Carbon Black Dispersion Research Articles

카본블랙의 표면개질이 중합토너의 특성에 미치는 영향

Carbon black was surface-modified to prepare styrene-based suspension polymerized toner with excellent carbon black dispersibility inside toner particles. Carbon black was oxidized first to introduce hydroxyl groups on the surfaces, then esterification between the hydroxyl groups and carboxyl groups of organic acids (oleic acid, palmitic acid, acrylic acid) was followed to obtain organically surface-modified carbon black. The surface-modification of carbon black was confirmed by FTIR. Apparent carbon black dispersibility in the monomer mixture of the binder resin was tested and the particle size of dispersed carbon black was measured by particle size analyzer. Optical micrographs showed that carbon black dispersibility inside toner particles was improved considerably when the carbon black surfacemodified with oleic acid was used. The polymerized toner prepared with the carbon black surface-modified with oleic acid showed ideal particle size and size distribution as a toner.

The origin of synergism between an organoclay and carbon black

Synergistic effects between a montmorillonite (Mt), modified with an organophilic ammonium as the compensating cation (OMt), and carbon black (CB) are reported in the literature. This work proposes the pronounced interaction between the organophilic ammonium cation and CB as a phenomenon at the origin of the synergism. A nanocomposite based on poly(1,4-cis-isoprene) containing both CB and OMt, formed in situ through the reaction between Mt and di(hydrogenated tallow)-dimethylammonium chloride (2HTCl), was prepared. Moreover, nanocomposites containing only CB in the presence and in the absence of 2HTCl were comparatively prepared and analysed. Synergism between OMt and CB was investigated by studying the filler networking process in the PI matrix through dynamic-mechanical tests and by assessing the nanocomposite structure by transmission electron microscopy analysis. It was found that 2HTCl promoted a pronounced enhancement of the non linear dynamic-mechanical behaviour of the nanocomposite material, with a much improved CB dispersion and a remarkable reduction of bound rubber. These effects were reduced in the presence of Mt, that involved the ammonium salt in the formation of OMt. The amount of 2HTCl required to achieve the largest non linear behaviour and the lowest bound rubber was calculated to correspond to a monolayer of the ammonium salt on the carbon black surface.

Effect of Poly(Vinyl Pyrrolidone) on Dispersing Carbon Black Particles

The effects of poly (vinyl pyrrolidone)(PVP) on dispersing carbon black (CB) particles were investigated by measuring Z-average particle size, Zeta potential and centrifugal stability of CB dispersions. Addition of PVP in a dispersing medium significantly reduces the size of suspended CB particles, especially in water. The dispersing efficiency of PVP was found to have been enhanced by adding an anionic surfactant, sodium methylenedinaphthalene disulphonate (NNO) in the aqueous media. The particle size of CB dispersed with PVP and NNO was 175.7 nm, significantly smaller than that dispersed with PVP and sodium dodecyl sulfate (SDS). The performance of PVP-encapsulated CB particles and that of PVP-adsorbed CB particles were also compared. The particle size and Zeta potential of PVP-encapsulated CB particles were similar to those of PVP-adsorbed CB particles using ultrasonic method, but the centrifugal stability of PVP-encapsulated CB dispersions was significantly improved. The relative absorbency of PVP/CB dispersions was increased from 42.0% to 63.7%. However, the PVP-encapsulated layer can be destroyed by prolonged ultrasonic treatment because the ultrasound over a long period of time can not only break up the flocculation bridge in the crosslinking matrix of PVP, but also flake off the PVP shells on the surface of CB particles.

Influence of gel content on the physical properties of unfilled and carbon black filled natural rubber vulcanizates

Recently, gel content has been considered as a standard property for evaluating commercial grade natural rubber (NR). In this study, NR containing various amounts of gel was prepared by accelerated storage hardening as a model to clarify the influence of gel content on the physical properties of both unfilled and carbon black filled vulcanizates. Furthermore, the NR samples were investigated to determine the effect of gel fraction on Mooney viscosity and the structure of the gel after mastication. The results revealed that Mooney viscosity was related to the percentage of gel fraction that has been proven to be the result of interactions between proteins and phospholipids at chain ends. After mastication, although the gel fraction of NR can be decomposed to ∼0% w/w, the interactions of proteins and phospholipids at the chain ends still existed, corresponding to the gel content of the raw rubber. In the case of unfilled vulcanizates, the gel content showed no effect on cure characteristics, crosslink density and ultimate tensile strength, whereas the upturn of stress occurred at a smaller strain when the gel content increased. However, in the case of carbon black filled vulcanizates, the gel content played a dominant role in the carbon black dispersion, which was poorer when gel content increased, contributing to a decrease of crosslink density and ultimate tensile strength.

Comparative Study of the Low-Temperature Single Step Mixing and Multi-Stage Process Mixing

In this paper, we conduct a comparative experiment of the low-temperature single step mixing and multi-stage process mixing with low temperature single process mixing experiment platform. The experimental results show that the low-temperature single step mixing, compared with the traditional multi-stage process mixing, can save energy of about 13.3% and improve production efficiency of about 200%. The performance of final mixing has a significant increase in Mooney viscosity, the carbon black dispersion, and the physical and mechanical properties of the vulcanized rubber.

Comparison of Toxicity and Deposition of Nano-Sized Carbon Black Aerosol Prepared With or Without Dispersing Sonication

Nanotoxicological research has shown toxicity of nanomaterials to be inversely related to particle size. However, the contribution of agglomeration to the toxicity of nanomaterials has not been sufficiently studied, although it is known that agglomeration is associated with increased nanomaterial size. In this study, we prepared aerosols of nano-sized carbon black by 2 different ways to verify the effects of agglomeration on the toxicity and deposition of nano-sized carbon black. The 2 methods of preparation included the carbon black dispersion method that facilitated clustering without sonication and the carbon black dispersion method involving sonication to achieve scattering and deagglomeration. Male Sprague-Dawley rats were exposed to carbon black aerosols 6 hr a day for 3 days or for 2 weeks. The median mass aerodynamic diameter of carbon black aerosols averaged 2.08 μm (for aerosol prepared without sonication; group N) and 1.79 μm (for aerosol prepared without sonication; group S). The average concentration of carbon black during the exposure period for group N and group S was 13.08 ± 3.18 mg/m3 and 13.67 ± 3.54 mg/ m3, respectively, in the 3-day experiment. The average concentration during the 2-week experiment was 9.83 ± 3.42 mg/m3 and 9.08 ± 4.49 mg/m3 for group N and group S, respectively. The amount of carbon black deposition in the lungs was significantly higher in group S than in group N in both 3-day and 2-week experiments. The number of total cells, macrophages and polymorphonuclear leukocytes in the bronchoalveolar lavage (BAL) fluid, and the number of total white blood cells and neutrophils in the blood in the 2- week experiment were significantly higher in group S than in normal control. However, differences were not found in the inflammatory cytokine levels (IL-1β, TNF-α, IL-6, etc.) and protein indicators of cell damage (albumin and lactate dehydrogenase) in the BAL fluid of both group N and group S as compared to the normal control. In conclusion, carbon black aerosol generated by sonication possesses smaller nanoparticles that are deposited to a greater extent in the lungs than is aerosol formulated without sonication. Additionally, rats were narrowly more affected when exposed to carbon black aerosol generated by sonication as compared to that produced without sonication.

Effect of reynolds number on the dispersion of carbon black in natural rubber latex and filler-rubber interfacial interaction in high-speed jet flow field

A novel strategy of high-speed impinging jet processing technique was developed to prepare rubber composites by directly mixing natural rubber latex (NRL) with carbon black (CB). The results showed that CB could be more evenly dispersed into natural rubber by jet compounding technique, compared with the traditional dry process. The dispersion of carbon black was improved at higher Reynolds number because of more intensive shear force. Furthermore, a high performance of natural rubber latex/CB composite was gained by jet compounding technique. When compared to the traditional dry process, the mechanical properties and abrasion resistance of the composite prepared by the jet compounding technique were greatly improved because of the improved filler–rubber interaction at higher Reynolds number. POLYM. COMPOS., 34:1071–1075, 2013. © 2013 Society of Plastics Engineers

Adsorption and Rheology of Graphitic Carbon Black Nonaqueous Dispersions Prepared Using Nonionic Surfactants

Rheological and conductivity measurements are reported to investigate the dispersibility of graphitic carbon black dispersions selected as a model for carbon nanotubes. The effectiveness of three dispersants in nonpolar organic solvents were investigated namely polyhydroxystearic acid (Hypermer LP1), PEG 30-dipolyhydroxystearate (Hypermer B246), and polyisobutylene succinimide (OLOA 11000). Hypermer LP1 is homopolymer and Hypermer B246 is polyhydroxystearic acid/polyethylene oxide/polyhydroxystearic acid ABA block copolymer while OLOA 11000 has polar head group (polyamine) attached to a hydrocarbon chain (polyisobutylene). Two nonpolar organic solvents decalin and xylene were selected for the present work. The experimentally determined relative viscosity as a function of effective volume fraction Φ′ curves were compared with the theoretical curves calculated using Kreiger-Dougherty equation for the hard sphere dispersions. The comparison showed that Hypermer B246 and OLOA 11000 dispersions in xylene could be prepared at somewhat higher solid fraction than those dispersions stabilized by Hypermer LP1. Also Hypermer LP1 dispersions do not agree with the Kreiger-Dougherty equation curve, which showed that Hypermer LP1 is not an effective stabilizer. In oscillatory measurements, high values of storage and loss modulus at high volume fractions were obtained indicating strong repulsive interactions between the carbon black particles using Hypermer B246 and OLOA 11000. The dispersions prepared using these surfactants showed lower electrical conductivity as compared to other dispersions prepared without dispersants. Also higher relative conductance was obtained in case of dispersions made by Hypermer LP1 as compared to other dispersions made by Hypermer B246 and OLOA 11000.

OVERCOMING INCOMPATIBILITY PROBLEMS IN ELASTOMER BLENDS BY TAILORED SURFACE PROPERTIES OF RUBBER ADDITIVES

ABSTRACT Rubber is a challenging composite material, whose functionality strongly depends on the affinity of the different materials in the composite and its morphology. One way to tailor polarity and chemistry of the filler surface is plasma coating. When using acetylene, thiophene, or pyrrole as monomers, the coating results in a reduced polarity of the filler compared with untreated silica, and unsaturated C–C bonds are formed on the surface. This improves the compatibility of the filler–polymer blends. In a SBR/EPDM blend, the filler–polymer compatibility is improved for all plasma-coated fillers compared with untreated silica. The best dispersion is achieved by plasma–pyrrole coating, as measured by the Payne effect and reinforcement parameter. The rubber–filler interaction is also highest for this blend, as measured by the bound rubber content. As expected, this results in improved tensile properties. In NBR/EPDM, the filler–filler interaction is significantly reduced by the plasma–pyrrole coating, which indicates a balanced compatibility of the pyrrole-treated silica in both polymers. The properties of the vulcanizate show the combinatorial effect of dispersion, filler–polymer interaction, polymer entanglements, and cross-link density. All plasma-treated, silica-filled NBR/EPDM materials show a considerable increase in tensile strength compared with untreated silica, with polyacetylene-treated silica resulting in the best properties. When plasma-coated curatives are used in SBR/EPDM blends, the scorch safety of the compounds is increased and the rupture energy is enhanced. In NBR/EPDM blends, all packages of the modified curatives provide an increased maximum torque compared with the control. Mechanical properties of the NBR/EPDM blend are improved even more than they are with SBR/EPDM. This indicates a more-balanced distribution of cross-links, along with a more-homogeneous carbon black dispersion over the different rubber phases. A better polarity match between additives and polymers usually results in improved material properties. The wide variety of monomers for the plasma polymerization allows researchers to tailor the surface properties of the additives.

Scaling in Electrical Conductivity Measurements and Rheological Measurements of Monarch 700 Dispersions Stabilized by Polymers

For making stable dispersions of graphitic carbon black (Monarch 700), the effectiveness of three dispersants/polymers (hypermer LP1, hypermer B246, and OLOA 11000) in xylene is investigated. Hypermer LP1 (polyhydroxystearic acid) is a homopolymer and hypermer B246 (PEG 30-dipolyhydroxystearate) is a polyhydroxystearic acid/polyethylene oxide/polyhydroxystearic acid ABA block copolymer, while OLOA 11000 (polyisobutylene succinimide) has a polar head group (polyamine) attached to a hydrocarbon chain (polyisobutylene). Well-dispersed graphitic carbon black dispersions were prepared using dispersants at optimum concentrations. Percolation threshold and rheological threshold were determined by analyzing the variations in electrical conductivity and elastic modulus with concentration of carbon black. Above threshold concentration, scaling law was applied to experimental data of rheology (dynamic measurements) and electrical conductivity measurements to evaluate quality of the system. Effectiveness of polymers was investigated on the basis of value of critical exponent (t and t′, respectively) in scaling power law. Hypermer LP1 was proved to be a poor dispersant for Monarch 700 dispersions while other two polymers were found to be effective stabilizers.

Morphology, interfacial interaction, and properties of a novel bioelastomer reinforced by silica and carbon black

AbstractA novel poly(diisoamyl itaconate‐co‐isoprene) (PDII) bioelastomer was prepared by redox emulsion polymerization based on itaconic acid, isoamyl alcohol, and isoprene. Carbon black (CB), silica, and silica with coupling agent (bis(3‐(triethoxysilyl)‐propyl)tetrasulfide [TESPT]‐silica) were used as fillers to reinforce the novel elastomer. The difference in morphology, interfacial interaction, thermal properties, and mechanical properties of PDII composites filled with different fillers was studied. The homogeneous dispersion of silica and CB in the PDII matrix was confirmed by scanning electron microscopy and transmission electron microscopy. Silica had homogenous dispersion possibly because of the formation of hydrogen bonds between the silica silanols and the PDII macromolecular chains. PDII/silica and PDII/TESTP‐silica have lower crosslink density and crosslinking rate than PDII/CB owing to the adsorption of accelerators by the silanols in the silica surfaces. PDII/silica had comparable tensile strength but higher elongation at break than PDII/CB. The tensile strength of PDII/TESPT‐silica was higher than PDII/CB and PDII/silica. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Coloration of Cotton Fabrics with Waterborne Carbon Black Dispersions

Using ultrafine carbon black (CB) dispersions to dye cotton fabrics back is feasible through an exhaustion procedure. The effects of CB particle size, the type of dispersants, electrolyte concentration and cationic modification of cotton on the colour yields of CB dyed cotton fabrics have been investigated. CB particle size ranging from 130nm to 200nm is appropriate to achieve a deep black shade in cotton fabrics. Cationic dispersant improves the K/S values and wash fastness of the CB dyed cotton fabrics. However, caution should be exercised in adding electrolytes to CB dispersions. Cationic modification of cotton is an effective method to achieve higher K/S values of CB dyed fabrics. It is desirable to dye cotton fabrics with ultrafine CB particles instead of with sulfur dyes and reactive dyes.

Conductive Rubber Nanocomposites as Tensile and Pressure Sensors

A conductive silicone rubber (SR) composite, filled with both carbon nanotubes (CNT) and carbon black (CB) is prepared by a simple ball milling method. Because of the good dispersion and synergistic effects of CNT and CB, the SR composite shows improvement in mechanical properties. As well, due to the assembly of conductive pathways generated by the CNT and CB, the nanocomposite becomes highly conductive at a comparatively low concentration, with very high sensitivity for tensile and compressive stress. These outstanding properties show that the SR composite has potential applications in tensile and pressure sensors.

Silicone rubber nanocomposites containing a small amount of hybrid fillers with enhanced electrical sensitivity

A conductive silicone rubber (SR) composite, filled with both carbon nanotubes (CNTs) and carbon black (CB) is prepared by a simple ball milling method. Because of the good dispersion and synergistic effects of CNT and CB, the SR composite (SR with 2.5phr CB and 1.0phr CNT hybrid fillers) shows improvement in mechanical properties such as tensile strength and strain to failure. As well, due to the assembly of conductive pathways generated by the CNT and CB, the nanocomposite becomes highly conductive at a comparatively low concentration, with high sensitivity for tensile and compressive stress. Long-term measurement of properties shows that the SR composite maintains the excellent electrical properties under different strain histories. These outstanding properties show that the SR composite has potential applications in tensile and pressure sensors.

Carbon Black Selective Dispersion and Electrical Properties of Epoxy Resin/Polystyrene/Carbon Black Ternary Composites

Carbon black (CB) selective dispersion and conductive properties of immiscible thermoplastic/thermosetting polymer blends consisting of polystyrene (PS) and epoxy resin (EP) were investigated in this paper. The results showed that CB particles are preferentially localized in EP phase in PS/EP blends. The blend with 10 pbw (parts by weight) PS presented an EP continuous phase structure, and both blends with 20 pbw and 30 pbw developed into a bi-continuous phase structure. The selective dispersion of CB particles was explained by thermodynamic parameters. The phase structures of blends have important influences on both conductive and dielectric properties. The blends with 10 pbw PS has a very low percolation threshold nearly 0.25wt%.

Preparation of nanoscale carbon black dispersion using hyper-branched poly(styrene-alt-maleic anhydride)

Hyper-branched poly(styrene-alt-maleic anhydride) (BPSMA) was used as a dispersant to disperse carbon black (CB) in aqueous media. The dispersing ability of BPSMA for CB was estimated by measuring the particle size, zeta potential, stability to temperature and centrifugal stability of BPSMA-dispersed CB dispersions. The experimental results showed that BPSMA prepared with a molar ratio of 4-vinylphenyl methanethiol (VPMT), St and MA at 6:47:47 and a mass ratio of BPO and (VPMT+St+MA) at 1:50 exhibited optimal dispersing ability when the CB dispersion was at pH 8, and a mass ratio of BPSMA and CB was about 1:5. Compared to linear poly(styrene-alt-maleic anhydride) (LPSMA), BPSMA prepared CB pigment dispersion with a smaller particle size, a more narrow particle size distribution and higher stabilities.

Highly conductive coatings of carbon black/silica composites obtained by a sol–gel process

Conductive submicronic coatings of carbon black (CB)/silica composites have been prepared by a sol–gel process and deposited by spray-coating on glazed porcelain tiles. Stable CB dispersions with surfactant were rheologically characterized to determine the optimum CB-surfactant ratio. The composites were analyzed by Differential Thermal and Thermogravimetric Analysis and Hg-Porosimetry. Thin coatings were thermally treated in the temperature range of 300–500°C in air atmosphere. The microstructure of the coatings was determined by scanning electron microscopy and the structure evaluated by confocal Raman spectroscopy. The electrical characterization of the samples was carried out using dc intensity–voltage curves. The coatings exhibit good adhesion, high density and homogeneous distribution of the conductive filler (CB) in the insulate matrix (silica) that protects against the thermal degradation of the CB nanoparticles during the sintering process. As consequence, the composite coatings show the lowest resistivity values for CB-based films reported in the literature, with values of ∼7×10−5Ωm.

Aqueous carbon black dispersions prepared with steam‐jet‐cooked corn starch

AbstractThe utilization of jet‐cooked waxy and normal corn starch to prepare aqueous dispersions of hydrophobic carbon black (CB; Vulcan XC‐72R) is reported. Blending into aqueous jet‐cooked dispersions of starch followed by high‐pressure homogenization produced stable aqueous CB dispersions. The dispersed CB particles were shown to have starch adsorbed onto their particle surfaces. The adsorbed starch imparted hydrophilic properties to the CB, and after extensive washing to remove dissolved and loosely bound starch, the CB particles remained well dispersed in water. Thermogravimetric analysis, Fourier transform infrared spectroscopy, acid and enzymic starch digestion experiments, and microscopy (light and transmission electron microscopy) were used to characterize the starch‐coated CB particles. The method described herein demonstrates a simple, effective, and environmentally friendly method for preparing aqueous CB dispersions. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Investigating the effectiveness of PEO/PPO based copolymers as dispersing agents for graphitic carbon black aqueous dispersions

The dispersability of graphitic carbon black, selected as a model for carbon nanotubes, has been investigated using a combination of rheological, conductivity and atomic force microscopy (AFM) techniques. The effectiveness of three PEO/PPO based non-ionic dispersants, namely polyethylene oxide polypropylene oxide ABA copolymers (synperonic PE/F 103 with 2×16 ethylene oxide units and PE/F 108 with 2×148 ethylene oxide units) and NPE1800 (nonyl phenyl polypropylene oxide-polyethylene oxide with 27 ethylene oxide units), is reported. Adsorption isotherms were determined for these dispersants. The adsorption isotherms of PE/F 103 in comparison with PE/F 108 revealed that in molar terms (μmol/m2) the adsorption decreases for PE/F 108 with more ethylene oxide units, indicating that adsorption is governed by size of the PEO (polyethylene oxide) chain length. Also, the synperonic PE series which has polypropylene oxide as an anchor group and does not contain any aromatic ring in their anchoring group, gave lower adsorption amounts (in moles) as compared to the NPE 1800 which contains an aromatic ring (nonyl phenyl) in its anchoring group as well as propyleneoxide. The relative viscosity-effective volume fraction Φ′ curves are compared with the theoretical curves for the hard sphere dispersions calculated using Krieger–Dougherty equation. For the graphitic carbon black studied here, in an aqueous medium, neither PE/F 103, nor PE/F 108 showed good agreement with the Krieger–Dougherty equation; the viscosities were all much higher than that predicted by that equation. Whilst NPE 1800 produced dispersions of lower viscosity and the viscosity values showed a good agreement with the Krieger–Dougherty equation. The results achieved from oscillatory measurements showed that PE/F 103 and PE/F 108 dispersants showed a frequency cross-over of G′ and G″ at lower volume fractions. Also they produced dispersions of high electrical conductivity, suggesting that these systems are aggregated. In the AFM force spectroscopy measurements, the interactions between the adsorbed layers of PE/F103 were initially attractive, whilst somewhat surprisingly the PE/F 108 adsorbed layers only showed repulsive interactions on approach and separation. NPE 1800 stabilised systems exhibited much lower viscosity and elastic modulus than the PE/F stabilised dispersions; produced dispersions of lower electrical conductivity and showed repulsive interactions in AFM, suggesting that these systems are much more stable than the carbon black dispersions bearing adsorbed PE/F polymers.The results indicated that synperonics (PE/F 103 and PE/F 108) are not a good dispersants for graphitic carbon black and by consequence for carbon nanotubes; whilst NPE 1800 is a suitable dispersant for these dispersions and could be a good dispersant for carbon nanotubes.

Preparation and properties of carbon black filled EPDM/POE thermaplastic vulcanizates

AbstractTPVs filled with different amounts (0–50 phr) of carbon black were prepared via melt mixing by dynamic vulcanization in Haake plasticorder at 150°C and 40rpm and then the properties of them were studied. Torque‐time curves showed that the curing degree reached a biggest value at 10 phr and then decreased with the increase of filling content while the curing rate was always rising. Mechanical properties such as tensile strength, tear strength, modulus as well as hardness increased with the increment of carbon black content while the tension set at break was reduced dramatically. Two phase morphology was observed by SEM photographs and the effect of carbon black on curing extent was testified. To illuminate the effect of carbon black, curometer curves and carbon black dispersion pictures were also analyzed. Rubber processing analyzer (RPA) experiments proved that there was a progressive nonlinear behavior, which was more and more clearly expressed with the increment of carbon black content and could be explained via the Payne effect. But the TPVs containing highest carbon black exhibited the fastest drop of G′ with increasing strain amplitude as obtained from the value of G0′ − G∞′. The order of tanδ at different carbon black content was tanδ (10 phr) < tanδ (0 phr) < tanδ (30 phr) < tanδ (50 phr) at lower strain amplitude. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012