Carbon Black System Research Articles

Enhanced advanced oxidation treatment through the synergy of chloride ion activation and electro-Fenton process

A photoelectrocatalytic system has been developed utilizing the WO3@BiVO4 photoanode and the oxidized carbon black (CB) cathode, enabling the synergistic advanced oxidation treatment by combining chlorine radicals and hydroxyl radicals. The WO3@BiVO4 heterojunction is prepared through hydrothermal growth of BiVO4 onto the surface of WO3 synaptic structure. The as-prepared WO3@BiVO4|Pt system demonstrates a remarkable degradation efficiency of organic pollutants with 97.1 % in 30 min under visible light irradiation with a 1.2 V bias, which is 1.24 times higher compared to the WO3|Pt system. Furthermore, even when utilizing actual seawater as the electrolyte, the treatment efficacy remains high at 92.8 % within 20 min. The oxidized CB cathode is obtained by calcining commercial CB in the air atmosphere. The WO3@BiVO4|CB system achieves the degradation efficiency of 85.9 % within 10 min in simulated seawater, utilizing the electro-Fenton process at 0.2 V. The WO3@BiVO4|CB system effectively removes organic pollutants through the synergistic effect of combining the WO3@BiVO4 photoanode with CB-A cathode. Additionally, impressive degradation efficiency of 97.8 % is achieved in 15 min when using simulated seawater as the electrolyte. The •OH, •Cl, and •Cl2− play the key role in the WB|CB-A synergistic system. The combined action of anodic active chlorine radicals and cathodic electro-Fenton process in the WO3@BiVO4|CB system demonstrates effective microorganism sterilization, resulting in a 92.5 % reduction within 15 min

THE PAYNE EFFECT: PRIMARILY POLYMER-RELATED OR FILLER-RELATED PHENOMENON?

ABSTRACT The hysteretic softening at small dynamic strains (Payne effect)—related to the rolling resistance and viscoelastic losses of tires—was studied as a function of particle size, filler volume fraction, and temperature for carbon black (CB) reinforced uncrosslinked styrene–butadiene rubber (SBR) and a paste-like material composed of CB-filled paraffin oil. The low-strain limit for dynamic storage modulus was found to be remarkably similar for CB-filled oil and the CB-filled SBR. Small-angle X-ray scattering (SAXS) measurements on the simple composites and detailed data analysis confirmed that the aggregate structures and nature of filler branching/networking of carbon black were virtually identical within oil compared to the high molecular weight polymer matrix. The combined dynamic rheology and SAXS results provide clear evidence that the deformation-induced breaking (unjamming) of the filler network—characterized by filler–filler contacts that are percolated throughout the material—is the main cause for the Payne effect. However, the polymer matrix does play a secondary role as demonstrated by a reduction in Payne effect magnitude with increasing temperature for the CB-reinforced rubber, which was not observed to a significant extent for the oil–CB system.

STRUCTURE ANALYSES OF SWOLLEN RUBBER–CARBON BLACK SYSTEMS BY USING CONTRAST VARIATION SMALL-ANGLE NEUTRON SCATTERING

Abstract In a previous study [Takenaka et al., Macromolecules 42, 308 (2009)], we have investigated the polymer layers absorbed on silica (Si) particles in rubber–Si systems with the contrast variation small-angle neutron scattering (SANS) method. We have investigated the polymer layers absorbed on carbon black (CB) particles in rubber–CB systems with contrast variation SANS method. The scattering intensities of specimens swollen by the solvents having various scattering length densities were measured. The contrast variation SANS for the specimens yielded partial scattering functions: the scattering function for polymer–polymer correlation SPP(q), the scattering function for CB–CB correlation SCC(q), and the scattering function for polymer–CB correlation SPC(q). The analyses of SCC(q) explored the structures of the aggregates formed by CB particles. The analyses of SPC(q) and SCC(q) clarified the existence of dense polymer layers around CB aggregates. Several characteristic parameters are estimated from the analyses, such as the size of aggregates, the thickness of layers, and the volume fractions of polymer layers and matrix. We found that the adsorption layer around CB aggregates is thicker than that around Si aggregates in rubber–Si systems.

The conductive property of polyurethane/expanded graphite powder composite foams

Polyurethane (PU)/expanded graphite powder (EGp) composite foams have been prepared by filling mold curing reaction. The morphology and electrical properties of the prepared PU/EGp composite foams have been investigated. The percolation threshold effect of PU/EGp composite foams occur at the content around 5 wt% of the EGp, which is much lower than that of graphite nanosheets (GN) composite and carbon black (CB) composite. The resistivity of PU/EGp and PU/GN composite foams can reach at about 106 Ω cm, while CB system can only reach at about 108 Ω cm. The resistance of PU/EGp composite foams shows negative temperature coefficient effect and negative pressure coefficient effect.

The physical properties of polyurethane/graphite nanosheets/carbon black foaming conducting nanocomposites

Using polyester polyol and diphenylmethane diisocyanate (MDI) as basic component, and using graphite nanosheets (GN) and carbon black (CB) as conductive filler, polyurethane/graphite nanosheets/carbon black foaming conducting nanocomposites have been prepared by filling mold curing reaction. The morphology, electrical properties and mechanical properties of the prepared PU/GN foams have been investigated. It showed that the percolation threshold effect of PU/GN composite occurred at the content around 12 wt.% of the GN, which was lower than that of carbon black (CB) composite. Besides, PU/GN foams showed much better conductive properties and mechanical properties than that of CB system.

Polymer Grafting onto Carbon Black by Solid State Method

To modify carbon black (CB) surface, the in situ grafting of natural rubber (NR) onto the CB surface by solid state method was investigated. The torque value of CB/NR blend system in Haake internal mixer and FT IR spectra of grafted carbon black (GCB) illuminated that the grafting reaction took place and the decomposed NR was grafted onto the CB surface. From the TGA results the grafting percentage of NR onto CB was determined to be from 7.3% to 44.0%. The Orthogonal design (ORD), which was used to investigate which process parameter significantly influenced the grafting reaction, showed that the degradation time of NR and mixing temperature played an important role in the grafting process. Based on above results, it was considered that the grafting mechanism is radical reaction of the active radical of CB formed by shear force and polymer radical formed by NR decomposition. In addition, the mechanical properties of vulcanized NR filled with GCB were enhanced to a large extent compared with CB system.

Studies of electrical and mechanical properties of poly(vinyl chloride) mixed with electrically conductive additives

AbstractDifferent samples of poly(vinyl chloride) (PVC) compositions were formulated from PVC, a polar plasticizer such as dioctylphthalate (DOP), and variable proportions of electrically conductive additives such as fast extrusion furnace (FEF) carbon black (CB), poly(vinylpyridine) (PVP), or polyacrylonitrile (PAN). Epoxidized soybean oil was added as a heat stabilizer. Samples of the PVC–CB system were also prepared by dispersing different concentrations of CB into the PVC matrix. The electrical studies showed that the addition of CB to the PVC–DOP system produces a plasticized PVC with high electrical conductivity whereas the compounding of PVC with CB produces a sample with much higher electrical conductivity. The effect of the structure of PVP and PAN on the electrical and mechanical properties of the PVC–DOP system was also studied to obtain a semiconductive plasticized PVC with good mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1590–1598, 2004

Conductive polymer composites (CPC): influence of processing conditions, shear rate and temperature on electrical properties of poly(butylene terephthalate)/poly(amide12‐b‐tetramethyleneglycol) – carbon black blends

AbstractConductive Polymer Composites (CPC) have been obtained by blending two immiscible polymers, poly(butylene terephthalate) (PBT) and poly(amide12‐b‐tetramethyleneglycol) (PEBAX) with carbon black (CB). The extrusion process allows to obtain anisotrope co‐continuous structures of various morphologies depending on composition and experimental conditions. It is possible to enhance CPC conductivity with appropriate processing temperature (Tp) and screw speed (Ω), without changing the composition of the blend. The best results are obtained with Ω =5 rpm and Tp=260°C. PBT/PEBAX‐CB resistivity evolution with Tp and Ω doesn't follow a linear law as expected from previous studies with poly(butylene terephthalate)/poly(ethylene)‐CB and poly(butylene terephthalate)/poly(ethylene‐co‐ethyl acrylate)‐CB systems. CB distribution has a more important impact on conductivity than polymers phase morphology. A good control of these parameters is essential to reproduce and optimize electrical properties.

Morphology and electric conductivity of cross-linked polyethylene-carbon black blends prepared by gelation/ crystallization from solutions

Ultra-high-molecular-weight polyethylene (UHMWPE) – carbon black (CB) blends were prepared by gelation/ crystallization from PE dilute solutions containing CB particles. The UHMWPE/CB composition chosen were 1/0.15, 1/0.25, 1/0.5, 1/0.75, 1/1, 1/3, 1/5, and 1/9, etc. The cross-linking of PE chains was performed by chemical reaction of dicumyl-peroxide at 160 °C. X-ray diffraction patterns indicate that the crystallinity of PE within the blends decreased drastically through the chemical reaction at high temperature. The sample preparation method by gelation/crystallization provided the UHMWPE–CB system with various CB contents up to 90% and the conductivities for the resultant specimens were in the range from 10-9 to 1 Ω-1 cm-1 corresponding to the electric conductivity range of semiconductors. The blends assured thermal stability of electric conductivity by cross-linking of PE chains, although the mechanical property such as the storage and loss moduli were very sensitive to temperature. The conductivity of the blends with CB content ≥20% were almost independent of temperature up to 220 °C and the values in the heating and cooling processes were almost the same. On the other hand, for the UHMWPE–CB blends with 13% CB content corresponding to the critical one, temperature dependence of electric resistivity showed positive temperature coefficient (PTC) effect. The PTC intensities for non-cross-linked and cross-linked materials were lower than that of the corresponding low-molecular-weight-polyethylene (LMWPE)–CB blend but the maximum peak appeared at 160 °C which is higher than the peak temperature of LMWPE–CB blend.