电磁纺织品研究进展

从具有电磁学性能的纤维及平面织物、多层复合平面织物、立体结构织物等的制备方法、基本性能、应用等方面,综述了电磁纺织品的相关研究进展。分析了含本征导电高分子的纺织材料、表面镀覆金属的纤维或织物、含金属或金属化纤维的织物、磁性纤维在电磁纺织品领域内的应用及特点;指出平面状电磁屏蔽织物开发中存在的问题,提出电磁纺织品应该向多层复合平面状织物及三维立体结构方向发展,应该注重包含特殊电磁性能的周期金属结构单元或周期性结构的应用。此外,阐述了基于纺织的导电复合材料、电磁屏蔽织物测试方法或理论模型以及该类织物在天线等上的应用。     

The electromagnetic shielding properties of some conductive knitted fabrics produced on single or double needle bed of a flat knitting machine

In recent years, the use of electrical and electronic devices has grown rapidly. These devices cause electromagnetic interferences, which could threaten human life. In order to solve this problem, intensive research to develop textile surfaces having electromagnetic shielding properties continues. In this paper, we study textile surfaces knitted with conductive copper and stainless steel wires wrapped with acrylic yarns and also core yarns produced by using conductive yarns to test the electromagnetic shielding properties of the fabrics. It was concluded that the knitted structure of the fabrics affected the electromagnetic shielding effectiveness (EMSE). Besides, the fabrics knitted on a double needle bed of the knitting machine with higher amounts of conductive yarns and unit weights could not provide the targeted improvement in the EMSE values with respect to the fabrics produced on a single needle bed of the knitting machine.     

不锈钢纤维/棉复合纱的开发及其性能

为更好地开发和利用功能性纱线和面料,以不锈钢短纤维、不锈钢长丝以及棉纤维为原料,采用一种长丝/短纤维复合结构纱线的纺纱工艺开发出不同金属纤维含量的新型复合结构纱线。对复合结构纱线的结构,毛羽,拉伸性能以及导电性能进行测试分析。同时测试了利用该种复合结构纱线开发出的电磁屏蔽面料的屏蔽性能。实验结果表明：利用此种复合结构纱线制作方法所开发出的纱线具有较优异的毛羽性能、力学性能和导电性能,并且不锈钢纤维含量对纱线性能有着较大的影响。利用该种复合结构纱线开发出的面料屏蔽率达到90%-99.9%,可用于日常生活用电磁防护装材料。     

电磁屏蔽织物的导电网格结构及其屏蔽效能的一般影响规律研究

分析了电磁屏蔽织物的纱线和织物的细微结构,提取了由具有加捻结构的金属纤维纱线构成的有效屏蔽网格结构,提出了对应的等效电路及通用影响参数。在1~18 GHz内,采用屏蔽室法,对裸铜丝、金属纤维纱线及织物样品的屏蔽效能进行了研究。结果表明:网格结构很好地反映了该类织物的有效屏蔽结构;金属纱线的周期间距是屏蔽效能的关键影响因素;金属纤维单向排列织物的屏蔽效能具有显著方向性;金属纤维纱线在交叉点处的导通概率对屏蔽效能的影响难以判断,尚需要进一步研究。研究结果对于电磁屏蔽织物具有普适性,为屏蔽效能定量数值计算提取了有效参数。     

Preparation and characterization of conductive and antibacterial polyacrylonitrile terpolymer yarns produced by one-step organic coating

In this research work, electrically conductive PAN yarns were produced by coating with copper sulfide and, afterward, evaluated. PAN yarns were treated in a bath containing divalent copper ions, a reducing agent, which is capable of reducing the divalent copper ions to monovalent copper ions and a sulfur-containing compound for sulfidation of copper ions attached to the samples. A pH controlling agent (an organic acid) may be used to enhance the quality of copper sulfide adsorbed by the yarns which, in turn, improves the electrical conductivity of the samples. Using the results obtained from this study, we had to develop appropriate suitable formulation for application and optimization of copper sulfide coating of PAN-based materials. The copper coating of PAN yarns resulted in a reduction of electrical resistivity to 1 × 10¹⁰ that of an almost infinite resistance for the untreated yarns. The influence of linear density of the samples on the electrical conductivity and the mechanical properties of the copper-coated PAN yarns were evaluated. Copper-coated PAN yarns displayed very high light fastness and a washing fastness property to multiple washes in terms of electrical conductivity changes. The coating of PAN yarns with copper sulfide confers good antibacterial performance and the antibacterial activity of coated yarns against S. aureus after eight home laundering cycles was not significantly reduced. Results showed that coating PAN samples with copper sulfide can produce samples with good antistatic and antibacterial properties while, at the same time, retaining touch, washability, and other physical properties of the starting samples.     

Coating of conductive yarns for electro-textile applications

Conductive yarns are used for integration of sensors and other electronic devices with textile fabrics through weaving, knitting, braiding or embroidery processes. In the lifetime of the textile also several washing cycles might occur. These processes involve rubbing which may lead to displacement of conductive fibres, causing short circuiting between the neighbouring conductive fibres. Also the textile products made with conductive fibres may have to work in the presence of water, where the exposed conductive fibres can get short circuited. In this work, an attempt has been made to protect silver-coated polyamide yarns with polypropylene (PP). This is done through wrapping the PP staple fibres around the silver-coated polyamide yarns through friction spinning and melting the PP sheath fibres in an oven. The influence of twist in the conductive yarns, amount of PP coating and the oven temperature during coating process on the tenacity, electrical insulation in the presence of water and flexibility properties of the coated yarns are studied. The PP coated yarns with plied conductive yarn in the core provide better flexibility but need higher amount of coating to provide complete electrical insulation in the presence of water as compared to those yarns with single conductive yarn in the core.     

Electrical conductivity and physiological comfort of silver coated cotton fabrics

The objective of present study was to develop multifunctional and wearable electrically conductive fabrics with acceptable comfort properties by in-situ deposition of silver particles. The effect of silver nitrate concentration and number of dips was investigated for change in electrical conductivity, EMI shielding, and antimicrobial properties of coated fabrics. The dynamic light scattering and SEM analysis were employed to study the morphology of deposited silver particles. The EMI shielding was found to increase with increase in concentration of silver particles. Later, the comfort and mechanical properties were studied. No significant decrease in air permeability and water vapor permeability was observed due to partial coverage of fabric pores by coating of silver particles. Moreover, the coated fabrics also showed promising behavior toward antimicrobial properties. When the durability of coated fabrics was examined against washing, the application of binder provided good retention of silver particles without loss of electrical conductivity of coated fabrics.     

Investigation of antibacterial and antifungal properties of tufting carpets containing metal composite yarns

In this research, antimicrobial (antibacterial and antifungal) properties of tufting carpets containing metal/texturized polyester composite yarns were investigated. Carpet contains different yarn groups such as pile yarns, ground warps and wefts. Backing fabric’s warp and weft yarns are suitable for gaining antimicrobial activity because of their placement and low usage amount. Thus, textured polyester yarns were commingled with copper, stainless steel metal wires and silver metalized polyamide yarn. Backing fabrics were produced with four different placements by composite yarns. Antibacterial activity tests were applied to carpet samples according to AATCC 100 standard against K. pneumoniae and S. aureus bacteria. AATCC 30 – Part 3 standard was used for determining antifungal activity against A. niger. Results show that the antibacterial activity increases with increasing in the amount of metal composite yarn in unit area. Carpet samples which include copper or metalized silver composite yarn in all warps showed antibacterial activity about 99%. Moreover, antifungal activity can be provided against A. niger when copper and metalized silver composite yarn is used in all warps of carpet samples.     

Electromagnetic shielding effectiveness of carbon/stainless steel/polypropylene hybrid yarn-based knitted fabrics and their composites

In this study, a range of conductive hybrid knitted fabrics and their composites have been investigated for shielding effectiveness in the frequency ranges of 50 MHz to 1.5 GHz (low frequency) and 4 to 8 GHz (C-Band). Carbon and stainless steel (SS) filaments were combined in Dref-3 spinning machine and different hybrid yarns were prepared. The plain- and rib-knitted fabrics were made in V-bed flat knitting machine from the prepared hybrid yarns. The composite laminate was prepared by sandwiching a ply of fabric between the polypropylene films in compression moulding machine at 180 °C for 5 min under a consolidation pressure of 12 bar. All the fabrics and composites were tested for shielding effectiveness (SE) in coaxial transmission line and C-band waveguide with the help of vector network analyser. It was observed that fabric having both conductive loop and inlaid yarns exhibited higher SE of 20.2 dB than other fabrics in low-frequency range. However, in the composite form, carbon composite with SS inlaid yarn showed better SE of 45 dB than other composites. In C-band frequency range, conductive loop fabric structures yielded high shielding effect in course direction compared to wales direction. Compared to fabric form, the composite showed higher SE for all frequency ranges. This study proposes that knitted fabrics and their composites can be utilized as electromagnetic shields in wide frequency ranges.     

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 (μm) 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 0–3000?MHz. 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 20?dB in higher frequencies and higher thermal absorbtivity values compared to twill fabrics.     

Electromagnetic shielding effectiveness of copper core-woven fabrics

Copper is selected as a conductive filler to produce copper core yarns to make woven fabric using a network analyser equipment, and the electromagnetic shielding effectiveness of these fabrics is measured in the frequency range of 20–18,000 MHz. With an increase in the number of conductive fabric layers, finer yarn count, warp density, weft density and cover factors, an increase in shielding effectiveness is observed. With an increase in copper wire diameter, a decrease in shielding effectiveness is observed.     

汽车纺织品用纱线的新功能

描述了表达导电织物EMI屏蔽效果和预测如何达到预定要求的纱线和织物结构的公式.介绍了Trevira Neckelmann公司生产的具有电磁屏蔽效果的纱线和织物的特性和应用.     

Development of water-, oil-repellent and flame-retardant cotton fabrics by organic-inorganic hybrid materials

In this study, water-repellent, oil-repellent and flame-retardant cotton fabrics were developed by solgel technique. With this aim, nanosols were prepared using tetraethylorthosilicate and hexadecyltrimethoxysilane as precursors, guanidine dihydrogen phosphate as flame-retardant agent and Guard AFB as conventional water–oil-repellent agent, solvents and chelating agents. Then, to AC105, VA7110, PU1110 and FC9005 as polymeric additives, with/without FX8000 or urea and formaldehyde as cross-linking agents, were added some nanosols to improve washing fastness of the fabric samples. Cotton fabrics were treated with nanosols without polymeric additives by pad–dry–cure process, while they were coated with nanosols containing polymeric additives by knife-over-roll coating. Water–oil-repellent properties, flame-retardant properties, washing fastness, contact angle, whiteness, tear strength and add-on values of the coated fabric samples were determined. It was found that the cotton fabrics with good water–oil-repellence and flame-retardant properties with relatively durable properties could be produced using nanosols containing guanidine dihydrogen phosphate and urea, together with tetraethylorthosilicate and hexadecyltrimethoxysilane as precursors, and lower concentrations of Guard AFB as commercial water–oil-repellent agent. However, the fabric samples were still not sufficiently durable when washed. It was deduced that the durability of cotton fabric during washing is developed by means of treatment with nanosols containing polyvinyl acetate-based polymer.     

涤纶/聚酰胺6纳米纤维包覆纱的连续制备及其应用

为制备兼具力学性能和导电性能的氨敏传感器基体材料,采用一种水浴静电纺丝法连续制备涤纶工业丝为芯,聚酰胺6纳米纤维为皮层的纳米纤维包覆纱(NCY),并采用原位聚合法对其进行导电处理,制备表面负载聚吡咯的导电纳米纤维包覆纱(NCY/PPy),借助扫描电子显微镜和傅里叶红外光谱仪对NCY和NCY/PPy进行表面形貌和化学结构分析,同时研究了NCY/PPy的导电性能、力学性能、氨敏性能。结果表明,NCY具有超高的比表面积;经导电处理后,负载的聚吡咯未堵塞纤维之间的空隙,纳米纤维包覆层仍保持多孔网状结构,当吡哜浓度为0.07 mol/L 时,NCY/PPy的电导率达7.19×10^-2 S/cm;高比表面积的纳米结构导电层,有利于提高气敏传感器对氨气的敏感性。     

动态力学载荷对超细镀金钼丝力学与电学性能的影响

为探究超细金属纱线在力学循环加载后的弯曲刚度下降和能量耗散行为,对不同结构镀金钼丝纱线进行了50次循环弯曲和200次往复摩擦实验,并对摩擦前后的表观形态、拉伸性能和电学性能进行了比较。基于镀金钼丝纱线的微观形貌和实验结果,结合能量损耗分析方法,研究其在弯曲循环载荷和摩擦往复载荷下的力学及结构响应,定量分析金属丝的可编织性。结果表明:镀金钼丝在循环弯曲和往复摩擦载荷下,微观和宏观结构受到损伤,力学性能下降,接触电阻略有增大;该条件下,双股镀金钼丝刚度和强度下降程度最大,不适合上机织造,单股和三股镀金钼丝动态力学性能稳定,且在动态载荷作用下能保持良好的电学性能,可用做电磁屏蔽织物等功能性材料编织。     

Development and characterisation of polyaniline/polyamide (PANI/PA) fabrics for electromagnetic shielding

In this study, novel conductive fabrics were developed by polymerising of aniline onto the polyamide (PA)-knitted fabrics. The fabric treatment was done by the chemical polymerisation method at 0.5, 0.8 and 1.2?M aniline concentrations. Hydrochloric acid as acidic medium and ammonium per sulphate as oxidant were employed during the polymerisation process. The polyaniline (PANI)-treated PA fabric structures were fully characterised and evaluated in terms of their electromagnetic shielding effectiveness, absorption and reflection characteristics and tensile properties. Additionally, the fabrics were examined by scanning electron microscope (SEM) for the surface morphology and Fourier transform infrared spectroscopy for the chemical functionality. The electromagnetic shielding effectiveness, absorption and reflection characteristics were determined by Network Analyzer with a frequency ranged from 15 to 3000 MHz. The electrical characteristics were measured by the two ends method. It has been concluded that the bursting strength values of the treated fabrics reduced when the amount of monomer in the concentrations decreased as compared to the untreated fabrics. It is interesting to note that 1.2 M treated fabric had the highest bursting strength values as compared to the other treated fabrics. It was also found that 0.5 M concentration of PANI-treated fabric had the lowest surface resistivity due to this it showed the highest conductivity value. Another important finding is that the 0.5 M-aniline treated fabric had the highest shielding effectiveness.     

棉/不锈钢长丝机织物的电磁屏蔽及折皱回复性能

为研究组织结构与磨损对织物屏蔽性能的影响,以及不锈钢长丝对织物折皱回复性的影响,使用自制的棉/不锈钢长丝包芯纱织制了3种不同组织的机织物,测试了织物在0.3~1 500 MHz频段上的电磁屏蔽性能,并使用平磨仪对各织物分别摩擦60、120、180、240 及300次后,测试了织物磨损后的电磁屏蔽性能;同时,采用视频序列法测试了织物的动态折皱回复角。结果表明：织物组织结构对电磁屏蔽性能有一定影响,平纹组织结构紧密,屏蔽效果好;经过若干次磨损后,织物的电磁屏蔽性能先小幅升高后逐渐降低;相同磨损条件下,试样耐磨性越好,屏蔽效能的降低幅度越小;由于不锈钢长丝的加入使织物的折皱回复性降低,可以采用浮长更长的组织改善织物起皱现象。     

影响金属纤维混纺织物屏蔽效能因素初探

电磁屏蔽织物是一种各向异性的屏蔽材料,其屏蔽效能受到诸多因素的影响,精确计算存在较大困难.文章依照电磁屏蔽的基本理论,介绍了金属纤维屏蔽织物屏蔽的机理与屏蔽效能的测试,着重分析了屏蔽织物相关的结构参数对织物屏蔽效能的影响,如织物组织、厚度、金属纤维混纺纱的结构、金属纤维含量对屏蔽效能的影响等.     

Devices for measuring electrostatic generation and dissipation on the surfaces of polymeric materials

Dynamic electrostatic generation and dissipation on polymer surfaces are of great importance for materials such as yarns and films. To support fundamental research in this area, innovative devices and experimental techniques that can lead to a better understanding of these phenomena are of obvious academic and industrial interest. This paper reports the development of devices for testing the electrostatic generation/dissipation properties of polymer surfaces. These devices include a tester for assessing moving yarns, a high-resistance system to measure the yarn's linear resistance, a tester for evaluating stationary fabrics or films while rubbing against a moving surface and a contact charge tester for investigating charge generated by contacting of two surfaces. These devices enable the study of the influences of relative moving speed, yarn tension, electrostatic charge properties of yarns, as well as contact pressure, rubbing speed, number of rubbings or contacts on the static charge properties of films.