Increasing Carbon Black Content Research Articles

Morphology and properties of carbon black‐filled thermoplastic vulcanizate (TPV) composites based on hydrogenated acrylonitrile butadiene rubber and thermoplastic polyester elastomer

AbstractThe unique morphology of thermoplastic vulcanizates (TPVs) reveals a significant correlation between the microstructure and performance, and the development of high‐performance TPV composites for specialized applications has become a current research priority. This study is devoted to developing heat‐ and oil‐resistant TPV composites filled with carbon black (CB) based on hydrogenated acrylonitrile butadiene rubber (HNBR) and thermoplastic polyester elastomer (TPEE) following the masterbatch procedure of dynamic vulcanization. Herein, it focuses on the effects of CB content on the morphology, filler network structure, and properties of the TPV/CB composites. As observed by morphological studies, CB nanoparticles are interconnected and aggregated to form a dual network structure of rubber and CB particles in the composite. With the increasing CB content, it's demonstrated that dual networks have enhanced and shifted to rigid. Consequently, the hardness, thermal stability, and oil resistance of TPV/CB composites are improved, with a 104% elevation in the stress at 300% strain. The flowability in the molten state, toughness (the elongation at break decreased from 690% to 310%), and elasticity deteriorated by oversized (0.5 ~ 1.2 μm) CB agglomerates and rigid rubber particles. This study gives new insight into the microstructure‐properties relationship of TPVs, offering theoretical guidance for fabricating HNBR‐based TPV composites.

Synergistic Effect of Styrene and Carbon Black on the Fatigue Properties of Styrene-Butadiene Rubber Composites.

The increase in the styrene content in styrene-butadiene rubber (SBR) can improve the abrasion performance and cutting resistance of rubber, which has received attention in the tire industry. The fatigue performance is the main evaluation index of rubber materials applied to tires. In this study, the effect of the styrene content and its interaction with carbon black (CB) on the dynamic fatigue performance and mechanism of SBR were investigated. The results indicated that the dynamic fatigue life of the rubber composite materials was prolonged with increasing styrene content; furthermore, it showed a trend of increasing and then decreasing with increasing CB content. At a certain CB content, styrene and CB displayed a synergistic effect on improving the dynamic fatigue life of the composite materials. The dynamic fatigue performance of SBR40/CB20 was the best. The expansion of the fatigue cracks followed the secondary cracking mechanism, which consumed a large amount of strain energy and slowed the development of the main crack. However, when the CB content exceeded 40 phr, the mechanism transformed to main crack self-propagation and the fatigue life decreased.

Non‐linear viscoelasticity of carbon black–fluoroether rubber mixture studied by large amplitude oscillatory shear tests

AbstractNon‐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.

A combination of experimental and theoretical approaches on SSBR/BR compounds reinforced by hybrid nano‐silica/carbon black: Mechanical and rheological properties

AbstractIn modern formulations for green tire treads, nano‐silica combined with silane coupling agents has recently partially replaced carbon black (CB) to improve the well‐known “magic triangle” of tire tread compounding. However, achieving adequate levels of CB in formulations is still a challenge. In this study, the effect of nano‐silica/CB hybrid reinforcements and silane coupling agents on rubber compound prepared by melt blending method was investigated. Microstructure, swelling, mechanical and rheological properties of highly filled SSBR/BR‐based compounds were investigated. The results showed that with the increase of CB content in SSBR/BR/TESPT/nano‐silica, the properties pass an optimum point. Various properties were confirmed by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) images. Estimation of the properties of tire tread compounds is inevitable due to the high cost of the components and the time and energy savings. For this purpose, different theoretical models were used. The Bergstrom‐Boyce, Ogden‐Roxburgh and Mooney‐Rivlin models were used to study the mechanical properties and the Herschel‐Bulkley, Power law and Carreau–Yasuda theories were used for the rheological properties. Among the theoretical models used, the Bergstrom‐Boyce model showed better correlation with the experimental data than other models.Highlights Compounds based on SSBR/BR rubber blends were prepared by the melt blending method. The effect of hybrid reinforcements and silane coupling agent as compatibilizer was studied. The microstructure, mechanical behavior, thermal and rheological properties of the compounds were investigated. The improved dispersion of the reinforcements in the SSBR/BR matrix was confirmed by microstructure analyses. Various theoretical models were applied to validate the experimental mechanical and rheological results.

Investigation of non-covalent interactions in Polypyrrole/Polyaniline/Carbon black ternary complex for enhanced thermoelectric properties via interfacial carrier scattering and π-π stacking.

The thermoelectric (TE) performance of conducting polymers can be improved by the incorporation of carbon nanomaterials. In this work, the impact of carbon black (CB) on polypyrrole (PPy) and polypyrrole/polyaniline (PPy/PANI) binary composite have been investigated. Herein, PPy/PANI binary composite was initially prepared through chemical oxidative polymerization and then solution mixed with CB to form PPy/PANI/CB ternary nanocomposite. The structural and morphological analyses confirmed the formation of composites, and the strong interaction present between polymer matrix and CB. This was further confirmed by theoretical study, which showed strong noncovalent interaction and high complex stability between the materials. The thermoelectric results showed that both the electrical conductivity (σ) and Seebeck coefficient (S) has been increased with the increase in CB content (from 10wt% to 30wt%) and temperature (303K to 373K), while the thermal conductivity (κ) increase was low. The ternary nanocomposite involving 30wt% of CB was found to be the most promising material which showed an enhanced power factor (PF) of 0.0251μW/mK2 and high figure of merit (ZT) of 4.37x10-5 at 370K. The enhancement in ZT for PPy/PANI/CB ternary composite is 2 times, 316 times, 17.3 times, 3.97 times, 11.7 times, and 6.8 times greater than other samples. The enhancement in power factor and ZT was due to energy filtering effect and strong non-covalent interactions between the homopolymers and CB.

Direct ink writing of reaction bonded silicon carbide ceramics with high thermal conductivity

Silicon carbide (SiC) ceramic is one of the most used ceramic materials due to its excellent mechanical and thermal properties but the cost is high in production. Three-dimensional (3D) manufacturing of ceramic materials provides the possibility to fabricate ceramic components with unique geometry structures and can save time and cost in producing form and function parts. In this paper, reaction bonded silicon carbide (RBSC) ceramic was fabricated through direct ink writing (DIW) technology. Reaction bonded silicon carbide (RBSC) means infiltration of carbon containing porous green parts with melting silicon, leading to form β-SiC. Remaining pores are filled by residual free silicon. Silicon carbide (SiC) based inks with different carbon black content at solid content of 36 vol% were prepared. The inks consisted of silicon carbide powder as inner filler, carbon black powder and low content sodium alginate as the binder. The effect of carbon black content on rheological behavior was studied. The results showed that the carbon black content played an important role in adjusting the viscosity, modulus and yield point. With the increasing carbon black content, shrinkage of the printed green parts decreased. When the carbon black content reached 20 wt%, the final DIW RBSC ceramics had low residual Si content. The maximum density, flexural strength and thermal conductivity were 2.91 g/cm3, 229 MPa, and 132 W/(m·K), respectively. This study shows a bright prospect of this innovated 3D printing technology for flexibly producing complex and net-shaped RBSC ceramic parts.

Polylactide/Carbon Black Segregated Composites for 3D Printing of Conductive Products.

One of the most important directions in the development of additive manufacturing or three-dimensional (3D) printing technologies is the creation of functional materials, which allow not only prototyping but also the manufacturing of products with functional properties. In this paper, poly-lactide acid (PLA) /carbon black (CB) composites with segregated (ordered) structure have been created. Computer simulation based on the Mamunya geometrical model showed that the CB content within φ = 2.5–5 vol.% in the polylactide matrix leads to the formation of a continuous electrically conductive phase with an increase of electrical conductivity σdc above the percolation threshold. The simulation results were experimentally confirmed by optical microscopy and studies of the electrical conductivity of the composites. It was found that increasing CB content from φ = 1 vol.% to φ = 7 vol.% in the composites causes insignificant (due to the segregated structure) phase changes in the polylactide matrix and improves the thermal properties of composites. Electrically conductive filaments for Fused Deposition 3D Printing (FDM) were developed from PLA/CB composites and then 3D printed. A correlation between the electrical conductivity σdc and the CB content φ for base composites, filaments produced from them, and final 3D samples, has been found. Conductivity varies within σdc = 3.1·10−11 − 10·10−3 S/cm for the filaments and σdc = 3.6·10−11 − 8.1·10−4 S/cm for the final 3D-products.

Fabrication and Characterization of the Porous Ti4O7 Reactive Electrochemical Membrane.

Preparation of the Magnéli Ti4O7 reactive electrochemical membrane (REM) with high purity is of great significance for its application in electrochemical advanced oxidation processes (EAOPs) for wastewater treatment. In this study, the Ti4O7 REM with high purity was synthesized by mechanical pressing of TiO2 powders followed by thermal reduction to Ti4O7 using the Ti powder as the reducing reagent, where the TiO2 monolith and Ti powder were separated from each other with the distance of about 5 cm in the vacuum furnace. When the temperature was elevated to 1333 K, the Magnéli phase Ti4O7 REM with the Ti4O7 content of 98.5% was obtained after thermal reduction for 4 h. Noticeably, the surface and interior of the obtained REM bulk sample has a homogeneous Ti4O7 content. Doping carbon black (0wt%-15wt%) could increase the porosity of the Ti4O7 REM (38–59%). Accordingly, the internal resistance of the electrode and electrolyte and the charge-transfer impedance increased slightly with the increasing carbon black content. The optimum electroactive surface area (1.1 m2) was obtained at a carbon black content of 5wt%, which increased by 1.3-fold in comparison with that without carbon black. The as-prepared Ti4O7 REMs show high oxygen evolution potential, approximately 2.7 V/SHE, indicating their appreciable electrocatalytic activity toward the production of •OH.

Thermoplastic Starch-Based Composite Reinforced by Conductive Filler Networks: Physical Properties and Electrical Conductivity Changes during Cyclic Deformation.

Conductive polymer composites (CPC) from renewable resources exhibit many interesting characteristics due to their biodegradability and conductivity changes under mechanical, thermal, chemical, or electrical stress. This study is focused on investigating the physical properties of electroconductive thermoplastic starch (TPS)–based composites and changes in electroconductive paths during cyclic deformation. TPS–based composites filled with various carbon black (CB) contents were prepared through melt processing. The electrical conductivity and physicochemical properties of TPS–CB composites, including mechanical properties and rheological behavior, were evaluated. With increasing CB content, the tensile strength and Young’s modulus were found to increase substantially. We found a percolation threshold for the CB loading of approximately 5.5 wt% based on the rheology and electrical conductivity. To observe the changing structure of the conductive CB paths during cyclic deformation, both the electrical conductivity and mechanical properties were recorded in parallel using online measurements. Moreover, the instant electrical conductivity measured online during mechanical deformation of the materials was taken as the parameter indirectly describing the structure of the conductive CB network. The electrical conductivity was found to increase during five runs of repeated cyclic mechanical deformations to constant deformation below strain at break, indicating good recovery of conductive paths and their new formation.

An Experimental Study on the Dielectric Properties of Rubber Materials.

According to specific formulas, the mixing of rubber samples occurs by two methods: open mixing and internal mixing. The effects of frequency, mixing process, carbon black (CB) content, zinc oxide (ZnO) content, and stearic acid (SA) content on the dielectric properties of rubber materials were studied. The results showed that the effects of the mixing process on the dielectric properties of the rubber samples cannot be ignored, and the appropriate mixing process should be selected when preparing the required rubber materials. The dielectric constant and loss factor of the rubber samples vary depending on the frequency. The dielectric constant had a peak and valley value, while the loss factor only had a peak. The dielectric constant and loss factor of rubber samples were significantly affected by the content of CB, ZnO, and SA. The peak frequency decreased with the increase in CB content, however, the dielectric constant increased with an increase in CB content. The higher the ZnO content, the lower the peak frequency. In addition, the dielectric constant and loss factor increased with an increase in ZnO content. The higher the SA content, the greater the peak frequency. In addition, the dielectric constant and loss factor decreased with an increase in SA content. It is hoped that the experimental results obtained can provide guidance for the study of the dielectric properties, microwave absorption properties, and microwave heating characteristics of rubber polymers.

Compressive Fatigue Behavior of Gum and Filled SBR Vulcanizates.

The influence of carbon black on physical mechanical properties, compressive fatigue life, and the temperature changes during compression fatigue process of styrene-butadiene rubber (SBR) vulcanizates were explored. A series of unfilled and filled SBR compounds were prepared, and the compressive fatigue behaviors of the vulcanizates were performed on a mechanical testing and simulation (MTS) machine. The top surfaces of the filled SBR were imaged using scanning electron microscopy (SEM) after 105 cycles of compressive fatigue. The filled SBR shows greater compressive fatigue resistance than the unfilled SBR. The incorporation of carbon black into SBR improves the creep resistance. The best compressive fatigue resistance for the filled SBR was achieved by the addition of 30 phr carbon black. With the increase of carbon black content, the energy dissipation and the heat build-up increase simultaneously. Furthermore, SEM images of the vulcanizates suggest that the crack propagation mechanism of the unfilled and the filled SBR was different. For the unfilled SBR, due to periodical compressive stress, the polymer chains can be destroyed, and the cracks can be easily initiated and propagated, showing serious damage on the top surfaces of the specimen. However, for the filled SBR, the carbon black agglomeration around the cracks can greatly delay the generation of the cracks, decrease the fatigue damage, and ultimately improve the fatigue resistance.

A study on the electrical and physical properties of mortar incorporating carbon black

In this study, carbon black was used to manufacture electrical conductive mortar, and the carbon black and mixing water were controlled. In carbon black, secondary particles were formed with primary particles sized 100 ~ 300 nm and the electrical conductivity was measured at 19.2S/m. Mixing water content had to be increased according to the increase of carbon black content to maintain uniform flow (190 ± 5 mm) of the carbon black-incorporated mortar and the mortar strength gradually decreased with the increase of water content. For OPC mortar, electric current was measured as 0.0024A, and a heating phenomenon was not observed. On the other hand, the electric current of mortar mixed with 10% of carbon black was 0.0855A, the highest among the specimens, and the electric resistance was 163Ω∙m, which was also the highest exothermic characteristic. However, when 10wt% of carbon black was used, the mortar properties deteriorated, and thus, countermeasures for this should be further studied.

A simple and reliable route to prepare high-temperature microwave high-performing absorbers

With extensive use of electronic devices and communication equipment, serious issue of electromagnetic wave pollution needs to be addressed as one of the priorities that demand social efforts. In this work, carbon black (CB)/SiO2 composites were synthesized via facile and reliable route and applied for microwave absorption at high-temperature environment around 673 K. Variations of complex permittivity and microwave absorption performance of composites under X-band of 8.2–12.4 GHz and temperature range of 298–673 K were analyzed in detail. Results showed that complex permittivity improved continuously with the increase in CB content and temperature. By elevating the temperature to 673 K, the composite with 10 wt.% of CB can achieve full coverage of effective absorption (RL <− 10 dB) over X-band with thin thickness of 2.9 mm. Therefore, this new composite material has good application prospect as high-temperature microwave absorber, considering its extraordinary properties and easy preparation.

Progression and characterization of polydimethylsiloxane-carbon black nanocomposites for photothermal actuator applications

The new development of polymer-based actuators triggers the progress of nanocomposites. Polymer materials are currently used in sensors, microfluidic devices, electrical and thermal actuators, and energy harvesting applications due to ease of availability, excellent tolerable properties, and customizable properties. The polymer-based nanocomposite can be driven by various stimuli, which is the actuator's emerging field. Thus, photothermal actuation is a thurst area of research transforming light energy into mechanical energy through the polymer material. The photo-responsive material can be prepared and tested for photo-actuation by incorporating the nanoparticles into the polymer. The present work focuses on developing polydimethylsiloxane (PDMS) and carbon black (CB) nanocomposite. The objective here is to investigate the photothermal actuator's performance by illuminating the infrared (IR) light source and studying its most influential characteristics, such as absorbance, thermal conductivity, and the thermal expansion coefficient.The PDMS / CB nanocomposite absorbs the IR light and then increases temperature, which is finally transformed into a beam deflection. Responses are measured as a result of time deflection using the Laser displacement sensor. It is noted that the deflection of the nanocomposite beam is linearly increased during illumination with light while it is exponentially decreasing when the light is turned off. The proposed polymer nanocomposite is approximately deflected by 9 mm in the duration of 16 s duration. Furthermore, the experimental deflection of the photothermal actuator is very close to theoretical results. The nanocomposite PDMS / CB reveals that there is an increase in absorbance by increasing the filler content. The nanocomposite conductivity is 35.2 % higher than the base material. As well, the thermal expansion coefficient decreases with an increase in carbon black content. The photothermal actuator's development is an ongoing process in which the material parameter, actuator geometry, and many more are modified. As a result, the photothermal bending performed can provide a means for various light-driven applications.

Influence of charge emission behaviors of semi-conductive shielding layer on charge accumulation properties of insulation layer for HVDC cable

Space charge accumulation is one of the key factors restricting the manufacture and application of high-voltage direct current (HVDC) cables. Semi-conductive shielding layer plays an important role in uniform electric field in HVDC cable, and its own emission properties directly affect the space charge behaviours in the insulation material. In the paper, charge injection property from semi-conductive layer to insulation layer have been focused emphatically based on experiment and simulation. The charge injection characteristics of semi-conductive layer under two typical electrode configurations of ‘Metal-Insulation layer-Metal’ (M-I-M) and ‘Semi-conductive layer-Insulation layer-Metal’ (S-I-M) have been studied. The conductive current and depolarization current of the insulation layer are compared. Finally, effect of particle size and concentration of carbon black (CB) in the semi-conductive layer on the interfacial electric field has been studied by electric field simulation. The experimental results show that the charge injection from the semi-conductive layer is more obvious under the action of low electric field of 5 kV mm−1 due to effect of CB particles. It can be seen from the depolarizing current curve that the charge injection quantity with S-I interface is greater than that of M-I interface. Further calculation results show that the maximum distortion electric field increases slightly with the increase of CB size. When CB content is 25%, the electric field distortion caused by interface CB particles is about twice of the average electric field (5 kV mm−1), increasing from 9.61 kV mm−1 at 10 nm to 10.15 kV mm−1 at 50 nm. The reduction of CB size in the semi-conductive layer within a certain range is conducive to the reduction of the interface electric field. The maximum distortion field gradually decreases with the increase of CB content at a certain range.

Fast‐Charge Limitations for Graphite Anodes with Si as Capacity‐Enhancing Additive

AbstractRate capability is always coming into the question when new materials are characterized; however, this question also arises when blends of different electroactive materials are used. This study was dedicated to the charge capabilities of graphite‐Si blends, in which Si acts as a capacity‐enhancing electrode additive (≤20 wt.% Si). As delithiated Si is considered poorly electronic conductor, one would assume that the presence of Si induces additional internal resistance that hampers fast charging of this type of electrodes. Current‐interruption measurements demonstrate that the internal resistance of graphite‐Si blends increases proportionally to the amount of Si in the electrode. This is also reflected in the respective charge capability tests, where electrodes with smaller Si content showed better power performance. With the aim to improve the charge capability of the electrode formulations, two approaches were evaluated: 1) addition of various amounts of conductive additive in the form of carbon black and 2) densification of electrodes. While the charge capability could be successfully improved by increasing carbon black content, densification mainly lead to performance deterioration.

Effects of carbon content on microstructure and mechanical properties of SiC ceramics fabricated by SLS/RMI composite process

Selective Laser Sinering (SLS) and Reactive Melting Infiltration (RMI) were combined to fabricate complicated SiC ceramics with high performance in the research. The influence of carbon content on green parts’ mechanical properties was studied. Then, the effect of carbon density on the microstructure of SiC was studied. The results showed that the density of sintered body increased first and then decreased with the increase of carbon black content. Due to the increase of carbon density, the siliconizing property of carbonated preforms is also improved by impregnating asphalt. When the carbon density was 0.6612 g/cm3, sintered density reached 2.899 g/cm3. But the flexural strength reached peak value of 190.19 ± 1.89 MPa as the carbon density decreased to 0.5542 g/cm3. Therefore, this research lays a foundation for laser sintering to fabricate high performance and complex structure SiC ceramics by regulating carbon content.

Polyaniline Electrode Activation in Li Cells

Polyaniline (PANi) can be used as an electroactive organic cathode material in Li-cells with multiple redox states. The theoretical specific capacity of the emeraldine base (PEB) is 150 mAh g−1. In this study, we show how the specific capacity of PEB90−xCBxPVDF10 cathodes is dependent upon the mass percentage of PEB and carbon black (CB) in the potential range of 2.0–4.0 V. The capacity of PEB90−xCBxPVDF10 cathodes is initially very low, steadily increasing during initial cycling. A constant capacity is eventually reached with continued cycling. Microscopic imaging and elemental analysis of cycled electrodes reveals how the electrode composition and morphology of PEB90−xCBxPVDF10 cathodes plays an integral role in the magnitude of the specific capacity during the initial and steady state cycles. We propose a diffusion-limited model as an attempt to elucidate the differences in the total specific capacity among PEB90−xCBxPVDF10 cathodes. From our findings, we propose that increasing CB content provides more ion-diffusion channels throughout the PEB90−xCBxPVDF10 cathodes. This model is consistent with our findings in that more CB content reduces the amount of cycles required to reach steady state cycling and increases the magnitude of the specific capacity at steady state.

Study on the Properties of Rubber with Different Contents of Carbon Black

In this paper, the rubber with different carbon black content was designed and its properties were tested to verify its effects on rubber properties. The results showed that with the increase of carbon black content, the hardness of rubber increased gradually, and the tensile strength, elongation and tear strength firstly increased and then decreased. The abrasive volume of vulcanization firstly decreased and then increased along with carbon black content. The heat generation of rubber increased slowly between 10 and 20 parts of carbon black content, while the heat generation of rubber increased rapidly between 30 and 40 parts of carbon black content. After thermo-oxidative ageing at 75°C for 96 hours, the hardness, tensile strength, elongation and tear strength of the rubber decreased to varying degrees. The properties of the rubber with carbon black content decreased rapidly between 10 and 20 parts, while the properties of the rubber with carbon black content between 30 and 40 parts decreased slowly.

Nano-indentation as a tool for evaluating the rheological threshold in polymer composites

We investigated the variation of nano-mechanical properties of Poly (propylene) (PP)/Carbon Black (CB) composite using nano-indentation and evaluated rheological threshold of the composites. PP/CB composites were prepared by melt-mixing process with varying CB content (0–20 wt %) using a micro-compounder. The rheological threshold of the composites was calculated using well known rheometer technique by power law relation. We also employed nano-indentation technique as an additional novel tool for evaluating rheological threshold in PP/CB composites. Rheological and nano-indentation measurements were correlated to assess the rheological threshold in PP/CB composites. The modulus of elasticity of PP/CB composites was increased from 0.8 GPa to 1.4 GPa with 20 wt % CB loading. There was a minor enhancement in the tensile strength of PP/CB composites with increase in CB content and the elongation at yield was decreased due to the brittleness imparted by CB. The thermal stability of PP/CB system also improved with CB content as the decomposition temperature was shifted from 450 °C to 500 °C.