Strong Strain Sensing Performance of Natural Rubber Nanocomposites

Abstract

A detail study concerning the strain (tensile) dependent electrical conductivity of elastomeric composites is reported in this present paper. Multiwall carbon nanotubes (CNT), conducting carbon black (CB), and their combinations were considered as conducting filler in cross-linked natural rubber matrix. The loadings of the fillers were considered from 3 to 11 phr (filler concentration close to their percolation threshold). Without hindering the elastic nature of the composite (reversible stretchability up to several 100%), the change of relative resistance, ΔR/R (ΔR is the change in the resistance with respect to strain and R is the initial resistance of the sample) of the CB filled composites was found to be as much as ∼1300 at around 120% elongation. This value is much higher than any other reported values obtained from conducting polymeric composites. It was found that CNT offered a strong strain dependent character in the regime 100% to 150% elongation, whereas, the carbon black filled natural rubber showed strong strain dependencies at 50% to 100% elongation strain. The combination of two different fillers could be exploited to tailor and manipulate the sensing operating regime from 50% to 150% strain depending on the ratios of the two filler system. Additionally, after several loading-unloading cycles, the conductivity of the sample was very stable for CB filled system but for CNT filled system the conductivity of the sample was altered. This type of elastic materials could be used in structural health monitoring, sensors in different dynamic elastomeric parts like tires, valves, gaskets, engine mounts, etc.

Effect of bis(triethoxysilylpropyl) tetrasulfide (TESPT) on properties of carbon nanotubes and conductive carbon black hybrid filler filled natural rubber nanocomposites

“…Furthermore, in Figure 8, the optimal conductivity of the vulcanizates with CNT/CCB hybrid filler was higher than with solely CCB or CNT. This correlates well to the previous work [28] which showed significantly the improvement of the conductivity of the NR composites with CCB/CNT hybrid filler. In addition, in Figure 8, it was found that the conductivity and percolation concentration were again improved by addition of TESPT silane coupling agent.…”

Synergistic effects of rubber band infused graphene nanocomposite on morphology, spectral, and dynamic mechanical properties

“…In recent years, graphene has received a tremendous amount of attention as a kind of unique filler to produce polymer nanocomposites with high performance and novel functionalities for applications such as reinforced nanocomposites, electrically conductive composites, ultrasensitive sensors, and supercapacitor electrodes . Graphene nanofillers have been extensively used in rubber nanocomposites on account of their small size and the corresponding increase in the surface area allowing significant improvement in the matrix properties at low filler loadings . Because conductive fillers have the very poor stretchability, it is imperative to design proper surface structure on elastic substrates and make an effective combination of conductive nanofillers with substrates, which both determine the sensing properties of the resultant sensors.…”

Highly Sensitive and Stretchable Resistive Strain Sensors Based on Microstructured Metal Nanowire/Elastomer Composite Films

“…Recently, many attempts have been made to address this conflict and achieve a large stretchability (>100%) and high gauge factor (>20) simultaneously in a single sensor platform . The unique architectures of CNTs, with their aligned wavy bundles and highly oriented fibers, have the potential to enhance the sensing performance by appropriately modulating the contact area between the CNTs upon stretching.…”

“…The piezoresistive responses of strain sensors based on elastomeric composites with conductive nanofillers (e.g., CNTs, CBs, mNWs, mNPs, and graphene) are highly dependent on the shape of the nanofillers. It is generally known that composite sensors with particle‐shaped nanofillers exhibit high piezoresistivity in the low strain regime, while wire (1D) and sheet‐shaped (2D) nanofiller‐based composite sensors can function even at relatively high strains with no electrical failure . In a synergistic approach, multidimensional hybrid nanofillers with mixed morphologies, such as CNT/CB and graphene/mNP, were used to form a material with superior piezoresistive behavior over a wide strain range compared to their single‐dimensional counterparts.…”

“…It is generally known that composite sensors with particle‐shaped nanofillers exhibit high piezoresistivity in the low strain regime, while wire (1D) and sheet‐shaped (2D) nanofiller‐based composite sensors can function even at relatively high strains with no electrical failure . In a synergistic approach, multidimensional hybrid nanofillers with mixed morphologies, such as CNT/CB and graphene/mNP, were used to form a material with superior piezoresistive behavior over a wide strain range compared to their single‐dimensional counterparts. Conductive elastomers and nanofillers were also systematically combined in the form of a double‐interconnected network and sandwich‐like multilayered structure .…”