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.     

Moisture and thermal permeability of the hollow textured PET imbedded woven fabrics for high emotional garments

This study examined the effects of the total porosity, pore size, and cover factor on the moisture and thermal permeability of woven fabrics made from DTY (draw textured yarns) and ATY (air jet textured yarns) composite yarns with hollow PET (polyethylene terephthalate) yarns. The wicking of the hollow composite yarn fabrics was found to be superior to that of the high twisted yarn fabrics, which may be due to the high porosity in the hollow composites yarns, but this was not related to the cover factor. The drying characteristics of the hollow composite yarn fabric with high porosity were inferior compared to the high twisted yarn fabrics due to the large amounts of liquid water in the large pores, which resulted in a longer drying time of the fabric. The thermal conductivity of the hollow composite yarn fabrics decreased with increasing measured pore diameter due to the bulky yarn structure. The effects of the hollowness of the yarn on the thermal conductivity were more dominant than those of the yarn structural parameters. The air permeability increased with increasing measured pore diameter but the effects of the cover factor on the air permeability were not observed in the hollow composite yarn fabrics. The effects of porosity on the moisture and thermal permeability of the woven fabrics made from the hollow composite filaments were found to be critical, i.e., wicking and air permeability increase with increasing porosity. In addition, the drying rate increased with increasing porosity and the thermal conductivity decreased with increasing pore diameter, but were independent of the cover factor.     

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.     

Investigation of air permeability of core spun cotton/spandex weft knitted structures under relaxation

In this research work, air permeability variations of core spun cotton/spandex single jersey and 1×1 rib knitted structures were studied under relaxation treatments. Results are compared with similar fabrics made from 100 % cotton material. Even though cotton/spandex fabrics knitted with same stitch lengths, their structural spacing and stitch densities vary with the progression of treatments. Similar behavior was also observed with 100 % cotton knitted structures. Under higher machine set stitch lengths (i.e., lower fabric tightness factor), higher structural spacing and lower stitch densities were resulted and those variations significantly affected on the air permeability variations of knitted structures. 1×1 rib knitted structures showed significantly higher air permeability than single jersey structures and it is more prominent with cotton rib structures. However, cotton/spandex 1×1 rib and single jersey structures have not showed such significant deviations. Air permeability of cotton/spandex and 100 % cotton rib and single jersey knitted structures decreased with lower machine set stitch lengths (i.e., at higher fabric tightness factors). There was a correlation with fabric tightness, air permeability, areal density and fabric thickness such as knitted fabrics became tighter, their weight and thickness were higher, while their air permeability was lower. Thus, fabric areal density and fabric thickness are positively correlates to machine set stitch length^?1 (fabric tightness factor). Air permeability of a knitted structure depends on material type, knitted structure, stitch length, relaxation treatment, structural spacing and stitch density.     

Comfort and handle related properties of P/V blended air-jet textured yarn fabrics

The effect of blend percentage on comfort and handle related properties of fabrics made from polyester/viscose blended air-jet textured yarn weft were studied and the results were compared with fabrics made from polyester/viscose ring-spun yarn wefts of similar linear densities. It is observed that with increase in polyester content in the blend, the air permeability and water vapour permeability reduces whereas thermal resistance, transverse wicking and shear rigidity increases both in ring-spun yarn and textured yarn fabrics and bending rigidity increases in textured yarn fabrics. Textured yarn fabrics exhibit lower air permeability and extensibility, higher thermal resistance, relative water vapour permeability, transverse wicking values and bending rigidity as compared to the ring-spun yarn fabrics.     

Investigating the effect of various blend ratios of prepared masterbatch containing Ag/TiO2 nanocomposite on the properties of bioactive continuous filament yarns

In this research, possibility of producing and processing antibacterial organic/inorganic nanocomposite polypropylene filament yarns for permanent antimicrobial efficiency has been investigated. First PP powder and inorganic nanocomposite filler were mixed in a twin screw extruder and modified masterbatch was produced. Continuous filament yarn was made by a pilot plant melt spinning machine from the blend of PP granule and various blending contents of the prepared masterbatch. Pure PP and all other combined samples showed acceptable spinnability at the spinning temperature of 240 °C and take-up speed of 2000 m/min. After producing as-spun filament yarns, samples were drawn, textured and finally weft knitted. Physical and structural properties of as-spun and drawn yarns with constant and variable draw ratios were investigated and also tensile and crimp properties of textured yarns were evaluated. Moreover, the DSC, SEM, FTIR techniques have been used for characterization of samples. Finally antibacterial efficiency of knitted samples was evaluated. The experimental results indicated that the maximum crystallinity reduction of modified drawn yarns has reached to 5 %. The observed improvement in the tensile properties of modified as-spun yarns compared to the pure PP was significant. Drawing process improved generally the tensile properties of as-spun yarns. Tensile properties of modified textured and drawn yarns were higher than the pure PP. An optimum of antibacterial activity has been observed in the sample containing 0.75 wt% of nano-filler. It is interesting that the optimum of tensile properties has been also obtained for the sample with maximum bioactivity.     

Effect of ultrasonic laundering on thermophysiological properties of knitted fabrics

The paper focuses on the application of ultrasonic energy in textile laundering. In recent years, there has been an increasing interest in ultrasonic energy application in textile industry; however, the effect of ultrasonic laundering on the thermophysiological properties of knitted fabrics has not been studied yet. This study was conducted by using polylactic acid (PLA), cotton, polyethylene terephthalate (PET), and poly acrylic (PAC) fibres containing yarns and their blends. Knitted fabrics, single pique, were made from these yarns by using weft knitting machine. The fabrics were washed ten times for 15 and 60 minutes under 40 °C by using conventional and ultrasonic washing methods. The main aim was to determine the effect of washing methods on the thermophysiological properties of the fabrics. It is also aimed to analyse and evaluate the thermophysiological properties of the PLA fabrics. The incorporation of 100 % PLA and cotton/PLA yarns into single pique knitted fabrics has been attempted to produce for the first time and studied their thermal comfort properties. The results show that the washing processes have a critical importance for the tested fabrics in terms of thermal conductivity, thermal resistance, thermal absorbtivity, water vapour permeability, and heat loss. It has been also demonstrated that the fabric cleaning by using ultrasonic method enhanced the properties of tested fabrics such as thermal conductivity and % recovery. It was also noted that 15 minutes ultrasonically washed fabrics had significantly lower thermal resistance as compared to conventionally washed fabrics.     

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.     

Dimensional stability of cotton-spandex interlock structures under relaxation

In this study, dimensional characteristics of core spun cotton/spandex interlock structures with high, medium and low tightness factors were studied under dry-, wet-, and full relaxation conditions. Results are compared with those for similar fabrics knitted from 100 % cotton. Dimensional characteristics of samples of core-spun cotton/spandex and cotton are measured by considering the changing of course-, wale- densities and stitch densities under dry, wet and full relaxation conditions. Based on these data, dimensional constants (U-values) were predicted under 95 % significance level. Higher U-values are reported with cotton/spandex interlocks than 100 % cotton and under full relaxation, cotton/spandex shows the U-values with lesser CV%. Stitch density growth is linearly correlated with tightness factor for both interlock material structures. Excellent resiliency property of cotton/spandex yarns increases tightness factors at machine off state and during relaxation states. Cotton/spandex interlock structures show more prominent co-relationship with their tightness factors on their dimensional parameters.     

Developing an intelligent fiber migration simulator in spun yarns using a genetic fuzzy system

The mechanical and physical properties of spun yarns and fabrics depend not only on mechanical properties of the fibers making up the yarn, but also geometrical arrangement of fibers, known as fiber migration. The main aim of this research is to introduce a new approach to predict migratory behavior of spun yarns. Achieving the objectives of this research, general physical, mechanical and structural properties of spun yarns together with existing standards were thoroughly studied. A hybrid intelligent model was developed based on a Genetic Fuzzy System (GFS) to model the relationships between migration of fibers in spun yarns and some physical and mechanical properties of spun yarns. Results indicated that the developed fuzzy expert system can be used as an intelligent simulator to predict yarn migratory parameters.     

The effects of texturing induced microstructural changes on the relaxation behaviour of polyamide 66 multifilament yarns

Polyamide 66 multifilament yarns are textured in order to be endowed the properties of natural staple fibre yarns for textile applications. Texturing changes crystallinity, orientation and promotes the formation of stable secondary links between the macromolecular chains. Two polyamide yarns with the same linear density but composed of filaments of different fineness were textured by the air-jet and the false-twist procedures. The microstructural changes induced by texturing modify the relaxation behaviour of yarns. By the application of the Nutting’s power law which relates stress, strain and time, the influence of texturing and filament fineness on the relaxation behaviour of the yarns stretched form 15% to 25% was studied. Relationships between Nutting’s model parameters and crystallinity, orientation and stability of secondary crosslinks formed during texturing were also studied.     

The effect of the processing factors on the physical properties of high shrinkable nylon composite yarns

This paper is aiming to develop high shrinkable differential shrinkage and mixed fibre nylon composite yarns by applying the high shrinkable polyester manufacturing technology. The wet and dry thermal shrinkages and mechanical properties of developed nylon composite yarns are measured and discussed with processing factors in the spinning and texturing processes. And the effects of the processing factors on the physical properties of high shrinkable nylon composite yarns are investigated. For this purpose, twenty seven nylon 30d/12f SDY were prepared with variation of spinning temperature, 2nd godet roller temperature and draw ratio on the spinning machine. The optimum spinning condition which showed maximum wet thermal shrinkage and stress was determined and high shrinkable nylon 30d/12f SDY spun under this optimum condition used as a core and three kinds of regular nylon filaments used as sheath were processed on the texturing machine with variation of 1st and 2nd heater temperatures. The optimum texturing process condition was decided through analysis of dry thermal shrinkage of these core and sheath nylon filaments. Finally, high shrinkable differential shrinkage and mixed fibre nylon composite yarns were made under the optimum texturing condition on the texturing machine, its wet thermal shrinkage was 13.8 %, which was much more higher than that of regular nylon composite yarns. The differential shrinkage effect of the developed nylon composite yarns was found in the yarn surface and cross section profiles by microscope and SEM.     

Effect of various parameters on the chemical grafting of amide monomers to poly(lactic acid)

Radical melt graft copolymerizations of poly (lactic acid) (PLA) with amide monomers using benzoyl peroxide as an initiator during reactive extrusion is studied. The effects of two monomer types at various concentrations, reaction temperatures and initiator concentrations on the grafting yield are investigated. The results showed that percentage of grafting was significantly enhanced by increasing benzoyl peroxide concentrations up to 12 mpm and then decreased by an increase in the initiator concentration. Furthermore, increasing each monomer concentration up to 450 mpm, improved the grafting yield significantly. Further increase brings about a marked fall in the grafting yield. Fourier Transform Infrared Spectroscopy (FTIR), back titration and nitrogen analyses confirmed that monomers of acrylamide and methacrylamide were successfully grafted onto PLA. The Gel Permeation Chromatography (GPC) data showed that the molecular weight of the grafted PLA samples under optimum conditions does not show any dramatic drop of PLA molecular weight by thermal degradation or hydrolysis of polyester chains, while the polydispersity index is poorly affected by the chemical modification of PLA. Also, the monomer structures affected the grafting yield as well as polymer chain combination. In addition under the same conditions, the grafting yield of acrylamide was more than that of methacrylamide. Thermal properties, molecular weight, density, moisture regain and tensile properties of the samples were also measured.     

Enhanced mechanical performance of CNT/Polymer composite yarns by γ-irradiation

Multiwall carbon nanotube (CNT) spun yarns were subjected to γ-irradiation in an oxygen rich environment, followed by the application of epoxy to form CNT/epoxy composite yarns with a high CNT fraction. The method for fabrication of the CNT/polymer composite yarns was presented, and the effect of γ-irradiation on the mechanical performance of the pure CNT spun yarns and their epoxy composite yarns were studied. The γ-irradiated CNT yarns were also characterized by X-ray Photoelectron Spectroscopy and Raman spectroscopy. The results of this study have demonstrated that the γ-irradiation is an effective micro-engineering tool to improve mechanical properties of the CNT spun yarn and its epoxy composite yarn.     

Fabrication and characterization of dense Chitosan/polyvinyl-alcohol/poly-lactic-acid blend membranes

Dense membranes of Chitosan (CS)/Poly(vinyl alcohol) (PVA)/Poly(lactic acid) (PLA) blend were successfully fabricated using casting technique. The mechanical properties, moisture regain and water vapor permeability of polymer blend membranes were estimated by tensile test, moisture regain rate and dish method test respectively. The microstructures, morphology, chemical composition and thermal properties were also characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) respectively. Results indicated that there were interactions and good compatibility among CS, PLA and PVA. And the blend membranes have good breaking elongation and slightly decreased breaking strength, and show best moisture regain at the case of CS60 (the content of CS in the blends is 60 %). They also have excellent porous structure, which is beneficial to their air permeability and may also contribute to cell regeneration. With the adding of PVA content, the melting peaks of blend membranes reduce and gradually close to that of PVA, demonstrating that the regularity of CS molecular chain may be destroyed and hydrogen bonds of macromolecules in polymers were newly formed. As a result, solution blending of the three polymers could complement their disadvantages and significantly improve the membrane performance of a single polymer, thus promote the mechanical and biological properties of blend membrane.     

Evolution of moisture management behavior of high-wicking 3D warp knitted spacer fabrics

Moisture management behavior is a vital factor in evaluating thermal and physiological comfort of functional textiles. This research work studies functional 3 dimensional (3D) warp knitted spacer fabrics containing high-wicking materials characterized by their profiled cross section. These spacer fabrics can be used for protective vest to absorb a user’s sweat, to reduce the humidity and improve user’s thermal comfort. For this reason, different 3D warp knitted spacer fabrics were produced with functional fiber yarns in the back layer of the fabric (close to the body) and polyester in the front and middle layers (outer surface). Comfort properties such as air and water vapor permeability and wicking and other moisture management properties (MMP) of different fabric samples were measured. It is demonstrated that by using profiled fibers such as Coolmax fiber, moisture management properties of spacer fabrics can be improved, enabling them to be use as a snug-fitting shirt worn under protective vests with improved comfort.     

Comfort characteristics of fabrics made of compact yarns

Comfort is one of the most important aspects of clothing. Thermal comfort is related to fabric’s ability to maintain skin temperature and allow transfer of perspiration produced from the body. Properties like thermal resistance, air permeability, water vapor permeability, and liquid water permeability are suggested as critical for thermal comfort of clothed body. In this study the fabrics developed from the EliTe compact yarns are compared with the fabrics made from normal yarns. The thickness of the fabrics made from EliTe® compact yarns is also slightly less than the fabrics made from normal yarns. Fabrics made from EliTe® compact yarns have shown greater air permeability as compared to the fabrics made from normal yarns. It is observed that, thermal resistivity values of the fabrics developed from EliTe® compact yarns are lower than the fabrics made from normal yarns indicating they are cooler fabrics compared to normal fabrics. Fabrics developed from the EliTe® compact yarns have shown slightly higher values of MVTR (moisture vapor transmission rate) as compared to the fabrics made from the normal yarns. The wicking characteristic of fabrics developed from EliTe® compact yarns was slightly higher than the fabrics developed from normal yarns.     

A neural network model for prediction of strength loss in threads during high speed industrial sewing

In this paper artificial neural network (ANN) model has been designed to predict the strength loss in threads during high speed industrial sewing. Four different types of threads (Mercerized cotton, polyester staple spun, polyester-cotton core spun and polyester-polyester core spun) were taken for the study. The other input parameters include thread linear density, fabric area density, number of fabric layers, stitch density and needle size. In order to reduce the dependency of the results on a specific partition of the data into training and testing sets, a four-way cross validation tests were performed, i.e. total data was divided into training and testing set in four different ways. The predicted tenacity loss was correlated to the experimental tenacity loss and correlation coefficient between the actual and predicted tenacity loss obtained. It was observed that the neural network system is able to predict the tenacity loss of threads after sewing with good correlation and less average error. The relative contribution of each parameter to the overall prediction of the tenacity loss was studied by carrying out the sensitivity analysis of the test data set. The results of sensitivity analysis show that thread type is the most important input parameter followed by thread linear density, number of fabric layers, fabric area density, needle size and the stitch density.     

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.     

Modeling spun yarns migratory properties using artificial neural network

The mechanical and physical properties of spun yarns and fabrics depend not only on properties of constituent fibers, but also the yarn structure characterized by geometrical arrangement of fibers in the yarn body. Although there are many studies related to analyzing the migratory properties of spun yarns, there are no studies available about predicting yarn migration parameters. Therefore, the main aim of this research is to introduce a new approach to predict migratory properties of different kinds of spun yarns, namely siro, solo, compact and conventional ring-spun yarns. To achieve the objectives of the research, general physical and mechanical properties of spun yarns together with existing standards were thoroughly studied. Spun yarn migratory properties were predicted using intelligent technique of artificial neural network (ANN). Results signified that the ANN models can predict precisely the yarn migratory properties on the basis of a series of yarn physical and mechanical properties.