An-Pang Chen

Manufacturing techniques and electrical properties of conductive fabrics with recycled polypropylene nonwoven selvage

In this research, an original rotor twister machine, with a speed of 8000 rpm, spun complex ply yarns from recycled polypropylene nonwoven selvage (PPNS) and various metal wires. The core yarn was pieces of 30 g/m2 recycled PPNS and the wrap yarns were 80 μm stainless steel wires. Furthermore, 80 μm stainless steel wires and 80 μm copper wires, parallel to the core yarns, reinforced the complex ply yarns. Yarns were manufactured with wrap numbers of 0.5, 1.5, 2.5, 3.5, and 4.5 turns/cm. Complex fabrics were woven with the complex ply yarns as the weft yarns and PVC-coated PET filaments as the warp yarns. These fabrics were evaluated for surface resistivity and electromagnetic shielding effectiveness (EMSE). The presence of copper reinforcement wires was found to lower the surface resistivity of the fabrics. The lowest surface resistivity was recorded for a fabric woven from yarns with a wrap number of 4.5 turns/cm; that surface resistivity was 28.7 Ω/sq. EMSE measurements showed that fabrics with varied lamination angles provided good electromagnetic shielding. The optimum EMSE measured in this research was 56.1 dB on incident frequency as 2.36 GHz, for a fabric with 0°/90°/0°/90°/0°/90° lamination angles.

Physical properties of the functional bamboo charcoal/stainless steel core-sheath yarns and knitted fabrics

In this study, bamboo charcoal/stainless steel (B/S) core-sheath yarns were made of stainless steel wires and bamboo charcoal polyester textured yarn using a rotor twister machine. The speed of rotor twister was from 7000 to 11000 rpm and the wrapped amount varied from 2 to 7 turns/cm. The tenacity of 3.08 g/d was obtained when the speed of rotor twister was 8000 rpm and wrapped amount was 4.0 turns/cm. The tensile strain of 24.9% was yielded when the speed of the rotor twister was 7000 rpm and the wrapped amount was 5.0 turns/cm. The laminated amount of the knitted fabrics varied from 1 to 6 layers. The far infrared ray emissivity of the knitted fabrics was 0.934 when the laminated amount was 2 layers and wrapped amount was 6 turns/cm. Finally, the optimum anion density of the knitted fabrics was 610 ions/cm3.

Electromagnetic shielding effectiveness and functions of stainless steel/bamboo charcoal conductive fabrics

Following technological advancements, there is a growing population of cellular phone and computer users. However, these electronic instruments cause electromagnetic waves, negatively influencing users’ health or precision instruments’ malfunction. Therefore, shielding electromagnetic wave becomes an important matter. In this study, stainless steel wires and bamboo charcoal roving are made into conductive yarn with 6 turns/cm by ring spinning machine. On a 14-gauge automatic horizontal knitting machine, the resulting yarn is then knitted into stainless steel/bamboo charcoal conductive fabrics and then evaluated for the electrical property and functions. According to experimental testing, electromagnetic shielding effectiveness (EMSE) of the fabrics increases with an increase in stainless steel content and number of lamination layers. In particular, when laminated at an angle of 0°/45°/90°/−45°/0°/45°, the fabrics have an EMSE of above 30 dB at an incident frequency between 2010 and 2445 MHz. The far infrared emissivity increases with bamboo charcoal content, reaching the maximum of 0.9 ɛ, when the fabric was made by one-cycle polyethylene terephthalate (PET)/stainless steel/bamboo charcoal plied yarn in the first feeder and four-cycle PET/bamboo charcoal plied yarn in the second feeder.

Antibacterial properties and electrical characteristics of multifunctional metal composite fabrics

In this research, a hollow spindle spinning machine was used to manufacture the multifunctional metal hybrid yarns with stainless steel wire (SSW) as core material, antibacterial nylon (AN) filaments and bamboo charcoal polyester filaments (BC-PETs) as inner and outer wrapped yarn, respectively. The wrapping numbers of produced metal hybrid yarns varied from 8.0 to 15.5 turns/cm. Furthermore, metal composite woven fabrics were fabricated with the metal hybrid yarns as weft yarns and PET filaments as warp yarns on a loom. These woven fabrics were evaluated in terms of far infrared (FIR) emissivity, anion density, electromagnetic shielding effectiveness (EMSE) and surface resistance. The antibacterial activity of the woven fabrics was assessed against both Staphylococcus aureus and Escherichia coli according two test methods AATCC100-2004 and 90-2011, respectively. The wrapping numbers showed a significant influence on the FIR emissivity and anion density of the produced woven fabrics. The presence of SSW in the hybrid yarns decreased the surface resistance and improved the EMSE of the woven fabrics. EMSE measurement showed that FH-15.5 woven fabrics with 0°/90°/0°/90° lamination angles displayed a better electromagnetic shielding behavior than with 0°/45°/90°/−45° lamination angles.

Determination of electromagnetic shielding and antibacterial properties of multifunctional warp-knitted fabrics

Electromagnetic (EM) radiation, bacterial cross-infection, and electrostatic discharge hazards in working environments produce risks in workplace safety in EM industries and hospitals. Although many kinds of EM-shielding fabrics have been produced, few studies have focused on their antibacterial and other functional characteristics. In this study, a series of multifunctional EM-shielding fabrics possessing EM-shielding, antibacterial, antistatic, and thermal protective functions were produced. A vector network analyzer and a coaxial transmission holder were used to assess the EM-shielding performance of the multifunctional EM-shielding fabrics. The effects of layer numbers and angles of EM-shielding fabrics on the shielding level were investigated. The antibacterial ability of EM-shielding fabrics is essential for wearers who work in environments with poor indoor air quality. The test results showed that these fabrics showed excellent antibacterial activity against Escherichia coli and Staphylococcus aureus based on inhibition zone. The presence of stainless steel wires and bamboo charcoal polyester yarns in the multifunctional fabrics provided great EM-shielding and thermal insulation properties, respectively. Moreover, using different yarns as the back face of the warp-knitted fabrics could also impart different thermal properties for the fabrics. These findings provided technical bases to design personal protective clothing with EM-shielding to mainly protect the workers from EM radiation, bacterial infection, and electrostatic discharge.

Stainless steel/polyester woven fabrics and copper/polyester woven fabrics: Manufacturing techniques and electromagnetic shielding effectiveness:

This study uses metallic wires, stainless steel (SS) wires, and copper (Cu) wires as the core and 75 denier polyester (PET) fibers as the wrap material to form the metal/PET wrapped yarns. The optimal SS/PET and Cu/PET wrapped yarns are then made into different woven fabrics. The test results of the metallic wrapped yarns show that the optimal tenacity occurs with the wrapping count being 12 turns/cm, while the metal/PET woven fabrics have a low surface resistivity due to the conductive metal/PET wrapped yarns along the weft direction. An increasing number of laminating layers increases the electromagnetic shielding effectiveness (EMSE) while decreasing the air permeability of the woven fabrics. The laminating angle is also proportional to the EMSE of the woven fabrics. In sum, the combination of metal wires and PET fibers provides the resulting woven fabrics with good EMSE.

Properties and Manufacture Technique of the Functional Bamboo Charcoal/Metal Complex Fabrics

Functional textiles of far infrared emissivity and electromagnetic shielding are attracting increasing attention, thus in this research we fabricated the bamboo charcoal/metal complex yarns with stainless steel wires or copper wires as the core yarn and bamboo charcoal polyester textured yarn as the wrapped yarn, using a rotor twister machine. The two manufacture parameters were rotor speed (7000–11,000 r/min) and wrapped number (2–7 turns/cm), and the bamboo charcoal/metal complex yarns which had optimum breaking strength and elongation became the weft yarns of the bamboo charcoal/metal complex woven fabrics. After the complex woven fabrics were tested in tensile strength and tensile strain, they were changed with different lamination numbers for the tests of the far infrared emissivity, anion density and air permeability. When the core yarn was 80 ìm stainless steel wires, the complex woven fabrics had the optimum tensile strength and air permeability of 364.8 N and 174.8 cm3/s/cm2. When the lamination number was 2, the complex woven fabrics had the optimum far infrared ray emissivity of 0.94.

Functional Properties and Electromagnetic Shielding Behaviour of Elastic Warp-knitted Fabrics

An investigation was made on the electromagnetic shielding behaviour and other functional properties for manufactured multifunctional elastic warp-knitted fabrics. Bamboo charcoal polyester/Crisscross-section polyester (BC-PET/CSP) blended yarns were used as the back of the warp-knitted fabric while conductive composite yarns were used as the front. The variation in the far infrared emissivity and anion density of elastic-warp knitted fabrics produced with different proportions of BC-PET content were studied in detail. Moreover the electromagnetic shielding effectiveness (EMSE) of the fabrics with different elongation was measured in this study. The experimental results showed that increased elongation almost did not significantly affect the EM shielding behaviour of fabric K1 in the elongation range of 0 - 40%. Finally to increase the EMSE of the fabric, the lamination method was used in this study. EMSE measurement results showed that two layer K1 warpknitted fabrics with 90° interval displayed a better shielding effect against the EM wave compared to that with a 0° interval.

Evaluation on manufacturing technique and electromagnetic shielding effectiveness of functional complex fabrics

Modern technology has advanced swiftly, and thus, people have higher and higher demands for functional textiles. In order to have textiles with electromagnetic shielding effectiveness (EMSE) and far infrared emissivity, in this research, we fabricated three types of bamboo charcoal/metal (BC/M) complex yarns with metal wires as the core yarn and bamboo charcoal textured yarn as the wrapped yarns, with a rotor twister machine. Two manufacture parameters for the complex yarns were rotor speed (8000 rpm) and wrapped number of the BC/M complex yarns (4 turns/cm). BC/M complex woven fabrics were made of cotton yarn (warp yarn) and BC/M complex yarns (weft yarns), using a loom machine. The surface resistivities of BC/M complex woven fabrics were first measured. Then, EMSE evaluation was performed to test BC/M complex woven fabrics with different lamination angles. The BC/M complex woven fabrics exhibited higher surface resistivity than other woven fabrics by 1.71 × 1010 Ω/Sq; and the EMSE was 50–60 dB when the lamination number was 6 at incident frequencies between 1.83 and 3 GHz, which was satisfactory.

Structure design and property evaluation of silver/stainless steel composite fabric

This study presents a fabrication method for functional commingled yarns and prepared conductive knitted fabrics for shielding electromagnetic waves and electrostatic discharge. Stainless steel filament was used as core yarn, polyethylene terephthalate filament or silver yarn was used as wrapped yarn producing polyethylene terephthalate/polyethylene terephthalate/stainless steel filament or silver/silver/stainless steel filament commingled yarns via filaments hollow spindle spinning system and then knitting into silver/stainless steel composite fabric. The effects of cycle number and metal content on air permeability, surface resistance, and electromagnetic shielding properties of resultant knitted fabrics were discussed. Besides, influences of number of layers and lamination angle on electromagnetic shielding were also investigated intensively. The result shows that, conductive composite fabrics made by silver/silver/stainless steel filament commingled yarns and 450D polyethylene terephthalate plied filaments had higher surface resistance of 3.4 Log(Ω/sq) and 5.6 Log(Ω/sq), respectively, in coursewise and walewise directions. Electromagnetic shielding varied with number of layer, lamination angle, cycle number, and metal content. When six layers of conductive knitted fabrics were laminated with 45°, electromagnetic shielding reached 15 dB at 1–3 GHz frequency. The highest air permeability, 317.6 cm3/cm2/s, occurred at single-layer conductive composite fabric.