Study On Preparation And Properties Of Highly Conductive Silver-coated Glass Fibers

Electromagnetic shielding materials play an important role inpreventing leakage,pollution and interference of the electromagnetic wave.Common electromagnetic shielding materials are made by combining conductive fillers with matrix.Conductive fillers commonly used at present are prepared by metal-plating on the surface of particles.In order to improve the adhesion between metal and particles,chemical modification of particle surface is necessary.Dopamine modification is an efficient,convenient and environment friendly method to improve the interfacial adhesion between silver and matrix.This is due to the phthalic dihydroxyl structure in the dopamine molecule,which gives it good adhesion.However,dopamine is expensive and has long reaction time.Catechol and polyamines can compensate for dopamine.This modification method not only has low cost,but also has fast reaction speed.It is suitable for industrial mass production.Tannic acid comes from natural plants and can be chelated with Iron ion(Fe³⁺)to be deposited on the surface of the matrix,making the surface adhesive.In this paper,PCPA modification and tannic acid-Fe³⁺modification methods were used to modify the surface of glass fiber（GF）,and the highly conductive glass fiber/silver composite was prepared by electroless plating.The main work is as follows:（1）Silver-coated GF（GF/PCPA/Ag）with high electrical conductivity was prepared by surface modification of poly（catechol/polyamine）（PCPA）and electroless silver plating.The relationship between the molar ratio of catechol and polyamine（Tetraethylenepentamine）and electrical conductivity was studied.X-ray photoelectron spectroscopy（XPS）,scanning electron microscopy（SEM）and X-ray diffraction（XRD）were used to study the PCPA on GF surface and the silver layer on GF/PCPA/Ag surface.It was found that continuous,uniform and dense silver layer was formed on GF surface.After high temperature heat treatment,the roughness of the silver layer of GF/PCPA/Ag decreases and the electrical conductivity increases.The optimal heat treatment temperature and time are500℃and 0.5 h,respectively.Finally,GF/PCPA/Ag was combined with silicone rubber to obtain a composite with a conductivity of 150 S/cm.These results indicate that GF/PCPA/Ag can be used as highly conductive filler and has a good application prospect in electromagnetic shielding materials.（2）GF surface was modified by fast chelation of tannic acid（TA） and iron ion(Fe³⁺),and then electroless silver plating was carried out to prepare GF/silver highly conductive material.The prepared glass fiber/silver highly conductive material was characterized by SEM,EDS,XPS and electrical conductivity,and the TA-Fe³⁺chelation system and silver were successfully coated on GF surface.The prepared glass fiber/silver highly conductive material has high electrical conductivity.The high aspect ratio of the fiber can form lap effect,reduce the percolation value of electromagnetic shielding materials,reduce the amount of filler,and has potential applications in electromagnetic shielding materials.