Preliminary Research On Pressure-sensitive Components Base On Carbon Nanotube Filled Polymer Composites

With piezoresistive properties, polymer composite, whose resistance varies with the change of the applied pressure, can be used as sensitive material of pressure sensors. Pressure sensor sensitive materials should have greater pressure resistance strength, smaller deformation, better repeatability, and certain flexibility. It should also match with the contact materials. However, for a long period of time, the development of polymer composites has been constrained by the manufacturing process and the limited choices of filling materials, thus the sensors made have poor reproducibility, large errors and other defects. So it’s still at experimental stage. With the development of technology in the21st century, polymer composites have been making great progress.The conductivity of carbon nanotube is good and the types are abundant. A small amount of carbon nanotube as the conductive phase are filled into the polymer matrix to form a conductive network, which ensures the flexibility and piezoresistive sensitivity of polymer composite materials. So polymer composites filled with carbon nanotube are the new research subject of piezoresistive composites. The main contents of this research include:(1)The preparation of polymer composites. With MWNT as the conductive phase and room temperature vulcanized silicone rubber as the matrix phase, a co-solution blending method, assisted with ultrasonic wave and stirring dispersion treatment, is applied to manufacture pressure sensitive composite which possess good flexibility.(2) Test platform. It uses C8051F330as the control circuit chip, collecting the voltage signal. Then through A/D conversion, upload the data to the host computer via the serial, where processing, analysis, the storage, and display are done.(3) Analysis of experimental data. This research analyzes the conductive mechanism of the composites filled with carbon nanotube, the conductive mechanism of composite materials, the effect of the diameter of carbon nanotube on pressure sensitive composites, the hysteresis error, and the algorithm of piezoresistive transformation.(4) Preliminary study on the sensor sensitive elements.The results of this research provide theoretical and experimental basis for further study on the piezoresistive characteristics of polymer composites filled with carbon nanotube, and lay the foundation for the development of polymer-composites-based flexible pressure sensors.