Preparation And Properties Of Nylon 66 Fiber Composite Electromagnetic Shielding Material

With the development of electronic instrument with high frequency,informatization and digitization,the energy density of radiation interference in the external environment will inevitably increase,and witch will cause an unprecedented influence of the environment,coordination of ecological environment,human living space and social sustainable development.Therefore,the exploration and research of composite electromagnetic shielding?EMS?materials has become an important task to human health.With the advancement of society,shielding materials are expanding toward to low density,easy processing,and high shielding effectiveness.PA66?nylon 66?fabric has the advantages of low density,corrosion resistance,easy to cut and low price,and can be used as a lightweight composite EMS substrate.Electroless metallized fabrics have excellent electrical conductivity and machinability,but single chemical plating has its insurmountable disadvantages.Composite plating can be combined with electroless plating and electroplating.Compared with electroless plating,the electroplated layer is dense,fastness and anti-corrosion.This study is based on a PA66 plain weave fabric with an are al density of 40g/m²,a warp and weft density of 3.3 tex,a thickness of 50?m and a size of 200×200mm.Through the ways of pre-treated,electroless plated with Ag,Cu or its composite coating before electroplating Ni.The method provides a composite electromagnetic shielding fabric with light weight,good corrosion resistance and high shielding effectiveness.The different pretreatment conditions of PA66 were studied and types of electroless plating on PA66 surface were optimized and effects of different selection on the property of electroplated nickel on the surface of conductive PA66 were researched.The specific study contents are as follows:?1?By comparison,organic solvent similar compatibility principle is used to remove photoresist and degreasing effective.Exploring the solvent type-weight loss rate,immersion time-weight loss rate law,found that the volume ratio of 1:1:1 acetone:ethanol:water solvent immersion 60min of removing photoresist and degreasing completely.Observing the weight loss rate of roughening,the SEM morphology of roughening and the SEM morphology of nickel plating after roughening,and found that the crude HCl/acetic acid in ethanol solution was obtained at a temperature of 30?,acetic acid concentration of 1 mol/L,hydrochloric acid of 1.5 mol/L,and time of 40 min.The chemical plating effect is best after the coarsening.The experiment selected the Sn-Pd solution for sensitization and activation,and the HCl solution was degummed.?2?By gravimetric method,the AgNO₃ concentration was 40g/L,the time was90min,the optimum PA66 plated Ag surface density was 56g/m² at 15°C?The optimal PA66 plated Cu surface density 52 g/m² was obtained at a volume ratio of 1:3,time15min and temperature 65°C.The density of PA66 electroless plating Ag/Cu?69 g/m²?has a higher areal density than Cu/Ag?63 g/m²?.Observation of physical,OM and SEM images showed that the coating of electroless Ag/Cu fabric coating was the most complete.EDS and XRD showed that the corresponding metal coating was obtained by chemical plating and shielding performance test showed that the electroless plating Ag/Cu fabric EMI was the best.?3?Through the physical,OM,SEM,EDS diagrams discovered that after the surface of the conductive PA66 is plated with nickel.The surface coverage of the fabric is relatively complete.But the Ag/Cu-plated Ni coating is the most uniform and dense.High XRD peak intensity indicates the Ag/Cu-plated Ni has strong surface metal properties.VSM showed that the saturation magnetization of PA66-Ag/Cu-Ni?42emu/g?was significantly higher than that of PA66-Cu/Ag-Ni?31 emu/g?.Tafel shows that the corrosion potential of PA66 composite Ag/Cu-Ni increases with the increase of plating time,and the corrosion current value becomes smaller and smaller.So its corrosion resistance is getting better and better.The shielding mechanism of the composite electroplated fabric shows that the magnetic layer is increased and the shielding performance of the material is increased.Shielding performance tests show that PA66-Ag/Cu-Ni shielding effectiveness?80dB¹04dB?is best.