Effect of Vulcanization on the Electro-Mechanical Sensing Characteristics of Multi-Walled Carbon Nanotube/Silicone Rubber Composites

Abstract

In order to realize effective monitoring for the working performance of seismic isolation structures, a multi-walled carbon nanotube (MWCNT)/methyl vinyl silicone rubber (VMQ) composite was prepared via mechanical blending using dicumyl peroxide (DCP) and 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexane (DBPMH) as vulcanizing agents. The effects of the different vulcanizing agents on the dispersion of the MWCNT, electrical conductivity, mechanical properties, and resistance–strain response of the composites were investigated. The experimental results showed that the percolation threshold of the composites prepared with the two vulcanizing agents was low, while the DCP-vulcanized composites showed high mechanical properties and a better resistance–strain response sensitivity and stability, especially after 15,000 loading cycles. According to the analysis using scanning electron microscopy and Fourier infrared spectroscopy, it was found that the DCP contributed higher vulcanization activity, a denser cross-linking network, better and uniform dispersion, and a more stable damage–reconstruction mechanism for the MWCNT network during the deformation load. Thus, the DCP-vulcanized composites showed better mechanical performance and electrical response abilities. When employing an analytical model based on the tunnel effect theory, the mechanism of the resistance–strain response was explained, and the potential of this composite for real-time strain monitoring for large deformation structures was confirmed.

Enhancement of the Electric-Force Response of Carbon Black/Silicone Rubber Composites by Silane Coupling Agents

“…The peaks at 1006 cm −1 and 1005 cm −1 are attributed to the stretching vibration of Si-O-Si. The characteristic peak of CB-KH550/VMQ composites shifted from 1006 cm −1 to 1005 cm −1 as seen in the local zoomed-in image, which is consistent with the changes concluded in other studies [ 37 ], and the change is attributed to the formation of hydrogen bonding between the residual oxygen-containing groups of the nanofillers and the Si-O-Si groups in the silicone rubber matrix, which facilitates the compatibility.…”