Synthesize Of Coated Conductive Filler And Their Conductivity Influence In Epoxy Resin

With the development of electronic industry becoming more and more quickly, the electromagnetic radiation harm also intensifies, which has become the third largest killer of the health hazard. So the requirement for electromagnetic shielding materials are growing demand for conductive filler. Non-metallic powder composite has the same function of metallic materials (such as electrical conductivity). Not only he price and density of the non-metallic powder are low, but also the materials have high and low temperature resistance. Meanwhile has good high polymer material compatibility. So the metallization of inorganic non-metallic materials used as conductive filler have good market prospects. Epoxy resin conductive adhesive is a kind of adhesive substance with certain conductive property after solidification or drying, which can realize electronic packaging and adhesion of materials, which consist of epoxy matrix, thinner curing agent filler. Epoxy resin conductive adhesive have a widely used.This topic are using mica powder, glass beads, copper powder, glass fiber as base material, using chemical preparation of silver plating composite filler. Optimizing the preparation technology, and finds the best conditions of electroless. Then put the conductive fillers into the epoxy resin testing conductivity.The factors affecting the yield of target product were investigated as follows:(1) With mica powder as core material, then use of two-step sensitization-activation pretreatment, using the method of chemical plating in the surface coating layer of silver. The optimized condition as follows:the dosage of coarsening is 20g/L, the concentration of sensitizing liquid is 20g/L, time is 20min, activate of liquid concentration is 3g/L In the process of follow-up pH is 12, main salt concentration is 15g/L, the concentration of glucose is 37.5g/L, mica with silver nitrate mass ratio on the chemical quality is 2.5:1. The Ag/mica volume resistivity is 0.088Ω·cm(2) With glass beads as core material, using the method of chemical plating in the surface coating layer. The optimized condition as follows:surfactant concentration is 20g/L, silver salt concentration is 13.5g/L, and the reducing agent concentration is 40g/L, pH is 12. The Ag/microsphere has a best properties and the volume resistivity is 0.063Ω·cm.(3) With glass fiber as the core materials, use of coupling agent by molecular self-assembly method for pretreatment. Using the method of chemical plating in the surface coating layer, the optimized condition as follows:The loading capacity is 2.5g, concentration of coupling agent 2mL, coupling time is 100min, the main salt concentration is 20g/L, reducing agent concentration is 35g/L, the volume resistivity is0.054Ω·cm(4) With copper powder as core material, coating silver on its surface the optimized condition as follows:concentration of activation is 7g/L, copper powder and silver nitrate mass ratio is 15:1, concentration of main salt is 20g/L. The chemical plating of copper powder has the best properties and the volume resistivity is 0.031Ω·cm.Using four composite powder as a conductive fillers putting into epoxy resin and then preparing conductive adhesive. Discussing the influence of the content of filler and conductive behavior on composite materials.