芳纶/不锈钢纤维混纺机织物电磁屏蔽性能研究

为制备综合性能优异的电磁屏蔽织物,采用芳纶/不锈钢纤维混纺纱,通过改变组织结构、厚度、叠合角度的方法来织造电磁屏蔽织物,并分析其电磁屏蔽性能。结果表明:三原组织中,平纹织物的电磁屏蔽效能最佳,缎纹织物的电磁屏蔽效能最差;织物厚度增加,电磁屏蔽效能随之增强;织物叠合角度为45°时明显优于叠合角度0°和90°时的电磁屏蔽效能;芳纶/不锈钢纤维混纺机织物还具有优异的阻燃性能、机械性能和耐水洗性能。     

Electromagnetic shielding effectiveness and mathematical model of stainless steel composite fabric

In this paper, a kind of novel filaments/short fibers composite yarns containing stainless steel (SS) were produced by an innovative ring-spinning method. On the basis of the shielding mechanism of the electromagnetic (EM) shielding material, a method for fabricating a multifunctional SS composite fabric with EM shielding characteristics was successfully developed. Coaxial transmission line method was used to investigate the influences of different factors, such as radiant frequency, metal content, metal mesh size, and geometry, on electromagnetic shielding effectiveness (EMSE) of the composite fabrics in the frequency range of 15–3000?MHz. The notabilities of these factors were examined using analysis of variance (ANOVA). A regression model equation was setup using the above factors as variables, and verification of accuracy and practicability to this model was also carried out. The experimental results indicate that average EMSE of composite fabrics is 20.76–51.92?dB in the frequency of 15–3000?MHz, which indicates that the influence of the studied factors was considerable.     

Investigation of electromagnetic shielding properties of metal composite tufted carpets

Abstract

In this research, it is aimed to develop tufted carpets with electromagnetic shielding (EMSE) effectiveness. For this purpose, stainless steel, copper, silver wires, and metalized silver PA filaments were commingled with textured polyester yarn to produce composite yarn. Composite yarns were used in tufted carpet backing fabric with different densities and directions. The EMSE of carpet samples was measured in the frequency range of 0.8–5.2?GHz by free space technique. The effects of metal type, composite yarn density, and placement direction on the EMSE were statistically analyzed in 0.8–3.0 and 3.0–5.2?GHz frequency ranges separately. Stainless steel and silver wires provided better EMSE in the range of 0.8–3.0?GHz. Stainless steel showed better EMSE in lower frequencies than 3?GHz. The metallized silver was more effective above 3?GHz. The increase in metal density significantly increased EMSE for all metal types. Carpets containing metal in two directions provided multidirectional shielding and maximum EMSE reached up to 44?dB level. As a result of the study, tufted carpets which can provide multi-axial protection were produced successfully.     

防电磁辐射聚吡咯/ 棉织物的制备及其性能

为获得具备吸波特性的防电磁辐射织物,采用液相化学氧化法制备聚吡咯/棉高分子涂覆类织物,借助法兰同轴法测试织物电磁屏蔽效能,运用KES织物风格仪分析织物物理力学性能,在综合考察制备工艺对织物电磁屏蔽效能的影响以及织物经吡咯处理后的风格变化的基础上,获得最优制备工艺参数。同时,分析了织物电导率、厚度、电磁波频率以及表面孔洞面积对聚吡咯/棉复合织物电磁屏蔽效能的影响。在此基础上,建立了聚吡咯/棉复合织物及表面具有孔洞的复合织物的电磁屏蔽效能预测模型。结果表明：随着织物电导率、厚度的增加,屏蔽效能随之增加;随着电磁波频率的增加,电磁屏蔽效能呈现下降趋势;孔洞大小对电磁屏蔽效能影响显著。     

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.     

双层及多层电磁屏蔽织物的屏蔽效能

为研究多层电磁屏蔽织物屏蔽效能情况,通过改变叠层角度、间距、叠层方式、层数,构建正交导电网格结构和单方向金属纱线平行结构的双层及多层电磁屏蔽织物,采用法兰同轴法测试其0.3~1.5 GHz内的屏蔽效能。结果表明,经纬向具有同样金属纱线间距时,织物屏蔽层厚度小于趋肤深度则双层织物的屏蔽效能明显高于单层织物,超过趋肤深度后增加不显著;3层及以上织物的屏蔽效能增加不明显;随层间距离增加,屏蔽效能呈增加趋势。仅纬向含金属纱线的双层织物,随双层织物中纬纱交叉角度的增加,逐渐形成金属纱线正交网格结构,屏蔽效能增大;双层织物中纬纱对齐叠放时,层间距离增加则屏蔽效能增大,纬纱垂直叠放时,层间距离增加则屏蔽效能降低。     

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。     

金属纤维混纺屏蔽织物屏蔽效能

依照电磁屏蔽的基本理论，在分析金属纤维屏蔽织物屏蔽机理的基础上，给出了估算织物电磁屏蔽效能的计算方法并作了简要分析，探讨了金属纤维混纺纱的结构、金属纤维含量与织物紧度对屏蔽效能的影响。分析表明，屏蔽织物中导电网网间孔缝线经对屏蔽效能有较大影响，而织物总紧度并不总是与织物的屏蔽效能成正比。     

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.     

Investigation of electromagnetic shielding effectiveness of needle punched nonwoven fabric produced from conductive silver coated staple polyamide fibre

In this paper, electromagnetic shielding effectiveness (EMSE) of needle-punched nonwoven fabric produced from silver-coated staple polyamide fibre having a fineness of 1.7 dtex was investigated. This production was carried out at Automatex needle punching line, which consists of carding, cross lapper and needle punching machine. After production, the surface resistivity measurements of needle-punched nonwoven fabric was carried out in accordance with ASTM D 257-07 standard. The EMSE of the as-produced needle-punched nonwoven fabric was determined using a network analyzer as specified in ASTM D4935-10 in the frequency range of 15–3000 MHz. Electromagnetic shielding test shows that needle-punched nonwoven fabric produced from 1.7-dtex silver-coated polyamide fibre has the highest shielding value of 36.53 dB in the frequency range of 15–3000 MHz. The EMSE of needle-punched nonwoven fabric with fibre fineness of 1.7 dtex increased from 11.00 dB maximum to 36.53 dB in the 15–3000 MHz frequency range. It was seen that as the frequency increases, reflection values of the needle-punched nonwoven fabric decrease at floating mode, while absorption values of the nonwoven fabric increase at floating mode in the frequency range of 15–3000 MHz. EMSE results of the needle-punched nonwoven fabric produced from 1.7-dtex silver-coated staple polyamide fibres were compared to carbon fabric and needle-punched nonwoven fabric made from stainless steel fibres.     

几种电磁屏蔽面料屏蔽效能的研究

选择铜镍涂层织物、银纤维交织织物、铜镍金属丝织物、不锈钢交织织物4种电磁屏蔽面料进行研究,利用同轴传输线法测试它们的电磁屏蔽效能。结果表明:材料中的金属丝比例越大,织物的电导率越大,电磁屏蔽效果越好。在金属丝含量相同的情况下,银丝的电磁屏蔽性能优于不锈钢。经洗涤后,银纤维交织织物和不锈钢交织织物的电磁屏蔽效果没有明显变化,而铜镍涂层织物和铜镍金属丝织物的电磁屏蔽性能均有明显衰减。     

电磁屏蔽织物的发展现状及研究方向

介绍了有电磁屏蔽功能的金属纤维和纱线混编混纺织物、纤维表面镀金属织物、电磁屏蔽涂层织物、涂覆金属盐的织物和共混纺丝织物的制备方法、性能特点、研究现状以及应用领域,并指出了其研究方向.认为混编混纺织物应在确保屏蔽效果前提下减少金属纤维用量,以提高其可染性和可洗性;化学镀织物的研究方向是用等离子体和激光技术作前处理,改进镀液配方,开发多元复合镀层产品.     

呼吸性电磁屏蔽织物的开发

基于织物化学镀技术,对锦纶织物的聚氨酯涂层进行化学镀镍,开发出了呼吸性电磁屏蔽织物,对镀镍织物的功能性和服用性能进行了测试和分析。结果表明,镀镍织物具有良好的导电性、透湿性能、电磁屏蔽性能及耐用性等;随着增重率的变大,电磁屏蔽性能、透湿性和导电性明显改善,随后变化趋缓。镀层对织物的服用性能有不利影响,因此在满足呼吸性和电磁屏蔽性能的前提下,应尽量减小镀层厚度。     

双层防电磁辐射织物的屏蔽效能

为研究开发高性能电磁屏蔽材料,介绍了双层屏蔽织物屏蔽电磁波的原理,初步探索双层屏蔽织物屏蔽效能的影响因素,并采用法兰同轴法测试了3组双层防电磁辐射织物的屏蔽效能。测试结果表明,屏蔽织物中金属纤维体积含量增加,双层织物的屏蔽效能增大;织物中间间距增大,双层织物屏蔽效能增大;两层织物的经纬向一致时,双层织物屏蔽效能要高于其经纬向不一致时的屏蔽效能。     

Investigation of electromagnetic shielding effectiveness of needle punched nonwoven fabrics with staple polypropylene and carbon fibres

Conductive needle punched nonwoven fabrics are developed from staple polypropylene (PP) and varying weight fractions (10, 20 and 30 wt.%) of staple carbon fibres. A fibrous webs of staple PP and carbon fibres were formed at a wool-type carding machine, and these webs subsequently bonded on needle punching machine with 132 punches/cm² and 13.5 mm needle penetration depth. The electromagnetic shielding effectiveness (EMSE), absorption and reflection characteristics of as-produced needle punched nonwoven fabrics were determined using a network analyser as specified in ASTM D4935-10 in the frequency range 15–3000 MHz. The surface resistivity measurements were carried out in accordance with ASTM D 257-07 standard. These results indicate that the EMSE values increase incrementally with frequency in the 15–3000 MHz range. The nonwoven sample with 30 wt.% carbon fibre showed the lowest surface resistivity of 3.348 kΩ and corresponding highest EMSE of ~42.1 dB in the 3000 MHz frequency range. In comparison, the highest EMSE values from 10 to 20 wt.% staple carbon fibre were found to be 15.6 and 32.2 dB in the 3000 MHz frequency, respectively. It was observed that the absorbance and reflectance curves of each nonwoven fabric move at opposite directions to each other. It was found that as the amount of carbon fibre in the nonwoven fabric increases, absorbance values decrease, but reflectance values increase. The resultant nonwoven fabric samples are expected to be used as garment interlining after thermal bonding and wall interlayer in the future.     

防电磁辐射挂帏类织物的开发

介绍由不锈钢纤维和锦纶、棉纱织制的挂帏类织物的开发,该织物具有较好的电磁辐射防护性能。对该织物的电磁屏蔽性能做了测试和分析,结果表明:织物的电磁屏蔽效能不但与金属丝含量有关而且与纱线结构有关。     

纺织品防电磁辐射技术

介绍了电磁屏蔽织物生产中具有代表性的四类技术:利用金属纤维、碳纤维等与纺织纤维混纺;通过一定的化学、物理反应形成多离子织物;电磁辐射防护纤维;涂层防辐射织物。对于防电磁辐射织物的进一步研究与开发具有重要意义。     

织物防电磁辐射性能影响因素的研究

通过对不同金属纤维、不同金属纤维含量、不同纱线结构、不同织造方式、不同织物组织等防电磁辐射织物的屏蔽效能进行检测,探讨了织物防电磁辐射性能的影响因素,为防电磁辐射织物的开发设计提供参考。     

玻璃纤维/碳纤维织物基复合材料的电磁屏蔽性能

为增强碳纤维织物复合材料对电磁波的阻抗匹配性,减少二次反射,采用玻璃纤维调控碳纤维织物组织结构,并将其与水性聚氨酯复合,设计并制备了5种玻璃纤维/碳纤维(G/C)织物复合材料。借助超景深显微镜、矢量网络分析仪、模拟日光氙灯光源系统、红外热成像仪对G/C织物复合材料的形貌结构、电磁屏蔽性能、介电性能以及光热转化性能进行表征和分析。结果表明：在12.1 GHz下,纬纱采用2根玻璃纤维和单根碳纤维交替排列织造的G/C织物复合材料的屏蔽效能高达38.7 dB;G/C织物复合材料的组织结构变化可有效调控多种介电极化弛豫机制;G/C织物复合材料表面温度在模拟日光氙灯光源照射下响应速度快,其中玻璃纤维和碳纤维单根交替排列的G/C织物复合材料在2 kW/m²光照强度下照射300 s时,其表面温度可达71.8℃。     

组织结构对针织物电磁屏蔽效能的影响

设计了几种代表性织物组织结构的不锈钢纤维混纺针织物,研究了织物组织结构对针织物电磁屏蔽效能的影响。织物组织结构选择充满系数较高的双罗纹组织、打鸡双面组织、添纱衬垫组织、衬纬组织和绕经组织,以降低织物厚度、密度、孔隙等因素对织物电磁屏蔽效能的影响。对所有织物进行了电磁屏蔽效能测试,结果显示:双罗纹织物、双面织物、添纱衬垫织物、衬纬织物的电磁屏蔽效能都很不理想,且远远低于含不锈钢纤维机织平纹布,但是绕经织物的电磁屏蔽效能要比其他组织的针织物的屏蔽效能高得多,基本能达到国标上对屏蔽服的屏蔽效能要求。绕经织物与其他几种针织物最大的不同就是在纵向多了一些连续的含不锈钢纤维的混纺纱。说明针织物组织结构是影响电磁屏蔽效能的关键因素,可通过在织物纵横向形成纵横交错的导通的金属网栅的方式来改善不锈钢纤维混纺针织物的屏蔽效能。