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Carbon nanomaterials, particularly carbon nanotubes (CNTs), are widely used as reinforcing fillers in rubber composites for advanced mechanical and electrical applications. However, the influence of rubber functionality and its interactions with CNTs remains underexplored. This study investigates electroactive elastomeric composites fabricated with CNTs in two common diene rubbers: natural rubber (NR) and acrylonitrile-butadiene rubber (NBR), each with distinct functionalities. For NR-based composites containing 2 vol% CNTs, mechanical properties, such as elastic modulus (2.24 MPa), tensile strength (12.48 MPa), and fracture toughness (26.92 MJ/m3), show significant improvements of 125%, 215%, and 164%, respectively, compared to unfilled rubber. Similarly, for NBR-based composites, the elastic modulus (5.46 MPa), tensile strength (13.47 MPa), and fracture toughness (82.89 MJ/m3) increase by 94%, 22%, and 65%, respectively, over the unfilled system. Although NBR-based composites exhibit higher mechanical properties, NR systems show more significant improvements, suggesting stronger chemical bonding between NR chains and CNTs, as evidenced by dynamic mechanical, X-ray diffraction, thermogravimetric, and thermodynamic analyses. The NBR-based composite at 1 vol% CNT content exhibits 261% higher piezoresistive strain sensitivity (GF = 65 at 0% ≤ Δε ≤ 200%) compared to the NR-based composite (GF = 18 at 0% ≤ Δε ≤ 200%). The highest gauge factor of 39,125 (1000% ≤ Δε ≤ 1220) was achieved in NBR-based composites with 1 vol% CNT content. However, 1.5 vol% CNT content in NBR provides better strain sensitivity and linearity than other composites. Additionally, NBR demonstrates superior electromechanical actuation properties, with 1317% higher actuation displacement and 276% higher electromechanical pressure compared to NR at an applied electric field of 12 kV. Due to the stronger chemical bonding between the rubber and CNT, NR-based composites are more suitable for dynamic mechanical applications. In contrast, NBR-based CNT composites are ideal for stretchable electromechanical sensors and actuators, owing to the high dielectric constant and polarizable functional groups in NBR. [ABSTRACT FROM AUTHOR]

This review article focuses on the potential of cobalt oxide composites with conducting polymers, particularly polypyrrole (PPy) and polyaniline (PANI), as advanced electrode materials for supercapacitors, batteries, and supercapatteries. Cobalt oxide, known for its high theoretical capacitance, is limited by poor conductivity and structural degradation during cycling. However, the integration of PPy and PANI has been proven to enhance the electrochemical performance through improved conductivity, increased pseudocapacitive effects, and enhanced structural integrity. This synergistic combination facilitates efficient charge transport and ion diffusion, resulting in improved cycling stability and energy storage capacity. Despite significant progress in synthesis techniques and composite design, challenges such as maintaining structural stability during prolonged cycling and scalability for mass production remain. This review highlights the synthesis methods, latest advancements, and electrochemical performance in cobalt oxide/PPy and cobalt oxide/PANI composites, emphasizing their potential to contribute to the development of next-generation energy storage devices. Further exploration into their application, especially in battery systems, is necessary to fully harness their capabilities and meet the increasing demands of energy storage technologies. [ABSTRACT FROM AUTHOR]

Wearable technology refers to the devices that are integrated with textiles, or implanted in the body or plants for smart monitoring. Hence, this wearable technology has attracted tremendous attention from researchers globally due to its smart functions to be useful for mankind. The key target of this review is to examine the potential of rubber composite materials for such wearable devices. The rubber composites reviewed explore silicone rubber as a rubber matrix (SR). Another objective includes the use of multi‐walled carbon nanotubes (MWCNTs) in pristine and functionalization forms explored as reinforcing fillers. Moreover, prospects of CNT including their structure, properties, and types are explored both in pristine and functionalized state are reviewed. Following this, the mechanical, and electrical, properties of such composites are reviewed. The reported results show that the reinforcing properties are strongly improved by adding functional groups to CNT in rubber composite. These improvements in reinforcing properties are assisted by the functional groups like carboxyl (OH), carbonyl (CO), epoxy, and alkoxy (CO) on the surface of filler are useful. They assist in improving the filler‐rubber compatibility thereby improving filler dispersion and thus finally mechanical and electrical properties. Following this, such improved properties are explored for specific real‐time wearable technologies. This real‐time monitoring includes nursing plant pulse growth monitoring, health monitoring, and humidity sensors. The review further proposes that the functionalized CNTs can be useful for obtaining robust real‐time strain‐sensing monitoring. Moreover, it assists in obtaining sharp response time, strain sensitivity, and good stretchability. Finally, the prospects and challenges are explored discussing the real‐time monitoring of these sensors. Highlights: Configurations for nursing plant growth and other monitoring parameters are reviewed.The properties of pristine and functionalized carbon nanotubes reinforced silicone rubber for wearable technology were reviewed.The mechanical, and electrical aspects of functionalized carbon nanotubes were comparatively reviewed.Applications such as wearable strain sensors, humidity sensors, and wearable plant pulse monitoring sensors were reported. [ABSTRACT FROM AUTHOR]

Multifunctional stretchable rubber composites are gaining attention due to their unique electrical, mechanical, and magnetic properties. However, their high production costs pose economic challenges. This study explores the use of cost-effective metal powders—iron, aluminum, and their 1:1 (vol/vol) hybrid filler—in styrene–butadiene rubber composites, varying from 10 to 20 vol%. The effects of these metal particles on the mechanical, electrical, morphological, and swelling properties were investigated. Metal particles generally act as non-reinforcing fillers but can significantly enhance the mechanical modulus, electrical, and magnetic properties based on the filler structure and the filler–rubber interactions. Iron-based composites exhibit significant electrical conductivity and excellent magnetic properties. Aluminum enhances the modulus, while the combination yields average mechanical properties with added magnetic characteristics. Iron demonstrates higher reactivity with sulfur-based crosslinking ingredients, adversely affecting the rubber matrix's crosslinks, as shown by swelling tests. This reactivity is attributed to iron's transition metal characteristics. At 20 vol%, iron-filled composites display the highest magnetic anisotropic effect on toughness (~25%) under a magnetic field by permanent magnets and excellent electrical conductivity (1.5 × 10−2 S/m). While iron significantly boosts the electrical and magnetic properties, higher filler amounts degrade the mechanical properties. These composites are currently suitable for electrical and smart mechanical applications, but incorporating reinforcing fillers could enhance their robustness for broader applications. [ABSTRACT FROM AUTHOR]

Energy harvesting systems fabricated from rubber composite materials are promising due to their ability to produce green energy with no environmental pollution. Thus, the present work investigated energy harvesting through piezoelectricity using rubber composites. These composites were fabricated by mixing titanium carbide (TiC) and molybdenum disulfide (MoS2) as reinforcing and electrically conductive fillers into a silicone rubber matrix. Excellent mechanical and electromechanical properties were produced by these composites. For example, the compressive modulus was 1.55 ± 0.08 MPa (control) and increased to 1.95 ± 0.07 MPa (6 phr or per hundred parts of rubber of TiC) and 2.02 ± 0.09 MPa (6 phr of MoS2). Similarly, the stretchability was 133 ± 7% (control) and increased to 153 ± 9% (6 phr of TiC) and 165 ± 12% (6 phr of MoS2). The reinforcing efficiency (R.E.) and reinforcing factor (R.F.) were also determined theoretically. These results agree well with those of the mechanical property tests and thus validate the experimental work. Finally, the electromechanical tests showed that at 30% strain, the output voltage was 3.5 mV (6 phr of TiC) and 6.7 mV (6 phr of MoS2). Overall, the results show that TiC and MoS2 added to silicone rubber lead to robust and versatile composite materials. These composite materials can be useful in achieving higher energy generation, high stretchability, and optimum stiffness and are in line with existing theoretical models. [ABSTRACT FROM AUTHOR]

This document discusses the advancements in functional rubber and elastomer composites. It begins by highlighting the innovations of mastication and vulcanization, which have greatly expanded the applications of rubber. The document then explores the development of synthetic rubbers and their various properties, as well as the use of elastomers in advanced technologies such as electronics and robotics. The importance of fillers in rubber composites is emphasized, along with the need for alternative or modified fillers. The document also provides an overview of published articles that focus on improving the properties of rubber composites through various techniques. It concludes by emphasizing the potential for further advancements in functional rubber and elastomeric materials and the need for continued research in this field. [Extracted from the article]

Vulcanization is a chemical modification of rubber that requires a considerable amount of thermal energy. To save thermal energy, the kinetics of rubber vulcanization should be improved. In this article, the curing properties of rubber vulcanization are thoroughly investigated using the moving die rheometer (MDR) technique. To enhance the kinetics in different stages of ZnO-based sulfur vulcanization systems, small amounts of MgO were added. The results revealed that the small amount of 1 to 2 phr (per hundred grams of rubber) of MgO in the controlled 5 phr ZnO-based curing systems can significantly improve the curing kinetics. For example, the optimum curing time of 1 phr MgO added to the 5 phr ZnO-containing semi-efficient vulcanization system at different temperatures was more than half that of the controlled 5 phr ZnO-only compound. While maintaining a similar rate of vulcanization, the vulcanization temperature can be reduced by up to 20 °C by using MgO as a co-cure activator, which exhibits similar or better rheometric mechanical properties compared to the controlled compounds. With the addition of MgO as a co-cure activator, the vulcanization reactions become very fast, enabling vulcanization to be completed, even at the boiling point of water (100 °C) with an affordable curing time (<1 h). By reducing the vulcanization temperature, the scorch safety time can be enhanced in the ZnO/MgO-based binary cure activator-containing vulcanizates. Overall, MgO could be a potential candidate as a co-cure activator with ZnO for the vulcanization of rubber, offering better economical and eco-friendly methods. [ABSTRACT FROM AUTHOR]

The contribution from specific interactions between rubber and filler sometimes plays a crucial role in the mechanical reinforcement and electromechanical sensitivities of rubber composites. This research explores the physical, mechanical, and electromechanical properties of styrene‐butadiene rubber (SBR) composites reinforced with carbon nanotubes (CNTs). Mechanical, thermodynamic, and scanning electron microscopy studies reveal that CNTs primarily enhance the mechanical properties through physical interactions with the rubber. Notably, π‐stacking interactions between the aromatic π‐electrons in SBR and the delocalized π‐electrons in CNTs contribute to significant improvements in mechanical strength. For instance, adding 4 phr (per hundred grams of rubber) of CNTs results in an impressive 871% increase in fracture toughness compared to unfilled rubber. These composites also exhibit remarkable stress and strain improvements even with small amounts of CNTs, making them suitable for robust strain sensing applications. Specifically, the composite containing 3 phr of CNTs demonstrates superior strain sensitivity (2.87 < GF < 48.62), a wide detection range (0% < Δε < 187%), and excellent linearity (0.927 < R2 < 0.995). Lower CNT content enhances sensitivities but reduces overall linearity, while higher CNT content improves linearity but decreases sensitivity. Moreover, these composites perform exceptionally well under compressive forces, even at a 0.5 N applied force. Given their excellent response to mechanical forces and strain, these composites hold promise for applications like electronic skin, strain sensors, and energy‐harvesting devices. Highlights: Carbon nanotubes (CNTs) were used as reinforcing fillers in SBR composites.CNTs significantly improve physical, mechanical, and electrical properties.Primarily, π‐stacking may be involved in enhancing these properties.The composites exhibit strong strain and force‐sensing capabilities.These composites could be valuable for wearable electronics in the future. [ABSTRACT FROM AUTHOR]

The different configurations of the composites originated with machine or human motion, and their mechanical stability for wearable electronics is in focus. Here, the study highlights that these configurations are critical for wearable devices. To achieve these aspects, the electroactive and dielectric silicone rubber (SR) was used as a host matrix. This SR not only provides flexibility, twisting, or stretchability for such devices, but its lightweight makes them comfortable for robust wearable devices. The reinforcing fillers such as graphite nanoplatelets (GNP) or diatomaceous earth (DE) and their hybrids are used. The electromechanical properties of the device were performed using the universal testing machine. The output voltage generated at 15 phr filler was 0.3 mV (GNP), 0.15 mV (DE), and 0.22 mV (hybrid). Similarly, the biomechanical properties were studied with human motion joints such as thumb pressing or wrist bending. The output voltage at 15 phr was best for thumb pressing and it was 0.42 mV (GNP), 0.18 mV (DE), and 0.25 mV (hybrid). In the same way, the mechanical aspects studied in this work are compressive modulus, tensile strength, and fracture strain. For example, the compressive modulus was 1.28 MPa (control) and increased at 15 phr filler to 2.44 MPa (GNP), 3.2 MPa (DE), and 2.75 MPa (hybrid). Similarly, the mechanical stretchability of the devices was 134% (control) and changed at 15 phr filler to 128% (GNP), 78% (DE), and 109% (hybrid). Overall, the work demonstrates the method to develop a device with high mechanical, electromechanical, and biomechanical properties and their usefulness for wearable electronic devices. [ABSTRACT FROM AUTHOR]