No Palladium Activation Of Chemical Silvering Glass Fiber Preparation And Application

With the high conductivity, excellent chemical resistance and high tensile strength and heat resistance, silver-coated glass fiber has a wide application in conductive polymer material. By using Palladium-free activation pre-treatment, silver-coated glass fiber was prepared under different processes. The key factors and their effects on the silver-coated glass fiber resistivity and coating surface were studied. Conductive adhesive which using Silver-coated glass fiber for its conductive filler was prepared, the effect of hybrid filler and its loading on conductive adhesive were studied. By using X-ray diffraction (XRD), the glass fiber surface which using palladium-free activation pre-treatment was analysis. The surface morphology of silver-coated glass fiber was observed by scanning electron microscopy (SEM). The resistivity of silver-plated glass fiber and the bulk resistivity of conductive adhesive were tested. The following results can be summarized.(1) Palladium-free activation pre-treatment is suitable for electroless silver plating on glass fiber, and experimental study of the three reducing agents found that when using glucose as reducing agent, the chemical reaction was stable, and the silver-plated glass fiber has the minimum resistivity. Experiment also explored the influence of different sodium hydroxide concentration on the glass fiber and found that the higher the concentration of sodium hydroxide, the faster the chemical reaction reacted, at the same time, the coating become thicker. The study also found that reaction temperature on the impact of electroless plating is similar to sodium hydroxide concentration, that is, the higher the temperature, the greater the coating thickness, but the poorer the quality of coating surface. Experimental study on different fiber loading in the glass fiber electroless silver plating and found that when the fiber loading is 15g/L, the reaction have the highest silver utilization and lower costs, and also have the lower resistivity of the silver glass fiber.(2) Mechanical stirring and ultrasonic treatment was studied, it's found that the coating surface of the glass fiber is more uniform by ultrasonic treatment, grain size is also smaller, but some glass fiber does not covered by silver coating, which eventually led to its higher resistivity.(3) Conductive mechanism of silver-coated glass fiber was analyzed, the resistivity of silver-plated glass fiber and the contact resistivity between fibers both have influence on the resistivity of silver-coated glass fiber powder. With the mechanism, the problems in the experiment were explained.(4) Conductive adhesive with the conductive filler of silver-coated glass fiber was prepared successful. The study found that the relationship between the filler loading and the bulk resistivity conform to percolation phenomenon. Experiments also examined the differences between silver flake and silver-coated glass fiber and found the conductive network of conductive adhesive was easier formed by using long diameter silver-coated glass fiber conductive filler. However, the mechanical properties of the system become worse. Finally, the measures to improve the mechanical properties were also discussed.