Dielectric behaviors of carbon nanotube/silicone elastomer composites

Carbon nanotubes (CNTs) with different aspect ratios were modified by a silane coupling agent. The modified CNTs were embedded into a silicone elastomer (SE) matrix to obtain the composites. The dielectric behaviors of the composites with different frequencies of outer electric field were investigated. The results showed that the CNTs were modified by a silane coupling agent to improve the interaction with the SE matrix. The dielectric loss and permittivity of the SE were enhanced by the addition of CNTs. The CNTs with larger aspect ratios had a more effective dielectric loss and permittivity-enhancing effect. There were three existent polarization mechanisms in the composites, and the response times of the three were different. When the field frequency increased, a polarization mechanism or two would not catch up with the increase, and the dielectric loss and permittivity would obviously be affected. The CNTs with larger aspect ratios had a more effective dielectric loss and permittivity-enhancing effect. According to the Debye equation, CNT/SE composites have a similar function as the parallel RLC circuit.