Effect Of Carbon Black Content Research Articles

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.

Low‐cost carbon black‐loaded functional films for interlaminar toughening and in‐situ delamination monitoring of carbon fiber/epoxy composites

AbstractFunctional polyethersulfone (PES)/carbon black (CB) films were fabricated and interleaved into carbon fiber/epoxy composite laminates to simultaneously improve the mode I interlaminar fracture toughness (GIC) and delamination monitoring sensitivity. It was found that when the CB content in the functional film was 7.5 wt%, the initial and propagation GIC of the laminate achieved the greatest improvements of 99.16% and 82.83%, respectively. The toughening mechanism was mainly attributed to the formation of phase separation structure, the plastic deformation of PES and the pull‐out of epoxy and CBs. Meanwhile, a delamination increment‐resistance change relationship equation was proposed to predict the delamination increment of the laminate during mode I delamination. Moreover, the effect of CB content in the film on the delamination monitoring sensitivity was investigated. The pure PES film showed the largest sensitivity coefficient k of 4.55, which was much higher than that of Control (0.14). When the CB content was in the range of 2.5–7.5 wt%, both GIC and k remained at relatively high levels, indicating that PES/CB films have promising applications in advanced multifunctional composites due to their low cost, simple manufacturing process, and large‐scale industrial manufacturability.

Ballistic tests of double-based propelling charges with different carbon black content

Nitrocellulose and nitroglycerin are the main components of double-base propellants comprising up to 95% of their total mass. A chemical stabiliser and a burn rate modifier are required components, added in amounts of several percent. The study analyses the effect of carbon black content, contributing less than 1% of the propellant mass, on the burning rate of differently shaped propelling charges. The experiments, carried out on high energetic, double-base propelling charges, showed that the carbon black content significantly affects the burning rate of the propelling charge in the rocket motor chamber.

Vpliv črnega ogljika na mikrostrukturo in lastnosti prevodnih kompozitov ogljik/keramika

Vpliv črnega ogljika na mikrostrukturo in lastnosti prevodnih kompozitov ogljik/keramika

Effects of carbon black content and size on conductive properties of filled high‐density polyethylene composites

AbstractThe high‐density polyethylene (HDPE) composites filled with four kinds of carbon blacks (CB) were prepared to investigate the effects of the size and content of the CB on the electrical properties of the HDPE/CB composites. It was found that the composites presented conductive percolation behavior, the CB with different size filled‐systems had different percolation thresholds; the higher the structure property of the CB, the larger the particle surface area, and the smaller the particle size, the better was the conductivity, and the lower was the percolation threshold of the composites. In addition, the HDPE/CB composites showed significant positive temperature coefficient (PTC) effect and negative temperature coefficient effect. The bigger the filler particle diameter, the higher was the PTC intensity of the HDPE composite systems under the same CB weight fraction.

Effect of Carbon Black on Characteristics of a Selected EPDM-Based Thermal Insulator Composite

Ethylene-propylene-diene terpolymer (EPDM) based thermal insulator represent efficient class of the high temperature thermal insulators due to their excellent thermal, mechanical and ablative properties. This classed insulator is often reinforced by Kevlar pulp and fumed silica. Ammonium Sulphate and antimony trioxide mixture as a flame retardant was added. Carbon black (CB) was added to enhance the elastomer ablative properties. different concentrations of CB were investigated. In this work, the effect of carbon black content on the characteristics of a selected EPDM based insulating formulation has been investigated. The tensile strength, hardness and elongation have been slightly improved. The thermal stability via thermal gravimetric analysis (TGA-DTG) and differential scanning calorimetry (DSC) also has been slightly improved. Whereas the ablation resistance has been considerably improved. the weight loss from sample containing 10 phr decreased by 28% relative to the neat specimen.

Investigation on electrically conductive aggregates produced by incorporating carbon fiber and carbon black

This paper reports on an investigation of newly developed electrically conductive aggregates (ECAs) through the semi-dry mixing method and the pelletization technique. Carbon fiber and carbon black were incorporated into the aggregates as conductive fillers, while ordinary Portland cement and fly ash were used as matrix materials. The effects of carbon fiber and/or carbon black dosages on the electrical resistivity, water absorption and crushing strength of ECAs were studied. For ECAs with carbon fiber only, the threshold percolation of carbon fiber was identified to be 1.0% by volume. The ECAs with 1.0% carbon fiber exhibited 3.4Ω·m electrical resistivity, 13.08% water absorption and 1.57MPa crushing strength. Moreover, the effect of carbon black content was investigated when the content of carbon fiber was kept at 0.5vol.%. The threshold percolation of carbon black for ECAs with 0.5vol.% carbon fiber was 2.0% by weight. These ECAs possessed 7.34Ω·m resistivity, 24.41% water absorption and 0.95MPa crushing strength. Scanning electron microscope was employed to study the conductive network formed by two conductive components, which helped to illustrate the conductive mechanism of carbon fiber and carbon black inside the ECAs.

Si/SiC optical coatings for C/SiC composites via gel-casting and gas silicon infiltration: Effects of carbon black content

The dense Si/SiC coatings are fabricated by means of gel-casting (GC) and gas silicon infiltration (GSI) for the first time, using carbon black and α-SiC as raw materials. The influences of the carbon black content on the properties of the coating samples have been investigated. Results show that, with the increase of the carbon black content, the viscosity of the slurry increase dramatically, the density and the porosity are closer to theoretical results, leading to the higher density after GSI. And the β-SiC content increases as well as the Si content decreases, resulting in the increase of the mechanical and the thermal matching properties. It is also worth noting that the roughness of the coating of φ160 mm comes to 0.57 nm after polished. The study highlights that the combined application of the GC and the GSI processes can produce high-quality Si/SiC coatings that are suitable in the space optical applications.

Effect of carbon black content and particle size on the phase evolution of aluminum oxy nitride (AlON)

In this work aluminum Oxy-nitride (γ-AlON) crystals were synthesized by Co-precipitation processing from Al(NO3)3 solution, magnesium acetate and nanosized carbon particles as the source of Al3+, Mg2+ and reducing agent, respectively. The effects of the nanosized carbon and Mg2+ content and particle size on the formation of AlON phase were investigated by means of XRD, SEM and EDS analysis. Our results indicated that AlON powder could be synthesized when the resultant precursors were calcined at 1700°C for 2h under flowing N2. Under optimal additional content of C (7.1wt%), the resultant AlON powders exhibited the primary particle size of about 2–4µm with a specific surface area of 3m2/g.

Effect of carbon black content on the microwave absorbing properties of CB/epoxy composites

To prevent serious electromagnetic interference, a single-layer and double layer wave-absorbing coating employing complex absorbents composed of carbon black with epoxy resin as matrix was prepared. The morphologies of carbon black /epoxy composites were characterized by scanning electron microscope and atomic force microscope, respectively. The carbon black particles exhibit obvious polyaromatic were characterized by X-ray diffraction. The electromagnetic parameters of carbon black were measured in the frequency range of 8–12 GHz by transmission/reflection technology, and the electromagnetic loss mechanisms of the two particles were discussed, respectively. The microwave absorption properties of the coatings were investigated by measuring reflection loss using arch method. The effects of carbon black mass ratio, thickness and double-layer on the microwave absorption properties were discussed, respectively. The results showed that the higher thickness, higher ratio and double-layer of carbon black /epoxy content could make the absorption band shift towards the lower frequency range. Significantly, the wave-absorbing coating could be applied in different frequency ranges according to actual demand by controlling the content of carbon black in composites.

Effect of Carbon Black Content and Molding Pressure on the Thermal Conductivity of SiC/Si Ceramic Composites

SiC/Si ceramic composites have been considered as promising candidate materials for heat exchanger due to their good thermal conductivity and corrosion resistance. In this work, the SiC/Si ceramic composites were fabricated by liquid silicon infiltration technique, and the effect of carbon black content and molding pressure on thermal conductivity of the composites was studied. With carbon black content increasing from 5 wt. % to 25 wt. %, the thermal conductivity increased from 42.36 W/(m·K) to 65.60 W/(m·K) when molding pressure was fixed as 50 MPa. With molding pressure increasing from 30 MPa to 110 MPa, the thermal conductivity of SiC/Si ceramic composites with 20 wt. % carbon black content increased firstly, and then decreased, obtaining a maximum thermal conductivity of 71.62 W/(m·K) under 90 MPa. The SiC/Si ceramic composites with an optimal thermal conductivity of 76.55 W/(m·K) at room temperature were obtained when carbon black content and molding pressure were 25 wt. %, 90 MPa, respectively.

Effects of Carbon Black and the Presence of Static Mechanical Strain on the Swelling of Elastomers in Solvent.

The effect of carbon black on the mechanical properties of elastomers is of great interest, because the filler is one of principal ingredients for the manufacturing of rubber products. While fillers can be used to enhance the properties of elastomers, including stress-free swelling resistance in solvent, it is widely known that the introduction of fillers yields significant inelastic responses of elastomers under cyclic mechanical loading, such as stress-softening, hysteresis and permanent set. When a filled elastomer is under mechanical deformation, the filler acts as a strain amplifier in the rubber matrix. Since the matrix local strain has a profound effect on the material’s ability to absorb solvent, the study of the effect of carbon black content on the swelling characteristics of elastomeric components exposed to solvent in the presence of mechanical deformation is a prerequisite for durability analysis. The aim of this study is to investigate the effect of carbon black content on the swelling of elastomers in solvent in the presence of static mechanical strains: simple extension and simple torsion. Three different types of elastomers are considered: unfilled, filled with 33 phr (parts per hundred) and 66 phr of carbon black. The peculiar role of carbon black on the swelling characteristics of elastomers in solvent in the presence of mechanical strain is explored.

Effect of carbon black content on the swelling of elastomers in solvent in the presence of static mechanical loading

The effect of carbon black on the mechanical properties of elastomers is of great interest because filler is one of the necessity items for manufacturing of rubber products. While fillers can be used to enhance the properties of elastomers, it is known that filler yields to significant inelastic responses such as stress-softening, hysteresis and permanent set. Moreover, under tensile loading, the filler acts as a strain amplifier in the rubber matrix resulting in a higher local strain state in the matrix as compared to the applied macroscopic strain. The study of the effect of carbon black content on the swelling characteristics of elastomeric components undergoing mechanical loading and simultaneously exposed to aggressive solvent is a prerequisite for durability analysis. The present study investigates the effect of carbon black content on the swelling of elastomers in solvent in the absence and in the presence of static tensile loadings.

Plasma preparation of carbon black used in conductive coatings

A conductive coatings was prepared using a kind of spherical carbon black (CB) as conductive pigment and polyacrylate (PA) as polymer matrix. The conductive pigment CB nanoparticles were prepared by AC plasma arc method, and then treated with concentrated nitric acid. The pristine and oxidized CB nanoparticles were characterized by scanning and transmission electron microscopy. Afterwards, CB powders were dispersed in PA to produce conductive coatings. The effects of CB content and titanium coupling agent on the volume resistivity were investigated. Furthermore, the rheological and mechanical properties of PA/CB coatings were also investigated. The results showed that the volume resistivity of the PA/CB films was decreased with the increasing of CB content and the electrical percolation threshold was about 2.0 wt%. An interesting result could be observed that the rheological threshold value was close to electrical percolation threshold. In addition, the tensile properties were improved with the addition of CB nanoparticles. POLYM. COMPOS. 37:1078–1084, 2016. © 2014 Society of Plastics Engineers

Tensile, Electrical Conductivity, and Morphological Properties of Carbon Black–Filled Epoxy Composites

This work investigates the effect of carbon black content on the tensile, electrical, and morphological properties of epoxy matrix. Carbon black–filled epoxy composites were obtained by mixing the desired amount of carbon black from bamboo stem (BS-CB), oil palm empty fruit bunch (EFB-CB), and coconut shell (CNS-CB) with the epoxy resin. Tensile and electrical properties of carbon black from three different sources (BS-CB, EFB-CB, and CNS-CB) used to fill epoxy composite with 5% filler loading were measured and the results indicated improvement in tensile and electrical properties. The diffraction patterns of X-ray diffraction (XRD) indicated nonlinear crystalline amorphous structure of the CB.This article has been corrected with minor changes. These changes do not impact the academic content of the article.

카본블랙을 첨가하여 제조한 다공성 BaTiO3계 세라믹스의 미세구조 및 PTCR 특성 변화

As a pore precursor, carbon black with different content of 0 to 60 vol% were added to (Ba,Sr)<TEX>$TiO_3$</TEX> powder. Porous (Ba,Sr)<TEX>$TiO_3$</TEX> ceramics were prepared by pressureless sintering at <TEX>$1350^{\circ}C$</TEX> for 1h under air. Effects of carbon black content on the microstructure and PTCR characteristics of porous (Ba,Sr)<TEX>$TiO_3$</TEX> ceramics were investigated. The porosity of porous (Ba,Sr)<TEX>$TiO_3$</TEX> ceramics increased from 6.97% to 18.22% and the grain size slightly decreased from <TEX>$7.51\;{\mu}m$</TEX> to <TEX>$5.96\;{\mu}m$</TEX> with increasing carbon black contents. PTCR jump of the (Ba,Sr)<TEX>$TiO_3$</TEX> ceramics prepared by adding carbon black was more than <TEX>$10^5$</TEX>, and slightly increased with increasing carbon black. The PTCR jump in the (Ba,Sr)<TEX>$TiO_3$</TEX> ceramics prepared by adding 40 vol% carbon black showed an excellent value of <TEX>$9.68{\times}10^5$</TEX>, which was above two times higher than that in (Ba,Sr)<TEX>$TiO_3$</TEX> ceramics. These results correspond with Heywang model for the explanation of PTCR effect in (Ba,Sr)<TEX>$TiO_3$</TEX> ceramics. It was considered that carbon black is an effective additive for preparing porous <TEX>$BaTiO_3$</TEX> based ceramics. It is believed that newly prepared (Ba,Sr)<TEX>$TiO_3$</TEX> cermics can be used for PTC thermistor.

Effects of Carbon Black Content on Microwave Absorbing and Mechanical Properties of Linear Low Density Polyethylene/Ethylene-Octene Copolymer/Calcium Carbonate Composites

Calcium carbonate (CC) and carbon black (CB) filled composites based on linear low density polyethylene (LLDPE) and ethylene-octene copolymer (POE) were prepared by means of melt blending. The microwave absorbing performances were measured using the arch method and the electromagnetic parameters of composites were determined by transmission/reflection method. The structure and surface morphology were observed using transmission electron microscopy (TEM). LLDPE/POE/CC/CB composites show excellent microwave absorption ability. The dielectric loss from the filler CB is responsible for the microwave absorption of polymer composites. CB can effectively improve the mechanical properties of LLDPE/POE/CC composites.

Physico-chemical properties of low density polyethylene and ethylene vinyl acetate composites cross-linked by ionizing radiation

Conductive polymers consisting of low density polyethylene (LDPE), ethylene vinyl acetate copolymer (EVA) and carbon black (CB) were prepared by melt mixing. LDPE/CB, EVA/CB and LDPE/EVA/CB composites were irradiated by electron beam over the range 50–200 kGy. The effect of CB content, CB type, content of the EVA and irradiation dose on the physico-chemical properties (gel content, volume resistivity, mechanical and thermal properties) was investigated. The gel content increased as a function of both increasing irradiation dose and CB content, and a significant improvement in the mechanical properties (tensile strength and elongation at break) was observed. By increasing the CB content, the volume resistivity dropped by several orders of magnitude. Thermogravimetric analysis parameters including onset temperature ( T i, °C), differential thermogravimetric peak temperature (DTG, °C) and temperatures at 50% and 95% weight losses were investigated. Thermal stability of the conductive composites was enhanced by addition of either CB or EVA and the degree of enhancement was correlated to their contents. The melt flow index decreased with incorporation of CB leading to more viscous matrix.

Effect of carbon black content on microcellular structure and physical properties of chlorinated polyethylene rubber foams

Chlorinated polyethylene rubber (CPE) foams filled with various content of carbon black were prepared by compression molding. The effect of carbon black content on the cure characteristics, foam characteristics and physical properties of the CPE compounds were investigated. The results showed that adding ZnSt as activator could lower the decomposition temperature of azodicarbonamide. The results of a moving die Rheometer suggested that the cure characteristics were influenced by the content of carbon black, and the cure rate index increased with carbon black content. The morphology and physical properties results indicated that the content of carbon black played important roles in the cell morphology and physical properties of CPE rubber foams.

Effects of Carbon Black Content on Cure Characteristics, Mechanical Properties and Swelling Behaviour of 80/20 NBR/CIIR Blend

The influences of carbon black loading on rheological and mechanical properties were investigated for 80/20 NBR/CIIR blend vulcanized with a semi-efficient system. The swelling behaviour of the vulcanizates in six different solvents was studied as well. Carbon black (type N347) was used as filler and the loading range was from 40 to 100 phr. Results showed that cure rate index, hardness, tensile strength and stress at 100% elongation increase with increasing carbon black loading while scorch time, cure time, elongation at break and resilience decrease. It was also found that the solvent uptake decrease linearly with increasing carbon black loading.