| In recent years,with the progress of science and technology and the popularization of smart products,smart products have been deeply penetrating into all aspects of life.Among them,smart apparel has become one of the hottest topics in the field of textile and widely used in military,healthcare,sports and other fields.Smart apparel utilizes advanced materials and textile technology to embed miniature and flexible electronic components in apparel to realize the functions of textile apparel such as perception,calculation and communication of information.The smart clothing is composed of sensor unit,driving unit and control unit.The sensing part is mainly realized by textile material.When the textile material is changed or stimulated by the external environment,its structure,vibration,electrical property,color changing and adjusting temperature and other changes,so that clothing has a sensing function,and through the drive unit and the control unit for the perception of the signal processing.As a kind of common conductive fiber,metal has a wide range of value in the preparation of fabric flexible sensors.However,poor weaving of metal and it needs to be combined with other fibers to improve its weaving and comfort.At present,many researchers have done a lot of research on the knitted flexible sensors,but there are few researches on the woven flexible sensors,therefore,it is of certain value to study the preparation of metal/silk fabric and evaluate its wearability and sensing performance.It can provide a certain theoretical basis for the subsequent development of good conductive woven flexible sensors with good comfort.In this paper,the structure and properties of the selected stainless steel wire,copper wire and mulberry silk were characterized by scanning electron microscopy(SEM),digital multimeter,yarn strength and elongation and length measuring instrument.With stainless steel wire and copper wire as core yarn and mulberry silk as outsourced yarn,16 kinds of metal/silk composite yarn were prepared by wrapping technology.The structure,mechanical properties,tribological properties and electrical conductivity of the composite yarn were determined by polarizing microscope,yarn length measuring instrument,yarn strength and elongation tester,yarn dynamic friction coefficient tester and digital multimeter.The effects of the parameters of metal variety,fineness of metal and fineness of the outsourced yarn on the properties of the composite yarn were studied,and the processing parameters of wrapping were optimized.24 kinds of metal/silk fabrics were prepared by using the optimized two kinds of composite yarns and interwoven with mulberry silk.The influence of the structure of tissue and the proportion of composite yarn on the wearability and sensing properties of the conductive fabric was studied by testing the mechanical properties,permeability,wrinkle recovery,bending rigidity,cyclic resistance,the change of resistance at 5 min after full load,and the effect of different drawing rates on fabric resistance change.The main conclusions are as follows:1.The structure and properties of the materials were characterized,stainless steel wire and copper wire fiber is uniform,there surface have longitudinal stripes and the fiber has low oxygen content good antioxidant capacity and excellent linearity in resistance.The metal has good continuity and good extensibility.The surface of metal is smoother,and the cohesion between fibers is small.It can be combined with other fibers to improve its weaving and comfort.16 kinds of metal/silk composite yarn were prepared by wrapping process with different fineness and variety of metal wire as core yarn and mulberry silk with different density.By analyzing the morphology,mechanical properties and electrical conductivity of composite yarn,we know that for different diameter and diameter of metal,from of outer yarn,the structure of composite yarn is different.The forming of the stainless steel/silk composite yarn is better when the diameter of stainless steel wire was 0.021 mm and 0.035 mm,the density of silk was 88.9dtex,130 dtex and 88.9 dtex.When the diameter of copper wire is 0.035 mm and 0.065 mm,the density of mulberry silk is 44.4 dtex,88.9 dtex and 88.9 dtex,130 dtex,the composite yarn has high coverage,good evenness and good shape.The breaking strength of the composite yarn increased with the increase of silk density,the higher the twist degree of the outer yarn,the worse the dry evenness of the composite yarn and the lower the elongation at break.The surface friction property of the composite yarn is affected by the yarn structure,when the silk density is88.9 dtex,the surface friction coefficient of the composite yarn is the smallest and the surface roughness is small.The resistance linearity coefficient R2 and sensitivity GF of the composite yarn increase first and then decrease with the increase of silk thread density,when the density of mulberry silk is 88.9 dtex,the correlation coefficient R~2of the composite yarn is the largest.Based on the comprehensive analysis of the properties of the composite yarn,the wrapping process is optimized,the optimized two kinds of composite yarns are 0.035 mm stainless steel wire+88.9dtex mulberry silk,0.035 mm copper wire+88.9 dtex silk.2.24 kinds of metal/silk fabrics were prepared by using the optimized two kinds of composite yarns as weft yarn and interwoven with mulberry silk by configuring different parameters such as organization and insertion ratio.By measuring the performance,it is found that adding a composite yarn to the weft can improve the permeability of the fabric,three kinds of tissue permeability in descending order is plain>satin>twill.The higher the proportion of the composite yarn in the weft,the smaller the wrinkle recovery angle of the fabric,the worse the fabric's crease resistance.The crease resistance of stainless steel wire/silk fabric is better than that of copper wire/silk fabric,in three kinds of tissues,the wrinkle resistance of plain is the worst,the wrinkle resistant of satin fabric is the best,twill fabric between the two.The higher the proportion of the composite silk in the fabric,the more rigid the fabric feel,and the hand feel of the copper wire/silk fabric is more rigid than the stainless steel wire/silk fabric.It is known from the analysis of the sensing properties of the fabric.From the fabric resistance elongation curve,it can be seen that the linear correlation coefficient R~2of 24 kinds of fabric samples is above 0.953,the resistance change is stable,and the electrical conductivity is good.It shows that the metal/silk fabric has good electrical conductivity.It is known from the sensitivity GF value that the higher the ratio of the composite wire in the fabric,the lower the sensitivity of the fabric.The content of composite yarn effects on fabric sensitivity is more obvious when the fabric stretching back 20 times,with the decrease in the proportion of composite yarn in the weft,the linear sensitivity of the fabric is increasing,and the sensitivity is highest when the insertion ratio is 6:1.It is known that the fabric has the highest correlation coefficient R~2when the fabric stretching rate is 100 mm/min,and the stability of the resistance change is better.To the stainless steel/silk fabric,the stress relaxation characteristics is in a stepwise trend when the insertion ratio is not at the same time,and with the decrease of the proportion of composite yarn in the fabric,the stress relaxation parameters of delta?R firstly increased and then decreased,the?R value is relatively large when the insertion ratio was 4:1.Meanwhile,the stress relaxation of copper wire is more stable.The stress relaxation characteristic of stainless steel wire/silk fabric is worse than copper wire/silk fabric. |
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