Conductive Carbon Black Research Articles

Comprehensive Analysis of Mechanical Properties of CB/SiO2/PVDF Composites.

Damage is a key problem that limits the application of polymer membranes. In this paper, conductive carbon black (CB) and silicon dioxide (SiO2)-reinforced polyvinylidene fluoride (PVDF) composites were prepared using a solution mixing method. Through a uniaxial tensile test, the fracture and damage characteristics of the material were analyzed. When the structure had inevitable notch damage, changing the notch angle was very helpful for the material to bear more load. In addition, when there were two kinds of fillers in the PVDF matrix at the same time, there was an interaction between particles. The microstructure of the composite was characterized by scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and thermogravimetric (TG) analysis. The experimental results indicate that, when the ratio of CB:SiO2:PVDF was 1:4:95, the general mechanical properties of the composite were the best.

Fabrication of a strain sensor from a thermoplastic vulcanizate with an embedded interconnected conducting filler network

Conductive polymer composites for use as stretchable strain sensors have recently been developed for use in wearable electronic devices capable of detecting various stimuli such as human body motion. In this work, we report the development of a flexible strain sensor based on conductive thermoplastic vulcanizate (TPV) by the incorporation of conductive carbon black (CCB). By adopting special processing conditions, the percolation threshold of the CCB could be minimized to a value as low as ~4 wt% as compared to a value of 10 wt% for conventional TPV. Under static and cyclic loading, the strain sensing behavior of the conductive TPV depended on the morphology and filler content. The result also revealed that interconnected TPV exhibited superior piezoresistive characteristics with good sensitivity. Therefore, the good strain sensing performance of this conductive TPV can be considered as a promising material for use in wearable human-motion and wearable strain sensors.

Strain-rate independent small-strain-sensor: Enhanced responsiveness of carbon black filled conductive rubber composites at slow deformation by using an ionic liquid

Small-strain-sensors, based on conductive carbon black (CB) filled conductive rubber composites (CRCs), have been developed. An ionic liquid (IL) was used to improve the way that the piezoresistive response is independent of strain rate at small strains. Cyclic sensing behaviour at small strains was investigated under a sequential alteration of strain rates. At small strains, the CRCs without IL respond inefficiently to slow deformation cycles, giving a strain-rate dependent sensitivity. On the contrary, the presence of IL enhances the response to slow deformations. At elongations up to 3%, the loosely packed conducting parts and the sufficient rubber-filler interaction achieved with the use of an IL/CB ratio of 1.0 make the piezoresistive responses efficiently independent of the strain rates. Also, the sensitivity is at least threefold higher, compared with CRCs without IL. So, the IL enables the construction of strain-rate independent small-strain-sensor.

Laser sintering of cryogenically ground polymer powders into high-performance parts: The role of dry particle coating with a conductive flow agent

The poor processability of cryogenically ground polymer powders rendered by their irregular shapes greatly hinders their applications in the selective laser sintering (SLS) technique. In this study, nonconductive silica (SiO2) nanoparticles and conductive carbon black (CB) nanoparticles were coated onto cryogenically ground polyamide 12 (PA12) powders and acted as flow agents to alleviate the flow problem. It was found that the addition of SiO2 or CB nanoparticles both greatly improved the flowability of cryogenically ground powders, thereby facilitating a successful sintering process. However, significantly improved mechanical performance and reduced structural defects were achieved only upon the addition of CB nanoparticles. The underlying mechanism was suggested to be related with the higher conductivity, lower friction, smaller adhesion energy and higher laser absorption efficiency of CB-coated powders. Therefore, conductive and radiation-adsorbing particles such as CB can serve as a multifunctional agent to enable the sintering of polymer powders with irregular shapes into parts with improved mechanical performance.

Enhancement of power generation with concomitant removal of toluene from artificial groundwater using a mini microbial fuel cell with a packed-composite anode

Composite beads are packed in the anode chamber of a microbial fuel cell (MFC), providing more area for microbial attachment and growth, increasing the efficiency of removal of toluene from toluene-contaminated groundwater. The composite beads were fabricated by integrating carbon coke (CC) with a relatively large specific surface area to which microorganisms easily adhere with conductive carbon black (CCB), which has low electrical resistance. Since the advantages of both are complementary, the power generation of MFC is improved. The single layer-packed anode MFC (SP-MFC) completely degraded 200 mg L−1 of toluene - 2.3 times faster than the non-packed anode MFC (NP-MFC). The high power density (44.9 mW m-3) and oxidation peak (1 mA), with low internal resistance (207 Ω) revealed that SP effectively improved the power generation efficiency. A composition ratio (CRCCB:CC) of composite beads of one to two yielded the best performance with a removal efficiency of 100 % – 76 % faster than CC. The closed circuit voltage of CR1:2 MFC reached 340 mV, which was 16 times that of CC; the power density and oxidation peak reached 103 mW m-3 and 1.38 mA, respectively. Therefore, CR1:2 effectively increased the overall removal efficiency and power generation of the MFC.

Conductive and fire-retardant wood/polyethylene composites based on a continuous honeycomb-like nanoscale carbon black network

This study prepares multi-functional wood/polyethylene composites (WPCs) by addition of a small amount of nanoscale conductive carbon black (CCB), leading to honeycomb-distributed WPC (WPCH-CCB). The conductivity, electromagnetic interference shielding (EMI SE), and flame-retardancy of WPCH-CCB were comparatively studied with the uniformly-distributed WPC (WPCU-CCB) prepared through a conventional melt-blending process. The conductivity and EMI SE of the WPCH-CCB reached up to 1.5 × 10−2S·cm−1 and 20.2 dB at 3 wt% CCB content, respectively. In comparison, the conductivity and EMI SE of the WPCU-CCB only had 8.3 × 10−14S·cm−1 and 5.0 dB. Moreover, the cone calorimetric analysis revealed that the WPCH-CCB had lower smoke production and heat release than the WPCU-CCB.

Practical and Durable Flexible Strain Sensors Based on Conductive Carbon Black and Silicone Blends for Large Scale Motion Monitoring Applications.

Presented is a flexible capacitive strain sensor, based on the low cost materials silicone (PDMS) and carbon black (CB), that was fabricated by casting and curing of successive silicone layers—a central PDMS dielectric layer bounded by PDMS/CB blend electrodes and packaged by exterior PDMS films. It was effectively characterized for large flexion-angle motion wearable applications, with strain sensing properties assessed over large strains (50%) and variations in temperature and humidity. Additionally, suitability for monitoring large tissue deformation was established by integration with an in vitro digestive model. The capacitive gauge factor was approximately constant at 0.86 over these conditions for the linear strain range (3 to 47%). Durability was established from consistent relative capacitance changes over 10,000 strain cycles, with varying strain frequency and elongation up to 50%. Wearability and high flexion angle human motion detection were demonstrated by integration with an elbow band, with clear detection of motion ranges up 90°. The device’s simple structure and fabrication method, low-cost materials and robust performance, offer promise for expanding the availability of wearable sensor systems.

An Integrated Structural Air Electrode Based on Parallel Porous Nitrogen-Doped Carbon Nanotube Arrays for Rechargeable Li-Air Batteries.

The poor discharge and charge capacities, and the cycle performance of current Li–air batteries represent critical obstacles to their practical application. The fabrication of an integrated structural air electrode with stable parallel micropore channels and excellent electrocatalytic activity is an efficient strategy for solving these problems. Herein, a novel approach involving the synthesis of nitrogen-doped carbon nanotube (N-CNT) arrays on a carbon paper substrate with a conductive carbon-black layer for use as the air electrode is presented. This design achieves faster oxygen, lithium ion, and electron transfer, which allows higher oxygen reduction/evolution reaction activities. As a result, the N-CNT arrays (N/C = 1:20) deliver distinctly higher discharge and charge capacities, 2203 and 186 mAh g−1, than those of active carbons with capacities of 497 and 71 mAh g−1 at 0.05 mA cm−2, respectively. A theoretical analysis of the experimental results shows that the parallel micropore channels of the air electrode decrease oxygen diffusion resistance and lithium ion transfer resistance, enhancing the discharge and charge capacities and cycle performance of Li–air batteries. Additionally, the N-CNT arrays with a high pyridinic nitrogen content can decompose the lithium peroxide product and recover the electrode morphology, thereby further improving the discharge–charge performance of Li–air batteries.

Flexible and wearable carbon black/thermoplastic polyurethane foam with a pinnate-veined aligned porous structure for multifunctional piezoresistive sensors

In this paper, flexible conductive carbon black (CB)/thermoplastic polyurethane (TPU) foam (CTF) with an intriguing pinnate-veined aligned porous structure was fabricated via a unidirectional freeze-drying process. The density, porosity and average pore size of the composite foam are 0.13 g cm−3, 83.7% and 24.9 μm, respectively. CB particles are uniformly dispersed in the skeleton of the as-prepared foam, resulting in a low percolation threshold of 0.48 vol%. The CTF is capable of distinguishing different compressive strain by change of the relative resistance. Its responsive behaviors towards compressive strain present an excellent linear characteristic with a high gauge factor (GF) up to 1.55. In the piezoresistive tests, the CTF shows a fast response/relaxation time (150/150 ms), fascinating recoverability, excellent response stability within a wide workable detection range up to 80% strain (corresponding pressure of 584.4 kPa) and a superior durability (>10000 cycles), which is mainly related to the pinnate-veined aligned porous structure along the orientation direction. The CTF was then assembled as a wearable sensor to monitor various human motions such as arm bending, squatting, tiptoeing, etc., showing good detection performances. The sensor can also deal with water pollution through oil/water separation, suggesting its multifunctionality and promising prospects in complicated situations.

Broadband Electromagnetic Response and Enhanced Microwave Absorption in Carbon Black and Magnetic Fe3O4 Nanoparticles Reinforced Polyvinylidenefluoride Composites

High-efficiency Electromagnetic Interference (EMI) shielding materials are essential in the harsh environment created by unwanted electromagnetic (EM) signals. In this work, polyvinylidenefluoride (PVDF) composites reinforced with magnetic Fe3O4 nanoparticles and cost-effective conducting carbon black (CB) were derived by a solution mixing and coagulation method. Coagulation is found to be an effective method to fabricate uniform composites of materials having higher tendency to form aggregates. The three-dimensionally extending conducting network created by CB and the hopping electrons from Fe3O4 result in high electrical conductivity of PVDF/CB/Fe3O4 composites (PCF). The permittivity, permeability and impedance spectra in the 10 MHz–1 GHz broadband region indicate that dielectric loss is dominating over magnetic loss and is attributed to the collection of a large number of capacitive regions at the interfaces formed by CB and Fe3O4, which results in the enhanced interfacial polarization losses in PCF composites. The composites exhibit EMI shielding effectiveness (EMI SE) greater than 20 dB and their shielding mechanisms involve dielectric losses, magnetic losses and their synergistic interaction. The matching input impedance of the composites allows the radiations to enter into the material and it undergoes multiple internal reflections at the interfaces and the energy of the internally reflected radiation is subsequently absorbed by CB. These different mechanisms result in an absorption dominated EMI shielding with a total EMI SE of 55.3 dB (99.9997% of shielding) for PCF-40 composite having thickness 2 mm and an average skin depth of 0.37 mm in the X-band microwave region.

Synergistic effect of conductive carbon black and silica particles for improving the pyroresistive properties of high density polyethylene composites

Smart heating devices, assembled by the conductive polymer composites (CPCs) with positive temperature coefficient (PTC), have been wildly used in automobile, spacecraft, smart building, due to their outstanding self-regulating performances. Unfortunately, the intrinsic drawbacks of CPCs such as resistance instability and poor PTC reproducibility vastly restrict the prosperity of smart heaters. Herein, a facile and valid strategy based on doping silica nanoparticles in conductive carbon black (CB)/high density polyethylene (HDPE) composites is proposed to enhance the comprehensive PTC properties. The synergistic effect of conductive CB and silica, evidenced by the simultaneously enhancement of the conductivity, resistance stability and PTC reproducibility of Silica/CB/HDPE composites, has been demonstrated as the content of silica reaching 3.0 vol % when CB loading is just above its percolation threshold. Our morphology studies suggest that this effect is attributed to the improved dispersion of CB with the intercalation of silica particles. It is believed that this work offers a facile and low cost method for fabrication of high-performance self-regulated heating material.

Conductive nylon-MXD6 composites prepared by melt compounding associated with formation of carbon black-covered PET domains serving as big conductive particles

This contribution reports an economic yet scientifically-sound approach for the preparation of conductive nylon-poly(m-xylene adipamide) (MXD6) on the basis of a two-level percolation mechanism through addition of poly(ethylene terephthalate) (PET) and carbon black (CB). The primary percolation is percolation of CB in the surfaces of PET domains, and the secondary percolation involves formation of conductive network by highly conductive CB-covered PET domains serving as big conductive particles and CB aggregates in the matrix phase acting as bridges. When 20 wt% of MXD6 was replaced by PET, the percolation threshold of CB dramatically decreased by 83%, resolving the main problem encountered in the preparation of conductive nylon/CB composites. The thermodynamic driving force for assembly of CB on the surface of PET domains is the formation of Janus-type CB particles during compounding as a result of hydrogen bonding and π-π interactions between CB and the two polymers. The effects of PET content and polyester type on electrical conductivity of the composites were discussed in terms of conduction mechanism and interaction difference of CB with MXD6 and the polyester.

Effect of Conductive Carbon Black on Mechanical Properties of Aqueous Polymer Binders for Secondary Battery Electrode.

To predict the cyclic stability of secondary battery electrodes, the mechanical behaviors of polymer binders and conductive composites (BCC) is of great significance. In terms of uniaxial tension, tensile stress relaxation, and bonding strength tests, the present study encompasses a systematic investigation of the mechanical properties of two typical aqueous binders with different contents of Super-S carbon black (SS) under a liquid electrolyte. Meanwhile, the microstructure of cured film and the surface morphology of the bonding interface are investigated in detail. When the weight ratio of SS increases from 0% to 50%, the cured BCC films manifest a higher ratio of tensile strength to modulus and a shorter characteristic relaxation time. Moreover, suitable loadings of SS can improve the tensile shear strength and remarkably reduce the percentage of interface failure of aqueous polymer-bonded Cu current collector. Nevertheless, an excess of carbon black amount cannot maintain its enhancing effect and can even impair the adhesive layer. Finally, a sodium alginate-based polymer composite holds much more superior mechanical properties than the mixture of sodium carboxymethyl cellulose and styrene-butadiene rubber at the same content of carbon black. Noticeably, the two kinds of aqueous polymer doped by 50 wt % of SS exhibit the best adhesive properties.

Conversion of Black Carbon Emitted from Diesel-Powered Merchant Ships to Novel Conductive Carbon Black as Anodic Material for Lithium Ion Batteries.

Waste soot generated from diesel engine of merchant ships has ≥ 2 µm agglomerates consisting of 30–50 nm spherical particles, whose morphology is identical to that of carbon black (CB) used in many industrial applications. In this study, we crystallized waste soot by heat treatment to transform it into a unique completely graphitic nano-onion structure, which is considerably different from that of commercial conductive CB. While commercial CB has a large specific surface area because of many surface micropores generated due to quenching by water-spraying in the production process, the heat-treated waste soot has a smooth micropore-free surface. Thus, the treated waste soot acquires the shape of CB but has a much smaller specific surface area. When the treated soot is used as a conductive material in lithium ion battery (LIB) half cells, the Coulombic efficiency of the entire anode is improved significantly owing to its low specific surface area; the electrochemical performance of the LIB is considerably enhanced compared to that of conventional conductive materials. Thus, polluting soot generated in marine propulsion can be transformed into a new class of CB with a unique structure by simple heat treatment; this soot can also be used as an inexpensive conductive material to enhance the LIB performance.

A simple strategy for flexible electromagnetic interference shielding: Hybrid rGO@CB-Reinforced polydimethylsiloxane

In this work, we investigate the electromagnetic interference (EMI) shielding properties of blends of easily available carbon black (CB) with high-surface-area reduced graphene oxide in a polydimethylsiloxane (PDMS) matrix. The chemical composition and morphology of the rGO@CB/PDMS composite are characterized using different techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, atomic force microscopy, and field effect scanning electron microscopy. The hybrid filler could effectively improve the electrical conductivity and dielectric loss, and hence the shielding efficiency, and retain its performance even after repeated bending for 100 times. The microwave absorption mechanism of the samples is discussed in detail in terms of their complex permittivity and microstructure. A three-dimensional layered framework is formed within the composite, which in turn leads to multiple reflections of the microwaves at the layer boundaries, subsequently dissipating them as heat due to the presence of conductive CB particles. Because of this, the hybrid rGO@CB/PDMS composite displays superior absorption-dominated shielding property, with a shielding efficiency (SE) of ∼28 dB. The synergetic effect of the hybrid fillers resulting from multiple reflections suggests new pathways for designing flexible shielding materials for practical EMI applications.

Numerical simulation of the effective permittivity of low‐density polyethylene composite filled by carbon black

The effective permittivity of low-density polyethylene with the conductive carbon black (CB) was modelled by COMSOL. The impact of CB content on the electric properties of the composites with different geometry of the inclusions was investigated. The modelling outcomes evidenced that the simulation was in good agreement with the experiment results at low-filler concentration. The effect of moisture on the effective permittivity of the composites was also investigated. A thin layer of adsorbed water on the surface of the CB particles was found to significantly increase the conductivity, which is in agreement with experimental results.

Evaluation of particle dispersion behaviours in Lithium-ion battery slurry by electrical impedance spectra-tomography method

This paper investigated the particle dispersion behaviours of Lithium-ion battery (LIB) slurry by using electrical impedance spectra-tomography (EIST) method from the perspective of experiment and simulation. In the experiment, an EIST system composed of Field—Programmable Gate Array (FPGA), multi-plexer, switch circuit and 8-electrode sensor is developed to measure the frequency response of LIB slurry under two different conditions, which are rotation speed n=0rpm with rotation time t=0min and n=100rpm with t=6min. In the simulation, four different geometry structure models, which are (a) Carbon Black (CB) linear formation, (b) CB aggregation, (c) CB & LiCoO2aggregation and (d) network dispersion, are established. Six frequencies, which are f=1 kHz, f=10 kHz, f=50 kHz, f=100 kHz, f=250 kHz and f=500 kHz, are used for the reconstructed conductivity images of LIB slurry in both the experiment and the simulation. The numerical simulation is used to verify the correctness of the experiment results. After combining the experiment and the simulation, it is concluded that the agglomeration behaviours of CB and LiCoO2particles appear within LIB slurry in the case of n=0rpm with t=0min, while CB path and part LiCoO2particles coated by CB particles appear in the case of n=100rpm with t=6min. Moreover, high frequencies are suitable to distinguish high conductive CB components from LIB slurry. Furthermore, the developed EIST system has the capability of monitoring particle dispersion behaviours in LIB slurry, which has the potential to be used for the on-line measurement of LIB slurry in order to improve the performance of LIB.

Enhancement of Percolation Threshold by Controlling the Structure of Composites Based on Nanostructured Carbon Filler

The effect of a multicomponent polymer binder composition on the electrical conductivity of composites filled with carbon black (CB) is reported. Composites based on a mixture of polypropylene and styrene-ethylene-butylene-styrene (SEBS), plasticized with industrial oil, and filled with electrically conductive CB, were prepared using a twin-roller mixer. The presence of various regions in the volume of the binder and the distributions of CB in binder regions was investigated by scanning electron microscopy. The formation of a special conductive network of CB is observed in the investigated composite. The electrical characteristics of the composites were investigated by means of impedance spectroscopy. On the basis of Raman spectroscopy, it was found that CB is predominantly located in the elastomer (in SEBS plasticized with industrial oil), which forms a continuous phase. It has been shown that the spatial distribution of CB (under constant loading of the filler) can change the conductivity of composites by as much as 5 orders of magnitude, and provides a low percolation threshold.

Electrochemical behavior of a composite material containing 3D-structured diatom biosilica

3D-structured diatom biosilica mixed with conducting carbon black was investigated as an active electrode material for lithium-ion batteries. Diatom biosilica was obtained by cultivation of the selected diatom species under laboratory conditions. Several instrumental techniques (XRD, FTIR, Raman, SEM-EDX, TGA) were used to characterize the physicochemical properties of applied biosilica. It was evidenced that the prepared new composite material has a significant impact on the electrochemical properties of the electrode. The ratio 1:1 of biosilica and carbon black exhibited a specific capacity of 400 ± 9 mAh/g over 90 cycles. Such a ratio ensured proper electric contact between biosilica particles. The specificity of the faradaic process suggests that biosilica-based electrodes might be suitable in large-scale energy storage applications.

Room-Temperature Ferromagnetic Sr3YCo4O10+δ and Carbon Black-Reinforced Polyvinylidenefluoride Composites toward High-Performance Electromagnetic Interference Shielding.

In this study, we fabricated composites of conducting carbon black (CB), room-temperature ferromagnetic Sr3YCo4O10+δ (SYCO) and polyvinylidenefluoride (PVDF) by the solution mixing and coagulation method for the first time. During the nucleation process of PVDF, the presence of SYCO and CB individually facilitates the crystallization of polar β and semipolar γ phases along with the nonpolar α phase in PVDF. The dc electrical conductivity of PVDF raised from 1.54 × 10–8 to 9.97 S/m with the addition of 30 wt % of CB, and it is nearly constant with respect to the SYCO content. The PVDF/CB/SYCO composites (PCS) possess high permittivity and its variation is in accordance with the content of polar phases in PVDF. Moreover, the complex permittivity and permeability spectra from 10 MHz to 1 GHz indicate that the dielectric loss dictates over magnetic loss in these composites. The electromagnetic interference shielding effectiveness (EMI SE) of PCS composites is higher than that of PVDF/CB and PVDF/SYCO composites in the 8.2–18 GHz region. Addition of SYCO in the PVDF/CB matrix enhances shielding by dominated absorption with minimal reflection. The analysis of the shielding mechanism suggests that in addition to conducting and magnetic losses due to CB and SYCO, respectively, the synergy among CB, SYCO, and PVDF promotes shielding by matching the input impedance to that of free space, enhancing multiple internal reflections from SYCO and subsequent absorption by CB, eddy current losses, dielectric damping losses, interfacial polarization losses, and so forth. These different mechanisms result in an enhanced EMI SE of 50.2 dB for the PCS-40 composite for a thickness of 2.5 mm.