Green Synthesis Of Metal Nanoparticles Using Plant Fiber Extracts For Preparation Of Conductive Ink

Silver nanoparticles are widely used in the field of biological and antibacterial materials because of its excellent electromagnetic and antibacterial properties.But the cost of silver is very high,which greatly limits its application in various fields.Therefore,it is a pressing problem which needs to be solved to reduce the use of silver under the premise of ensuring the characteristics of silver.According to the idea of composite material,the shell structure of the silver coated on the powder can not only maintain its electromagnetic performance,but also greatly reduce the cost.As a kind of inorganic material,silica is easy to obtain,has a wide range of raw materials,low cost,and stable physical.Therefore,it is often used as a basic material for composite materials.In this research,the extract of corn straw was used as a reducing agent to prepare silver nanoparticles.Then,silver-coated silica conductive particles are obtained and applied to the preparation of conductive inks Finally,the electrical conductivity of the composite was investigated.Firstly,in this thesis,glucose was used as reducing agent to prepare silver nanoparticles applied in conductive ink.The study found that when the molar ratio of glucose to silver nitrate was 2:1,the molar ratio of PVP to silver nitrate was 1.5:1,PH value was 11,the molar ratio of PVP to AgNO₃ was 1.5:1,reaction temperature was 50°C,reaction time was 120 min,the silver nanoparticles with uniform particle radius and good dispersibility were obtained.In addition,UV curable conductive ink with 25%silver conductive colloid under the condition of 70%silver content was obtained.Its conductivity was high?3.7×10⁴ S/m?and cost was chape.Then,corn straw extract was used as reducing agent for the synthesis of silver nanoparticles.This method is unprecedented.The ultrasonic cell crushing time for corn stalk extract,the amount of silver nitrate,the reaction time and the reaction temperature for the synthesis of silver nanoparticle have great effect of its homogeneity.The results shown that when ultrasonic time was 20 min,reacting time was 30 min,temperature was 80°C,and the amount of AgNO₃ was 0.20 g.AgNPs with a narrow particle size distribution?10²3nm?was obtained.The main particle morphology was spherical.Finally,silver was cated on the surface of SiO₂ which was modified with propyltrimethoxysilane.The amount of modifier and reducing agent in the preparation experiment and silver content were studied.The research found that when silver content was70%,the molar ratio of MPTMS to silica was 1:5,silver nitrate concentration was 0.08 mol/L,the formed silver core-shell structure was dense and the conductivity was strong.With the further increase of the reducing agent,the conductivity is not increased importantly.In this thesis,the silicon sphere with particle size of 80nm is coated,when the silver content is 90%,the silver-plated conductive ink was prepared with a resistance of 1.09?and a conductivity of9.17×104 S/m.The use of silver has dropped by 25.4%,demonstrating that this research method can indeed significantly reduce the cost of using silver.