Technical Yarns Research Articles

A mini review on the ballistic protection performance of 2D and 3D woven fabric structures woven from technical yarns for body armormaterials in military application

This mini-compilation study included a review study conducted on the ballistic protection performances of 2D and 3D structured woven fabric structures for body armor materials in military applications. As conclusion, orthogonal type 3D woven fabric structures have higher ballistic protection performance compared to conventional 2D woven fabric structures by locking the high-performance yarns used and preventing slippage between layers. It is recommended to use ceramic-structured front plates such as B4C to break armor-piercing bullets, reduce penetration, and absorb a significant portion of their high kinetic energy. UHMWPE, PPD-T, and PBO technical yarns, which have fine yarn counts (between 466 dtex and 933 dtex) can be produced by 1x1 plain woven fabric construction as woven fabric structures (lamina). They must have also high warp and weft density values ​​(between 30 and 40 warp/cm and weft/cm), and orthogonal 3D woven fabric structure, high warp, and weft yarn tension (between 20 cN and 50 cN per warp yarn), 160 rpm as production speed, and multi-layered (between 13 layers and 16 layers in lamina form) in honeycomb (sandwich) geometry. Moreover, the impregnation process can be applied with CaCO3, SiO2, PVB, or CNT particles (in the particle size range of 100 nm to 400 nm) with chemicals such as PEG (in the range of 60% to 75% concentrations), in the range of 80 °C to 160 °C temperatures and between 1 hour and 3 hours. Coating (STF applications) is extremely important and successful for ballistic protection performance at IIIA, III and IV levels for NIJ standards. Future studies should include orthogonal 3D structured woven fabric applications from UHMWPE, PPD-T, or PBO technical yarns by applying STF technology in this field. They should be also examined comparatively from an experimental perspective.

Investigation of the Basic Dimensional Properties and Biomechanical Performance of Artificial ACL Grafts Produced by 3-D Braiding Method

In the current study, an investigation of basic dimensional properties and biomechanical performance of artificial ACL grafts produced by the 3-D braiding method was carried out. Artificial ACL grafts were produced using the 3-D braiding process. All 3-D braiding grafts were produced using various technical yarns for raw and bio-finishing grafts. Ethylene oxide (EtO) sterilization was applied to all grafts. The effects of yarn types, yarn counts, and 3-D braiding constructions on EtO sterilized raw and bio-finished artificial ACL grafts were examined. In conclusion; the tensile strength and thickness values of all 3-D braiding structured ACL grafts were suitable for artificial ligament grafts. Additionally, its grammage values were extremely light. The yarn type, yarn count, and 3-D braiding construction were the most effective process parameters on thickness, grammage, and tensile strength values. They can be improved by using x2-layered 3-D braiding structures, thicker yarn counts, and more than 1 core yarn in similar studies to be conducted in the future.

An experimental study for chemical characterization of artificial anterior cruciate ligament with coated chitosan as biomaterial

Abstract The importance and aim of this experimental study is that raw artificial anterior cruciate ligament samples were produced with various 3-D braiding constructions with various technical yarns using the 3-D braiding method. Later, it is aimed to determine the chemical bond changes between raw samples with ethylene oxide (EtO) sterilization and bio-chemical finishing samples by applying padding process and EtO sterilization processes for all samples with 3-D braiding structures, due to the cross-linking of biocompatible chitosan (CHI) with biological cross-linker glutaraldehyde (GA). The importance of this experimental study is that it is the first experimental chemical analysis in this field in the world scientific study. Padding and EtO sterilization processes were applied on all samples and compared to various technical yarns with 3-D braiding structures thanks to biocompatible CHI. Chemical analysis was interpreted for all samples. It was determined that the applied temperature, concentration, pH, yarn types, characteristic bonds in the chemical structure of the technical yarns, applied bio-chemical finishing process and EtO sterilization had effect on the formation, shifting and breaking of chemical bonds. It was determined that the yarn number, braiding geometry, braiding angle (°) and braid construction had no effect on the formation or shifting of chemical bonds. New bonds were formed thanks to CHI and GA due to their extremely reactive between 5 and 5.5 pH. They reacted quickly with Schiff base bond in all samples. CHI was ionized in all samples. It was determined that new bonds were formed in UHMWPE, PPD-T and HT PET structures. The most common bond formations were HT PET > PPD-T > UHMWPE. The reasons for these chemical structure changes in all samples depended on their chemical structures, bond types, molecular weights, reactivities, ease and speed of diffusions, crystallinities of technical yarns and all chemicals used. In order to increase the formation of new chemical bonds the pH should be between 5 and 5.5. GA concentration should be a minimum of 25% or higher. The dissolution time of CHI should be minimum 3 h or more. The dissolution process temperature of CHI should be minimum of 70°C or higher. The absorption, adsorption and chelation properties of CHI on all samples will also be evident successfully as in this experimental chemical study.

Evaluation of the Effect of Sizing Compositions on the Properties of Hydrated Cellulose Technical Yarn

The influence of sizing compositions on the reinforcing properties of hydrated cellulose technical yarns has been investigated. The optimal mode of modification of hydrated cellulose yarns has been determined. The evaluation of the structural properties of the modified yarns has been carried out. The kinetic features of the modified yarns wetting by an epoxy oligomer have been studied.

Godet rolls for drawing fibers to technical yarns

Godet rolls for drawing fibers to technical yarns

Technological Development of a Yarn Grip System for High-Speed Tensile Testing of High-Performance Fibers

Abstract Particularly in terms of carbon fiber (CF) rovings and further high performance fibers, it is a highly demanding task to clamp technical yarns with low elongations at break during high-speed tensile tests due to their sensitivity to shear stress. For fibers to be tested, a low elongation at break results in short testing times and requires high acceleration. In this paper, four different yarn grips that can be applied with various test machines will be introduced and compared to a wedge screw grip. By using most sensitive CF rovings, advantages and disadvantages of these gripping devices will be qualitatively evaluated by means of testing machines with test speeds of up to 20 m/s and strain rates of up to 200 s−1, respectively. Hence, the reproducibility and precision of test results were considerably enhanced by optimizing the geometry and mass of yarn grips. Moreover, theoretical approaches and calculations for the design of yarn grips suitable for test speeds of up to 100 m/s will be presented.

Effectiveness of Modifying Viscose Technical and Basalt Yarns Used to Reinforce Epoxy Plastics

The effectiveness of modifying viscose technical and basalt yarns with organosilane finishes A-174 and A-187 was evaluated and found to increase their stress-strain and adhesive properties. The finish was confirmed to be stably bound to the fibrous filler surface. A mechanism for the chemical reaction of the most effective modifier A-187 with the studied yarns was proposed.

New Flex Fatigue Tester for Fiber Reinforced Polymer Composite

Textile materials are widely used in the industrial textiles. The yarn and fabric fatigue are not easily prearranged hence, in most cases the apparatuses used for applying cyclic loading under flex fatigue conditions will affect only one section of the yarn and fabric and the results will depend on the level of heterogeneity of the tested material. The common methods of flex fatigue testing are to pull the tested specimen, hold under tension, backward and forward over a fixed roller or grip one end of the specimen while its free end is bent so, the specimen element is alternated between straight and bent form. The new suggested principle is the fixation of the yarns or fabrics in the internal part of rubber tire wheel and pressing it by the pressure of internal rubber tube with the external wheel under predetermined load to give the required bending deformation on the specimen. The theoretical calculation of the design indicates that the testing specimen is subjected to pure bending. In this work, a setup was built up and several types of the technical yarns, fabrics, as well as flexible composites, were tested.it was proves the degradations of the material under the flex fatigue. .

Motorized Jacquard technology for multilayer weaving damages study and reduction: Shed profile and close shed profile

Materials used for composite reinforcements usually have high mechanical performances which are linked to a very sensitive and brittle behaviour to friction. The weaving process applied to delicate yarns, like glass, carbon and some other technical yarns, generate damages which tend to reduce the performances of the final composite. Shedding may be a major weaving stage for the generation of yarn damages. Based on a specific weaving pattern, it was observed that different shedding configurations could influence yarn damages at the shedding step. The specificity of the motorized Jacquard device is used to generate different movements and geometry configurations. A particular methodology needed to be set in order to confirm these observations and bring out a clear effect of shedding parameters on yarn damages. After damages have been identified and classified, some experiments will count the damage occurrences and evolutions in time according to shedding parameters. The aim of this research is first to show a clear effect of shedding on warp damaging thanks to the quantification of damages and then to set out an optimized configuration of shedding parameters which may reduce deterioration involved in high-density multilayer woven fabrics.

Knit Band Sensor for Myoelectric Control of Surface EMG-Based Prosthetic Hand

Surface electromyography (sEMG) sensor is widely used to operate a myoelectric prosthesis and it has been further developed for various applications. In this paper, a multi-channel sEMG knit band sensor is newly suggested to be worn easily by amputee for myoelectric prosthesis. The band sensor was fabricated by knitting the silver-plated conductive yarn for electrodes with the moisture-wicking technical yarn for the comfort, ultimately, to record eight-channel sEMG signals simultaneously. Several experiments were conducted to verify the performance of knit band sensor. The normalized correlation between the developed knitted electrodes and the disposable (Ag/AgCl) electrodes is very high (0.95) at the same muscular area. The average signal-to-noise ratio value of the knitted electrodes (17.91 dB) was higher than that of the disposable electrodes (13.30 dB). For the performances of motion classification, overall classification accuracy of the knitted electrodes (93.2%) was higher than that of the disposable (87.9%). These experimental results have supported that the developed knit band sensor was as effective as the disposable electrodes.

Investigating the unwinding behavior of technical yarns and development of a new sensor system for the braiding process

A new cost-efficient sensor module for the detection of thread tension anomalies in braiding machines was developed. The sensor module is mainly attached to the body of the braiding machine and works by contactlessly detecting the positions of the levers of the yarn tensioning units of the bobbin carriers through magnets and stationary Hall effect sensors as the bobbins pass by. This way, time-discrete estimations of the tension of the moving braiding yarns can be calculated. The sensor module was validated by investigating the unwinding behavior of several kinds of technical yarns from bobbins on a stationary test stand which simulates the unwinding process during braiding. Flawless reference measurements revealed that the signals from the Hall probe are in good agreement with precise yarn tension measurements obtained simultaneously from a deflection roller based yarn tension measurement device. Further measurements with purposefully provoked unwinding-related irregularities showed that braiding defects are foreshadowed by prominent variations in yarn tension which the Hall effect sensors are able to detect. Finally, experiments with the sensors installed into a running braiding machine were conducted. In this near-production environment, the sensor module was capable of identifying irregularities soon enough before major braiding defects evolved.

Global Output of Chemical Fibres in 2014

In 2014, the global output of all types of textile fibres was 93.7 million tons, which was higher by 4.1% than in 2013, including synthetic by 3.1%, hydrated cellulose by 0.3%, and natural by2.5%. The chemical fibre output was 63.2 million tons, where polyester (PE) dominated with a 74% share. Among the chemical fibre manufacturing countries, China occupied the overwhelmingly dominant place with 68% of the global output. The share of this country in the PE fibre domain was 71% of capacity, 69% of output, 65% of consumption, and 36% of export (of which 53% was technical yarns) globally. The scales of manufacture of other types of chemical fibres were much smaller in 2014 (global share, %): hydrated cellulose 10, polyamide (PA) 8, polypropylene (PP) 5, and polyacrylonitrile (PAN) 2. Currently, PP fibres play the leading role in nonwoven raw materials market.

Situation in Russian Chemical Fibre Market

In 2014, chemical fibre demand and consumption in Russia stayed practically at the level of the preceding year. Production (capacity utilization factor 59%) and import rose respectively by 1.9 and 3.5%, export declined by 9.1%. Demand and consumption of viscose staple fibres grew respectively by 21.4 and 29.9% and their import, in consequence, shot up by 25.3%. Demand and consumption of polyester (PE) staple fibres increased a little and production, more noticeably (by 11.5%), import fell slightly and export, quite substantially (by 44.2%). Demand and consumption of polyacrylonitrile (PAN) fibres, primarily as tow procured mostly by import, went up by more than 40%. Progress in polypropylene (PP) staple fibre market was marked. Compared to 2013, demand, consumption, production, and import of polyamide (PA) textile yarns improved with forced reduction of their export by 17%. The results with regard to PE textile yarns were negative in 2014 when their demand, consumption, production, import, and export dropped by 16, 17, 40, 12, and 50%, respectively. On the contrary, demand and consumption of PP textile yarns rose steeply (by 68 and 79%, respectively). Rise of all indicators, except import, to the 3-5% level was noted for PA technical and cord yarns. Import of PE technical and cord yarns is continuing unabated. The year under report was a fiasco in the domestic market of PP film yarns that were being actively introduced into the national economy until recently. The problems of chemical fibre development in Russia are being solved for the most part pretentiously without definite involvement of power structures. The strategy until 2030, even in the case of its realization, is characterized by a twofold drop in the output of this product against the pre-restructuring level and continuation of import by no less than 40% of the total volume of their consumption.

Eğrilebilir Karbon Nanotüpler ve Bu Özel Liflerden Üretilen Teknik İplikler

Eğrilebilir Karbon Nanotüpler ve Bu Özel Liflerden Üretilen Teknik İplikler

Global and Russian Output of Polyester Fibres in 2013

In 2013, the global polyester (PE) fibre output was 46.7 million tons, including 32.3 million tons as complex yarns (textile, technical, monofilament, etc.) and 15.4 million tons as staple fibre and tow, which provided a growth of 8 and 2%, respectively, over 2012. The leading place here belongs to China, which accounted for 72% of the global PE fibre output and for about 90% of the output of the Asian region as a whole. In a few other countries, including the USA and Germany, the output rose perceptibly, by about 4%. In Western Europe, production of nonwovens from PE staple fibre is developed extensively. The situation in Russia, however, is much worse, especially in terms of consumption and output volumes. The share of PE fibres in the total volume of chemical fibres in the country in terms of demand, output, import, and export in 2013 was respectively 60, 40, 70, and 20%. The staple fibre produced was primarily derived from secondary polyethylene terephthalate (PET), the output of textile yarns fell by 30%, and technical yarns were imported fully.

The creep master curve construction for the polyamide 6 by the stepped isostress method

The creep test illustrates the tendency of materials to deform under constant loading; however, this test requires a very long testing time. The use of the time-stress superposition principle (TSSP) allows the prediction of the material performance very beyond the testing time by the construction of the creep master curve. Recently, a new accelerated creep testing method, called the stepped isostress method (SSM) was proposed. This technique requires specific handling of the test data in the construction of the master curve. Initially the method was used on technical yarns. This paper focuses on the effectiveness of this method for specimens having a large thickness. The considered material is a polyamide 6. A smooth creep master curve has been obtained. The obtained master curves by the SSM technique and the classical TSSP method are consistent. This result proofs the robustness of the SSM technique in the construction of the master curve.

Chemical Fibres in Global and Russian Markets in 2012

The global textile fibre market in 2012 reached 85.8 million tons, surpassing the 2011 level by 4.5%. The output of chemical fibres rose by 6% to 56 million tons, including synthetic fibres by 5.6%. Amongst the latter, polyester fibres (PEF) occupy the leading place. Their production in 2012 reached 41.4 million tons, rising above the preceding year by 6.1%, including textile and technical yarns by 9 and 2%, respectively. The output of cellulose fibres grew for the first time by 10.2% to the 5.2 million ton level, including viscose staple fibre by 13%. The global chemical fibre production structure is dominated by PEF (74%), followed by cellulose (9%), polyamide (7%), polypropylene (5%), and polyacrylonitrile (4%). Spandex, aramid, carbon, and others constitute 1%. In regional term, China is the unchallenged ruler – 65% of global chemical fibre production is concentrated in this country, followed far behind by India and the USA (5% each), Taiwan (4%), and South Korea (3%). The remaining countries account for 18%. The situation with chemical fibres in Russia is as gloomy as before. The demand for them exceeds consumption on average by 6% and production by 62% and is made good by import. On the whole, chemical fibre production in the country rose by 2.7% to 140,000 tons, which is extremely low compared to the pre-restructuring time. The demand and import fell relative to 2011 by 3.0 and 3.5%, respectively. The growth of production of acetate tow, PEF staple fibre, spunbond, and a whole range of polypropylene products in this period can be considered positive.

Assessment of the stepped isostress method in the prediction of long term creep of thermoplastics

To predict long term creep of thermoplastics, methods based on the time–temperature superposition principle (TTSP) or on the time–stress superposition principle (TSSP) are commonly used. These methods enable the construction of a creep master curve without a lengthy experimental program. Recently, a new accelerated creep testing method, termed the stepped isostress method (SSM), was proposed and used to predict long term creep of technical yarns. This paper focuses on the processing aspects of the SSM test data and its validity in the creep prediction of thick thermoplastic specimens. Excellent correlation is obtained between the master curves constructed by the classical TSSP method and those constructed by the SSM method. The variation of the SSM testing parameters has no significant effect on the obtained master curves, which constitutes proof of the SSM robustness. Further, the trend of the SSM shift factors in terms of the creep stress obeys the Eyring equation.

Characterization of the Mechanical Properties of Technical Fibers at Extreme Strain Rates

AbstractTechnical textiles can be subject to mechanical stress with strain rates far from the quasi‐static conditions of common standardized tests. The objective of the presented work was therefore to study the mechanical properties of technical yarns made of PA 6.6, PA 4.6, and PET under strain rates up to 200 s−1, making use of a “falling weight” apparatus. It can be summarized that the moduli at specific points of the stress–strain‐curve increase with the strain rate to values up to 50% higher than the data determined under quasi‐static strain. Saturation is observed for strain rates larger than 50 s−1. The analysis of failure morphology by scanning electron microscopy revealed molten material at the ends of broken fibers. This indicates thermal failure of the fibers due to local concentration of energy loading.magnified image

Experimental study on dyeing technical PET yarns having different TiO2 contents

TiO2 contents in yarns can influence color yield so that dyeing quality of industrial poly ethylene terephthalate (PET) yarns can be improved through the adjustment of TiO2 contents. To evaluate the dyeing performance of color yield, the chips which included the different TiO2 contents of 330, 550, and 1,100 ppm respectively were used to produce the yarns of different TiO2 content by a spin-draft machine. The physical and structural properties of the yarns were measured to investigate effect of the TiO2 contents on them. Dye uptake and dyeing rate were also evaluated using a colorimeter to compare the yarns having different TiO2 contents. The experimental results showed that there were no appreciable variation in physical and structural properties among the yarn samples and no difference were observed among the dyed fabric samples with regard to dyeing uptake and dyeing rate. However, the color yield of dyed fabrics increased as TiO2 contents decreased in the yarns especially when the fabric samples were dyed to pale shade. The physical reasoning could be proposed on why the yarns having low TiO2 contents appeared to have higher color yield after dyeing.