Investigation of inter fiber cohesion in yarns. I. Influence of certain spinning parameters on the cohesion in cotton yarns

This paper investigates the influence of raw material and process parameters in spinning that affect the inter fiber cohesion in yarns. An instrument has been developed for measuring the minimum twist of cohesion. With regard to the raw material parameters, the influence of different cotton fiber mixings for a given count of yarn is investigated. Also the effect of spinning to varying counts for a given cotton variety is studied. With regard to the process parameters, studies have been carried out to investigate the influence of noil extraction in comber, number of draw frame passages, draft pressure in ring frame and direction of twist. Cohesion improved with increase in the noil extraction percentage in the comber. Increase in the number of draw frame passages also improved the cohesion. Draft pressure in ring frame improved the fiber cohesion in yarn up to a pressure of 2.1 kg/cm². Direction of twist had no effect on the cohesion.     

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.     

Comparative study on the characteristics of knitted fabrics made of vortex-spun viscose yarns

Murata vortex spinning system is based on the air jet spinning system. The vast majority of previous works deal with the properties of vortex spun (VS) yarn and the spinning system. In this study, we investigated knitted fabrics from VS yarn in comparison with fabrics from ring (RS), compact (CS) and open-end rotor (OES) spun yarns made from viscose. The effect of yarn spinning system on dimensional and physical properties of knitted fabrics was explained with specific attention to fabrics from VS yarn. Shrinkage of fabrics from VS yarn has the lowest at widthwise direction, while having the highest at lengthwise direction. It is shown that the order of fabric spirality and twist liveliness for yarns from different spinning systems are quite similar. However, relation between loop shape factor and angle of spirality is inconsistent. Angle of spirality of fabrics from VS yarn is higher than fabrics from OES yarn, but lower than that of others. The bursting strength of fabrics from VS yarn is lower than that of those from RS and CS yarns and higher than that of those from OES yarn. From this study, it is also evident that fabrics from VS yarn have the lowest pilling tendency and highest resistance to abrasion.     

Investigation on the physical and structural properties of melt-spun multifilament yarns,drawn yarns and textured yarns produced from blend of PP and oxidized PP

In the present study, effect of OPP (oxidized PP) fraction on the mechanical and structural properties of produced fibers is investigated. Polypropylene powder without antioxidant materials was oxidized at the suitable thermal condition. The various fractions of OPP were blended with PP in the chips shape, and employed as starting material in a melt spinning machine for production of filament yarn. Then as-spun filaments were drawn and finally textured. Structural properties including density, birefringence and FTIR and physical properties consisting of shrinkage, tensile properties and crimp properties were measured. Results show that blending of OPP with virgin PP reduces tacticity and crystallinity, but it hasn’t any effect on orientation. Physical properties of drawn yarns and textured yarns were reduced with increasing of OPP fraction. Moreover, increasing of OPP fraction in blend, reduce crimp properties of textured yarn.     

Effect of blends proportion on the characteristics of dry and Pre-wet nylon/viscose blended air-jet textured yarns

Blending of nylon filament with viscose can overcome the drawbacks of these yarns. Thermoplastic and thermoset filament yarns can be blended in air-jet texturising method. The characteristics of nylon/viscose blended filament yarns are required to be understood in order to convert them in to useful products. Therefore, nylon/viscose blended yarns in different proportions were produced using nylon 6 and viscose filament yarns in air jet texturising machine. The textured yarns were also produced in dry and pre-wet conditions to understand the effect of water on textured yarn characteristics. It was found that the loops frequency, bulkiness of nylon/viscose blended textured yarns increase with increase in viscose proportion. The Loops stability, tenacity and breaking elongation decrease with increase in viscose proportion. Pre-wet textured yarn show higher loops, bulkiness, and good loop stability than their corresponding dry textured yarns.     

The effect of blend ratio and process parameters on tensile properties of polyester/viscose blended needle-punched nonwovens

In this study, the tensile strength and elongation of polyester/viscose blended needle-punched nonwovens were analyzed. For this purpose, five different blend ratios of polyester/viscose webs were produced, cross-lapped and needled in four different mass per unit areas and three different needling/punching densities. The tensile properties of the nonwovens were determined by performing the standard test methods and the data obtained from tests were statistically analyzed in Design Expert software. In addition, a mixture process crossed regression model with two mixture components (polyester and viscose blend ratios) and two process variables (fabric mass per unit area and needling density) was developed to analyze the tensile strength and elongation of polyester/viscose blended needled nonwovens. In conclusion, the regression model indicated that the tensile strength of the needle-punched nonwovens decreases with the increase of polyester proportion in the mixture and increases with the increase in mass per unit area and punching density.     

Influence of deposition parameters and kinetics of electroless Ni-P plating on polyester fiber

The electroless nickel-phosphorous (Ni-P) plating on polyester fiber using sodium hypophosphite as a reducing agent in alkaline medium was studied. The effects of plating parameters including concentrations, pH and bath temperature of the plating bath on deposition rate of the electroless Ni-P plating were investigated. The results reveal that the deposition rates increase with the increase in the concentration of nickel sulfate, sodium hypophosphite, pH and bath temperature, respectively. However, it is determined that the deposition rates decrease with the rise of sodium citrate. The kinetics of the deposition reaction was investigated and an empirical rate equation for electroless Ni-P plating on polyester fiber was developed.     

A comparative study on performance properties of yarns and knitted fabrics made of biodegradable and conventional fibers

Biodegradable products are parts of a natural cycle. The biopolymers and the fibers that can be produced from them are very attractive on the market because of the positive human perception. Therefore, PLA being a well known biodegradable fiber and some conventional fibers were selected for the current study to examine the differences between them and to emphasize the importance of biodegradability beside fabric performance. 14.8 tex (Ne 40/1) combed ring spun yarns produced from biodegradable fiber PLA, new generation regenerated fibers Modal and Tencel, synthetic and blends 50/ 50 % cotton/polyester and 50/50 % viscose/polyester, polyester were selected as yarn types and by using these yarns, six knitted fabrics were produced and some important yarn and fabric properties were compared. In this context, moisture and the tensile behavior of yarns and pilling, bursting strength, air permeability and moisture management properties of the test fabrics are discussed.     

Comparative study on the effect of blend ratio on tensile properties of ring and rotor cotton-polyester blended yarns using concept of the hybrid effect

Study on the characteristics of blended ring and rotor spun yarns is a topic of major interest to the researchers. The overall properties of these blended yarns are affected by the relative proportion, properties of the components and their interactions. The main focus of this work is on comparing and analyzing effects of blend ratio on tensile properties of the yarns produced in different spinning systems using concept of hybrid effects that has not received enough attention from researchers. Various blends of cotton-polyester ring and rotor spun yarns were prepared. Tensile properties of the samples were examined as well. Interactions between cotton and polyester fibers was evaluated through predicting strength and elongation at break of the yarns using simple rule of mixtures (ROM) and hybrid model. Experimental results showed that, the effect of different blend ratios on tensile properties of the samples is different. In comparison with 100 % cotton yarn, promotion in braking strength of the ring and rotor spun samples occurred after increasing fraction of the polyester fiber to 50 and 66.5 % respectively. The prominent finding of the present work is that the trend of change in tensile properties of different yarns versus blend ratio is predictable via hybrid model and migration behavior of the constituent fibers. Coefficients representing the intensity of the interaction and migration index of the fibers were calculated and all results were discussed based on these calculated factors.     

The mechanism and/or prediction of the breaking elongation of polyester/viscose blended open-end rotor spun yarns

In this study, an analysis on the breaking elongation mechanism of the polyester/viscose blended open-end rotor spun yarns has been carried out. In addition, a back propagation multi layer perceptron (MLP) network and a mixture process crossed regression model with two mixture components (polyester and viscose blend ratios) and two process variables (yarn count and rotor speed) are developed to predict the breaking elongation of polyester/viscose blended open-end rotor spun yarns. Seven different blend ratios of polyester/viscose slivers are produced and these slivers are manufactured with four different rotor speed and four different yarn counts in rotor spinning machine. In conclusion, ANN and statistical model both have given satisfactory predictions; however, the predictions of ANN gave relatively more reliable results than those of statistical models. Since the prediction capacity of statistical models is also obtained as satisfactory, it can also be used for breaking elongation (%) prediction of yarns because of its simplicity and non-complex structure. In addition, it is also found in this study that yarn count, rotor speed and breaking elongation of polyester-viscose fibers and the blend ratios of these fibers in the yarn have major effects on yarn breaking elongation.     

Processing parameters optimization of multiple quality characteristics of open-end rotor spinning process for Bamboo charcoal and CVC blended fibers

In the field of yarn spinning engineering, the importance of the processing parameters taken depends directly on the quality characteristics of the yarn. This study aimed to find the optimal processing parameters for an open-end rotor spinning frame at work to identify its multiple quality characteristics for yarn. In this study, Bamboo charcoal and cotton 70 %/polyester 30 % (CVC) blended fibers were adopted as the materials, and the open-end rotor spinning frame was used to spin the yarn. In order to identify optimal conditions of an open-end rotor spinning frame, the Taguchi experimental method was applied to design open-end rotor spinning experiments, and the L₉ orthogonal array was chosen in accordance with nine sets of experiments and contained four control factors and three levels. Furthermore, a response surface methodology (RSM) was used to obtain the models of significant processing parameters for the strength, unevenness, I.P.I, and hairiness. Based on experiments designed to obtain an open-end rotor spun yarn Ne 30, the strength, unevenness, imperfection indicator/km (I.P.I) and hairiness were then chosen as the quality characteristics. In addition, grey relational analysis integrated the optimal processing parameter of multiple quality characteristics, and a confirmation experiment was performed. In conclusion, the optimal processing parameters under steady spinning conditions were a rotor speed of 88000 rpm, a feed speed of 0.392 m/min, and a winding speed of 39.466 m/min.     

Predicting the unevenness of polyester/viscose blended open-end rotor spun yarns using artificial neural network and statistical models

In this study, an artificial neural network (ANN) and a statistical model are developed to predict the unevenness of polyester/viscose blended open-end rotor spun yarns. Seven different blend ratios of polyester/viscose slivers are produced and these slivers are manufactured with four different rotor speed and four different yarn counts in rotor spinning machine. A back propagation multi layer perceptron (MLP) network and a mixture process crossed regression model (simplex lattice design) with two mixture components (polyester and viscose blend ratios) and two process variables (yarn count and rotor speed) are developed to predict the unevenness of polyester/viscose blended open-end rotor spun yarns. Both ANN and simplex lattice design have given satisfactory predictions, however, the predictions of statistical models gave more reliable results than ANN.     

Mechanical properties of composites made from locally manufactured carbon fabrics and the composites produced from air-textured glass yarns

Composite materials have a wide range of applications in structural components because of their high strength-to-weight and stiffness-to-weight ratios. However, the most crucial and common life-restricting crack growth mode in laminated composites i.e. delamination is of great concern. Air jet texturing was selected to provide a small amount of bulk to the glass yarn. The purpose was to provide more surface contact between the fibres and resin and also to increase the adhesion between the neighbouring layers. These were expected to enhance the resistance to delamination in the woven glass composites. The development and characterisation of core-and-effect textured glass yarns was presented in the previous paper. This paper describes the comparison of the mechanical properties of composites produced from air-textured glass yarns and the composites made from locally manufactured carbon fabrics. The tensile, flexure and inter-laminar shear strength (ILSS) were compared and it was observed that although glass fibres are inferior to carbon fibres in terms of mechanical properties however, the flexure strength and ILSS of glass based composites increases after texturing and were found closer to the properties of carbon based composites.     

Durum wheat quality in Mediterranean environments: II. Influence of climatic variables and relationships between quality parameters

A total of 10 field experiments were carried out during the 1998 and 1999 growing seasons both in the north (Lleida) and the south (Granada and Jerez) of Spain. In Lleida and Granada, the experiments were conducted under both irrigated and rainfed conditions, while the Jerez trials were carried out only under rainfed conditions. Ten durum wheat genotypes were used in this study. Quality determinations consisted of 1000-kernel weight (TKW), test weight, vitreousness, ash content, protein content, pigment content and SDS sedimentation test. The influence of environment was predominant in determining the majority of quality traits, although pigment content and SDS volume were also genetically controlled. Environmental effects, studied by the mean of the climatic patterns influencing each trial, showed that total water input during grain filling appears to negatively affect grain quality by reducing test weight, grain vitreousness, and SDS volume, and by increasing ash content. High seasonal temperatures increased pigment content in the grain, but reduced TKW. From the correlations between quality parameters, an inverse and interesting relationship was found between protein content and SDS volume. Relationships between quality traits appear to be influenced to a certain extent by climatic conditions during grain filling and, depending on temperatures and water input during this phase, correlation coefficients can be either positive, negative or close to zero.     

Theoretical study on the bending rigidity of filament yarns with an elliptical cross-section using energy method. II. Numerical evaluation

This is the second part of a series of work investigating on the bending rigidity of filament yarn with an elliptical cross-section. In the present paper, the quantitative error analysis of the earlier simplification of a circular cylindrical of yarn geometry under deformation is evaluated, and the effects of filament properties on yarn bending rigidity are also evaluated. It is highly useful in preciously predicting yarn bending property from filament behaviors for virtual processing of textile materials. So the explicit formula derived in the Part I of this series for the elliptical cylindrical of yarn geometry is used to compute the quantitative error of the earlier model. The four characters, including the eccentricity of elliptical cross-section of yarn, the ratio of bending to torsional rigidity of filament, the helix angle of filament on yarn surface and the number of filaments inside the yarn, are adopted to quantify the bending rigidity relationship between the filaments and yarn. Based on the analytical method, the earlier method in which the circle shape takes place of the elliptical shape of yarn cross-section for simplification is evaluated. The simulation results show that the relative error of the circle assumption is not higher than 10 % when the eccentricity of yarn cross-section is lower than 0.8. However if the eccentricity is higher than 0.8 and the helix angle is larger than 30 degrees, it is suggested to conduct the deformation analysis based on the elliptical cross-section of yarn.     

Dimensional stability of single jersey fabrics of lincLITE® and conventional yarns. II. Fabric dimensional changes

Dimensional changes of single jersey fabrics made from LincLITE® and conventional yarns (39 tex and 48 tex) with different twist factors and fabric tightness factors are investigated under dry-, steam- and full- relaxation treatments. Results showed that linear and area shrinkages, fabric density and stitch density values were affected by tightness factors, relaxation treatment, yarn twist and feeder blending. Generally, higher length shrinkages and width increases were reported with LincLITE® and conventional fabrics. Tightness factors and twist factors significantly affected LincLITE® and insignificantly affected conventional fabrics in concern of change of shape and area shrinkages. Thus, fabric density values and reciprocal of stitch lengths showed linear correlations with intercepts, which decreased on full relaxation. Also, it showed higher regression correlation coefficient factors from LincLITE® and conventional fabrics.     

Influence of process parameters on yield and composition of gluten fractions obtained in a laboratory scale dough batter procedure

The influence of process parameters during the dough formation step on wheat flour gluten agglomeration and composition in a laboratory scale gluten–starch separation process was studied. In the process, in which a dough was transformed into a batter then poured over a set of vibrating sieves (400, 250 and 125 μm), increasing water contents, mixing times and speeds during dough development all had a positive effect on gluten agglomeration as indicated by an increased gluten protein recovery on the 400 μm sieve. This showed the importance of optimal gluten hydration and development at the dough making stage of the process. The total level of gluten recovered on the three sieves was not affected significantly by the variables. Changes in gluten agglomeration behaviour coincided with changes in the carbohydrate composition of the gluten fractions. When the gluten protein recovery on the 400 μm sieve increased, the arabinose and xylose contents of the fractions decreased, while the starch content increased.     

Effect of weaving process on tensile characterization of single and multiple ends of air-entangled textured polyester yarns

The tensile properties of air-entangled textured polyester single and multiple yarn ends before and after weaving were analyzed. The effects of weaving process considering fabric unit cell interlacement and number of yarn ends were evaluated by regression model. For this purpose, plain, ribs and satin woven fabrics were produced. The yarns were raveled from fabrics, and the tensile tests were applied to these yarns. The developed regression model showed that the number of interlacement and crimp ratio on the warp and weft yarns influence their tensile strength. Tensile strength of raveled yarns decreased compared to that of the bobbin yarn due to the effect of weaving process. This property degradation on the ravel yarns considered process degradation. Generally, when the number of warp and weft yarn ends increases, the warp and weft yarn tensile strengths for each fabric type decrease, whereas the warp and weft yarn tensile elongations slightly increase. The results from regression model were compared with the measured values. This study confirmed that the method in the study can be a viable and reliable tool. The research finding could be useful those who work on preform fabrication.     

Effects of material parameters and process conditions on the roll-drafting dynamics

Roll drafting, a mechanical operation attenuating fiber bundles to an appropriate thickness, is an important operation unit for manufacturing staple yarns. It influences not only the linear density regularity of the slivers or staple yarns that are produced, but also the quality of the textile product and the efficiency of the thereafter processes. In this research, the dynamic states of the fiber bundle in the roll drafting zone were analyzed by simulation, based on the mathematical model that describes the dynamic behavior of the flowing bundle. The state variables are the linear density and velocity of the fiber bundles and we simulated the dynamics states of the bundle flow, e.g., the profiles of the linear density and velocity in the draft zone for various values of the model parameters and boundary conditions, including the initial conditions to obtain their influence on the dynamic state. Results showed that the mean velocity profile of the fiber bundle was strongly influenced by draft ratio and process speed, while the input sliver linear density has hardly affected the process dynamics. Velocity variance of individual fibers that could be supposed to be a disturbing factor in drafting was also influenced by the process speed. But the major disturbance occurred due to the velocity slope discontinuity at the front roll, which was strongly influenced by the process speed. Thickness of input sliver didn’t play any important role in the process dynamics.