Study On The Preparation And Sensing Properties Of Carbon Nanotubes/ Polydimethylsiloxane Composite Yarn

With the development of information technology and related peripheral technology, especially the rapid development of computer technology, the sensor technology has been a revolutionary progress. Sensor has combined with information technology especially the microprocessor to produce all kinds of powerful smart sensors.Carbon nanotube yarn has excellent mechanical, electrical properties and special piezoresistive effect and as a result, it has a broad application prospect in the field of intelligent material. The pure carbon nanotube yarn and different concentrations of carbon nanotubes / polydimethylsiloxane(CNT/PDMS) composite yarn was the object of study of the paper and the changes between pure yarn and composite yarns in appearance and mechanical, electrical, sensing properties were studied; and the principle of strain sensing of pure carbon nanotube yarn and CNT/PDMS composite yarns were investigated. Eventually the optimal ratio of PDMS was obtained which makes that the mechanical and sensing properties of the composite yarn is the best, and then the yarn can be applied to the field of intelligent sensing to prepare intelligent fabric in the future.The research contents are as follows:1 In this article CNT/PDMS composite yarns were prepared with different concentrations by dripping leaching and the concentration of PDMS were 0%, 1%, 3%, 5%, 7% and that 0% refers the carbon nanotube yarns were only treated by solvent toluene. C-CNT yarns were studied by thermogravimetric analysis to know the actual content of PDMS in the composite yarn and to provide basis for the discussion about related performance. The changes of diameter and irregularity of diameter of X-CNT composite yarns and C-CNT composite yarns were studied and surface morphology, then the improvement of the irregularity of diameter of X-CNT composite yarns and C-CNT composite yarns was found, but that were not obvious.2 The effects of solvent toluene and different concentration of PDMS solution on the tensile and wear properties of X-CNT yarn and C-CNT yarn were studied. It was found that the tensile properties of X-CNT and C-CNT composite yarns improved after treating by toluene, the strength of X-CNT yarns increased by 8.61% and the strength of C-CNT yarns increased by 77.67%; the elongation at break of X-CNT yarns increased by 42.81%, and the elongation at break of C-CNT yarns increased by 48.24%. the performance of X-CNT composite yarn is the best when the concentration of PDMS solution is 5% and the strength of which increased by 71.07%, modulus of which increased by 54.69% compared with the original X-CNT yarn; the performance of C-CNT composite yarn is the best when the concentration of PDMS solution is 1% and the strength of which increased by 113.89% compared with the original C-CNT yarn. But when the concentration of PDMS solution is 3%, the wear resistance of the composite yarn is the best, this is mainly due to the diameter that when the concentration of PDMS solution is 3%, the diameter of the C-CNT composite yarn is much larger than that of the concentration of PDMS solution is 1%. The relevant property of C-CNT yarn is generally better than that of X-CNT yarn after comparison and analysis.3 The effects of solvent toluene and different concentration of PDMS solution on the sensing properties of X-CNT yarn and C-CNT yarn were studied. The sensing coefficient of X-CNT yarn increased by 52.17% and the sensing coefficient of C-CNT yarn was increased by 254.29% after treating by toluene. When the concentration of PDMS solution is 5%, the sensing coefficient of X-CNT composite yarn is the maximum and it was increased by 195.65% compared with the original X-CNT yarn. The sensing coefficient of C-CNT composite yarn is the maximum when the concentration of PDMS solution is 1% and it was increased by 394.29% compared with the original C-CNT yarn. And the properties of electronic fatigue of X-CNT yarn and C-CNT yarn were studied. It was found that the performance of X-CNT yarn when the constant elongation rate of is 1.5% was better than that of the X-CNT yarn when the constant elongation rate of is 1%; and the performance composite C-CNT yarn was better than that of the original C-CNT yarn;and the electrical sensitivity of C-CNT yarn was superior to X-CNT yarn.