Research On Piezoresistive Properties Of Carbon Black/Aluminum Silver Powder Filled Conductive Rubber And Sensor Design

Intelligence is one of the important development directions in the process of research and development of modern robot.Aiming at the development of robot which has perceptive ability proposes more precise and more stringent technical requirements.It is urgent to develop a kind of functional material with good flexibility and excellent conductivity.Therefore,conductive silicone rubber was produced.Particles with conductive property as fillers were filled in the rubber matrix.A kind of composite functional material by a certain process was prepared which is conductive silicone rubber.The choice of conductive fillers has a decisive influence on the properties of conductive silicone rubber.This paper introduced the development of conductive silicone rubber at home and abroad,analyzed the main research trends and types of conductive silicone rubber and compared the advantages and disadvantages of the conductive fillers.In view of the advantages and disadvantages of conductive fillers,carbon black and aluminum powder were selected as conductive fillers to test the property of conductive rubber with different content of the two fillers.Based on conductive rubber and piezoresistive sensing principle design sensor,the practicability of the new material was verified.The main research contents are as follows:(1)We studied the conductive mechanism,piezoresistive property and relaxation property of conductive silicone rubber and introduced three kinds of percolation models for the formation of conductive channels based on conductive composites of two kinds of conductive theory of macro and micro.The results showed that conduction path theory acted as dominant when the concentration of conductive filler is relatively larger,and electron tunneling theory acted as dominant when the concentration of conductive filler is relatively smaller.The conductivity of conductive silicone rubber is the result of the two theories.(2)Based on the analysis of the type and content of raw materials,different experimental samples were prepared with solution blending method by selecting 107 silicone rubber as the base rubber,carbon black and aluminum powder as conductive filler particles,hexane as solvent,TEOS as coupling agent,two methyl silicone oil as diluent and some auxiliary additives.The performance of samples were tested by the inspection instrument.An optimized experimental scheme was proposed by analyzing and discussing the experimental data so as to prepare conductive silicone rubber with good comprehensive properties.(3)This paper studied the different samples of electrical conductivity,the piezoresistive property.Analysis of conductive property shows that comparing of without the addition of aluminum powder and the little of aluminum powder,this situation could improve the conductivity of composites when the filler is content.Therefore,carbon black and aluminum powder mixed could improve the conductive property of conductive silicone rubber.So the cost can be reduced by reducing the amount of carbon black.Analysis of piezoresistive property shows that samples with different content of carbon black and aluminum powder have almost the same curves of piezoresistive property.Through comparison,the samples of A34(25% carbon black + 3% aluminum powder)and A35(28% carbon black + 3% aluminum powder)have not only good conductivity,but also a wide range of piezoresistance.This paper studied the change of resistance with time under constant external force with the experiment of resistance relaxation.We analyzed the mechanism of producing relaxation phenomenon and the effect on the internal structure of conductive silicone rubber with external force.The research results show that the produce of relaxation property is not only related to the applied pressure and time,but also with the addition of conductive fillers.It is very significant to study the relaxation property of the stability and sensitivity of materials.(4)This paper established piezoresistive model based on piezoresistive sensing principle according to the characteristics of new conductive silicone rubber material and design requirements of the sensor.The sensor inspection experiments are completed based on the study of the property of conductive silicone rubber and design of the external circuit of piezoresistive sensor.It's show that the sensor model proposed in this paper could measure the pressure size in a certain range.The experimental results showed that this kind of conductive silicone rubber has the advantages of good conductivity,wide resistance range and small relaxation property.The sensor making with the conductive silicone rubber has good characteristics such as high accuracy.It has certain reference value to study of conductive silicone rubber material and sensor.