Preparation And Properties Of Polyamide Conductive Fiber And Its Compound Material

Surface metallization of flexible non-metallic materials (fiber, fabric, film) is an important way to achieve functional materials. After metalization, the flexible materials have the similar functions with metal, such as electrical conductivity, electromagnetic wave emission and absorption features, electrical heating and some metal-specific anti-bacterium features. Therefore, the metallized flexible material have a wide range of applications, which can be used as antistatic, conductive and shielding materials in various applications such as electromagnetic shielding, electromagnetic compatibility, static elimination, flexible wires and so on.In all metals, silver has the lowest resistivity and excellent antibacterial function, so silver is the preferred choice to metallize surface of the flexible non-metallic materials. Currently the methods of surface deposition of silver onto non-metallic substrates include physical deposition and chemical deposition. Chemical liquid deposition has the advantages of high efficiency, adjustable deposited layer, no limit on the shape of substrate material and easy mass production, which is an important way to metallize non-metallic materials.In this paper, Nylon 6 fiber was used as the substrate material, and silver deposited conductive nylon fiber was prepared through liquid chemical deposition. Then the conductive nylon fiber was compounded with low density polyethylene by injection molding to made electrically conductive compound materials. The influence of the silver deposition conditions on the process of deposition, fiber structure and properties was studied, and the effects of conductive fiber length, conductive filler content, injection molding conditions and surface modification of nylon conductive fiber by coupling agents on the compound material properties were also examined.The main contents and conclusions are as follows:(1) The pre-treatment conditions of chemical silver deposition on nylon fiber surface were studied and determined. After surface roughening in 140ml/L HCl solution, surface sensitization in 10g/L SnCl2 and HCl 100ml/L mixed solution, and surface activation in 1g/L AgNO3 solution, the following electroless chemical deposition process could achieved.(2) Dextrose was adopted as reducing agent, ammonia solution of silver was used as the oxide solution and silver source during the silver deposition process. Experiments showed that the way of solution mixing, the concentration of various reagents(AgNO3, C₆H₁₂O₆, NaOH, PEG10000), pH value, the use of surfactants had effects on silver deposition rate and coating quality. Through orthogonal tests optimum deposition conditions were obtained as follows: temperature 25℃, AgNO3 5g/L, C₆H₁₂O₆ 8g/L, NaOH 1.5g/L, PEG10000 0.2g/L.(3) It was found that the conductive fiber length-diameter ratio, the weight content of fiber, injection temperature, injection pressure have obvious influences on the conductive and mechanical properties of the compound materials. The optimum preparation condition was achieved based on the conductivity and mechanical properties.(4) The effects of surface modifications of the silver deposited nylon fibers with coupling agents were studied. It was found coupling agent with hydrosulfide groups has better effect than that with amino groups due to the stronger interaction between–SH and silver. Key words: chemical silver deposition; nylon-6 fiber; low density polyethylene; conductive...