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The present study provides a state of the art on methods for evaluating active chain density of rubbers from swelling experiments. This review focuses more particularly on the effects of components that are known to limit the swelling, and which typically results in an overestimation of the active chain density. These components are commonly considered as insoluble. Different corrections dealing with the two principal insoluble components, namely zinc oxide (Zn0) and carbon black (CB) filler, are thoroughly investigated. A comparative study on the same natural rubber (NR), either filled and unfilled, vulcanized with three different vulcanization systems, is performed to evaluate the relevance of each predictive approach. The results obtained highlight their respective limitations. In particular, it is shown that the swelling ratio of unfilled and filled natural rubbers are linearly related, suggesting that fillers have no significant effect on the overall number of cross‐links formed during vulcanization. As a result, we propose a unified approach for correcting the ZnO content for unfilled NR and both the ZnO and CB contents for filled NR. By comparing with results issued from uniaxial tensile tests, it is shown that the use of a mechanical response is a relevant alternative for determining the active chain density. [ABSTRACT FROM AUTHOR]

Highlights Silica is a renewable resource that has become the primary filler for the rubber used in eco‐friendly tires. However, silica tends to agglomerate in the rubber matrix, particularly, micro‐ and nano‐scale silica, which limits its application. When ordinary‐particle‐size silica with low cost and high stacking density is modified using appropriate methods, high dispersion in rubber and good performance can be achieved with common processing equipment, which has significant engineering application value. In this study, silica particles with different sizes (nano‐scale, 19 and 45 μm) were treated with a 3‐mercaptopropyltriethoxysilane coupling agent (KH580). Subsequently, the silica with the ordinary particle size of 300 mesh (45 μm) was coated with natural latex (NL), and the mechanical properties of the modified silica‐filled styrene‐butadiene rubber (SBR)/carbon black (CB) compounds were investigated. The results revealed that the mechanical properties of the NL‐coated 45 μm silica‐filled composite improved significantly, particularly, in the area of tear strength and elongation at break, the composite properties were improved by 17.1% and 118.2%, respectively. Excellent performance over composites filled with coupling agent‐treated micron‐ and nanoscale silica. Enhancing the surface modification of silica through latex coating provides a means to improve the efficiency of industrial production and reduce costs. The low‐fine silica treated with KH580 has good dispersibility. Improved mechanical compatibility of NL‐coated silica with rubber. Improvement in strain performance of composites after NL coated with silica. The effect of silica dispersion on composite properties is greater than the effect of particle size. Industrial silica can be successfully addressed, paving the way for extensive utilization. [ABSTRACT FROM AUTHOR]

Untreated pyrolytic tire char was used in natural rubber (STR20) composites as single filler at loadings of 30–70 phr and co‐filler with carbon black (N330) at a total loading of 50 phr. The results were compared with rubbers filled with N330 and crumb rubber at 30 phr. The effects of fillers on cure characteristic, crosslink density, filler dispersion in natural rubber vulcanizates and their mechanical properties were investigated. The slight reversions were seen for the cure characteristics of 70 phr‐char‐filled and all co‐filler samples because the sulfur amount in the char together with the added sulfur could shift the vulcanization system from EV to SEV, whereas plateau cure curves were seen for the rest. While the highest tensile strength of char‐filled sample was obtained at 50 phr loading, whose tensile strength was about 88% of the N330 sample at 30 phr, 70‐phr‐char filled sample was superior in surface hardness, abrasion resistance and tear strength to N330 sample at 30 phr. For rubber with co‐fillers, the mechanical properties depended on the mass ratio of N330 to pyrolytic tire char. Therefore, it is possible to use untreated char as reinforcing filler for suitable applications according to their properties. [ABSTRACT FROM AUTHOR]

Semi-IPN composites of natural rubber (NR), hydrophilic sodium carboxymethyl cellulose (CMC) and carbon black (CB) with different compositions have been created by solution casting process in an attempt to develop a novel adsorbent under various pH ranges for the cationic dye methylene blue (MB). The produced NR/CMC film can be employed as an adsorbent of MB dye, according to the results, which demonstrate that composites with 2% CMC and 0.2 g CB displayed a maximum adsorption capacity of 1.72 mg/g and a dye removal efficiency of 85.22% at pH 9. The semi-IPNs were characterised using X-ray diffraction, Thermogravimetry, FTIR, and SEM methods. The NR/CMC semi-IPN composites' SEM micrographs showed a continuous, homogenous and porous structure. The films' equilibrium swelling characteristics were examined. For the NR98%CMC2% polymeric composition, containing 2% glutaraldehyde (GA) and 0.02 g CB loading, a maximum tensile strength of 3.3 MPa was achieved. In a 12-month period with 2% CMC, the NR/CMC semi-IPN showed a 70% biodegradation rate, while the pure NR showed only a 20% degradation rate. X-ray diffraction analysis shows that the addition of CMC reduces the crystallinity of natural rubber. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigates the efficiency of already developed surface‐modified carbon black (CB), both independently and in conjunction with nano‐silica, as a hybrid filler, to the properties of natural rubber (NR) compounds. The modification process, followed by coupling agent treatment, enhanced cross‐link density and curing characteristics, though the inclusion of nano‐silica alone negatively affected curing due to its inherent polarity and tendency to agglomerate. The filled compounds with modified CB exhibited significant improvements in mechanical properties, notably tear resistance. Moreover, the combination of nano‐silica with modified CB yielded compounds with superior tear resistance, attributed to synergistic effects. CB surface modification exhibited varying effects on the glass transition temperature, with enhancements observed in tan δ at lower temperatures, indicating improved ice and wet grip potential. Also, it reduced rolling resistance after treatment with a coupling agent. While thermal stability remained consistent across the studied compounds, swelling resistance varies with filler type and ratio. Thermodynamic analysis confirmed the positive impact of CB surface modification on the elasticity and chain mobility of the investigated rubber compounds. It was concluded that the strategic selection of fillers and modification approaches were essential for achieving optimal results in the rubber compound's performance and application. [ABSTRACT FROM AUTHOR]

This paper delves to improve the upper‐limit temperature of hydrogenated nitrile rubber (HNBR) through regulation of the vulcanization process, filler system and cross‐linking additive. The tensile test and scanning electron microscope images showed that the aging at 180°C significantly accelerated the deterioration in the property of HNBR compared with 150°C aging. The results showed that a higher dosage of bis(1‐(tert‐butylperoxy)‐1‐methylethyl)‐benzene curing agent reduced the compression set of HNBR without sacrificing its tensile strength. Carbon black N539‐filled HNBR exhibited high tensile strength, while carbon black N774‐filled HNBR showed high heat resistance and low compression set. When the HNBR sample was reinforced with 20 phr of N539 and 20 phr of N774 carbon black, it achieved low compression set, high tensile strength, and heat resistance simultaneously. Then, N,N′‐bismaleimide‐4,4′‐diphenylmethane (BMI) was introduced into the HNBR composite as a cross‐linking assistant agent. The residual strength of BMI‐modified HNBR was 20.3 MPa (the retention rate of 92.3%), and its compression set was as low as 19.2% after aging at 180°C for 72 h. Even after aging the composite at 180°C for 168 h, its strength retention rate remained at 83.2% (18.3 MPa). The approach provided here increased the upper‐limit temperature range of HNBR to 180°C. [ABSTRACT FROM AUTHOR]

Rubber–metal parts inside the car require rubber compounds capable of ensuring optimal function and maximum service life without interface delamination. From this perspective, the strength of the bond which is created by the chemical interaction of rubber and metal by an adhesive is decisive for ensuring the functionality of the entire compound. It is dependent not only on the choice of the right adhesive but also on the rubber compound ingredients and their amount. Here, the influence of different types of carbon blacks as well as different curing systems in combination with a commonly used adhesive is described. The durability of the metal–adhesive–rubber bond is characterized by a specially designed shear strength analysis under quasi-static loading, whereas a significant influence of the structure of the carbon black has shown. It has also been observed that the presence of monosulphidic bonds has a positive effect on the shear strength. [ABSTRACT FROM AUTHOR]

Carbon black (CB) is the most frequently applied conductive additive in rubber and polymer composites. This project aims to investigate the electrical/dielectric properties of a hybrid composite based on butadiene rubber and N-234 type of low-cost CB prepared via an oxidative chlorophosphorylation reaction. The properties are described by conductivity (σ) and dielectric constant (έ) frequency dependence at ambient temperature. The conductivity mechanism is explored based on the structure of CB and composite measured by X-ray powder diffraction analysis. Graphite-like structure and semi-crystalline intercalate phase were observed in the X-ray powder diffraction patterns of CB and composite, respectively. The σ and έ obtained values show the positive contribution of CB filler in the electrical/dielectric properties of the modified polymer through enhancing the crystallinity, providing a new conductive pathway with a higher probability of charge carriers tunneling and founding a higher polarized system based on the microscopic structure of obtained composite. A low-cost conductive/polarized composite of higher permittivity in comparison to a modified polymer was obtained. The composite is suggested for use in energy storage and electric devices. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study focuses on reusing the waste fishing nets with natural rubber (NR) to create a value‐added composite material. WNF fibers at different loadings (2, 4, and 6 phr) and lengths (2, 3, 5, and 7 mm) were investigated for a general tire formulation. The anisotropic nature of WNF was evident in tear strength, with optimal results for 2 mm, 2 phr fiber loading. It displayed 15.87% improvement longitudinally compared with the control. Further, it displayed improved 5.55% hardness, whereas resilience, abrasion volume loss, and tensile strength were decreased. In the second stage, these fibers treated with KOH (2%, 6%, and 10%) with the expectation of enhancing the mechanical properties. The 2% KOH‐treated sample presented a significant escalation in hardness (+12.50%), resilience (+6.25%), abrasion volume loss (+3.63%), tear strength (+17.23%), and tensile strength (+8.20%) as of the control. Partial replacement of carbon black (CB) with 2% KOH treated 2 mm 2 phr WNF was evaluated. A 9% of CB in rubber compound was easily supersede by WNF. Our findings indicated that WNF fibers could be reuse as a filler in rubber composite where special property enhancements are advantageous in tire technology. [ABSTRACT FROM AUTHOR]

Rubber nanocomposites exhibit strain softening under large‐amplitude oscillation shear and large‐strain cyclic tension while the softening behaviors are hard to regulate in industry. Herein, an oligomer deep eutectic solvent (DES) synthesized from polyethyleneglycol and tetrabutylammonium bromide is used to mediate the vulcanization and softening behaviors of natural rubber (NR) gums and their nanocomposites. The results show that DES could accelerate NR vulcanization and improve crosslinking density. For the hydrophilic silica nanocomposites, DES could greatly reduce tanδ and weaken weak strain overshoot accompanying Payne and lower percentages damping accompanying Mullins effects. The effects in nanocomposites filled with hydrophilic/hydrophobic silica and carbon black are investigated and compared. The investigation provides a new way for tailoring elasticity and dissipation of vulcanizate nanocomposites filled with hydrophilic silica. [ABSTRACT FROM AUTHOR]

Given the increasing need for sustainable solutions and the large amount of improperly discarded end‐of‐life tires, recovered carbon black (rCB) from tire pyrolysis was investigated as a filler for rubber composites. This study considered rCB as an alternative to commercial carbon black due to its sustainability and CO2 emissions reduction. Composites with varying rCB contents (0 to 50 per 100 rubber) were produced and assessed for mechanical properties, such as hardness, abrasion resistance, and rheometric tests. The findings were used to train artificial neural networks (ANNs) with MATLAB software to predict rCB contents. Input parameters included optimal curing time, minimum and maximum torque, and results of mechanical tests like Shore A hardness and abrasion loss. The model was trained on data from 90 samples, with 10 reserved for validation. The predicted outcomes closely matched the experimental data, with a maximum prediction error of less than 3%. This indicates that ANNs are effective tools for intelligently modeling the curing process of natural rubber mixtures, minimizing material waste, optimizing production time, and determining suitable carbon black contents for desired mechanical properties. [ABSTRACT FROM AUTHOR]

This study investigates the impact of aging in methyl diethanolamine (MDEA) solution on cured rubber compounds comprising ethylene‐propylene‐diene monomer rubber (EPDM), butyl rubber (IIR), and blends, utilizing nano (nZnO) and conventional (ZnO) zinc oxides as curing activators. The analysis reveals that MDEA solution induces degradation in the rubber matrix by grafting amine and amide groups onto the rubber backbone, particularly affecting unsaturated units in diene monomers in EPDM and isoprene units in IIR. The Fourier‐transform infrared (FTIR) analysis validated the addition of these functional groups. Aging contributed to the formation of a thin rubber layer covering carbon black particles, likely due to un‐crosslinking and rubber chain scission, resulting in changes in bound rubber as observed in scanning electron microscopy (SEM) images. Tensile strength and elongation at break typically decreased with aging, with EPDM compounds exhibiting the highest initial tensile strength and IIR compounds demonstrating superior initial elongation. Hardness remains largely unaffected by aging. This study showed the detrimental effects of MDEA exposure on rubber compounds, emphasizing the critical importance of material selection and property tailoring for specific applications in MDEA‐rich environments, such as gas refineries. [ABSTRACT FROM AUTHOR]

Composites revolutionize material performance, fostering innovation and efficiency in diverse sectors. Elastomer-based polymeric composites are crucial for applications requiring superior mechanical strength and durability. Widely applied in automotives, aerospace, construction, and consumer goods, they excel under extreme conditions. Composites based on recycled rubber, fortified with reinforcing fillers, represent a sustainable material innovation by repurposing discarded rubber. The integration of reinforcing agents enhances the strength and resilience of this composite, and the recycled polymeric matrix offers an eco-friendly alternative to virgin elastomers, reducing their environmental impact. Devulcanized rubber, with inherently lower mechanical properties than virgin rubber, requires enhancement of its quality for reuse in a circular economy: considerable amounts of recycled tire rubber can only be applied in new tires if the property profile comes close to the one of the virgin rubber. To achieve this, model passenger car tire and whole tire rubber granulates were transformed into elastomeric composites through optimized devulcanization and blending with additional fillers like carbon black and silica–silane. These fillers were chosen as they are commonly used in tire compounding, but they lose their reactivity during their service life and the devulcanization process. Incorporation of 20% (w/w) additional filler enhanced the strength of the devulcanizate composites by up to 15%. Additionally, increased silane concentration significantly further improved the tensile strength, Payne effect, and dispersion by enhancing the polymer–filler interaction through improved silanization. Higher silane concentrations reduced elongation at break and increased crosslink density, as it leads to a stable filler–polymer network. The optimal concentration of a silica–silane filler system for a devulcanizate was found to be 20% silica with 3% silane, showing the best property profile. [ABSTRACT FROM AUTHOR]

This study investigates the profound impact of vulcanization methods on ethylene–propylene–diene monomer (EPDM) composites, with a particular focus on elucidating significant findings and achievements. Exploring eight composites, including sulfur and peroxide‐cured variations, we conducted an in‐depth evaluation of the crucial physico‐mechanical properties of the composites. The study extends to encompass the effects of vulcanization on heat aging parameters, providing a comprehensive understanding of the materials' resilience. Utilizing thermogravimetric analysis, differential scanning calorimetry, and Fourier transform infrared spectroscopy, our research delves into the processes, revealing critical insights into the thermal behavior and composition of the composites. Paint compatibility, a pivotal aspect in automotive applications, was rigorously examined through four different test methods. Surface morphology, investigated through scanning electron microscopy and atomic force microscopy, yielded valuable findings on the role of vulcanization in shaping surface roughness and enhancing paint compatibility. Additionally, the quantitative measurement of surface energy using the sessile drop method provided a deeper understanding of the adhesion properties. The findings distinctly underscore the superiority of peroxide‐cured composites, marking a significant stride toward their potential to revolutionize automotive applications. This research not only contributes to the knowledge base but also sets a foundation for advancements in EPDM composite materials, positioning them as key players in driving innovation within the automotive industry. Highlights: Developed a peroxide‐cured EPDM rubber composite with a rough surface.A rough surface is more paint‐compatible than a smooth surface.The roughness of peroxide‐cured EPDM is greater than that of sulfur‐cured one.Peroxide curing introduces more polar functional groups and cross‐links.Peroxide‐cured EPDM has higher thermal stability than sulfur‐cured EPDM. [ABSTRACT FROM AUTHOR]

In this study, natural rubber (NR)/polybutadiene rubber (PB) blend-based composites were prepared using graphene as a partial replacement for carbon black (CB) in different parts per hundred rubber (phr) percentages. In a previous study, the vulcanization characteristics, viscoelastic behavior, and static mechanical properties were reported, and the compound labeled as compound 2 (with 2.5 phr of graphene and 52.5 phr of carbon black) showed optimum properties. Herein, we report the dynamic mechanical properties and the transport properties of the formulations to establish further characterization of the compounds. Three different organic solvents comprising benzene, toluene, and xylene were employed to analyze the sorption characteristics. The obtained data were also modeled with different theoretical predictions. The dynamic mechanical properties showed that certain compounds can be considered to be green tire formulations, as there were appreciable changes in the tanδ values at different temperatures (−25 °C to 60 °C). The thermogravimetric analysis showed that compound 2, with 2.5 phr of graphene, has a higher t50 value among the studied formulations, which indicates higher thermal stability than the base compound. The partial replacement of 2.5 phr of graphene in place of carbon black (total 55 phr) led to appreciable improvements in terms of thermal stability, transport properties, and dynamic mechanical properties. [ABSTRACT FROM AUTHOR]

Nanocomposites based on chlorobutyl rubber (CIIR) have been made using a variety of nanofillers such as carbon black (CB), nanoclay (NC), graphene oxide (GO), and carbon black/nanoclay hybrid filler systems. The hybrid combinations of CB/nanoclay are being employed in the research to examine the additive impacts on the final characteristics of nanocomposites. Atomic force microscopy (AFM), together with resistivity values and mechanical property measurements, have been used to characterise the structural composition of CIIR-based nanocomposites. AFM results indicate that the addition of nanoclay into CIIR increased the surface roughness of the material, which made the material more adhesive. The study found a significant decrease in resistivity in CIIR–nanoclay-based composites and hybrid compositions with nanoclay and CB. The higher resistivity in CB composites, compared to CB/nanoclay, suggests that nanoclay enhances the conductive network of carbon black. However, GO-incorporated composites failed to create conductive networks, which this may have been due to the agglomeration. The study also found that the modulus values at 100%, 200%, and 300% elongation are the highest for clay and CB/clay systems. The findings show that nanocomposites, particularly clay and clay/CB hybrid nanocomposites, may produce polymer nanocomposites with high electrical conductivity. Mechanical properties correlated well with the reinforcement provided by nanoclay. Hybrid nanocomposites with clay/CB had increased mechanical properties because of their enhanced compatibility and higher filler–rubber interaction. Nano-dispersed clay helps prevent fracture growth and enhances mechanical properties even more so than CB. [ABSTRACT FROM AUTHOR]

A systematic study of the effects of the binder matrix on the microwave absorption properties of functional carbon nanoparticle-impregnated rubber composites is reported herein. Flexible rubber composites were fabricated by loading of conductive carbon black (CB) in three different elastomeric binder host matrices: silicone rubber, acrylonitrile butadiene rubber (NBR) and ethylene propylene diene monomer (EPDM) rubber. The DC conductivity, morphology and complex dielectric permittivity were investigated using the four-point probe contact method, scanning electron microscopy and vector network analyzer instrumentation, respectively. The percolation threshold was found to be lowest for CB-silicone rubber composites, i.e. 6 wt.% loading of CB, followed by 12 wt.% for CB-NBR composites and 16 wt.% for CB-EPDM composites. The rheological behavior of these composites was also studied, and their correlation with the observed percolation threshold (DC conductivity) of composites is discussed. The microwave absorption properties (reflection loss [RL]) were calculated based on the measured electromagnetic parameters over a frequency range of 6–18 GHz for each composite system. The significant microwave absorption (RL > −10 dB) properties can be tuned by varying the thickness in the range of 1.7–3.0 mm in these composites. The studies presented in the paper provide a basic framework for selection of an appropriate binder matrix for the development of stealth composites, according to the desired area of application. [ABSTRACT FROM AUTHOR]

To understand the effects of additives on the properties of rubber grades suitable for sealing applications in high-pressure H 2 gas infrastructure, five acrylonitrile butadiene rubber (NBR) vulcanizates with different fillers and curing agents are investigated. Structure-property relationships of these grades are correlated with the additives and properties required for high-pressure gas atmospheres are evaluated. Further, the influence of the exposure to high-pressure hydrogen, i.e., hydrogen uptake and morphological changes after exposure, is evaluated. With the addition of a silica filler and a coupling agent for improved filler-matrix interfaces, similar overall properties, e.g. crosslink density, tensile strength, and storage modulus are obtained, compared to a carbon black (CB) filled grade. Density reduction after hydrogen exposure is significantly higher for CB-filled NBR, indicating higher hydrogen uptake in CB-filled rubber compared to silica filled NBR grades, or slower gas desorption. However, CB-filled specimens show to be less prone to filler migration than the silica-filled samples. • Effects of NBR formulations on properties for high-pressure gas systems were tested. • Functionalized silica enhances typical properties to a comparable range like CB. • The balance of additives results in suitable RGD performance. • Silica filled NBR shows lower H 2 uptake compared to non-plasticized CB filled NBR. • Morphology of CB filled NBR is less affected by H 2 than silica filled grades. [ABSTRACT FROM AUTHOR]

This study employs potassium ferrate (K2FeO4) for the oxidation treatment of multi‐walled carbon nanotubes (MWNTs) under neutral and acidic conditions. A wet flash evaporation process is utilized to prepare natural rubber/MWNTs/carbon black composites, enhancing the performance of rubber composites. The increased oxidation level of MWNTs enhances their hydrophilicity, increases the quantity of oxygen‐containing hydroxyl groups on the surface, promotes dispersion within the natural rubber matrix, and ultimately improves the performance of the rubber products. The effective dispersion of MWNTs reduces electron transport resistance, forming a favorable electron transport channel in natural rubber. Experimental results indicate that K2FeO4 achieves the highest oxidation degree and optimal performance in an acidic environment. Compared to untreated MWNTs rubber composites, the oxidized MWNTs rubber composites exhibit a 34.9% reduction in the Payne effect, a 15.7% decrease in wear, a 12.7% reduction in rolling resistance, and a two‐order‐of‐magnitude increase in conductivity. This study provides a novel approach for preparing water‐dispersible MWNTs and high‐performance rubber composites, holding potential applications in premium rubber products and conductive rubber fields. Highlights: The wet flash refining process improved the dispersion of MWNTs.K2FeO4 oxidation of MWNTs was enhanced under acidic conditions.Oxidized MWNTs combined with CB to form a CB‐MWNTs‐CB filler network.Oxidized MWNTs and CB increased the "ball‐chain" arrangement in NR. [ABSTRACT FROM AUTHOR]

During and after the COVID-19 pandemic, the world has become more aware of environmental concerns and the importance of sustainability. Using natural rubber instead of synthetic rubber is one step toward a greener environment in a variety of technological applications, including the fabrication of vehicle tires. The objective of this work is to optimize the formulation for the production of airless tires, primarily for military vehicle applications, using natural rubber. Two natural rubber types, SIR 20 and RSS 1, with carbon black variants N220 and N550 as reinforcing agents present novel synergistic effects, and potentially tailor the properties of the rubber compound more precisely to meet the demanding requirements of military vehicle tires. A comprehensive assessment was conducted to evaluate various physical, damping, processing, and mechanical properties under standard conditions and subsequent aging at 70 °C for 72 h. Comparative analysis against control samples revealed notable improvements, particularly in abrasion resistance, crucial for tire wear. The combination of RSS 1 and CB N220 showed significant enhancements in strength and rigidity, suggesting their viability as alternative fillers. Leveraging dynamic mechanical analysis (DMA) results, the rubber compound underwent optimization to meet airless tire requirements, encompassing durability, comfort, and performance. This nuanced understanding of rubber's viscoelastic behavior holds paramount importance in designing puncture-resistant airless tires with optimal performance attributes. Combination of innovative materials and advanced characterization techniques to address the specific challenges of enhancing airless tire performance for military vehicles in challenging operational environments. [ABSTRACT FROM AUTHOR]

To elucidate the specific mechanical impact of carbon black (CB) filler–rubber interactions on reinforcement, CB particles are subjected to graphitization at 1300 °C and oxidation through concentrated nitric acid treatment to modulate their surface activity. Alongside untreated CB particles, the influence of surface activity and the oxygen distribution are investigated to assess their role in shaping CB aggregate structures using X‐ray absorption spectrum (XAS) and X‐ray computed tomography (CT) with spatial resolution of 30 nm. Meanwhile, virgin and modified CBs are blended in natural rubber with varying amounts (10, 30, 50 phr) and the aggregates distributions in rubber are investigated by nano‐CT. Combined with the mechanical properties of rubber composites and parameters of filler networks, the mechanical contributions arising from filler–rubber interactions are quantified. The findings underscore the robust interactions between oxidized CB and rubber matrix, exhibiting a mechanical property enhancement ratio of ≈59.2% at low strains in comparison to normal CB filler. The results indicate the synergies encompass of filler network, rubber chains, and filler–rubber interactions all play important roles for reinforcement, which aligns with the broader understanding of filler–rubber interactions and CB reinforcement mechanisms. [ABSTRACT FROM AUTHOR]

In this paper, the effect of non‐relaxing torsion loadings on the fatigue lifetime reinforcement of carbon black filled natural rubber is fully addressed. Torsion fatigue tests with different loading ratios have been performed with highly notched axisymmetric‐shaped specimens. Finite element analysis is used to predict the mechanical state at any point in the specimens. The prediction is significantly improved by taking into account the heterogeneous accommodation. The first Haigh diagram under fatigue torsion is built and analyzed by calculating the minimum loading in terms of the Cauchy stress as the normal stress to the crack for the minimum angle prescribed during the cycle. A strong lifetime reinforcement has been observed, which is found to be of the same amplitude to the one obtained under uniaxial tension with the same material. This has been confirmed by specific tests that combined non‐relaxing torsion and non‐relaxing tension loadings. Post‐mortem analysis carried out at the macroscopic and the microscopic scales enabled us to identify damage mechanisms, especially in the cases where the lifetime reinforcement was observed. [ABSTRACT FROM AUTHOR]

We report efficacious vibration damping of carbon black reinforced nitrile butadiene rubber‐polyvinyl chloride blend (NVC) vulcanizates in a constrained layer damping (CLD) configuration. The objective is to compare numerical simulations using finite element method (FEM) and the widely used Ross‐Kerwin‐Ungar (RKU) model with the experimental results. NVC blend (50:50 by weight), was compounded with carbon black as reinforcing filler and vulcanized using a sulfur‐based curative system. Significant reinforcement and toughening were observed for the carbon black reinforced vulcanizates compared to the pristine blend. The viscoelastic properties of the vulcanizates were assessed using dynamic mechanical analysis (DMA), exploring their behavior concerning temperature variations and different frequencies to generate the Prony series coefficients for input in FEM analysis. Vibration damping experiments were conducted using the Oberst beam method in a single cantilever mode, with steel as the vibrating substrate, aluminum as the constraining layer, and the NVC vulcanizates as viscoelastic materials (VEM). Numerical simulations were performed using FEM to analyze mode shapes and frequency response function (FRF), and the RKU model was employed to quantify CLD system loss factors (SLF). The salient finding of this study was the observed SLF values in the range of 0.08–0.20 in the frequency regime of 200–2000 Hz. These values qualify the studied material as effective VEMs for CLD treatment of structural vibrations. This study supports design optimization efforts in a wide range of engineering applications where effective vibration damping is critical. Highlights: Enhancement of NVC blend properties through carbon black reinforcement.Detailed analysis of viscoelastic behavior using DMA.Validation of findings through experimental modal analysis.Promising results in terms of system loss factors for CLD applications. [ABSTRACT FROM AUTHOR]

Nanoparticle (NP)‐filled natural rubber (NR) has attracted much attention owing to their prominent mechanical strength, stiffness, and wear resistance. In this study, the static and dynamic mechanical properties of carbon black (CB)/carbon nanotubes (CNTs) hybrid filled NR nanocomposites are investigated using coarse‐grained molecular dynamics (CGMD) simulations. The non‐bonded coarse‐grained force fields for the CB/CNTs hybrid filled NR nanocomposites are constructed by combining several methods (i.e., effective force coarse‐graining, iterative Boltzmann inversion, and energy matching methods). The uniaxial tensile results indicate that the gradual replacement of CB by the same weight percentage of CNTs significantly improves the mechanical performances of the nanocomposites and increases the heterogeneity of the stress and strain distributions in the nanocomposites, which can be ascribed to the high mechanical strength of CNTs and the formation of the rigid interface networks between CNTs and the NR matrix due to the wrapping behavior of NR molecular chains on the surface of CNTs. Furthermore, the dynamic shear results demonstrate that the introduction of NPs significantly enhances the Payne effect of the nanocomposites, and the higher the CNT loading in hybrid NPs, the stronger the Payne effect. It is also found that the breakup of NP networks plays a dominant role for the Payne effect of filled rubber as compared to the interfacial separation between NPs and the rubber matrix. The present multiscale computational framework can be further extended to other polymer nanocomposites, and sheds new light on the design and exploration of polymer nanocomposites through bottom‐up prediction. [ABSTRACT FROM AUTHOR]

This study investigated the synergistic effect of carbon black/multi-wall carbon nanotube (CB/MWCNT) hybrid fillers on the physical and mechanical properties of Ethylene propylene diene rubber (EPDM) composites after exposure to high-pressure hydrogen gas. The EPDM/CB/CNT hybrid composites were prepared by using the EPDM/MWCNT master batch (MB) with 10 phr CNTs to enhance the dispersion of CNTs in hybrid composites. The investigation included a detailed analysis of cure characteristics, crosslink density, Payne effect, mechanical properties, and hydrogen permeation properties. After exposure to 96.3 MPa hydrogen gas, the hydrogen uptake and the change in volume and mechanical properties of the composites were assessed. We found that as the MWCNT volume fraction in fillers increased, the crosslink density, filler–filler interaction, and modulus of hybrid composites increased. The hydrogen uptake and the solubility of the composites decreased with an increasing MWCNT volume fraction in fillers. Moreover, after exposure to hydrogen gas, the change in volume and mechanical properties exhibited a diminishing trend with a higher MWCNT volume fraction. We conclude that the hybridization of CB and CNTs formed strong filler–filler networks in hybrid composites, consequently reinforcing the EPDM composites and enhancing the barrier properties of hydrogen gas. [ABSTRACT FROM AUTHOR]

This paper presents an extensive experimental investigation on fatigue properties of carbon‐black filled isoprene rubber under complex loadings. A basic life prediction model taking strain energy density as fatigue parameter is first proposed based on fatigue crack growth tests and uniaxial tension fatigue tests under relaxing loads at room temperature. A database of fatigue life including relaxing and non‐relaxing is established through a great number of fatigue tests under five temperatures. Based on the database, two empirical parameters, that is, temperature factor (NRT/NHT) and life reinforcement factor (Re), are introduced to quantitatively characterize the coupling effects of high temperature and non‐relaxing loads on fatigue life. The fatigue mechanisms under different conditions are compared via wide‐angle x‐ray diffraction tests and postmortem analysis. It reveals that the weakening of life reinforcement at high temperatures is closely related to the strain induced crystallization behavior of rubber. [ABSTRACT FROM AUTHOR]

It has attracted tremendous attention for replacing petroleum‐based carbon black or mineral fillers with renewable, biology‐based and low‐cost cellulose. However, the reinforcing effect of cellulose, especially at the microscale, is still a great challenge in the polymer industry. In this work, a feasible surface modification method for microcrystalline cellulose powder (MCC) in all solid states is proposed by using rubber accelerators N‐cyclohexyl benzothiazole‐2‐sulphenamidee (CBS) and 2,2′‐dibenzothiazoledisulfide (DM). These accelerators not only accelerate the sulfur crosslink of nitrile butadiene rubber (NBR), but also graft to rubber molecular chains and form hydrogen bonds with MCC, resulting in good interfacial interaction and good dispersion of MCC in the NBR matrix. As a consequence, the tensile strength and elongation at break of NBR/10MCC reach up to 20.12 MPa and 511%, respectively, which are the highest values of NBR/MCC or cellulose nanocrystals (CNCs) composites we can find in the world and are comparable to those of carbon black or mineral fillers. This provides a more effective and environmentally friendly way of using MCC or CNCs in the polymer industry. Highlights: Microcrystalline cellulose powder can reinforce NBR.Hydrogen bonds have been established between accelerators and MCC.The tensile strength of NBR/10MCC composite reaches 20 MPa.The reinforcing mechanism is ascribed to the immobilized rubber layer. [ABSTRACT FROM AUTHOR]

The present research outlines the novel finite element analysis of green tire tread compounds based on solution styrene‐butadiene rubber/butadiene rubber (SSBR/BR) reinforced with a hybrid silica/carbon black filler system. For this purpose, a series of micromodels using representative volume elements (RVEs) were developed. The silica/carbon black ratio with a constant value of the reinforcement and considering periodic boundary conditions (PBCs) were established. The distribution of the reinforcing fillers in the matrix was inspired by transmission electron microscope (TEM) micrographs. A nonlinear hyperviscoelastic model was considered for the matrix and interphase zones and a linear elastic model for the reinforcement phase to predict the dissipation behavior at a moderate to high strain regime. To confirm the accuracy of the proposed model, the RVEs of hybrid systems were simulated and then compared with experimental data. The results showed that the proposed model is capable to predict the mechanical properties of rubber compounds. The presence of agglomerated fillers resulted in an increase in the dissipation behavior. This was confirmed by rubber process analyzer (RPA) and dynamic mechanical thermal analysis (DMTA) results. Highlights: Rubber compounds based on SSBR/BR reinforced with silica and/or carbon black were prepared by the melt mixing method.A multi‐scale finite element analysis of the particulate composites was developed using RVE.The distribution of reinforcing fillers in the matrix was inspired by TEM.The prediction of the stress–strain behavior of the hybrid composites was confirmed by the results of tensile tests.The simulated dissipation behavior of the composites was compared with RPA and DMTA analyses. [ABSTRACT FROM AUTHOR]

Hansen solubility parameter theory and rheological laws were employed to investigate the microscopic cross-linked network structure of the wear-resistant elastomer based on ethylene propylene diene monomers (EPDM)-polyamide elastomers (PAE)/graphite. With the condition of the same carbon black content, the wear volume of EPDM-PAE increased after added wax powder and decreased by adding five percent graphite. The role of microscopic cross-linked network on the wear-resistant properties was specifically characterized by a highly linear synergistic relationship between wear volume and cross-link density. The motion ability of micro chain segments has been characterized by the frequency sweep and the influence of the filler network has been represented by the strain sweep. Scanning electron microscope was used to characterize the micro filling structure, while stereomicroscope view was used to explore the wear interface. It was noteworthy that the graphite network layer formed on the abrasive surface on top of the abrasive grit wear transformed the wear mechanism into composite wear. This work was an innovative perspective to study rubber-plastic/solid lubricant-based wear-resistant elastomers, based on microscopic network structures, which could help to obtain new wear-resistant elastomers with specific properties. [ABSTRACT FROM AUTHOR]

The dispersion of a filler in a rubber matrix is a crucial parameter affecting the mechanical and dynamical properties of a rubber compound. It is the current issue of the rubber compounding industry because, most fillers are categorized as a mineral, while the rubber is an organic material. The surface modification of the filler has been accepted as an effective technique for the improvement of the abovementioned parameter. First, the surface premodification of commercial carbon black with a grade of N660 (CB) was implemented by four different oxidation methods. After that, among of used methods, the oxidation method using citric acid was selected to produce modified carbon black (CB‐Oxi) for further treatment. Subsequently, the coupling agent, Bis[3‐(triethoxysilyl)propyl] tetrasulfide (TESPT) was functionalized on the surface of CB‐Oxi to produce modified‐CB‐Oxi. Also, for comparison purposes, the TESPT functionalization was accomplished on untreated CB to form modified‐CB. The FTIR spectra of CB‐Oxi showed using the premodification method introduced the hydroxyl and carboxyl groups on the surface of CB. The correspondent spectra for modified‐CB‐Oxi confirmed the existence of silane groups on the surface of the carbon black. However, the mentioned silane groups were not observed on the surface of modified‐CB. The findings were strengthened by several characteristic techniques including, FESEM, XRD, EDS, CHNS elemental analysis, and RAMAN spectra. The FESEM graphs and elemental mapping showed homogeneous dispersion and uniform distribution of sulfur and silicon elements on the modified‐CB‐Oxi surface. According to RAMAN spectra, the disturbance in the structure of carbon black graphite was reduced after surface modification. modified‐CB‐Oxi is proposed as a potential substitute filler for current commercial carbon black in rubber compounding. [ABSTRACT FROM AUTHOR]

This study focuses on the evaluation of the dynamic mechanical properties, molecular structure, density, hardness, swelling behavior of natural rubber blends (NR) and nitrile rubber (NBR) reinforced with carbon black and/or nano-silica. An experimental work has been conducted to study of the effects of increasing NR content and incorporating nano-silica on the mechanical properties and molecular structure were studied using dynamic mechanical analysis (DMA) and Fourier transform infrared (FTIR) spectroscopy. The results show that increasing the NR content and/or incorporating nano-silica into the elastomer leads to a higher storage modulus with no significant change in the glass transition temperature. FTIR analysis indicates the compatibility of the polyblends and the presence of oxidation of the main polymer chain generated during the grinding of the rubber. Additionally, the results of the swelling study demonstrate that stronger molecular interactions occur on the surface of the nano-silica between the nitrile radicals in the NBR and the silanol (Si-OH) radicals. These findings suggest that blending NR and NBR with carbon black and/or nano-silica can improve the mechanical properties and compatibility of the resulting polyblends, with potential applications in the development of advanced elastomeric materials. [ABSTRACT FROM AUTHOR]

The partial or total replacement of carbon black by silica fillers is initiated through various techniques for environment-friendly, smart, and fuel-efficient NR composites for high-end dynamic applications like tyre tread. The smart properties such as low rolling resistance, better wet skid resistance, and abrasion resistance as well as noise reduction, create tyre tread compounds with superior performance. The endeavour to maximise the incorporation of eco-friendly ingredients like silica filler in rubber compound associates to produce a green tyre product indeed. The present review encompasses those approaches with a substantial contribution in the area along with critical insights in the respective efforts. Initially, the various types of commercially available silica fillers are discussed in brief, followed by the various approaches for surface modification in detail. Finally, the miscellaneous initiatives along with their achievements and drawbacks are included under five strategic verticals for better understanding along with vital remarks. [ABSTRACT FROM AUTHOR]

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This study reports on the highly simple fabrication of green carbon black (GCB) generated from scrap tires with acetic acid to improve the adsorption efficiency for water purification, which is thoroughly compared with conventional carbon black (CB) obtained from petrochemicals. Unlike traditional modification processes with strong acids or bases, the introduction of a relatively mild acid readily allowed for the effective modification of GCB to increase the uptake capability of metal ions and toxic organic dyes to serve as effective adsorbents. The morphological features and thermal decomposition patterns were examined by electron microscopy and thermogravimetric analysis (TGA). The surface functional groups were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The structural information (ratio of D-defects/G band-graphitic domains) obtained by Raman spectroscopy clearly suggested the successful fabrication of GCB (ID/IG ratio of 0.74), which was distinctively different from typical CB (ID/IG ratio of 0.91). In the modified GCB, the specific surface area (SBET) gradually increased with the reduction of pore size as a function of acetic acid content (52.97 m2/g for CB, 86.64 m2/g for GCB, 102.10-119.50 m2/g for acid-treated GCB). The uptake capability of the modified GCB (312.5 mg/g) for metal ions and organic dyes was greater than that of the unmodified GCB (161.3 mg/g) and typical CB (181.8 mg/g), presumably due to the presence of adsorbed acid. Upon testing them as adsorbents in an aqueous solution, all these carbon materials followed the Langmuir isotherm over the Freundlich model. In addition, the removal rates of cationic species (>70% removal of Cu2+ and crystal violet in 30 min) were much faster and far greater than those of anionic metanil yellow (<40% removal in 3 h), given the strong electrostatic interactions. Thus, this work demonstrates the possibility of recycling waste tires in the powder form of GCB as a cost-effective and green adsorbent that can potentially substitute traditional CB, and the modification strategy provides a proof of concept for developing simple fabrication guidelines of other carbonaceous materials. [ABSTRACT FROM AUTHOR]

The selective distribution of filler within polymer blends presents a compelling advantage, notably manifesting as a reduced percolation threshold when compared to an individual polymer matrix with a random filler dispersion. In this context, a thermoplastic elastomeric (TPE) blend comprising ethylene propylene diene rubber (EPDM) and linear low-density polyethylene (LLDPE), denoted as EL, has been meticulously formulated. The incorporation of varying amounts of conductive carbon black (Vulcan XC 72; VCB) into this TPE matrix has been achieved through conventional melt blending, yielding a composite material with exceptional electromagnetic interference (EMI) shielding effectiveness of -27.80 dB at 50 phr (parts per hundred rubber). This success is credited to the creation of a linked structure resulting from a dual-step percolation process. The selective distribution of carbon black (CB) throughout the TPE mixture results in a decreased critical concentration for connectivity and enhanced electromagnetic interference (EMI) shielding performance. This advancement underscores the potential of EPDM-LLDPE-VCB (ELV) composites to safeguard against electromagnetic radiation. It paves the way for their utilization in various techno-commercial applications, where a balance of mechanical strength, thermal stability, and flexibility is crucial. [ABSTRACT FROM AUTHOR]

Biomass renewable fiber has the advantages of low cost and environmental friendliness; however, its application as a reinforcement material is limited owing to its poor reinforcement effect. Thus, expanding its application is still a major challenge. This study investigates the effect of hemp fiber (HF) of different lengths on the mechanical properties and fatigue behavior of styrene-butadiene rubber/carbon black (SBR/CB) compounds using high-pressure low-shear extrusion. The results showed that the length of the HF retained by the extrusion process was approximately 10 times that of the traditional internal mixing process (internal mixing and open mixing). Interface bonding between the long HF coated with butadiene-vinyl pyridine latex (VPL) and the SBR/CB matrix was improved significantly. This inhibited the fatigue-crack propagation and considerably improved the dynamic fatigue life of the notched specimens. The dynamic fatigue life of the notched specimens of the composite prepared by the extrusion process was approximately nine times longer than that of the traditional internal mixing process. The results showed that the long HF length retained after the extrusion process effectively enhanced the strength of the rubber composites and significantly improved the dynamic fatigue life of rubber products under alternating stress. Highlights • The raw material, hemp fiber, is a renewable resource, low cost and environmentally friendly. • Pioneering a new process for preparing rubber composite materials, replacing the traditional process for preparing composite materials. • High-pressure, low-shear extrusion process retains the length of the hemp fibers and improves rubber composites properties. • Compared to traditional processes, long fiber length is 10 times longer by the extrusion process and fatigue life is increased to 9 times. • High-pressure, low-shear extrusion process enables mass production, opening up new ideas for rubber industrial production. [ABSTRACT FROM AUTHOR]

Graphene and its derivatives have been confirmed to be among the best fillers for rubber due to their excellent properties, such as high mechanical strength, improved interface interaction, and strain-induced crystallization capabilities. Graphene rubber materials can be widely used in tires, shoes, high-barrier conductive seals, electromagnetic shielding seals, shock absorbers, etc. In order to reduce the graphene loading and endow more desirable functions to rubber materials, graphene-based hybrid fillers are extensively employed, which can effectively enhance the performance of rubber composites. This review briefly summarizes the recent research on rubber composites with graphene-based hybrid fillers consisting of carbon black, silica, carbon nanotubes, metal oxide, and one-dimensional nanowires. The preparation methods, performance improvements, and applications of different graphene-based hybrid fillers/rubber composites have been investigated. This study also focuses on methods that can ensure the effectiveness of graphene hybrid fillers in reinforcing rubber composites. Furthermore, the enhanced mechanism of graphene- and graphene derivative-based hybrid fillers in rubber composites is investigated to provide a foundation for future studies. [ABSTRACT FROM AUTHOR]

Three types of composites were tested for electromagnetic interference (EMI) absorption shielding effectiveness, the curing process, and their physical–mechanical properties. For the first type of composites, nickel–zinc ferrite, manganese–zinc ferrite, and both fillers in their mutual combinations were incorporated into acrylonitrile–butadiene rubber. The overall content of the filler, or fillers, was kept at 200 phr. Then, carbon black or carbon fibers were incorporated into each rubber formulation at a constant loading of—25 phr, while the content of magnetic fillers was unchanged, at —200 phr. This work focused on the understanding of correlations between the electromagnetic shielding parameters and electrical conductivity of composites in relation to their EMI absorption shielding effectiveness. The absorption shielding abilities of materials were evaluated within a frequency bandwidth from 1 MHz to 6 GHz. This study revealed good correlation among permittivity, conductivity, and EMI absorption effectiveness. Although the absorption shielding efficiency of composites filled only with ferrites seems to be the highest, the absorption maxima of those composites reached over 6 GHz. The application of carbon-based fillers resulted in the higher electrical conductivity and higher permittivity of composites, which was reflected in their lower absorption shielding performance. However, the composites filled with ferrites and carbon-based fillers absorbed electromagnetic radiation within the desired frequency range. The presence of carbon-based fillers caused improvement in the tensile behavior of composites. This study also demonstrated that the higher the ratio of nickel–zinc ferrite in combined magnetic fillers, the better the absorption shielding efficiency. [ABSTRACT FROM AUTHOR]

In order to solve the problems of dust, low mixing efficiency, and poor quality stability in dry mixing and continuous mixing, this study combined the flocculation extrusion technology with continuous mixing technology of carbon black/additives/natural rubber composites. The flocculation of latex was achieved by carbon black itself and the shearing of the twin screw. The continuous mixing was carried out in a double‐rotor continuous mixer, which was composed of functional elements such as the exhaust section and extrusion section. The results showed that the technology promoted the formation of the filler‐rubber network, the sensitivity of viscosity to temperature was weakened, and the rubber was closer to a Newtonian fluid, with less extrusion swell phenomenon and no obvious spiral distortion. Compared with the dry mixing, the tensile strength, rebound rate, and abrasion resistance of the rubber composites prepared by this technology were increased by 11%, 31%, and 9%, respectively, providing theoretical and technical guidance for the green production and continuous production of high‐performance natural rubber composites. Highlights: The process is achieved by a twin‐screw extruder and a twin‐rotor continuous mixer.The process promotes the formation of the filler‐rubber network.The sensitivity of viscosity to temperature is weakened, with no spiral distortion.The tensile strength, rebound rate, and abrasion resistance are increased by 11%, 31%, and 9%. [ABSTRACT FROM AUTHOR]

Non‐linear viscoelastic characteristics of carbon black (CB)‐filled fluoroether rubber mixture samples are investigated by large amplitude oscillatory shear (LAOS) tests. Three analysis approaches based on LAOS tests are then used to discuss correlations between rheological behavior and CB‐filling amount. Each non‐linear viscoelastic parameter of the mixture presents a three‐stage characteristic with increasing CB content, which are attributed to the alteration of CB–elastomer network structure, corresponding to the state where gum continuous phase, CB–elastomer mesophase, and excessive CB agglomerates predominate in the mixture compound, respectively. According to the findings in engineering experiments, a CB content of 35–40 phr is recommended, taking into account tensile, hardness, and aging properties. Excessive CB agglomerates are found to reinforce CB–elastomer networks at elevated temperatures. For cold‐resistance properties, structural changes in CB–elastomer network are proven to exert little effect on Tg, but a higher CB content was found to slightly enhance the cold‐resistance coefficient, probably due to the decrease in velocity fraction of gum rubber. Highlights: LAOS tests were utilized to study the influences of CB on fluoroelastomer;Three‐stage alteration was observed in the mixture with increasing CB content;Correlation between CB content and the engineering properties was discussed. [ABSTRACT FROM AUTHOR]

Increasing industrialization and rapid change in market demand has led to aggressive competition impacting both business and environmental sustainability globally. In view of the new legislations, regulations and restrictions on the usage of hazardous materials, it becomes mandatory to use eco-friendly materials. In the present work, various petroleum-based and different modified vegetable oils are characterised for chemical and analytical properties. Styrene butadiene rubber (SBR) is extended with these oils at laboratory scale through emulsion polymerisation technique. Totally four number of petroleum-based oils like distillate aromatic extract (DAE), treated distillate aromatic extract (TDAE), residual aromatic extract (RAE) and naphthenic type oil and two number of modified vegetable oils, NO_2 and NO_6, are evaluated. All oils have shown compatibility with SBR latex which is confirmed by checking solvent extractables as well as oil leaching checking by visual inspection of oil extended rubber samples. These raw rubber samples are characterised for raw rubber properties as well as in ASTM-based rubber compound recipe to check their processing behaviour. Compounds prepared with both vegetable oil-based styrene butadiene rubber have shown comparable or slightly better processing properties as compared to compounds prepared with petroleum oil-based rubbers. Experimental compounds are also showing comparable carbon black dispersion and better polymer–filler interaction which may be due to the presence of various surface functional groups in vegetable oils. Microscopic pictures also confirm the comparable carbon black dispersion for all the samples. [ABSTRACT FROM AUTHOR]

Oxidative aging is a significant deterioration process that affects the performance and durability of rubber materials in various applications. Therefore, this study focuses on the development of new antioxidants‐based on polyaniline for ethylene propylene diene monomer (EPDM) rubber to enhance its resistance to oxidative aging. The novel polyanilines were prepared using in situ polymerization method and characterized using Fourier transforms infrared (FTIR) and thermogravimetric analysis (TGA). FTIR illustrates the success synthesis of polyanilines as it shows their characteristic functional groups. The thermal stability of the formed polyanilines is discussed through TGA and derivative of thermogravimetry (DTG) curves. The curves prove the good thermal stability of the synthesized polymers. The prepared polyaniline compounds were mixed to carbon black filled‐EPDM rubber composites using a roll mill and then vulcanized using sulfur curing process. Accelerated aging tests for the prepared EPDM rubber composites were conducted to evaluate the effectiveness of the antioxidants. Moreover, their impact on rheometer, mechanical, and swelling properties was studied. The results showed that the EPDM samples with the prepared polyaniline compounds exhibited improved oxidative properties compared to the EPDM sample with commercial antioxidant 2,2,4‐trimethyl‐1,2‐dihydroquinoline. These findings suggest that the novel antioxidants have the potential to enhance the durability and performance of EPDM rubber in various applications. [ABSTRACT FROM AUTHOR]

The significant rise in end‐of‐life tires (ELTs) globally poses immediate environmental and human health risks. Therefore, to promote ELTs recycling and to reduce tire industry carbon emissions, herein we present a facile approach for fine‐tuning the interfacial interactions between pyrolytic carbon black (P‐CB) obtained from ELTs and natural rubber (NR) matrix using phosphonium‐based ionic liquid (PIL). The reinforcing effect of PIL‐activated P‐CB was studied by replacing the furnace‐grade carbon black (N330‐CB) with varying PIL and P‐CB loadings. Adding PIL improved the filler dispersion and the cross‐linking kinetics with a substantially reduced zinc oxide (ZnO) loading. Considering the cross‐linking and viscoelastic properties, it was concluded that the composite, P‐CB/N330‐CB‐PIL (1.5)+ZnO (1) with half substitution of N330‐CB with P‐CB synergistically works with 1.5 phr PIL and 1 phr of ZnO resulting in improved dynamic‐mechanical properties with a minimal loss tangent value at 60 °C (tanδ=0.0689) and improved glass transition temperature (Tg=−38 °C) compared to control composite. The significant drop (~29 % lower) in tanδ could reduce fuel consumption and related CO2 emissions. We envisage that this strategy opens an essential avenue for "Green Tire Technology" towards the substantial pollution abatement from ELTs and reduces the toxic ZnO. [ABSTRACT FROM AUTHOR]

Reclaimed rubber (RR) from butyl tubes was evaluated as a partial and full replacement of a virgin rubber which is carboxylated nitrile butadiene (XNBR). This study involves the blending of carboxylated nitrile butadiene rubber with butyl reclaimed rubber (XNBR/BRR) in various loadings and cured with sulfur by using a two-roll mill. The objective is to investigate the effect of RR loading on crosslink density and mechanical properties of XNBR/BRR blends. The mechanical properties such as hardness, rebound resilience, tear strength, tensile strength, elongation at break, and modulus were evaluated. In this study, the amount of reclaimed rubber varied from 0 phr to 161 phr. The results showed that the rebound resilience, tear strength, and tensile strength had a reduction of 43%, 27%, and 67%, respectively. Also, the hardness and modulus increased by 17% and 60% each. As for the elongation at break, it had a decrease of 69% and then an increment of about 77%. These results appeared due to the low molecular 1 weight of the BRR800 and the presence of processing oil and carbon black in the reclaimed rubber itself. This study could prove that reclaimed rubber can be fully utilized by putting it to good use in producing good quality rubber-based products. [ABSTRACT FROM AUTHOR]

Waste from scrap tyres, due to its high volume (17 million Mg per year) and durability resulting from the physical and chemical properties, requires innovative approaches for efficient and environmentally friendly management. In many countries, the landfilling of waste tyres is banned (e.g., EU, USA, UK); however, waste tyres can be a source of valuable materials such as carbon black, pyrolysis oil, hydrogen-rich syngas, tyre char, as well as energy. The purpose of this article is to provide a synthesis of the state of knowledge regarding the thermal conversion of waste tyres by pyrolysis and gasification, taking into account the use of different measurement techniques and reactor types. These technologies are forward-looking and have a high degree of flexibility in terms of product sourcing, depending on the process conditions. The properties of waste from used tyres were analysed, i.e., the composition of the content of individual components and the main chemical substances. The results encompassed ultimate and proximate analyses of rubber from tyres, as well as the physical and chemical parameters of the tyre char obtained through pyrolysis. This article compiles available literature data regarding the impact of process and raw material parameters, such as temperature and time conditions, pressure, particle size, and catalyst addition on the pyrolysis and gasification processes. It also explores the influence of these factors on the yield and properties of the products, including pyrolysis oil, gas, synthesis gas, and tyre char. [ABSTRACT FROM AUTHOR]

The aim of the presented work was to obtain a new type of homogeneous composite based on an industrial polymer (polybutadiene, PB) and a well-known inexpensive filler (carbon black P-234, CB). For this purpose, the reaction of oxidative chlorophosphorylation (OxCh) was used. This makes it possible to introduce CB into the cross-linked structure of the modified polymer and ensure optimal distribution of the filler in it. The structure and thermal stability of the composite synthesized by the OxCh reaction were studied. Analysis of the composite by Fourier-transform infrared spectroscopy indicates a uniform distribution of carbon black in the network structure of the matrix and the physical interaction of the phases of the composite. Ultraviolet-visible spectrum data confirmed the improvement in light absorption in a wide range of the electromagnetic spectrum and the decrease in the optical band gap energy of the phosphochlorinated PB (PhPB) matrix with the addition of CB (Eg of PhPB = 3.25 eV; Eg of PhPB/CB composite = 2.28 eV). The influence of CB on the thermal stability of the PhPB matrix was studied using thermogravimetric and differential thermogravimetric analysis. After thermal analysis, the char yield for PhPB was 41 wt. %, and for PhPB/CB composite was 35.2 wt. %. Compared to PhPB, the increase in char yield, the decrease in maximum thermal decomposition temperature, and the high-integrated thermal decomposition temperature for the PhPB/CB composite show the improvement in the thermal stability of PhPB due to CB. [ABSTRACT FROM AUTHOR]

Manganese‐zinc ferrite, nickel‐zinc ferrite, and the combinations of both ferrites in constant level 200 phr were incorporated into acrylonitrile‐butadiene rubber. The amount of carbon black was constant in each composite −25 phr. The second series of composites was fabricated with similar composition, but the total content of ferrites or ferrites combinations was 300 phr, while the content of carbon black was 25 phr. The work was focused on investigation of electromagnetic absorption shielding effectiveness of composites and their physical‐mechanical properties. During the study, good correlation between conductivity, permittivity, and electromagnetic absorption parameters was established. Higher conductivity was reflected in higher permittivity of composites, which subsequently resulted in their lower absorption shielding performance. The experimental outputs revealed that absorption shielding effectiveness was enhanced with increasing with proportion of nickel‐zinc ferrite, which pointed out to higher absorption shielding potential of nickel‐zinc ferrite. The physical‐mechanical properties were found not to be influenced by the type of ferrite or ferrites combinations. The higher overall content of ferrites in rubber matrix caused the decrease in tensile characteristics of composites, suggesting that ferrites are inactive fillers considering the physical‐mechanical properties. [ABSTRACT FROM AUTHOR]