the folds on the samples are not distributed in the same manner.     

An investigation in structural parameters of needle-punched nonwoven fabrics on their thermal insulation property

The thermal characteristics of hollow polyester fibers were compared with solid polyester fibers in order to study their processing behavior and performance characteristics. The effects of different processing and structural properties including fiber diameter, bulk density of layer, and surface pressure on layers of needle-punched nonwoven fabrics with hollow fibers on thermal resistance properties were also investigated. The results show that hollow fibers have a higher thermal resistance in comparison with solid ones. This is a consequence of air trapping inside the fibers, higher bulkiness, and higher surface area of hollow fibers. Furthermore, thermal resistance of microfibers is better than those of macrofibers in both hollow and solid fibers. The thermal resistance of nonwoven subjected to this study, have an inverted-U-shaped pattern versus the bulk density of the fabric. The results also showed that thermal resistance of needle-punched nonwoven fabrics can be affected by the range of heater temperature during the test, however considerably can be affected by fabric thickness as a main structural property of nonwoven fabrics.     

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.     

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.     

Effect of polypropylene fiber cross sectional shapes on some structural/mechanical fiber properties and compressibility behaviour of plain knitted fabrics

Synthetic fibers are generally produced with circular cross sectional shapes. Other cross sectional shaped fibers such as trilobal, triangular, hollow and pentagonal fibers are also produced to improve some properties of fibers and fabrics such as lustre, handle, wicking rate, strength, stiffness and bulkiness. In this research we aimed to investigate compressional behaviours of fabrics knitted from polypropylene fibers having three different cross sectional shapes; namely circular, trilobal and triangular. Morphological, structural and mechanical properties of produced fibers were evaluated by using scanning electron microscopy, X-ray diffractometry, differential scanning calorimetry and tensile tester, respectively. In terms of structural and mechanical properties, no significant differences were found related to fiber cross sectional shapes. Then, plain knitted farbrics were produced and compressional properties of these fabrics were investigated. Fabrics knitted from trilobal fibers showed the highest compressibility properties and it is followed by fabrics which are produced from triangular and circular fibers.     

Effect of weight and apllied force on the friction coefficient of the spunlace nonwoven fabrics

Friction force that can be defined as the forces resisting relative to the movement between two surfaces contacting with each other plays an important role in textile industry. During usage, the fabrics continue to friction to the textile or the other surfaces and because of this problem fabric surface structure deteriorates. Therefore, most of the scientists have been designed different methods in order to estimate surface properties and friction of fabric before their usage. In this study, friction experiments have been performed by designed and manufactured two different systems which work as a horizontal platform and inclined plane. It has tried to investigate friction properties of polyester nonwoven fabric samples which are produced by spunlace methods (air laid and spunlace bonding) with different weights. While the selected fabric samples weight increase, it has been seen that a low friction force occurred because of more stable structure. And also, it has been observed that the higher vertical force (load) applied on the specimens the lower the coefficient of friction. These results shows that both measurement methods have similar tendencies based on the analyzed results.     

Dyeing properties of the disperse dyes containing cyano group based on benzisothiazole for polyester fabrics under alkali condition

One step dyeing of polyethylene terephthalate (PET) fabrics combining pretreatment and dyeing under the alkali condition was developed for cleaner production. One step dyeing of PET fabrics required that the dye used has good acid and alkali stability. In this paper, dyeing properties of three azo disperse dyes containing cyano group based on benzisothiazole, 3- (4-N-ethoxyl-N-cyanoethyl -phenyldiazenyl)-5-nitro-2,1-benzisothiazole (D1), 3-(4-N-ethyl-N-cyanoethyl- phenyldiazenyl)- 5-nitro-2,1-benzisothiazole (D2), and 3-(N-benzyl-N-cyanoethyl- phenyldiazenyl)-5-nitro-2,1-benzisothiazole (D3), were investigated under alkali condition. The results showed that polyester fabrics could be well dyed with D1, D2 and D3 under the acid condition. However, D1 was decomposed while dyeing at the alkali solution. D2 and D3 had excellent color yields under the alkali condition. The acid-alkali stability and the structure change were analyzed by UV-vis spectrum and high pressure liquid chromatography (HPLC). Gaussian 09 program package was used to optimize geometry by B3LYP method and 6-31G (d) basis set. The solvation energy of D1 in water was higher than those of D2 and D3. The electron withdrawn effect of the hydroxyl affected the energy gap of HOMO and LUMO orbits. D2 and D3 showed excellent stability in the strong alkali medium. And the dyed polyester fabrics with D2 and D3 at the alkali condition also had good fastness properties.     

Fabrication of novel multifunctional hybrid materials for PET/PA6 nonwoven fabrics finishing

A series of some novel hybrid materials prepared via a sol-gel process have been synthesized from methyltrimethoxysilane and titanium n-butoxide with heterocyclic thiazole azo dyes. Silica/titania/thiazole azo dyes hybrid materials were synthesized via a sol-gel process with a precursor system. Alternatively, the heterocyclic thiazole azo dyes were catalytically processed by means of hydrolysis-condensation reactions with appropriate amounts of a mixture of vinyltriethoxysilane, methyltrimethoxysilane, and titanium n-butoxide at a fixed molar ratio. The structure of these hybrid silica/titania/thiazole dye materials was characterized by Fourier transform infrared (FT-IR) analysis. The surface morphology of processed PET/PA6 nonwoven fabrics was evaluated by scanning electron microscopy (SEM). SEM images showed uniform dyeing, thereby confirming the reaction of the hybrid materials with the PET/PA6 nonwoven fabrics. The water contact angle, washing fastness, color evenness, air permeability, and weatherability characteristics of the as-prepared dyed PET/PA6 nonwoven fabrics were subsequently evaluated. Results revealed improved weatherability and good water repellency. Further, it was also revealed that dyeing and finishing could be achieved in a single bath, which is advantageous to reduce processing costs.     

Prediction and interpretation of hydraulic permeability for nonwoven fabrics considering hypothetical 2-D layer

The permeability defined by Darcy’s law indicates the degree of ability that a fluid can flow through nonwoven media under a differential pressure in laminar flow. The permeability generally indicates the specific permeability or absolute permeability. On the other hand, if the fluid is water, the permeability indicates the hydraulic conductivity or permeability coefficient. The permeability is one of the important properties for nonwoven media and a prediction of the permeability acts as a bridge between the manufacturing technology and performance requirements. Because capillary channel theory aims to make the flow of fluid easier and more understandable, many models are based on capillary channel theory. On the other hand, the theory has a limitation in that it is unsuitable for high porosity media. In this study, a very thin downstream layer, which was suggested by Lifshutz [9], was introduced to derive a prediction model of hydraulic permeability. Needle-punched and spunbonded nonwoven fabrics with various basis weights were used in the cross-plain water permeability test. From this ‘thin layer’ model, reasonable agreement between the predicted and experimental results was obtained.     

Continuous photografting of HEMA onto polypropylene fabrics with benzophenone Photoinitiator

Continuous photografting onto polypropylene fabrics in the absence of inert gases was carried out to improve hydrophilic property of PP fabrics, which was padded with a formulated solution of 2-hydroxyethyl methacrylate(HEMA) and benzophenone as a monomer and a photoinitiator, respectively. The grafting yield increased with increases in benzophenone concentration up to 30 % on the weight of the monomer and UV energy up to of 38 J/cm², while 30 % HEMA concentration was optimal for the grafting efficiency. The physicochemical properties of the grafted PP fabrics were monitored by FT-IR, SEM, zeta potential, and dyeability to a cationic dye. The grafting increased O_1s/C_1s content and remarkably produced more negative zeta potentials compared with the pristine PP fabric. Also the grafted PP showed the increased dyeability to cationic dyes with increasing graft yield resulting from the enhanced electrostatic interaction between the dyes and negatively charged surface of the grafted PP fiber. In addition, improved hydrophilic property of grafted PP fabrics was ascertained by more rapid water wetting time and higher water absorbency.     

Influence of the CF4 plasma treatments on the wettability of polypropylene fabrics

A plasma treatment using saturated CF₄ gas was employed to improve the resistance of polypropylene fabrics to water wetting. The fabrics were significantly fluorinated even within a short treatment time of 30 seconds. The result of contact angle measurement indicated that such highly hydrophobic surface was considerably durable even after 150 days of aging.     

A study on the compression behavior of spacer fabrics designed for concrete applications

Spacer fabrics have been used in many areas varying from medical applications to protection applications. Especially the three dimensional characteristic of spacer fabrics presents different opportunities for special applications. The compression resistant characteristic of spacer fabrics is one of their main properties. In this research the compression behaviour of spacer fabrics designed for concrete applications has been investigated. The effects of some parameters such as spacer yarn material, pattern and threading on the compression behaviour of spacer fabrics have been studied. According to the test results it was found that the material, pattern and the threading of spacer yarns are important parameters for the compression characteristics of spacer fabrics. It was also observed that the location angle of spacer yarn and the amount of the spacer yarns influence the compression behaviour of spacer fabrics.     

Studies on composite filaments from nanoclay reinforced polypropylene

The development of high tenacity, high modulus monofilaments from Polypropylene/Clay nanocomposite has been investigated. Pure sodium montmorillonite nanoclay was modified using hexadecyl trimethyl ammonium bromide (HTAB) via an ion exchange reaction. Pure and modified clay were characterized through X-ray diffraction, FTIR and TGA. The modified clay was melt blended with polypropylene (PP) in presence of a swelling agent. Composite filaments from PP/Clay nanocomposite were prepared at different weight percentages of nanoclay and the spinning and drawing conditions were optimized. The filaments were characterized for their mechanical, morphological and thermal properties. The composite PP filaments with modified clay showed improved tensile strength, modulus and reduced elongation at break. The composite filaments with unmodified clay did not show any improvement in tensile strength but the modulus improved. The sharp and narrow X-ray diffraction peaks of PP/nanoclay composite filaments indicate increase in crystallinity in presence of modified clay at small loadings (0.5%). The improved thermal stability was observed in filaments with modified as well as unmodified clays.     

Static lateral compression of hemp/filament hybrid yarn knitted fabrics

The novel designed hemp/filament hybrid yarns were used to produce knitted fabrics in order to investigate the influence of the unique internal structure of hybrid yarns on compressional behavior of clothing textile materials. The knitted fabrics are subjected to successive compression-release cycles and the compression-release curves obtained made it possible to calculate the particular compression parameters such as recoverable and irrecoverable compression. By using the parameters the non-elastic deformation components (viscoelastic and plastic deformation) are determined. In spite of generally accepted fact that van Wyk’s theory has some limitations, since it does not explain the hysteresis caused by fiber slippage and friction effects, the two-parameter mechanical model derived from van Wyk’s compression theory is applied successfully to determine the compression hysteresis.     

On Line study of optical and structural behaviour of annealed as spun isotactic polypropylene fibres under creep Deformation

Double-arm of multiple- beam Fizeau system in transmission, attached with a modified creep device was used to investigate the opto-viscoelastic properties of isotactic polypropylene (iPP) fibres under different annealing conditions. The mean refractive index, birefringence, orientation, density and crystallinity were calculated for the annealed iPP fibres during creep deformation. Crystallinity behaviour was investigated during creep experiments at different annealing conditions which indicated a remarkable improvement in the properties of the investigated samples. The creep compliance curves were obtained at three different values of stresses for different annealing temperatures and different times of annealing. An empirical formula was suggested to describe the creep compliance curve of annealed iPP fibre and the constants of this formula were determined from the fitting parameters of the obtained creep curves. Kelvin chain was used to model the mechanical behaviour of iPP fibre under creep process. Illustrations using graphs and microinterferogrames are shown.     

A study of abrasion and frictional behaviour of nonwoven interlining produced with different coating methods

Interlinings are produced recently not only natural and synthetics fibers but also fiber sheet form in nonwoven production methods. During usage, the fabric wears out and because of this problem fabric surface structure deteriorates. As a result of, investigation of fabrics surface and frictional properties has been important before usage of garments. For this reason, a patented laboratory instrument was designed which is based on horizontal working principle of accessing friction coefficient of fibrous textile surfaces. The tested materials were nonwoven interlining materials produced by spunbond methods. Abrasion resistance of paste dot-CoPES nonwoven interlining material is lower than others because of softness handle. On the contrary, friction coefficients have been obtained higher values.