Tailoring Triple Filler Systems for Improved Magneto-Mechanical Performance in Silicone Rubber Composites

Abstract

The demand for multi-functional elastomers is increasing, as they offer a range of desirable properties such as reinforcement, mechanical stretchability, magnetic sensitivity, strain sensing, and energy harvesting capabilities. The excellent durability of these composites is the key factor behind their promising multi-functionality. In this study, various composites based on multi-wall carbon nanotubes (MWCNT), clay minerals (MT-Clay), electrolyte iron particles (EIP), and their hybrids were used to fabricate these devices using silicone rubber as the elastomeric matrix. The mechanical performance of these composites was evaluated, with their compressive moduli, which was found to be 1.73 MPa for the control sample, 3.9 MPa for MWCNT composites at 3 per hundred parts of rubber (phr), 2.2 MPa for MT-Clay composites (8 phr), 3.2 MPa for EIP composites (80 phr), and 4.1 MPa for hybrid composites (80 phr). After evaluating the mechanical performance, the composites were assessed for industrial use based on their improved properties. The deviation from their experimental performance was studied using various theoretical models such as the Guth–Gold Smallwood model and the Halpin–Tsai model. Finally, a piezo-electric energy harvesting device was fabricated using the aforementioned composites, and their output voltages were measured. The MWCNT composites showed the highest output voltage of approximately 2 milli-volt (mV), indicating their potential for this application. Lastly, magnetic sensitivity and stress relaxation tests were performed on the hybrid and EIP composites, with the hybrid composite demonstrating better magnetic sensitivity and stress relaxation. Overall, this study provides guidance on achieving promising mechanical properties in such materials and their suitability for various applications, such as energy harvesting and magnetic sensitivity.

Modulating the Configurations of “Gel-Type” Soft Silicone Rubber for Electro-Mechanical Energy Generation Behavior in Wearable Electronics

“…They were traditionally developed for 0-dimensional materials such as carbon black but recently upgraded and become useful for 1-D, 2-D, and 3-D as well. Recently, Kumar et al added interacting factor parameters for hybrid fillers, which are based on the rule of mixing fillers in rubber composites [ 46 ]. In hybrid composites based on “gel-type” soft SR, the interacting factor plays an important role in predicting the theoretical values from the equations.…”

“…The following equations were used to predict the behavior of the modulus to validate the experimental results thus obtained. The Guth–Gold equations [ 46 , 50 ] were E MWCNT = E o [(1 + 0.67 × f MWCNT × ϕ MWCNT )] E DE = E o [(1 + 0.67 × f DE × ϕ DE )] E Hybrid = E o [(1 + 0.67 × f DE × ϕ DE ) + (1 + 0.67 f MWCNT × ϕ MWCNT )] × i …”

“…Similarly, the equations employed in determining modulus using Halpin–Tsai equations [ 46 , 51 ] were E MWCNT = E o [(1 + 2f MWCNT × ϕ MWCNT )/(1-ϕ MWCNT )] E DE = E o [(1 + 2f DE × ϕ DE )/(1-ϕ DE )] E Hybrid = E o [(1 + 2f MWCNT × ϕ MWCNT )/(1-ϕ MWCNT ) + (1 + 2 f DE × ϕ DE )/(1-ϕ DE )] × i …”

“…DE, and their hybrid. The “i" is the interacting factor based on the rules of mixtures in hybrid composites [ 46 ]. The “E o ” is the experimental value of unfilled rubber.…”

3D Printable Self‐Sensing Magnetorheological Elastomer

“…CIP itself showcases a reinforcement effect of TPS composite which is further increased if a small volume fraction of carbonbased nanomaterials is added. [43] By adding carbon-based nanomaterials, the mechanical properties, magnetic sensitivity, and energy generations could be varied in a wide range, depending on the relative volume fraction of the different fillers. [44] Overall, TPS-based hybrid composites' properties are highly tunable and make such MREs a good candidate for a wide plethora of applications.…”