Enhancing The Performance Of Carbon Fiber Reinforced Composite Structural Capacitors With Carbon Nanotubes

The structure capacitor integrates electrical properties with mechanical properties. It can save the space, reduce mass and increase the payload by dispersing the capacitor into the structure of the system. In this paper, we applied the carbon nanotubes and carbon fiber to capacitor based on the excellent mechanical and electrical properties and big specific surface area of carbon nanotubes as well the semiconductor properties of carbon fibers expecting to obtain high performance capacitor.The details of the research and the results are as follows:(1) Multi-Walled Carbon Nanotubes (MWNTs)/epoxy nanocomposites were prepared. And the effects of types and fraction of MWNTs on the curing behavior of epoxy and the conductive performance of the nanocomposites were investigated. The results showed that the addition of carbon MWNTs had no significant impact on the curing behavior of epoxy and the conductivity of nanocomposites was improved with the increase of MWNTs, but when the content exceeded 1.5wt%, the effect was not evident any more. when the content was certain, the smaller the diameter of MWNTs, the higher volume resistivity.(2) A series of structural capacitors were prepared using T300 carbon fiber woven cloth/ epoxy composite as electrode. The influences of MWNTs types and content on the capacitance, interlaminar shear strength, multifunctional performance of capacitors were investigated. The results showed that the capacitance reached 796 nF/m2 with the diameter of MWNTs increasing, increased by 81% compared with the capacitors without MWNTs. The capacitance and interlaminar shear strength increased first and then declined with the increase of MWNTs content, and the maximum value of multifunctional efficiency was 0.770.(3) A series of structural capacitors were prepared using T700 carbon fiber unidirectional cloth /epoxy composite as electrode and the effects of MWNTs types and content on the capacitance, interlaminar shear strength, multifunctional performance of capacitors were discussed. The results showed that the larger the diameter of MWNTs was, the greater the maximum value of the capacitance was and the maximum value was 875 nF/m2, increased by 92% compared to the capacitors free of MWNTs. The capacitance and interlaminar shear strength increased first and then decreased with increasing MWNTs content, the maximum value of multifunctional efficiency was 0.779.(4) It is found that the introduction of MWNTs led to the increase of multifunctional efficiency of capacitors strengthened by T300 carbon fibers and T700 carbon fibers, but the former's multifunctional efficiency increased more than the latter's, and the former's multifunctional efficiency was lower than the latter's.