| With the rapid growth of the demands for harmful microbiological defense and electronic equipment,materials with green antimicrobial and electromagnetic shielding effectiveness have become increasingly important in our daily life in recent years.The development of nanotechnology has also brought subversive reforms to the materials industry.In this paper,nanosilver particles were prepared by reducing the silver precursor solution with lemon grass extract and then mixed with polyvinyl alcohol as coating on 80g/m2 base paper.The high permeability and antibacterial of nanosilver is much higher than ordinary silver.The sintered nanosilver coating has good conductivity,which give the coating electromagnetic shielding effect.Plant reduction method is more safe,reliable,environmentally than others.Lemon grass extract as a reducing agent for the reduction of nanosilver particles here.First,the plant crude extract in lemon grass was extracted by ultrasonic extraction.The effects of different conditions(time,power,ethanol volume fraction,material ratio)on extraction rate and extraction of amide compounds were investigated.Then the nanosilver particles with uniform particle size were prepared by silver amide solution and the active substance of lemon grass,which average diameter is about 25 nm.The reaction conditions(time,tempreture,material ratio,quality of starch)on the size and distribution of silver nanoparticles were discussed.The different quality fraction of nanosilver were mixed with different concentrations of polyvinyl alcohol.The natural environmental coating on paper gives paper good antibacterial properties and electromagnetic shielding effectiveness.The effects of different concentrate nanosilver particles and PVA on the mechanical properties,antibacterial properties and electromagnetic shielding were investigated.Finally,the dried coated paper is sintered to melt the nano-silver particles to form a conductive grid structure,which give the paper conductive properties and electromagnetic shielding effectiveness.Select a set of sample paper to measure electromagnetic performance between 30 MHz and 1.5GHz.This paper introduces the preparation of natural environment-friendly nanosilver particles,the research background of antibacterial and electromagnetic shielding materials,the antibacterial and electromagnetic shielding mechanism of inorganic metal nanosilver,the common nanosilver synthesis method,the common role of lemon grass,and the development of plant reduction method.The optimum extraction conditions of lemon grass extract and the preparation of spherical nanosilver were determined.Finally,the nanosilver particles prepared by biosynthesis method were prepared into coating.The coated paper was prepared for characterization. |
