Electrical, electromagnetic shielding, and some physical properties of hybrid yarn-based knitted fabrics

Recently, increasing number of studies are performed on protective fabrics containing metal wires for electromagnetic shielding purposes. In the present paper, the hybrid fabrics in plain and rib structures were knitted by using single and double ply hybrid yarns obtained by acrylic (PAC) yarns plied with stainless steel wires having two different diameters. The physical properties including conductivity, air permeability, pilling, and abrasion resistance as well as electromagnetic shielding effectiveness (EMSE) were measured. The variations in EMSE as well as reflection, absorption, and transmission and in other physical properties of knitted hybrid fabrics were investigated considering wire content and weave structure. It was seen that an increase in the wire content significantly increased the conductivity. Rib fabrics exhibited better EMSE values as compared with plain fabrics. Fabrics using two-folded yarns exhibited better EMSE values. Fabrics using thinner wire exhibited higher EMSE values. The highest EMSE value was obtained for rib-knitted fabric with 35 micrometer (m) stainless steel wire

Investigation of electrical, electromagnetic shielding, and usage properties of woven fabrics made from different hybrid yarns containing stainless steel wires

This paper reports the results of a detailed study about specific properties of hybrid yarns and woven fabrics containing those yarns. For this aim, the fabrication procedures and physical properties of acrylic/stainless steel (SS) and cotton/acrylic/SS ply yarns were presented, and then, relations between those and electrical, electromagnetic shielding effectiveness (EMSE) and some usage properties of woven hybrid fabrics made from those with different constructions were investigated. EMSE of plain and twill fabrics were evaluated against radiating electromagnetic wave spectrum over a frequency 0-3000MHz. A comparison of physical properties of yarns regarding wire diameter and the use properties of fabrics regarding weave type, wire diameter, and yarn type measured were presented. The functional textile products of complex applications can be achieved with low cost, easily since those yarns and fabrics were produced on conventional textile manufacturing machines with small modifications. The present study indicated that use of SS wire-based yarns in fabrics significantly increased the air permeability, pilling resistance, thermal resistance, and the flexural rigidity of hybrid fabrics. The plain weave fabrics exhibited higher EMSE values over 20dB in higher frequencies and higher thermal absorbtivity values compared to twill fabrics

The influence of heat-setting process on physical properties of ribbon-type fancy yarns and fabrics produced from them

In this paper, the influence of heat-setting process on the properties of ribbon-type fancy yarns with different needle numbers and fabrics manufactured from them was investigated. With the increasing number of knitting needle, thicker fancy yams, higher strain, lower hairiness and so, thicker fabrics and higher mass per unit area and volume density, better abrasion resistance and higher thermal conductivity were obtained. The influence of heat-setting process was statistically significant on fancy yam and fabric properties at 95% confidence level (alpha = 0.05). Fabrics manufactured from heat-treatment applied yarns showed lower thermal absorptivity results giving warmer feeling compared to others

Polyacrylonitrile/polyvinyl alcohol-based porous carbon nanofiber electrodes for supercapacitor applications

Porous carbon nanofibers (PCNFs) were produced from polyacrylonitrile (PAN)/polyvinyl alcohol (PVA) hybrid nanofibers with different mixing ratios and used as the free-standing, flexible, high performance electrodes for the supercapacitors. The effect of PAN/PVA ratio, PVA removing and stabilization/carbonization process on the chemical structure, and the morphology of PAN/PVA hybrid nanofibers and PCNF were investigated by Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), and thermogravimetric analyzer (TGA). It was proved by FT-IR and FE-SEM analyses that PAN/PVA hybrid nanofibers are successfully produced and carbonized. In addition, the electrochemical performance of PCNF electrodes was analyzed by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) methods. Results showed that PCNFs exhibit higher specific capacitance and better electrochemical performance than neat carbon nanofibers (N-CNF). The specific capacitance of the EK5 PCNF (67/33 PAN/PVA wt ratio) was 157 F/g at 5 mV/s scan rate in 1 M H2SO4, while the specific capacitance of N-CNF was 96 F/g at the same conditions. Moreover, the PCNF showed excellent cyclic stability without losing performance through 2500 charge/discharge cycles at a current density of 2 A/g. As a result, free-standing, flexible, and high-performance PCNFs are excellent candidates as supercapacitor electrodes for flexible energy-storage devices

A study about photovoltaic fibers

This study presents a photovoltaic fiber structure which generates electricity by using solar energy. Polymer based materials were used to develop photovoltaic effect on flexible fibers. The photoelectrical parameters including short-circuit current density, open-circuit voltage and fill factor were measured to determine the power conversion efficiency of photovoltaic fibers. This structure of photovoltaic fiber may be used to generate power for small electrical devices in smart textile products after further optimization

Nanofiber mat-based highly compact piezoelectric-triboelectric hybrid nanogenerators

Studies on energy generation devices for necessary energy needs have been an increasing trend all over the world as the kinds and quantities of consumer gadgets have increased. Researchers have been studying nanogenerators for the last 15 years in response to this demand. The three main reasons for these studies are increased output power, application to consumer items, and mechanical stability. Hybrid nanogenerators, on the other hand, are a method of combining at least two energy conversion mechanisms, hence reducing the need for a single conversion mechanism. In this context, while triboelectric-piezoelectric combination hybrid nanogenerators are the most popular hybrid nanogenerator class, they have several drawbacks, such as non-compact and unstable structures. As a result, for the first time, a small hybrid polymer-nanofiberbased hybrid nanogenerator concept with high output voltage and current is disclosed in this study. A hybrid nanofibrous structure was created using an electrospinning apparatus with double and triple nozzles. As a result of the periodic-compression test, the resulting nanogenerators produced a maximum voltage density of 5350 V/m2 and a current density of 5454 A/m2. By hand tapping, the resulting master unit was able to light up 119 LEDs and charge a commercial capacitor up to 0.9 V

Mechanical properties of silage covering fabrics as agrotextiles

The woven agrotextiles used in a wide variety of agricultural applications in the product cultivation and protection activities, horticulture and floriculture, aquaculture, forestry as well as animal husbandry activities have an important role to protect silages from bird/insect attacks or damages related to environmental conditions. In this study, nine different woven silage covering fabrics made of polyethylene monofilaments were designed according to desired areal porosity ratio. Afterwards, the effect of weave type and weft setting on mechanical and air permeability properties of the produced agrotextiles were investigated. The obtained results were discussed statistically. The highest values for bursting and shear strength were measured as 2.60 kN and 0.25 kN for P1 plain fabric, respectively. Twill and mat fabric structures did not burst during testing

Photovoltaic applications for textiles

Until very recently, nearly all photovoltaic devices were hard silicon semiconductor based cells and therefore they were very limited in widespread applications. Flexible polymeric semiconductors are now opening a new area in which films and fibers are becoming a potential application form. Fibers and textiles are maturing fields for photovoltaic cells with promising different applications. Photovoltaics based on textiles can positively increase the number of applications available to solar technology by delivering lightness and flexibility of photovoltaics and extending integration to other textile materials. This paper summarizes photovoltaic technology and devices including possible new uses in fibers and textiles with advanced properties