Preparation Of High Conductive Composite Fillers By Tannic Acid And Iron Surface Modification

With the rapid development of electrical industry,electromagnetic shielding materials play an important role in preventing electromagnetic interference?EMI?.The high conductivitve filler in polymer materials,with low cost,low density,good conductivity,is an effective means to improve the performance of electromagnetic shielding.However,the domestic research in this area is relatively backward.Therefore,it is important to research and develop high conductivity composite fillers with excellent performance.Mussle-inspired dopamine modification has advantages which are easy to operate,reacting milding,eco-friendly and universal to various types of material.It is a simple and effective surface modification method,which can effectively improve the binding force between the silver particles and the substrate.Highly conductive silver-coated powder was prepared through dopamine modification.Nevertheless,the high cost of dopamine and long reaction time limit its industrial production and application.The excellent adhesion of dopamine comes from the ortho-phenolic hydroxyl in its structure.Therefore,we chose two low-cost tannic acid?TA?and iron(Fe³⁺)instead of dopamine to modify the surface of the matrix.Tannic acid?TA?a kind of polyphenol extracted from plants,is rich in catechol and pyrogallol groups.Tannic acid?TA?can be quickly chelated with metal ions(Fe³⁺)to deposit stable polyphenol-metal film on the surface of substrate,which is an efficient,environmental friendly surface modification method.The details are as follows:?1?First,the polyphenol-metal layer was quickly deposited on the surface of matrix by the complexation of tannic acid?TA?and ions(Fe³⁺).The optimal deposition conditions were as follows:the pH during reaction is 8.0,the concentration of Fe³⁺ is 0.12 g/L.The TA-Fe³⁺ modified aluminium powders were coated with silver through electroless plating.The silver-coated aluminum powders show high electrical conductivity of 10000 S/cm.The TA-Fe³⁺ surface modification method is environmental friendly,efficient and has a wide range of application.It shows broad application prospects in the field of surface modification and functionalization of materials.?2?Graphene oxide was modified by TA-Fe³⁺,and then a two-step electroless plating process was carried out to prepare silver coated graphene oxide.The silver-coated graphene oxide shows high electrical conductivity of 5000 S/cm.The two-step silver plating method is suitable for the substrate which is difficult to be plated with silver.This method can be used to prepare highly conductive silver-coated powder,which provides a new idea for the metal surface of materials.