| Carbon nanotubes have excellent mechanical,thermal and electrical properties,and are ideal materials for developing conductive fibers and constructing conductive circuits of electronic intelligent textiles.However,it is difficult to form a good electron transport path during the assembly process of carbon nanotubes,so the carbon nanotubes prepared by floating catalyst technique,array spinning technique and wet spinning technique are often of low conductivity,which cannot meet the needs of practical applications.Although researchers have proposed relevant improvement measures based on these spinning technologies,there are still problems such as insignificant effect,weak stability and high cost.To solve these problems,a new method based on the wet spinning technique was developed in this paper to improve the electrical conductivity of carbon nanotube fibers,and a novel carbon nanotube/silver composite fiber with high conductivity was prepared by the process of spinning solution design,silver chemical deposition,hot-pressing treatment and process parameters optimization.After optimizing the process parameters,the conductive circuit of the textiles with stable performance was also successfully constructed.The main research contents and results of this paper are shown as follows:(1)The spinning solution containing sodium cholate(SC),sodium carboxymethyl cellulose(CMC)and single-walled carbon nanotubes(SWNT)was prepared by high pressure homogenization method,and dispersion state of SWNT was characterized by transmission electron microscopy and UV-VIS-NIR spectroscopy.The results showed that the change of CMC content can affect the dispersion state of SWNT in the spinning solution,and a small amount of CMC was beneficial to the dispersion state of SWNT,while an excessive amount of CMC had a negative effect on the dispersion state of SWNT.The results of rotary rheometer test showed that the increase of CMC content can improve the viscosity of spinning solution,but didn't change the non-Newtonian fluid characteristics of shear thinning.(2)The properties of the initial fibers were tested by a universal material tester and a data collector,and the morphology of the fibers was characterized by a scanning electron microscope.The results showed that the presence of CMC affects the electrical conductivity and mechanical properties of the initial fibers.The presence of CMC in a certain content range could enhance the interaction between SWNT and improve the properties of the fibers,while the excessive content would hinder the electron transport in the fibers.Ultra-precision balance was used to calculate the linear density of the composite fibers after silver deposition.The results showed that the presence of CMC was beneficial to the adsorption of silver.The electrical conductivity of the composite fibers after hot-pressing was measured by using a data collector.The results showed that the electrical conductivity of the composite fibers was the highest when the concentration of CMC was 2 mg/m L,which could reach 5.9×10~6S/m.(3)The parameters of AgNO3 concentration,deposition reaction time,SWNT concentration and hot-pressing pressure were optimized.The results showed that the properties of the composite fibers after hot pressing treatment were better when the concentration of SWNT was 6mg/m L,the concentration of AgNO3 was 0.6mol/L,the deposition reaction time was 40 min,and the pressure was 10 MPa.In this case,the electrical conductivity of the composite fibers could reach 1.9×10~7 S/m,and the tensile strength could reach 80.6 MPa.(4)The application demonstration and environmental test of the textile conductive circuit constructed by composite fiber were carried out.The results showed that the conductive circuit constructed by composite fiber had good mechanical stability,cleaning resistance,environmental stability and timeliness. |
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