Carbon Black Filler Research Articles

The Effect of Type of Filler on Microphase Separation and Reinforcement in Polyurethane Based Composites

In order to investigate the effect of hydrophilicity and size of a filler on the reinforcement and supramolecular structure of polyurethane (PU) based composites, a sequence of polymer composites based upon oligomeric 4,4'-diphenylmethane diisocyanate (MDI) and propylene diol with molecular weight equal to 1000 were prepared via a simple in-situ method. Titanium (IV) dioxide (TO) was used as a microsized filler and an aerosol silica (AS) was used as a nanosized filler, both with hydrophilic surfaces. Carbon black (CB) was used as a microsized filler with a hydrophobic surface. The maximal degree of filling was varied from 5 wt% for AS, 25 wt% for CB, and up to 50 wt% for TO. It was shown that maximal reinforcement of the PU composites (up to one order of magnitude in improvement) could be obtained if the filler increases the microphase separation in the PU matrix. This effect was maximal for CB filler, although this filler was not active in the formation of hydrogen bonds. Thus, the neutral filler also changed the supramolecular structure of the polymer matrix. The strong reinforcement by the CB was connected with their nucleating ability, i.e. the possibility to produce a maximal number of rigid domains by CB/PU interactions in the PU matrix.

Natural rubber‐carbon black coagulation: Following the nanostructure evolution from a colloidal suspension to a composite

AbstractMaking elastomeric composite materials via heteroaggregation of a binary colloidal suspension of Natural Rubber (NR) latex and Carbon Black (CB) filler is an interesting production method to obtain an efficient dispersion in the polymer matrix. This study successfully employs an original approach of field emission scanning electron microscopy (FESEM) to investigate for the first time the nanostructure evolution of a coagulum originated from the aggregation of NR globules with CB filler in suspension. More specifically, we exploited a chemical fixation method allowing simultaneous acquisition of backscattered electron (BSE) and secondary electron (SE) imaging modes. Additionally, the role of external physical stresses, like mechanical shear and sonication was also investigated in terms of structural effect induced on the formed coagulum at the nanoscopic scale. Our results highlight destabilization of NR globules, either induced by direct interaction with small CB aggregates or governed by solvent evaporation. Reduction in the size of CB agglomerates, obtained using sonication, highly improved filler distribution and confirmed that the size of CB aggregates is an important parameter responsible for the destabilization of NR globules.

TPV: A New Insight on the Rubber Morphology and Mechanic/Elastic Properties

The objective of this work is to study the influence of the ratio between the elastomer (EPDM) phase and the thermoplastic phase (PP) in thermoplastic vulcanizates (TPVs) as well as the associated morphology of the compression set of the material. First, from a study of the literature, it is concluded that the rubber phase must be dispersed with a large distribution of the domain size in the thermoplastic phase in order to achieve a high concentration, i.e., a maximal packing fraction close to ~0.80. From this discussion, it is inferred that a certain degree of progress in the crosslinking reaction must be reached when the thermoplastic phase is melted during mixing in order to achieve dispersion of the elastomeric phase in the thermoplastic matrix under maximum stress. In terms of elasticity recovery which is measured from the compression set experiment, it is observed that the crosslinking agent nature (DCP or phenolic resin) has no influence in the case of a TPV compared with a pure crosslinked EPDM system. Then, the TPV morphology and the rubber phase concentration are the first order parameters in the compression set of TPVs. Finally, the addition of carbon black fillers leads to an improvement of the mechanical properties at break for the low PP concentration (20%). However, the localization of carbon black depends on the crosslinking chemistry nature. With radical chemistry by organic peroxide decomposition, carbon black is located at the interface of EPDM and PP acting as a compatibilizer.

Coppiced Biochars as Partial Replacement of Carbon Black Filler in Polybutadiene/Natural Rubber Composites

Although carbon black has been the dominant filler material for rubber composites for over a century, it is a finite, fossil fuel-based product that is sensitive to geopolitical issues and economics. Renewable sources of carbon need to be developed to replace carbon black in order to reduce dependence on petroleum. Biochar is the solid material left over after the anaerobic treatment of biomass at high temperature. In this work, two biochars made from coppiced hardwoods, Paulownia elongata and Populus tremuloides were used to partially replace carbon black in rubber composites using a 50/50 blend of butadiene rubber and natural rubber. Rubber composite samples using these biochars were able to replace 30% of the carbon black with virtually no loss in tensile strength, and improved elongation and toughness compared to the reference sample containing 100% carbon black.

Tritium Effects on Aromatic Carbon–Loaded Polymers

By incorporating carbon nanotubes (CNTs) and graphene nanomaterials with aromatic sp2 carbon structures, we have specifically tuned filled ethylene propylene diene monomer elastomer (EPDM) seal and gasket composite materials for radiation resistance. Our results show that CNTs and graphene have an increased ability to stabilize the EPDM matrix compared to standard carbon black (CB) as a radiation-resistant filler. Graphene outperforms both CNT and CB fillers when considering surface damage under conditions where beta exposure is an issue. Both graphene and CNT fillers offer significantly reduced changes in glass transition temperature under prolonged exposure to tritium compared to CB-filled standards, with a 2.5-fold and almost 5-fold reduction, respectively. Thus, CNT- and graphene-filled O-ring materials could be designed that would maintain acceptable seals significantly longer than currently used composites.

State-of-the-art for Magnetorheological Elastomers Fabrication and Hydro-tribological Characterisation

Magnetorheological effect on mechanical properties of its specific applications has been studied. Mechanical properties such as hardness, tribology characteristic and salt water and water absorption with hygrothermal effect will be further studied on wear performance of MRE on marine equipment applications. Isotropic, anisotropic and anisotropic with added N330 carbon black filler of Ni Zn Ferrite Magnetorheological Elastomers (MREs) were prepared with Ni Zn Ferrite filler, Ni1 - xZnxFe2O4 particles weight fraction of 70%. Images of Scanning Microscopy Electron (SEM) and Energy Dispersive X-Ray Analysis (EDX) are identified with the presence of the structure of Ni Zn Ferrite in the natural rubber matrix. Anisotropic Ni Zn Ferrite MREs with added carbon black filler given highest hardness value of 90.78; least effected on salt water and water absorption and hygrothermal effect; better wear performance with a low average specific coefficient of friction(COF), specific wear rate and least loss of wear volume. Therefore, it is most suitable use for future application in a wet environment for a long period.

Phenomenon of the percolation in composite materials based on a polymer binder with a dispersed filler phase

The paper presents the experimental results of studies of the thermal conductivity and electrical conductivity of composite materials based on dimethylsiloxane SKTN A and carbon black filler. The percolation and their similarity in the processes of heat transfer and electrical conductivity are analyzed. The correspondence of experimentally observed percolation threshold values to theoretical descriptions is discussed.

Effect of mineral fillers on physico-mechanical properties and heat conductivity of carbon black-filled SBR/butadiene rubber composite

Heat conductivity, curing rate and fatigue crack growth properties of carbon black-filled styrene butadiene rubber (SBR)/butadiene rubber (BR) blend that is frequently used in passenger car tire treads were simultaneously improved by a hybrid filler system of carbon black, high dispersible precipitated silica, modified layered silicate and ultra-light mixed filler of alumina and aluminum sulfate. An optimum formulation was obtained and a study of mechanisms governing composite properties has been performed according to the filler variables through the designing of experiments and the regression and statistical analysis and with the aid of composite characterization techniques such as dynamic mechanical analysis (DMA) and FE-SEM/EDX. Alumina could improve thermal conductivity, DeMatia crack growth, and the tensile strength of the rubber composite, along with relative maintenance of hardness and modulus. The effects of statistically significant interactions between silica and alumina on the abrasion behavior and thermal conductivity were observed, which was attributed to the presence of the silane coupling agent and the effect of modifying the alumina surface with the ethoxysilanes groups. The partial substitution of carbon black by high dispersible silica resulted in an increase in thermal diffusion coefficient, the improvement of heat buildup, resilience and DeMatia crack growth, and relative maintaining of tensile properties as well as a slight loss in abrasion and aging behavior of the tire tread composite. Through the increase of thermal diffusivity coefficient and a slightly improvement in the aging behavior, modified layered silicate (organoclay) caused a significant reduction in the optimum curing time of the tire tread composite. Some evidence has been provided for the interactions between modified layered silicate and silane coupling agent. The improvement in crack growth and thermal conductivity of the elastomer composite was attributed to smaller interparticle distances of hybrid filler system compared to those of carbon black filler system.

Enhanced electrical and dielectric properties of plasticized soy protein bioplastics through incorporation of nanosized carbon black

AbstractConductive soy protein biocomposite plastics with high performance were fabricated with glycerol as plasticizer and nanosized carbon black (CB) as conductive filler. Adopting a pretreatment of the CB nanofiller, its dispersion, and interaction with matrix was improved. The results indicated the existence of strong hydrogen bonding between soy protein matrix and CB fillers, which improved the interfacial bonding. The strong interactions between CB and protein restricted the mobility of protein segments, resulting in a dramatical reinforcing effect for the CB filled composites and enhanced mechanical properties. Besides, the incorporation of CB into soy protein increased the thermal stability as well as the water resistance of the composites. Moreover, a low percolation threshold of 0.76 vol% and fine electrical conductivity were obtained for the bionanocomposites, resulting in improved electromagnetic interference shielding properties. This work provides a simple and green way for the preparation of conductive and electromagnetic interference shielding materials from natural polymers.

Converting dead leaf biomass into activated carbon as a potential replacement for carbon black filler in rubber composites

In this work, the feasibility of converting dead leaf biomass into green activated carbon for use as a reinforcement filler in natural rubber composites was assessed. The dead leaf activated carbon (DLAC) was prepared by pyrolysis at 550, 700, 900, and 1000 °C at a heating rate of 10 °C min−1 under nitrogen gas flow of 100 cm3 min−1 and was activated by CO2 gas at the same flow rate when the pyrolysis temperature was reached. The properties of DLACs were characterized by particle size analysis, density, scanning electron microscopy, elemental energy-dispersive X-ray spectroscopy and Raman spectroscopy. The results revealed that the DLAC obtained by pyrolysis at 1000 °C had a small particle size of 28.86 μm; a highly porous structure; high carbon purity, at 82.58%; and a low density, at 1.588 g cm−3. The effect of different DLAC contents (5, 10, and 15 phr) on the curing properties and the physical and mechanical performance of the rubber composites was investigated and compared with rubber composites containing carbon black (CB). The results showed that the addition of DLAC increased the maximum torque and reduced the scorch and cure times. The tensile strength for rubber composites containing 15 phr of DLAC increased by 8%, the M100 and M300 improved 40%, and the elongation at break and crosslink density decreased by approximately 5% and 24%, respectively. The studied DLAC is a promising, cost-effective alternative to commercial carbon black for improving the performance of rubber composites.

Synergy studies on polyurethane–carbon black, multi-walled carbon nanotube-based heterogeneous electroactive shape memory nanocomposite system

This paper describes a multi-filler synergy study that was carried out for multi-walled carbon nanotubes (MWCNTs) and carbon black (CB) filler systems in polyurethane (PU) resin, and the individual contributions of the fillers were evaluated. The hybrid nanocomposite was found resistant to ultraviolet radiation and exhibited a high glass transition temperature enabling it suitable for space applications. The contributions of individual fillers in the hybrid system were compared with the binary nanocomposites of respective fillers and the advantages of hybrid system are also highlighted. The synthesized hybrid polymer nanocomposite (PU + CB + MWCNT) was found to have superior thermal, electrical and mechanical properties even at a very low content of reinforcements and a percolation threshold of 5% CB and 0.15% MWCNT combination was also observed. Shape memory effect of the hybrid system was evaluated and compared with binary systems. A faster recovery time of 41 s was observed for a combination of 5% CB and 0.25% MWNT against 50 s for 25% CB alone upon thermal actuation. On electrical actuation, the hybrid nanocomposite system was observed to have a three-fold faster recovery compared to the binary systems of CB alone. The hybrid system proves to be a reliable choice for replacing an expensive single reinforcement system of MWCNTs.

Conductive 3D printing: resistivity dependence upon infill pattern and application to EMI shielding

Polymers filled with conductive carbon black allow for the 3D printing of electrically conductive samples. The resistivity of these 3D printed samples depends on both the microscopic parameters of the carbon black filler and also on the macroscopic arrangement of the extrudites that build up the 3D printed sample. To investigate this dependence, we characterize the resistivity of five different printing infill patterns and find that a cross-ply pattern, which has extrudites oriented both in the direction of current flow and perpendicular to the direction of current flow has a lower resistivity of $$0.229\,\Omega {\text{m}}$$ than the resistivity of $$0.458\,\Omega {\text{m}}$$ found for a uni-ply pattern with all extrudites oriented in the direction of current flow. A Monte Carlo simulation of a large network of variable resistors illustrates the feasibility that the lower resistivity of the cross-ply pattern is caused by cross-flow which diverts current around areas of high local resistance. The same type of 3D printed conductive samples are tested as electromagnetic shields at frequencies up to 3.0 GHz using a custom-designed flanged coaxial sample holder. The shielding effectiveness of three sample infill patterns and four sample infill densities is compared. Cross-ply and angle-ply samples show the most efficient shielding effectiveness (normalized to sample density) of $$17.5\,{\text{dB}}/{\text{g}}\,{\text{cm}}^{3}$$ at an infill density of 50% and would be the infill pattern of choice in an application constrained by weight or material.

Multiscale Observation of the Fatigue‐Induced Damage Mechanisms in Carbon‐Black Filled Styrene‐Butadiene Rubber

AbstractFilled rubber materials exhibit a complex macroresponse characterized by stress softening, hysteresis, and dissipative heating when they are cyclically loaded. The relationship of these inelastic features to the microstructure changes is far from being fully established. This paper deals with the damage mechanisms in sulfur‐vulcanized styrene‐butadiene rubber (SBR) specimens in the diablo form reinforced with carbon‐black (CB) and zinc‐oxide (ZnO) fillers, and submitted to tension cyclic loading at room temperature. The microstructure alteration is characterized at different relevant scales and at different zones of the diabolo specimen by means of various technologies in the aim to report valuable insights about the mechanisms responsible for the macroresponse of this rubber‐filler material system. IR absorption spectra reveal that increasing filler content induces more interfacial interaction between CB and SBR chains. The environmental scanning electron microscopy (ESEM) observations show relevant altered morphologies of elastomeric chains with a predominant effect of both CB and ZnO fillers. A mesoscale observation of material density variation is presented using X‐ray computed tomography and the results are compared with those issued from ESEM.

Nanocarbon and macrocarbonaceous filler–reinforced epoxy/polyamide: A review

Epoxy is a thermosetting polymer and an engineering material for structural and composite applications. However, pure epoxy has disadvantages of stiffness and low toughness properties, so limiting its practical uses. Polyamide is an important thermoplastic polymer for commercial uses. Epoxy has been blended with polyamide (thermoplastic polymer) to enhance the toughness and mechanical properties. Consequently, epoxy/polyamide blend matrix has been developed for composite applications. Incorporation of carbonaceous nanoparticles in epoxy/polyamide blend has been used to improve the morphological and physical properties of these materials. This review describes scientific development in the field of epoxy/polyamide-based nanocomposite and composites. Epoxy/polyamide materials have been reinforced with micro- and macroscale carbonaceous fillers such as graphene, carbon nanotube, nanodiamond, carbon black, carbon fiber, and hybrid fillers. The strength, modulus, toughness, electrical, conductivity, thermal conductivity, and thermal stability properties of epoxy/polyamide have been influenced through the incorporation of nanofillers. The fundamentals and applications (coatings, adhesives, electronics, radiation shielding, automotive/aerospace) of these materials have been discussed. Toward the end, applications, future, and challenges of epoxy/polyamide-based nanocomposites have been comprehended.

Effect of Carbon Black/Bi2O3 Ratio on the Vulcanization Characteristic and Mechanical Properties of Rubber Compound

AbstractThis study aims to determine the effect of Bi2O3 as a substitute for carbon black (CB) fillers on the characteristics of vulcanization and mechanical properties of rubber compounds. The comparison of CB/Bi2O3 used are 50/0, 45/5, 40/10, and 35/15. Rubber compounds are prepared using two‐rolls mill. The rubber vulcanizates are prepared using hydraulic press at 150 °C. Vulcanization characteristics are determined by the moving die rheometer. Rubber vulcanizates are evaluated from aspects of physical and mechanical properties (tensile strength, elongation, density, hardness), morphology (SEM), and heat aging. It is found that rubber compounds containing high amounts of Bi2O3 show higher torque and higher optimum vulcanization time. In addition, rubber compounds with high Bi2O3 content show higher density, tensile strength, and elongation.

Conductive Electric Tapes Based on Silicone Pressure-Sensitive Adhesives

This paper assesses methods for the fabrication of single-sided electrically conductive tape. Silicone resin, dichlorobenzoyl peroxide, and various types of carbon fillers were used to prepare pressure-sensitive adhesives. Various carbon black and graphene filler concentrations in the range 1 to 25 wt.% were tested, whereas for carbon nanotubes the range was 0.25 to 10 wt.%. The adhesion, shear strength, tack, and shrinkage of the prepared tapes were determined. The most important property of the resulting tapes is their electrical conductivity. By using carbon black as a filler, it was possible to obtain a conductivity of 4.3 × 10−3 S/m, with carbon nanotubes 1.4 × 10−01 S/m and with graphene 5.9 × 10−3 S/m. Such electrically conductive silicone self-adhesive tapes are not yet commercially available on the market, but are expected to be useful in the electronic industry for the bonding of various materials. In the available literature provides no information about the self-adhesives tapes based on silicone pressure-sensitive adhesices which exhibit electrically conductive properties.

Fabrication of Conductive Filaments for 3D-printing: Polymer Nanocomposites

With the promise of producing electrically conductive circuits, 3-dimensional-printing (3DP) filaments infused with carbon nanostructures are now commercially available; however, it is still difficult to control the mixture homogeneity between the polymer and conductive charge thereby increasing its conductive mobility. Herein, we describe the fabrication, characterization and application of conductive polymernanocomposites processed into filament form intended for 3DP of electronic circuits. For this, graphene, carbon nanotubes and carbon black fillers were loaded into several resin matrixes including ABS, PLA, HDPE, LLDPE, PETG, and PP. Electrical measurements, thermal, crystallographic and morphological profiles are here described. Filaments obtained present values of resistivity and conductivity ranging from 0.2 to 1.4 S/cm and 0.71 to 5.0 S/cm respectively. Thermal analysis showed that the processing temperature of materials studied is inside the standard range for extrusion and 3D-printing. Microscopic analysis revealed a heterogeneous mix between resins and fillers. The electrical and thermal stress test showed increases in resistivity and decreases in conductivity of prepared filaments since these quantities are inversely proportional.

Electrical and mechanical properties of polypropylene/epoxy blend-graphite/carbon black composite for proton exchange membrane fuel cell bipolar plate

Conductive polymer composites (CPCs) exhibit favorable density and corrosion resistance for application as bipolar plate (BP) in proton exchange membrane fuel cell (PEMFC). However, achieving CPCs that combine the required level of electrical conductivity and mechanical strength is a challenge that has limited their application in PEMFC BPs. This study explored the potential of achieving CPC BPs with high electrical and mechanical performance by using carbon black (CB) as a secondary filler in graphite-polymer composites. Polypropylene (PP)/epoxy blend was selected as the matrix due to its good combination of strength and toughness as well as its potential to form a co-continuous morphology, which promotes the formation of more continuous conducting networks within the composite, leading to enhanced electrical performance. The PP/epoxy/graphite/CB composites were prepared by melt mixing in a Rheomixer at 190 °C and 60 rpm for 10 min, followed by compression molding at 200 °C and 6 metric tonnes for 10 min. The electrical conductivity of the composites increased from 49.26 Scm−1 to 90.34 Scm−1 (in-plane) and from 0.37 Scm−1 to 9.34 Scm−1 (through-plane) as the total filler content increased from 50 to 85 wt%. The flexural strength initially increased from 45.57 MPa at 50 wt% to 51.84 MPa at 60 wt% total filler content. Further increase in total filler content led to a decrease in flexural strength. The nanosize CB particles, used as a minor filler, filled the voids between the graphite particles, leading to the formation of more conducting pathways and higher electrical conductivities compared to the PP/epoxy/graphite composites without CB fillers. The PP/epoxy/graphite/CB composite with 80 wt% total filler content exhibited the most promising in-plane conductivity (88.5 Scm−1), through-plane conductivity (8.52 Scm−1), and flexural strength (28.53 MPa) for BP application.

Utilization of chitin powder as a filler in natural rubber vulcanizates: In comparison with carbon black filler

AbstractNatural rubber (NR) vulcanizates were prepared from natural rubber and chitin using a two-roll mill. The chitin was extracted from crab shell waste obtained from a local market in Oron, Akwa Ibom State, Nigeria using the chemical extraction method. The effects of the chitin at different contents (0–40 phr) on the mechanical properties of the NR/Chitin vulcanizates with carbon black as reference filler have been investigated. The tensile strength of the chitin filled natural rubber (NCH), and the carbon black filled natural rubber (NCB) vulcanizates were found to increase with an increase in filler content to reach optimum at 30 phr after which it decreased. The hardness, impact and abrasion resistance properties of the NCH and NCB vulcanizates increased as filler content increases. The tensile strength and abrasion resistance of the vulcanizates containing blends of varying percentages of carbon black to chitin (CBCH) increased as more carbon black (CB) is introduced while the hardness and impact strength increased with increase in chitin content. However, carbon black filled vulcanizates showed better property enhancement than the chitin filler.

Studies on the Physicochemical and Physico-Mechanical Properties of Activated Palm Kernel Shell blended with Carbon Black filled NR Vulcanizates

Palm kernel shell was activated using chemical activation of H3PO4 and KOH. Various amounts of activated palm kernel shell (APKS) couple with carbon black (CB) and other conventional ingredients were used to produce natural rubber vulcanizates (NR vulcanizates). The NR vulcanizates were compounded on a two-row mill and tested for its physico-mechanical properties. The results for characterization of physicochemical properties carried out on APKS were ash content (2.06%), moisture content (8.06%), %carbon (54.41%), particle size (4.00, 3.35, 2.00, 1.18mm), bulk density (0.62g/ml) and pH (5.3).The results show significant values for all, the moisture and ash content were within the recommended standard of ASTM (3-10max) and (< or =8) respectively. The filler loading concentrations CB/APKS were labeled as mixes 1 to 7. The composition of CB/APKS filler loading ratios were 30:0, 25:5, 20:10, 15:15, 10:20, 5:25, and 0:30 samples 1,2,3,4,5,6 and 7 respectively. Results obtained showed that CB/APKS filled vulcanizates exhibited improvement in the physico-mechanical properties investigated. The results obtained for CB/APKS across the samples filler loading shows that CB composition possess higher UTS, EB and rubber fatigue test while APKS filler loading composition exhibited higher hardness and young modulus. Abrasion resistance was excellent for both CB and APKS filler loading composition.Keywords: Activated Palm Kernel Shell, filler, carbon black, Chemical Activation, Natural Rubber.