Meng-Jiao Wang

Carbon black : science and technology

Manufacture of carbon black, Gerhard Kuhner and Manfred Voll mechanism of carbon black formation, Roop Chand Bansal and Jean-Baptiste Donnet microstructure, morphology and general physical properties, William M. Hess and Charles R. Herd surface groups on carbon blacks, Roop Chand Bansal and Jean-Baptiste Donnet carbon black surface studied by scanning tunnelling microscopy, Jean-Baptiste Donnet and Emmanuel Custodero surface energy of carbon black, Meng-Jiao Wang and Siegfrie Wolff fractal geometry, Alain Le Mehaute, et al fracture of carbon black filled vulcanizates at high temperature and under swollen conditions, Anil K. Bhowmick dynamic viscoelastic properties of loaded elastomers, Michel Gerspacher carbon black in plastics, John M. Funt, et al carbon black in zerographic toners, Paul C. Julien health effects of carbon black, Donald Rivin.

Filler—Elastomer Interactions. Part IV. The Effect of the Surface Energies of Fillers on Elastomer Reinforcement

Abstract Carbon black N110 and a precipitated silica, which have comparable surface area and structure, were selected as model fillers to study the effect of filler surface energies on rubber reinforcement. In comparison with carbon black, the surface energies of silica are characterized by a lower dispersive component, γsd, and higher specific component, γssp. It was found that the high γssp of silica leads to strong interaggregate interaction, resulting in higher viscosity of the compounds, higher αƒ, and higher moduli of the vulcanizates at small strain. The higher γsd of carbon black, in contrast, causes strong filler—polymer interaction, which is reflected in a higher bound-rubber content of the compounds and higher moduli of the vulcanizates at high elongation.

Filler-Elastomer Interactions. Part VII. Study on Bound Rubber

Abstract SBR compounds were filled with 17 carbon blacks covering the whole range of rubber grades and tested for bound-rubber content. It was found that the bound-rubber content of a polymer at hi...

Filler—Elastomer Interactions. Part III. Carbon-Black-Surface Energies and Interactions with Elastomer Analogs

Abstract The surface energies, both the dispersive component, γsd, and the specific component, γssp, of dry- and wet-pelletized carbon blacks, ranging from N110 to N990, were evaluated by inverse gas-solid chromatography at infinite dilution. The results indicate that the dispersive components of the surface energy of carbon blacks increase with increasing surface area. This dependence may essentially reflect an effect of microstructure on the surface energies, which can be confirmed by the relationship between the crystallographic parameters of crystallites and the graphitization of the carbon blacks. It was found that smaller crystallites characterized by a lower value of Lc lead to higher surface energy, whereas graphitization of the carbon black points toward lower surface energy, perhaps resulting from the growth of the quasi-graphite structure. Surface area dependence of the specific component of the surface energy characterized by the specific energy of adsorption of a polar probe follows the same ...

Filler-Elastomer Interactions. Part I: Silica Surface Energies and Interactions with Model Compounds

Abstract Inverse gas-solid chromatography, operated at infinite dilution, has been used to assess the surface energies of silicas, both fumed and precipitated. The dispersive components of the surface free energies of the silicas were calculated from the free energies of adsorption, corresponding to the —CH2— group, obtained from n-alkane adsorption. The specific components of the surface energies were evaluated separately by comparison of the free energies of adsorption of polar probes with those of n-alkanes, based on the surface areas covered by the probe molecules. The results indicate that while the dispersive components of silica surface energies is somewhat higher for the fumed silicas, the specific components are much higher for precipitated silicas, probably resulting from the higher silanol concentration on their surfaces. Moreover, the interaction able to take place between rubber matrix and the silicas are also estimated chromatographically from the adsorptions of low-molecular-weight analogs ...

Filler-Elastomer Interactions. Part VIII. The Role of the Distance between Filler Aggregates in the Dynamic Properties of Filled Vulcanizates

Abstract Based on the concepts of the occlusion of rubber and random packing of spheres whose volume is equivalent to that permeated by individual aggregates, an equation was deduced to estimate the distance between carbon-black aggregates in filled rubber. It was found that when the interaggregate distance reaches a critical point which is approximately identical for all carbon blacks investigated (furnace blacks), the elastic modulus measured at very low strain deviates from the modified Guth-Gold equation. Tan δ and resilience are mainly determined by the distance between aggregates. These phenomena are related to filler networking which is determined by the attractive potential and the distance between individual aggregates. Since the factor Sf, used to characterize the strength of secondary filler networks in hydrocarbon rubbers and measured by means of inverse gas chromatography, is approximately the same for all furnace blacks, the interaggregate distance seems to determine filler networking. A com...

Filler-Elastomer Interactions. Part V. Investigation of the Surface Energies of Silane-Modified Silicas

Abstract As shown in previous papers of this series, the main feature of silicas with regard to surface energy, which distinguishes them from carbon blacks, is a low dispersive component, γsd, and a high specific component, γssp, of surface energy. The low γsd, would result in a lack of interaction between filler and hydrocarbon rubbers, while the high γssp would suggest a high degree of agglomeration of the filler particles in the polymer matrix. In this study, the surface free energies and the energy distribution on the surfaces of precipitated silicas which had been modified with octadecyltrimethoxy silane, 3-thiocyanatopropyltriethoxy silane and bis(3-trimethoxysilylpropyl)-tetrasulfane, respectively, were investigated by chromatography at infinite dilution and at finite concentration. A comparison with the initial silica suggests a drastic decrease in surface energy, especially of the specific component, as a result of the modification and a strong dependence of surface energy on the chemical nature ...

Filler—Elastomer Interactions. Part IX. Performance of Silicas in Polar Elastomers

Abstract Inverse gas—solid chromatography of silicas showed that the free energies of adsorption of polar probes were much higher than those obtained with n-alkanes. This implies that polymer—silica interaction is more pronounced in polar rubbers than in nonpolar rubbers such as polybutadiene. Using a series of silica and carbon-black-loaded acrylonitnle—butadiene (NBR) compounds with different acrylonitrile (ACN) content, this paper shows the changes in viscoelastic properties of the silica compounds can be attributed to improved polymer—filler interactions relative to the interactions involved in carbon-black compounds.

Filler-Elastomer Interactions. Part VI. Characterization of Carbon Blacks by Inverse Gas Chromatography at Finite Concentration

Abstract Carbon blacks ranging from N110 to N990 were characterized by means of inverse gas chromatography at finite concentration. The isotherms, net heat, and spreading pressures for benzene and cyclohexane adsorption suggest a general trend of increasing surface activity with increases in specific surface area. This is in good agreement with surface-energy measurements reported previously. The energy-distribution function of adsorption shows that while the concentrations of low-energy sites are comparable for most of the carbon blacks, differences exist with regard to high-energy sites. These suggest that small-particle-size blacks possess a greater number of high-energy centers. The graphitization of carbon blacks results in a considerable reduction in their adsorption capacity and narrows the energy distribution of their surfaces. One can therefore conclude that high-energy sites play an important role in the determination of the surface energies and reinforcing ability of carbon blacks.

Observation of plasma-treated carbon black surfaces by scanning tunnelling microscopy

Abstract The graphitized carbon black N550G was treated in different atmospheric plasmas, such as air, ammonia, argon, and hydrogen. The plasma-treated surfaces were investigated by scanning tunnelling microscopy (STM) until atomic resolution. The surface chemical properties of these carbon blacks were characterized by electron spectroscopy (ESCA). It was found that air, ammonia, and argon plasmas result in a destruction of graphitic structure of graphitized carbon black surfaces. Chemical modification of the surface also takes place in air and ammonia plasma treatment. The hydrogen plasma, however, has only a little effect on the black surface. The surface energy of carbon blacks, measured by inverse gas chromatography, shows a good correlation with the defects of graphitic basal planes.