Preparation Of Nano-copper Conductive Adhesive By Using Alkaline Etching Wastewater

The purpose of the paper is to research the synthesis of nano-copper and the preparation of nano-copper conductive adhesive by using the alkaline etching wastewater. The paper has two content parts; the one including the synthesis of nano-copper using alkaline etching wastewater by liquid chemical reduction method, the other is the preparation of nano-copper conductive adhesive by adding the nano-copper powder as the conductive files into the epoxy resin.The alkaline etching wastewater as the copper material, the copper nanoparticles is prepared via liquid chemical reduction method. The paper discusses the effect of factors on the synthesis of copper nanoparticles, including concentration of the copper of the alkaline etching wastewater, kinds of reduction agent, reaction time, reaction temperature, concentration of CTAB and PVP, through lots of experiments, obtained the best reaction parameters; the N2H4·H2O is as best reduction agent, concentration of the reduction is0.523mol/L, reaction time is30min, reaction temperature is70℃, the concentration for CTAB and PVP is0.003g/L,0.002g/L respectively.The concentration of the copper of alkaline etching wastewater is obtained by AAS, the concentration of the copper is136.467g/L before reaction and the filtrate is less than2mg/L, so the recovery efficiency is above98%. As-obtained nano-copper has been characterized by XRD, SEM, EDS, XPS, UV-vis, FI-TR, TG/DT, Schemer equation and so on. The results shows that the copper nanopaticles is spherical shaped, well dispersed, excellently anti-oxidized, and less than100nm.The nano-copper powder as conductive files, epoxy resin as the substrate of conductive adhesive, low molecular polyamide as curing agent and other additive agents to preparation of nano-copper conductive adhesive. Studying the additive agents on synthesis of conductive adhesive, including toughening agent, silane coupling agent and reduction agent.Through a lot of experiments, SiO2is used as toughening agent, KH570is used silane coupling agent, and the reduction is HCHO, the best quality content is1.5%,4%.3.0-3.5%, respectively. At the same time, researching the content of nano-copper powder affection on the performance of conductive adhesive, the best content of nano-copper powder is80%. The shear strength and bulk conductivity of conductive adhesive is8.25MPa,2.35×10-3Ω·cm respectively with the best conditions.