Study On Controllable Preparation Of Silver Nanowires / Silver Powder By Rotating Bed With Helical Channels High-gravity Technology

Silver is the most conductive metal found so far.In the field of some high-end new materials,the core technologies of some key materials have not yet achieved breakthroughs,and the limitation of materials seriously affects our development of new applications.The market system has an urgent demand for large-scale production of basic materials.Among them,Nano silver wire(Ag NWs)and nanometer silver nanoparticles(Ag NPs)have been widely used in electronic industry,biological medicine,catalytic and photoelectric materials due to their excellent electrical conductivity and antibacterial properties.But currently,the preparation of nanometer Ag materials,there is a low production rate,easy to reunite,bad dispersibility,impurities and industrialized difficult problems,which greatly affects the application of nanometer Ag materials in various production fields,so to achieve high yield rate and the excellent properties of nanometer Ag mass preparation has been becoming the current mainstream material.In this paper,a new idea for largescale preparation of nanomaterials is proposed,that is,the combination of the unique Rotating Bed with Helical Channels(RBHC)high-gravity reactor of our research group and the improved polyol method to achieve Controllable preparation of Silver Nanowires and Silver Nanoparticles,and can be applied to large-scale production.By adjusting the variable parameters in the experiment,the size of the nanoparticles is controlled by adjusting the level of high-gravity;the morphology and size of the product are analyzed by characterization methods such as SEM and XRD,and the following conclusions are drawn:(1)The maillard reaction was introduced in the polyol system and the dihalogen ions bromine and chlorine were added to prepare the silver nanowires in a conventional reactor.The mechanism of the formation process was studied,and the influencing factors such as reaction temperature,concentration,halogen ions,PVP and silver nitrate mass ratio were mainly discussed.Finally,silver nanowires with a diameter of 25-45 nm and aspect ratio of 600 were prepared at a condition of160℃,20 mmol/L concentration,a mass ratio of PVP/ Silver nitrate which was 1/1,and introducing dihalogen ions.Through characterization,it can be seen that in addition to Ag NWs,some silver nanowires and silver halide particles were also generated.(2)Based on the optimal preparation of silver nanowires by conventional reactors,silver halide nanowires are prepared by combining with RBHC high-gravity reactor in the high gravity reactor,and then grown into silver nanowires by oil bath heating through reduction synthesis.Compared with conventional reactor,temperature,concentration,high gravity level,halogen ion,PVP/ Ag ion mass ratio and other influencing factors were discussed.The average particle size of prepared silver nanowires was less than 25 nm,the length was 20-35 μm,and the slenderness ratio was up to 1300.The results showed that the products had uniform particle size and good dispersion.The controllable preparation of silver nanowires was achieved by adjusting the rotor speed of the high-gravity reactor.(3)The RBHC high gravity reactor was used to prepare nanometer silver powder,and the influencing factors such as temperature,concentration,high gravity level,PVP/ Silver ion mass ratio were discussed.Finally,nano silver powder with a average diameter of 50 nm were prepared at a condition of 120℃,30 mmol/L concentration,1200 rmp speed,PVP/ Silver ion mass ratio of 1/1,and the characterized showed good uniformity and dispersion of the products,and not easy to agglomerate.The controllable preparation of silver nanowires was achieved by adjusting the rotor speed of the high gravity reactor.