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

Flexible strain sensors have a wide range of applications in the field of health monitoring of seismic isolation bearings. However, the nonmonotonic response with shoulder peaks limits their application in practical engineering. Here we eliminate the shoulder peak phenomenon during the resistive-strain response by adjusting the dispersion of conductive nanofillers. In this paper, carbon black (CB)/methyl vinyl silicone rubber (VMQ) composites were modified by adding a silane coupling agent (KH550). The results show that the addition of KH550 eliminates the shoulder peak phenomenon in the resistive response signal of the composites. The reason for the disappearance of the shoulder peak phenomenon was explained, and at the same time, the mechanical properties of the composites were enhanced, the percolation threshold was reduced, and they had excellent strain-sensing properties. It also exhibited excellent stability and repeatability during 18,000 cycles of loading–unloading. The resistance-strain response mechanism was explained by the tunneling effect theoretical model analysis. It was shown that the sensor has a promising application in the health monitoring of seismic isolation bearings

Improvement of shoulder peak effect in graphene/silicone rubber strain sensors by nanosilica

Conducting polymer composites (CPCs) typically exhibit shoulder peak phenomena in their resistive response signals, which greatly limits their practical application as strain sensors in the field of vibration damping. In this paper, nanosilica (SiO2) nanoparticles were incorporated into graphene (GR)/methyl vinyl silicone rubber (VMQ) composites to obtain the optimum content of SiO2 to eliminate the shoulder peak phenomenon. The results showed that the shoulder peak phenomenon of the resistance response signal of the composites disappeared after the addition of 30 % SiO2, which explained the mechanism of eliminating the shoulder peak phenomenon. Meanwhile, the tensile strength and Young's modulus of the composites were improved, and excellent resistance-strain response properties were obtained, including a wide sensing range (＞200 %), high sensitivity (GF = 839.02), fast response time (37 ms), and good durability and stability (9000 cycles at 50 % strain). It shows that the strain sensor has great potential for health monitoring in the field of vibration damping