Fabrication of High-Performance Natural Rubber Composites with Enhanced Filler–Rubber Interactions by Stearic Acid-Modified Diatomaceous Earth and Carbon Nanotubes for Mechanical and Energy Harvesting Applications

Abstract

Mechanical robustness and high energy efficiency of composite materials are immensely important in modern stretchable, self-powered electronic devices. However, the availability of these materials and their toxicities are challenging factors. This paper presents the mechanical and energy-harvesting performances of low-cost natural rubber composites made of stearic acid-modified diatomaceous earth (mDE) and carbon nanotubes (CNTs). The obtained mechanical properties were significantly better than those of unfilled rubber. Compared to pristine diatomaceous earth, mDE has higher reinforcing efficiencies in terms of mechanical properties because of the effective chemical surface modification by stearic acid and enhanced filler–rubber interactions. The addition of a small amount of CNT as a component in the hybrid filler systems not only improves the mechanical properties but also improves the electrical properties of the rubber composites and has electromechanical sensitivity. For example, the fracture toughness of unfilled rubber (9.74 MJ/m3) can be enhanced by approximately 484% in a composite (56.86 MJ/m3) with 40 phr (per hundred grams of rubber) hybrid filler, whereas the composite showed electrical conductivity. At a similar mechanical load, the energy-harvesting efficiency of the composite containing 57 phr mDE and 3 phr CNT hybrid filler was nearly double that of the only 3 phr CNT-containing composite. The higher energy-harvesting efficiency of the mDE-filled conductive composites may be due to their increased dielectric behaviour. Because of their bio-based materials, rubber composites made by mDE can be considered eco-friendly composites for mechanical and energy harvesting applications and suitable electronic health monitoring devices.

Mimicking Self-Powered Piezoelectric Energy-Generating Behavior in Silicone Rubber Composites under Compressive and Tensile Strains

“…particles in the rubber matrix. Alam et al 26 show that the oxygencontaining functional groups of D.E. act as a catalyst in enhancing interactions with the rubber matrix.…”

“…The other material of interest used as a filler in rubber composites in the present work is D.E . Alam et al show that D.E. contains various functional groups on its outer and inner octahedral sheets and leads to robust interfacial interactions in the composite.…”

Robust performance for composites using silicone rubber with different prospects for wearable electronics

“…The mechanical properties were best for DE‐filled composite followed by hybrid and lastly by GNP filler. The higher reinforcing properties for DE‐filled composites are due to the porous structure of DE that makes the polymer chain intercalation inside filler galleries of composites 61 . This intercalation is proposed to improve the interfacial interactions in the composite.…”

“…The higher reinforcing properties for DE-filled composites are due to the porous structure of DE that makes the polymer chain intercalation inside filler galleries of composites. 61 This intercalation is proposed to improve the interfacial interactions in the composite. Another reason is the large particle size of the DE that promotes better packing phenomena of filler-polymer microstructures in the composite.…”

Advances in Functional Rubber and Elastomer Composites

“…Additionally, rubber composites with specific fillers exhibit excellent electromagnetic wave absorption properties. Some rubber composites can even function as transducers, converting mechanical energy into electrical power, which can be utilized for generating green energy [ 10 , 11 ].…”