| Electronic products have got their population prompted by technology development, thus generating increasing electromagnetic (EM) radiation which is very harmful to human. In order to develop better EM shielding fabric to reduce the harm, in this paper, the development and limitations in previous researches were analyzed. Two kinds of novel filaments/short fibers composite yarns respectively containing stainless steel (SS) and single polymer (PET) filaments were produced by an innovative ring-spinning method. Based on the principle of EM shielding, a method for fabricating a multifunctional SS (PET) composite fabric with EM shielding characteristics using such novel yarns was successfully developed. This EM shielding functional fabric was designed to be applied in daily life and special occasions.In this paper, through using an innovative ring-spinning method, stainless steel (SS) filaments/short fibers and single polymer (PET) filaments/short fibers composite yarns were produced respectively. The properties of novel SS composite yarn were analyzed and studied, mainly including yarn’s internal structure, the effects of SS staple fiber content on hairiness, tensile and conductivity features of yarn. Total 34 kinds of fabrics with different structures were designed and manufactured by SS/cotton and PET/cotton composite yarns. Influence factors, like radiant frequency, SS content and metal mesh size were investigated according to EMSE tests of fabrics. Mathematical model was developed by analysis of variance (ANOVA) for EMSE study and predicting the shielding properties of fabric. In order to evaluate and select the optimum comprehensive performances of metal wire composite fabric, in this study, a comprehensive evaluation of the EM shielding and wearability of composite fabric were conducted by Grey clustering analysis (GCA) method based on the triangular whiten-weight function clustering method, which is mainly used to check whether the observation of objects belongs to different categories. The results are shown as follows:(1) Compared with conventional core-spun and wrapped yarns, the novel filaments/short fibers composite yarn has typical space structure. SS filaments make geometric helix distribution and conformation within the composite yarn; additionally, staple and filaments of SS fibers interconnect to some extent, widening its shielding region. The hairiness index reduces from 4.22 to 2.84 with the increasing of SS content in SS/cotton composite yarn; breaking strength and rupture elongation rises on the whole while decrease gradually following the increasing of staple SS; in a certain range, conductivity and electromagnetic shielding effectiveness (EMSE) grow along with the SS content increase, however, such promotion effect is not obvious when SS content exceeds a certain level.(2) In the frequency range of 15-3000MHz, the average EMSE of composite fabrics is 20.76-49.02dB and the percentage of EM shielding reaches up to 90.84-99.65%, corresponding to levels 4-5 and levels 3-4 in common and special occasions respectively. SS content, metal mesh size, mesh geometry and wrap/weft count have different effects on the EMSE of fabric, especially the former two factors. The data of fabric shielding properties predicted using Multiple Linear Regression theoretical model is almost consistent with that calculated directly from experiment, demonstrating that the mathematical model is rather reliable.(3) The findings indicate that SS content, metal mesh size, mesh geometry and wrap/weft count have different effects on the fabric wearability. With the increasing of SS content and decreasing of metal mesh size and wrap/weft count, the fabric wearability decreases. Mesh geometry almost has no influence on fabric wearability.(4) On the basis of analyzing 34 kinds of composite fabric, GCA suggests that the fabrics with 11-19% metal SS content and 0.4-1.6mm2 metal wire mesh size are optimum design qualities for both the EMSE and wearability. |
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