Relationship between Yarn Properties and Process Parameters in False-Twist Textured Yarn

The properties of false-twist textured yarns in the aspects of crimp characteristic and tensile behavior depend mainly on the draw ratio and the D/Y ratio. This study comprises investigations of the effect of D/Y ratio and draw ratio on the crimp and tensile properties and percent crystallinity. While there was no noticeable change on the percent crystallinity by altering these parameters, tenacity increased and crimp contraction decreased with increasing draw ratio, and crimp stability decreased when the D/Y ratio increased. K/S value also decreased with increasing draw ratio

Investigating electromagnetic shielding effectiveness of knitted fabrics made by barium titanate/polyester bicomponent yarn

Electromagnetic pollution is a problem that damages all creatures and electronic devices. Most of the electronic devices we use at homes emit electromagnetic radiation. Conductive textile surfaces are used for electromagnetic shielding applications. However, to provide electromagnetic shielding, there has not been any study on the bicomponent fiber production with barium titanate. For this purpose, in this study, bicomponent yarns were produced using three different adding ratios of barium titanate. The mechanical and electrical properties of the yarns were investigated. Knitted fabrics were produced from bicomponent yarns with two different fabric densities using a circular knitting machine. The effects of the additive ratio and the fabric density on the effectiveness of the electromagnetic shielding were also investigated. The fabric with the highest content of the barium titanate and greater fabric density showed the highest shielding effectiveness, reaching 25.95 dB at 0.02 GHz

IMPORTANT DEGRADATIONS IN POLYETHYLENE TERAPHTALATE EXTRUSION PROCESS

Polyethylene terephthalate (PET) is one of the most used thermo-plastic polymers. The total consumption of PET has been about 30 million tons in the year 2000. Polyester fibers constitute about 60 % of total synthetic fibers consumption. During extrusion, PET polymer is faced to thermal, thermo-oxidative and hydrolytic degradation, which result in severe reduction in its molecular weight, thereby adversely affecting its subsequent melt processability. Therefore, it is essential to understand degradation processes of PET during melt extrusion

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

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

Usage of barium titanate in fabric coating and investigation of some properties

In this study, nano-sized barium titanate powder was applied for the first time to polyester woven fabrics by knife coating at three different concentration rates. Some physical (thickness, mass per unit area, bending rigidity, air permeability and tear strength) properties, electromagnetic shielding efficiency and solar (transmittance, reflectance) properties of samples were presented. The samples were also characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Electromagnetic shielding effectiveness of the fabrics was determined according to the ASTM D4935-10 standard by using a coaxial transmission line measurement technique in the frequency range of 15-3000 MHz. The solar properties were measured according to EN14500 standard using a UV/VIS/NIR spectrophotometer and results were calculated according to EN 410 standard. Results revealed that the electromagnetic shielding effectiveness and solar reflectance property of samples improved with increasing barium titanate concentration

Influence of Stitching Parameters on Tensile Strength of Aramid/Vinyl Ester Composites

Stitching process is used to provide structural integrity and through-the-thickness reinforcement in the composite materials. In this study, the effect of sewing parameters on tensile strength in stitched composite laminates was examined. In the production of composite laminates, Twaron T-750 type plain weave fabric was used as reinforcement material and a Polives 702 Bisphenol-A type epoxy based vinyl ester as resin. The effects of stitch density and stitch direction or stitch pattern on tensile strength of composite samples were studied and, as a result of the experiments, it was observed that higher tensile strength occurs with low stitch densities in stitched laminates.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3829</p

DEVELOPMENT OF A LAN SYSTEM FOR TEXTILE COMPUTER INTEGRATED MANUFACTURING

Abstract: Today’s textile industrial complex is characterized by a multitude of conflicting demands: increased product flexibility, higher product quality and decreasing delivery times. To operate successfully in such a demanding and highly competitive global market, textile industry must deploy the state-of-the-art manufacturing and information management techniques. This paper outlines the construction of a LAN (Local Area Network) computer system, which is the base of a knowledge-based monitoring and management system, for a textile factory having the departments of weaving and dyeing. In the development of the network, hardware choices and programming methodologies; ISO 9000 standards, work in process tracking with barcode and the design of a future intelligent process management system that will effectively utilize the distributed databases in the enterprise are taken into consideration. The network software has a scaleable, 32-bit high-performance Client/Server structure running under Windows NT and Windows 95