Polyethylene Terephthalate Yarn Research Articles

Embroidered electrode with silver/titanium coating for long-term ECG monitoring.

For the long-time monitoring of electrocardiograms, electrodes must be skin-friendly and non-irritating, but in addition they must deliver leads without artifacts even if the skin is dry and the body is moving. Today's adhesive conducting gel electrodes are not suitable for such applications. We have developed an embroidered textile electrode from polyethylene terephthalate yarn which is plasma-coated with silver for electrical conductivity and with an ultra-thin titanium layer on top for passivation. Two of these electrodes are embedded into a breast belt. They are moisturized with a very low amount of water vapor from an integrated reservoir. The combination of silver, titanium and water vapor results in an excellent electrode chemistry. With this belt the long-time monitoring of electrocardiography (ECG) is possible at rest as well as when the patient is moving.

Engineering Geometry Method for Modeling the Structure and Performance Characteristics of Fabric Articles for Technical Purposes. Part 3. Modeling Results and their Experimental Testing

This paper considers modeling of the structure and performance characteristics of fabrics made from polyethyleneterephthalate yarns. The models can allow us to determine the following parameters and characteristics: the yarn length increment and crimp increment, the thickness of the fabric; the linear, surface, and bulk coverage by the yarns; the surface and bulk porosity; the surface and bulk density; the tensile forces and the tensile load–strain diagram for stretching of the fabrics in the longitudinal direction; the work done by the tensile forces and the air permeability in the working strain ranges. The experimental studies have confirmed the reliability of the modeling methods developed.

An experimental study and model development of poly(ethylene terephthalate) yarn morphology

AbstractIn this study, macromolecular arrangements in fibers were investigated and a novel approach based on model development for partially oriented (POY) polyethylene terephthalate (PET) yarn morphology was proposed. Differential scanning calorimeter (DSC) analysis, Fourier transform infrared (FT-IR) analysis, boiling water shrinkage and tensile tests were performed through the study. DSC thermogram, FT-IR spectra, stress-strain curve, the change in the boiling water shrinkage properties and data from the literature were used to develop the model for POY PET fiber morphology. In order to make a comparison, textured PET yarn morphology was also investigated. The neck formations during tensile tests, cold crystallization on the DSC thermogram, peak formation on the FT-IR spectrum of the POY PET yarn after texturizing and shrinkage test at 971 and 845 cm-1 and shrinkage phenomenon have been explained by this model.

Wet-chemical silvering of inert polyethylene terephthalate yarn in a spool dyeing apparatus

Inert polyethylene terephthalate (PET) yarns, which were spooled crosswise onto a cylindrical dyeing bobbin, were silvered successfully with a wet-chemical method by using a newly developed one-bath method on a laboratory scale. In order to characterize the silver coating such as design, homogeneity, and crack formation, the surface morphology (SM) was analyzed using scanning electron microscopy (SEM). The chemical compositions of the surface (percentage of carbon, oxygen, nitrogen, silicium, and silver) were investigated with energy-dispersive x-ray spectroscopy (EDX). Furthermore, the testing of textile-chemical and textile-physical properties such as the washing-fastness, tensile strength, and electrical conductivity was carried out.

Engineering Geometry Method for Modeling the Structure and Performance Characteristics of Fabric Articles for Technical Purposes. Part 1. Structure Modeling Method

We propose an engineering geometry method for modeling the structure of dryer fabrics made from polyethylene terephthalate yarns for the papermaking industry. The models can allow us to determine the following parameters: the shape and dimensions of the yarn cross section; the positioning of the yarns in the structure; the length increment and crimp increment for the yarns; the thickness of the structure; the linear, surface, and bulk coverage by the yarns; the surface and bulk porosity; the surface and bulk density.

Effect of Twist Coefficient and Thermal Treatment Temperature on the Properties of PET Yarn

Twisting has an influence on not only the strength, luster, softness, and elasticity of the yarns, but also the properties of the resulting fabrics. This study aims to evaluate how the rotor twister speed and the thermal treatment temperature influence the properties of the polyethylene terephthalate (PET) plied yarns and wrap yarns. Both yarn types are made with a twist coefficient of 1, 1.5, or 2, and then thermally treated in an oven at 70, 110, and 150 °C. The resulting plied yarns are wrap yarns are tested for tensile strength and elongation, and their surface is also observed by a stereomicroscope to determine the influences of the two parameters. The results of the experiment show that twist coefficient does not influence the tensile strength nor the elongation. The tensile strength of various plied yarns and wrap yarns is approximately 4.4cN/dtex; the variation in the twist coefficients is too small and thus hardly causes any significant differences in the yarns properties.

Composite yarns fabricated from continuous needleless electrospun nanofibers

In this work, a spinning metal wire collector was employed to continuously collect polyacrylonitrile (PAN) nanofibers produced by a disc fiber generator and coil them around a polyethylene terephthalate (PET) yarn. The obtained composite yarns exhibited a core/shell structure (PET yarn/PAN nanofibers) with nanofibers orderly arranged on the surface of the PET yarn. The electric field analysis showed that the position of metal wire had insignificant effect on the formed electric field and high intensity electric field was formed at the disc circumferential area, which provided a constant electric field for the production of uniform nanofibers. The spinning solution, spinning speed of metal wire, and winding speed were found to play an important role in producing good quality nanofiber yarns, in terms of morphology, strength, and productivity. Pure nanofiber yarns were obtained after dissolving the core yarns in a proper solvent. This method has shown potential for the mass production of nanofiber yarns for industrial applications. POLYM. ENG. SCI., 54:1495–1502, 2014. © 2013 Society of Plastics Engineers

Production of high bulk polyester filament yarn

This paper reports a method for producing high bulk polyethylene terephthalate (PET) filament yarns composed of shrink and nonshrink filament yarns. Normally, high bulk yarns are mainly made out of shrink and nonshrink staple fibers especially polyacrylonitrile through semi-worsted spinning process. The method described in this paper involves blending two PET filament yarns, one acting as shrink component and the other as nonshrink one, followed by a relaxation process. The amount of shrinkage of the shrink component can be regulated by the drawing ratio employed during the drawing of partially oriented PET yarn. Depending on the shrinkage of shrink component, a variety of high bulk PET continuous filament yarns can be produced. The method described in this paper has the advantage of a much shorter production route and production cost, when compared with the traditional semi-worsted spinning process. Some of the produced yarns showed a high similarity with the fancy boucle yarns.

Effect of Air-Jet Texturing on Adhesion Behaviour of Technical Polyester Yarns to Rubber

Air-jet texturing of technical polyester yarns was performed in order to improve its adhesion to rubber. The air-jet texturing parameters were selected with great care to minimize the mechanical loss. H-adhesion tests were used to characterize the adhesion of the yarns to rubber. A significant increase in the adhesion of dimensionally stable polyethylene terephthalate yarn, textured with an overfeed level of 15% (DSPET15), was recorded, while a decrease in the adhesion of high tenacity polyethylene terephthalate (HTPET) yarn was observed for all overfeed levels. The effects of air-jet texturing on the adhesion of technical polyester yarns were discussed in terms of changes in the yarn geometry and changes on the single fiber surfaces. Changes in the yarn geometry were investigated by optical microscopy studies, while changes on the fiber surface were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM) studies. It was observed that air-jet texturing alters both the yarn geometry and the single fiber surfaces, leading to a change in the adhesion to rubber.

Effect of the addition of a modifier in the supercritical dyeing of polyester

The aim of the work was to investigate the effect of an ethanol addition in the dyeing of a commercial polyethylene terephthalate yarn with supercritical carbon dioxide. The equilibrium uptake in the yarn and the partition coefficients of three azo dyes between the polymer and the fluid phases were experimentally measured under different working conditions and compared with the data obtained without any modifier. It was found that the presence of the modifier increases the dye concentration in the yarn and the solubility of the dye in the supercritical phase, allowing good dyeing results to be obtained under less severe working conditions. The partition coefficient data were also satisfactorily regressed with a semi‐empirical correlation, available in the literature for a different system and here adapted to the partition of a dye between a fibre and a supercritical bath.

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.

Biocatalytic modification of polyethylene terephthalate fibres by esterases from actinomycete isolates

The modification of polyethylene terephthalate (PET) fibres by extracellular enzymes produced by actinomycetes was investigated. Cultivation of isolates in media containing PET yarn and suberin, a plant polyester composed of aliphatic and aromatic moieties, induced the production of p-nitrophenyl butyrate hydrolyzing enzymes. Incubation of enzyme preparations from the isolates M5, M9 and Thermomonospora fusca KW3b with PET yarn resulted in an increase in the absorbance of the reaction mixtures at 240 nm indicating the release of terephthalic acid or its esters catalyzed by the enzymes. The results of dyeing of enzyme-treated PET fabrics with a reactive dye (CI Reactive Red 2) indicated an increase in hydroxyl groups at the fibre surfaces as a result of the enzyme treatment.

Market study: biomaterials supply for permanent medical implants.

The withdrawal of DuPont as a supplier of key raw materials created a major dislocation in the medical device industry. We studied the present and future impact caused by the market removal of polyethylene terephthalate (PET) yarn ("Dacron"), polytetrafluorethylene (PTFE) fiber and resin ("Teflon"), and polyacetal resin ("Delrin"). Findings were: 1) Dollar values of the permanent medical implant markets for PET yarn, PTFE fiber and resin, and polyacetal resin are a minute fraction, of their values for their other commercial markets; 2) The implant market value is clearly not commensurate with the liability risk; and 3) The majority of these materials consumed by this market are used in the production of lifesaving, permanent medical implants [e.g., vital blood vessel replacements made from knitted polyester (PET)]. The remainder is used in life-enhancing, permanent implants [e.g., hernia patches made of polyester (PET) fabric].

Multiple gamma radiation sterilization of polyester fibres

Gamma radiation with a dose of 2.5 Mrad has been found to be suitable to sterilize polyethylene terephthalate (PET) bulk materials intended for biomedical applications. The radiation stability of PET bulk materials and fibre may not however be taken as identical due to the changes in the polymer structure during the processing of bulk materials for fibre. The chemical changes occurring in PET fibres during single and multiple (prolonged) sterilization in air were investigated. It was found that single sterilization (2.5 Mrad) itself affected the PET yarn and fibre. This was exhibited by the increase of crystallinity from 30.5 to 37% in the case of yarn and from 40 to 44% in the case of fibre. The breaking load of the yarn also increased from 441 g to 451 g. These changes were attributed to the degradation of PET in the amorphous region and the recombination of degraded aliphatic segments. Sterilization at higher doses affected the crystalline region which decreased the crystallinity, breaking load and molecular weight. For samples irradiated at 2.5 Mrad, the breaking load increased, though the dispersity increased. This was attributed to cross-linking by recombination. The increase in crystallinity also enhanced the breaking load of the samples. Higher doses of sterilization led to drastic microstructural and macrostructural changes as seen from the molecular weight. It was inferred that the changes in crystallinity and microstructure that occurred during multiple sterilization might affect the biocompatibility of the material.

Change in polymer supermolecular structure on heat-treatment of technical purpose polyester yarns

By use of low-angle and large-angle x-ray scattering methods on specimens of technical polyethylene terephthalate yarn, it has been shown that:

Some features of the structure of oriented polyethylene terephthalate yarns in the initial period of heat treatment

The rearrangement in structure of PET yarn during short heat treatment times, that is, during the warming-up period and in the initial period of yarn heat treatment, has been examined from the evidence of isometric heating, IR spectroscopy, change in birefringence, density, and physicomechanical characteristics of yarn which has been heat treated in an air heating chamber at 200°C. It has been shown that during the time of warming up the yarn, structural changes are determined by relaxation processes. After heating, crystallization processes exert an important effect on the properties of the heat treated yarn. The complex character of the structural rearrangement leads to a nonhomogeneous change in physicomechanical properties of the yarn.

The Mechanical Properties of Textured Polyethylene Terephthalate Yarn

Cummerciat polyethylene terephthalate multifilament yarn was textured using the spindle false-twist method over a range of heater temperatures and contact times and at various tension and twist levels. The decrimping extension, initial modulus, tenacity, and fiber clongation of the various samples were measured on a tensile tester. The changes in these mechanical properties as functions of the texturing parameters are described and their structural dependence dis cussed in this paper.

Properties and Structures of Polyethylene Terephthalate Yarns in Conventional and Simultaneous Draw-Texturing

This study was conducted on sets of yarns produced by two different texturing processes. One set was generated via conventional technology with predrawn feeder yarn, whereas the second set was produced by simultaneous drawing and twisting of an undrawn feed yarn. “Grab samples” obtained from zones throughout the processes permitted discernment, to a degree not previously reported, of intraprocess changes in yarn structural and physical attributes. To correlate changes in fine structure with specific properties of the textured yarn, comparisons of output from each of the two contrasted processes (and in some instances within each process) were obtained by the following techniques: stress-strain, density, rates of chain scission during aminolysis, wide-angle x-ray diffraction, and electron microscope studies. Details about process parameters for yarn systems are also presented, along with twist levels and twist contractions in the preheater, heater, and output zones.

The Effect of Tension and Twist on the Structure and Dyeability of Textured Polyethylene Terephthalate Yarn

The changes in structure and dyeability characteristics of: a) polyethylene terephthalate (PET) yarn, textured at different tensions and various twist levels; and b) the textured samples after being relaxed in water at 80°C for 2 hours, are reported. The crystallinity of all textured samples was found to be higher than that of the untextured yarn, but in general, crystallite orientation, birefringence, and amorphous orientation decreased on texturing. The effect of tension and twist on these structural parameters is discussed in this paper. The textured samples, after being relaxed, show decrease in crystallinity, crystallite orientation, birefringence, and amorphous orientation. The dye uptake of the textured samples is considerably affected by tension in the crimping zone, and water treatment increases the dye uptake of the textured yarn. The structural dependence of dye-uptake data is analyzed.

Latent Crimp in False-Twist-Textured Polyethylene Terephthalate Yarn

The effect of tension in the winding zone of the false-twist-texturing process on the crimp properties of textured polyethylene terephthalate yarn has been investigated. It was found that, all other conditions remaining unchanged, high wind-up tension results in low crimp retraction. Post-texturing treatments enhance the crimp retraction of these yarns and demonstrate the role of wind-up tension in rendering the crimp latent.