Study On Preparation And Properties Of Silver Or Copper /carbon Fibers Functional Particles And Their Flexible Conductive Film

With the development and progress of science and technology, flexible conductive composites have met unprecedented opportunities for development. The previous preparation of high-conductive material use metal powder such as silver and copper powder as conductive fillers. Although the conductive performance of metal powder is good, but its application in conductive materials was limited due to its high cost and big density, so the new type of conductive fillers become the main development trend. In this paper, copper- or silver-based composites(CFs/Cu and CFs/Ag) using commercial carbon fibers as the templates were synthesized by electroless plating method. Then, the conductive film of silicon-rubber/copper-coated carbon fibers and silicon-rubber/silver-coated carbon fibers were prepared using the above composite particles as conductive fillers and silicon rubber as matrix material, respectively. The conductivity responses of the film under external field were studied. The main research contents and results are listed as follows:(1) The complete and uniform copper film or silver film was plated on the surface of carbon fibers successfully by electroless plating. Their volume resistivity can reach 6.63?10-3 and 5.59?10-3 ??cm, respectively. It was found that reaction temperature, sodium hydroxide contents and reaction time played important roles in the size of Cu particles and its distribution on the surface of carbon fibers. With glucose as the reducing agent, silver nitrate as the main salt, when reaction temperature was 30?C, NaOH was a requirement to obtain a complete coating. The increasing of glucose concentration and reaction time can make coating complete.(2) The silicon-rubber/copper-coated carbon fibers and silicon-rubber/silver-coated carbon fibers conductive film were prepared by silicon rubber as the matrix, xylene as solvent, ethyl orthosilicate as curing agent, CFs/Cu and CFs/Ag as conductive fillers.The preparation process, phenomena of percolation conductivity, mechanical properties and electrical conductivity and chemical stability were studied. The analysis was found that, under normal temperature, conductive film showed obvious seepage phenomenon, and the percolation thresholds of copper and silver conductive film were 0.84 vol.% and 0.78 vol.%, respectively. The addition of composite fillers to silicon rubber improved the conductivity of conductive film, but reduced the mechanical performance. By analyzing the conducing behavior, the results showed that the conductivity of the film was sensitive to the axial tensile stress. With the increasing of tensile strain and stretch cycle number, the conductive of film declined. At the same time, permanent deformation increased gradually, and the recovery became poor. By comparing the two kinds of conductive film, the results showed that CFs/Ag fillers were more cohesive to the silicon rubber matrix, and the adhesion strength of silver plating and carbon fiber was better. The silver coating was not easy to be oxidation, so the mechanical properties, electrical conductivity and chemical stability of silver conductive film are better than that of the copper conductive film.