Characterization of Immiscible Elastomer Blends

1993 ◽  
Vol 66 (3) ◽  
pp. 329-375 ◽  
Author(s):  
W. M. Hess ◽  
C. R. Herd ◽  
P. C. Vegvari
Keyword(s):  
Carbon Black ◽  
Phase Distribution ◽  
Domain Size ◽  
Carbon Black Particle ◽  
Quantitative Information ◽  
Equal Distribution ◽  
Tear Strength ◽  
Carbon Blacks ◽  
Vulcanized Rubber ◽  
Heat History

Abstract Considerable improvements have been made in the analysis of elastomer blends for composition, morphology and filler inter-phase distribution. GC, IR, NMR and thermal analysis (DTG, DSC, TG) techniques can provide quantitative information on composition. The latter three methods, along with SAXS, SANS, DMTA and microscopy (LM phase contrast, TEM, SEM, AFM) are also useful for resolving differences in blend homogeneity. The microscopical techniques are the most useful for characterizing morphology. TEM, in conjunction with cryosectioning and staining techniques, has provided the best means of resolving filler distribution to date. However, new AFM scanning modes may provide improved analyses in the future. Carbon black inter-phase distribution in blends of NR, SBR and BR can be controlled reasonably well by blending Banbury mixed masterbatches containing the desired carbon black loading in each polymer. Transfer of carbon black from one elastomer to another is favored by low unsaturation for the polymer originally containing the black, or a low heat history (e.g. solution and latex mixing) during preparation of the masterbatch. The overall polymer interaction with carbon black increases in the order: IIR, EPDM, NR, BR, SBR, the latter two being fairly close. Commercial carbon blacks will transfer extensively from an IIR Banbury masterbatch to NR, but not from EPDM to NR. Significant transfer to SBR occurs from both IIR and EPDM. Inert (partially graphitized) carbon blacks tend to distribute more evenly between the blend components regardless of which polymer contained them initially. Carbon black phase distributional variations can cause significant changes in unvulcanized and vulcanized rubber properties. For NR/BR and NR/SBR blends, reduced hysteresis generally occurs with a higher carbon black loading in the NR phase. Tear strength and cut growth tend to be maximized with higher carbon black in the continuous polymer phase, particularly when that phase is the higher strength polymer. The smaller the carbon black particle size, the greater the improvement in tear strength as a function of phase distribution. NR/BR fatigue life was maximized with about an equal distribution of carbon black in each polymer. This type of carbon black distribution also produced the greatest resistance to ozone cracking for NR/EPDM blends, which were further improved with very small domain size for the EPDM (disperse) phase. The abrasion resistance of NR/BR blends has indicated some improvement in the direction of higher carbon black in the BR. These results have been variable, however, and further study is needed for clarification.

Study on the Effects of Different Types of Carbon Black on the Performance of SBR2564S

2014 ◽  
Vol 971-973 ◽  
pp. 178-182
Author(s):  
Nai Xiu Ding ◽  
Yi Jia ◽  
Pei Yan Zuo ◽  
Li Li Wang ◽  
Hai Tao Wang
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Permanent Deformation ◽  
Poor Performance ◽  
Carbon Black Particle ◽  
Crosslinking Density ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Vulcanized Rubber ◽  
Black Particle

The curing characteristics,crosslinking density,compressive permanent deformation,the conventional mechanical properties and dynamic mechanical properties of SBR2564S filled with different carbon black were studied.The results indicated that with the increase in specific surface area of carbon black particles，Mooney viscosity of the resulting mixture increased while the scorch time decreased.As the carbon black particle size increases, tensile strength and tear strength of SBR2564S were reduced,rebound and compressive set were increased.The kinds of carbon black had little effect on the crosslinking density of vulcanized rubber of SBR2564S.It had poor performance on dynamic mechanical properties of the resulting mixture filled with small carbon black particle size.SBR2564S vulcanizates with good comprehensive properties was obtained when N330 was used.

Filler Choices in the Rubber Industry

1982 ◽  
Vol 55 (3) ◽  
pp. 860-880 ◽  
Author(s):  
E. M. Dannenberg
Keyword(s):  
Particle Size ◽  
Carbon Black ◽  
Size Range ◽  
Carbon Black Particle ◽  
Silane Coupling Agents ◽  
Particle Size Range ◽  
Calcium Carbonates ◽  
Rubber Industry ◽  
Carbon Blacks ◽  
Inorganic Fillers

Abstract A wide variety of inorganic fillers are produced for the rubber industry. The most important are the clays, precipitated silicas and silicates, and the ground and precipitated calcium carbonates. The silicas and silicates provide the broadest particle size range falling into the carbon black range from FEF (N550) to finer than SAF (N110). The clays and calcium carbonates are in the larger carbon black particle size range from coarser than thermal black (N990) to FEF (N550). if particle size were the only important parameter determining the usefulness of rubber fillers, these products would meet the requirements presently served by carbon black. Their failure to be interchangeable with the carbon blacks is due to their lower modulus and reinforcement performance. These deficiencies are caused by the nature of their surfaces, which are generally more polar and hydrated than carbon black. This makes them more difficult to adhere to and interact with the rubber phase. In order to improve the surface interaction of inorganic fillers with hydrocarbon rubbers, a number of new polymer-reactive, surface-treated products have been introduced. The addition of silane coupling agents during mixing has also been recommended. Silane treated clays and talc, and polymer-grafted clay and calcium carbonate are commercially available. These products are better than their base materials. For some applications, they have been suggested as alternatives to the lower reinforcing grades of carbon black. For the higher reinforcing carbon blacks, only the precipitated silicas with silane additives can be considered as alternatives. However, in tire tread applications, the performance of these combinations has not been clearly defined, and the high cost of the silanes makes their use with silica prohibitive. A more economic method for coupling may result from recent research on functionalized polymers capable of reacting with the surface silanol groups of silica. This survey also includes two finely divided carbonaceous fillers made from coal and petroleum coke. Blends of these materials with more reinforcing carbon blacks and other fillers have been recommended as alternatives to the carbon blacks in the thermal to SRF range. A number of commercial fillers have been suggested as alternatives to the lower reinforcing grades of carbon black for some applications. There are no satisfactory substitute products for the medium to high reinforcing grades of carbon black.

Light Scattering Study of Carbon Black Structure

1967 ◽  
Vol 40 (3) ◽  
pp. 919-920
Author(s):  
Jean-Baptiste Donnet ◽  
Claude Eckhardt ◽  
Paul Horn ◽  
Samuel Premilat ◽  
Andries Voet
Keyword(s):  
Mechanical Properties ◽  
Light Scattering ◽  
Carbon Black ◽  
Experimental Method ◽  
Aqueous Dispersions ◽  
Carbon Blacks ◽  
Vulcanized Rubber ◽  
Scattering Measurements ◽  
Scattering Study

Abstract Light scattering measurements on aqueous dispersions of carbon black confirm the hypothesis that mechanical properties of vulcanizates are closely related to structure of the carbon blacks used. This provides a simple experimental method for predicting the influence of a black on vulcanized rubber.

Interaction between Carbon Black and Polymer in Cured Elastomers

1951 ◽  
Vol 24 (3) ◽  
pp. 597-615
Author(s):  
R. S. Stearns ◽  
B. L. Johnson
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
Chemical Bonding ◽  
Physical Adsorption ◽  
Three Dimensional ◽  
Physical Property ◽  
Carbon Black Particle ◽  
Low Molecular Weight ◽  
Carbon Blacks ◽  
Black Particle

Abstract This research was initiated to determine whether the interaction at the interface between the surface of finely divided solids, such as carbon black, and cured elastomers is primarily physical or chemical in nature. Further, it was desired to correlate some physical property of the reinforced stock with the surface properties of the solid pigment. Through an examination of the thermodynamic changes accompanying the deformation of loaded stocks it is shown that physical adsorption of the van der Waals type occurring at the interface between pigment and polymer is inadequate to account for the experimental observations. However, if chemical bonding occurs at the interface between polymer and pigment, then the entropy of deformation of the stock may be correlated with the extent of this bonding. By a calorimetric method it was demonstrated that the surface of a carbon black particle contains sites that react with bromine to liberate the same amount of heat as low molecular-weight olefins. It is, therefore, proposed that a carbon black particle be considered as a disordered agglomerate of polymeric benzenoid type molecules which contain around their perimeters various functional groups. The existence of olefinic-type unsaturation on the surface of carbon blacks suggests strongly that, in the case of carbon blacks, the polymer and pigment are combined chemically through pigment-sulfur-polymer bonds into a continuous three-dimensional cross-linked matrix.

Characterization of Dispersions

1991 ◽  
Vol 64 (3) ◽  
pp. 386-449 ◽  
Author(s):  
W. M. Hess
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Black ◽  
Phase Distribution ◽  
Automated Image Analysis ◽  
Carbon Blacks ◽  
Transmission Electron ◽  
Vehicle Systems ◽  
Scanning Electron

Abstract The methods of pigment dispersion analysis have been reviewed in regard to their application to rubber, plastics, and other vehicle systems. The characteristics of dispersions have been divided into three categories: (1) agglomeration (2) microdispersion (networking) and (3) polymer-phase distribution. Stylus roughness measurements on cut surfaces offer the combination of simplicity and speed of operation with high accuracy and precision for measuring pigment agglomeration in elastomer systems of known composition. This method may also be applied to the surface of thin plastic extrudates. However, optical analyses of thin cryosections are preferred for most plastics or unknown rubber compounds containing high loadings of carbon black. X-radiography is generally preferable for the analysis of inorganic agglomeration in most polymeric vehicle systems. The scanning electron microscope is also applicable for this type of analysis and has the added capability of identifying unknown agglomerates by energy dispersive x-ray analysis. Automated image-analysis techniques may also be utilized in conjunction with microscopical methods for quantifying the agglomeration of most types of pigments. For carbon blacks, the most suitable materials for on-line image analyses with transmitted light are plastics, paints, and inks which contain low black loadings. Higher carbon-black loadings in rubber can be analyzed by incident light using metallographic polishing of sulfur-hardened specimens. The microdispersion of carbon blacks at the primary aggregate level can be measured by means of electrical conductivity. This method is not applicable to inorganic pigments, large-particle-size carbon blacks, or blacks at very high or low loadings. Pigment microdispersion in different vehicle systems may also be assessed by means of scanning electron microscopy of thick cross sections (plasma etched to enhance contrast) or by transmission electron microscopy of thin cryosections. The tendency for the finer pigments to form 3-dimensional network structures in elastomers may also be measured as a function of the augmentation of dynamic modulus from high to low strain amplitudes. Pigment phase distribution in elastomer blends may be studied by scanning electron microscopy or transmission electron microscopy of thin cryosections, in conjunction with a staining or etching procedure to produce contrast between the separate polymer components. Selective staining is applicable to blends of polymers which differ significantly in their relative levels of unsaturation (e.g., NR/CIIR). Pyrolytic etching (under vacuum) may be used to produce interzone contrast in blends of polymers which differ significantly in their resistance to thermal degradation (e.g., NR/BR, NR/SBR). Pyrolysis GC may be utilized to determine the amount of carbon black in the separate phases of certain elastomer blends. This method is based on the relative intensity of the primary GC peaks for the individual polymers. The chromatographs are obtained from the bound rubber (carbon-polymer gel) that is developed during the mixing of the compound.

Some Observations on Carbon Black

1930 ◽  
Vol 3 (1) ◽  
pp. 111-121
Author(s):  
C. M. Carson ◽  
L. B. Sebrell
Keyword(s):  
Zinc Oxide ◽  
Carbon Black ◽  
Adsorptive Capacity ◽  
Carbon Blacks ◽  
Vulcanized Rubber ◽  
Rubber Cement

Abstract Different carbon blacks have certain definite effects upon the vulcanized rubber stocks with which they are mixed. The experiments described herein may be grouped under four main heads: (1) adsorption, (2) effect of heat, (3) reaction with sulfur and zinc oxide, and (4) dispersion or rate of settling. The adsorptive capacity of the black is a measure of the rate of cure of the rubber mix, low-adsorptive blacks giving a faster curing stock than high-adsorptive blacks. An indication of the stiffening action of a carbon black may be secured by measuring the amount of carbon dispersed in a thin rubber cement which cannot be centrifuged out in a given time. The effect of temperatures from 500° to 1200° C. on carbon blacks is to render them highly adsorptive and also to give a rubber mix which cures faster and has a higher modulus. The reaction of carbon blacks with sulfur and zinc oxide in boiling xylene liberates a substance having accelerating properties in a pure gum mix.

New Dispersible Carbon Blacks

1964 ◽  
Vol 37 (4) ◽  
pp. 1006-1012 ◽  
Author(s):  
Andries Voet
Keyword(s):  
Carbon Black ◽  
Physical Properties ◽  
Carbon Black Particle ◽  
Radical Reactions ◽  
Free Radical Reactions ◽  
Carbon Blacks ◽  
Binding Material ◽  
Particle Bonding ◽  
Dry Mixing ◽  
Black Particle

Abstract It has been shown that the process of pelletization of a carbon black carried out to permit easier transportation through bulk handling, leads to irreversible changes in properties. There are strong indications that the pelletization process of carbon black involves free radical reactions, leading to chemical particle bonding. The superior physical properties of vulcanizates reinforced with unpelletized blacks indicate that chemical particle bonding is undesirable, since it reduces interaction between carbon black particle and polymer. In order to overcome chemical bonding of carbon black particles during pelletizing, carbon blacks were prepared the particles of which were covered withat least a monolayer of an oleaginous material compatible with the polymer. It was found that the product obtained could be pelletized to form predominantly physically adhering particles. These carbon black compositions disintegrate spontaneously in solvents for the oleaginous liquids, in view of the dissolution of the pellet binding material. The new carbon black compositions are ideally suited for black solvent masterbatching. In addition, they also show improved physical properties upon dry mixing with polymers in conventional dispersing equipment. Finally, they provide for a simple, rapid and efficient way to incorporate processing oils into polymers in conventional mixing equipment.

Carbon Black in NR/BR Blends for Truck Tires

1985 ◽  
Vol 58 (2) ◽  
pp. 350-382 ◽  
Author(s):  
W. M. Hess ◽  
P. C. Vegvari ◽  
R. A. Swor
Keyword(s):  
Fatigue Life ◽  
Carbon Black ◽  
Phase Distribution ◽  
Dynamic Properties ◽  
Performance Criteria ◽  
Polymer Phase ◽  
Tear Strength ◽  
Truck Tires ◽  
Bound Rubber ◽  
Heat Buildup

Abstract A series of ten commercial tread-grade carbon blacks were evaluated in a 60/40 NR/BR truck tire tread formulation. A number of important physical properties and performance criteria were assessed in terms of carbon black surface area and DBPA. Significant response equations were obtained for viscosity, bound rubber, resilience, heat buildup, tear strength, and dynamic properties. Dynamic modulus showed a much greater dependence on DBPA in comparison to previous studies on SBR/BR compounds. In a second designed experiment, a single carbon black (N299) was studied as a function of the NR/BR ratio and the amount of carbon black added to the BR phase. The BR black loading was varied at 30, 60, and 90 phr using separate masterbatches which were blended with NR-black masterbatches to give the same final composition for all of the compounds. Properties such as resilience, heat buildup, fatigue life, and tear strength were all improved in the direction of higher loadings of carbon black in the NR phase. A high loading of black in the BR phase caused low bound-rubber development and poor dispersion. This was found to be related to the viscosity ratio of the separate masterbatches. NR to BR viscosity ratios of about 1 to 3 produced good dispersion and high bound rubber. When the BR masterbatch viscosity was two to three times higher than the NR masterbatch, however, dispersion and bound-rubber development dropped sharply at the same total mixing energy. Low hysteresis properties were found to be most dependent on high bound-rubber development, with polymer phase distribution having a relatively minor influence. In contrast, tear strength and fatigue life reached their maximum levels when the NR was the more continuous polymer phase. High bound rubber also appears to enhance tear strength and fatigue life by improving the microdispersion of the carbon black.

Research on Electrical Double Percolation of Carbon Black-Filled Cement-Based Composites

2011 ◽  
Vol 311-313 ◽  
pp. 201-204
Author(s):  
Hong Zhong Ru ◽  
Ran Ran Zhao
Keyword(s):  
Carbon Black ◽  
Cement Paste ◽  
Volume Fraction ◽  
Carbon Black Particle ◽  
Carbon Black Content ◽  
Percolation Behavior ◽  
Key Factor ◽  
Binder Ratio ◽  
Black Particle ◽  
Double Percolation

Electrical conductive carbon black-filled cement-based composites are significant as multifunctional structural materials. Double percolation in carbon black-filled cement-based composites involves both carbon black particle percolation and cement paste percolation, which has great effect on the resistivity of composites. Based on double percolation theory, the influences of sand-binder ratio and carbon black volume fraction on the resistivity of carbon black-filled cement-based composites are investigated. The results show that besides carbon black volume fraction, sand-binder ratio is a key factor affecting double percolation behavior in carbon black-filled cement-based composites. At a fixed carbon black content in overall mortar, with increasing sand-binder ratio, the cement paste percolation though aggregate phase increases due to high obstruction of aggregate but the carbon black particle percolation in cement paste decreases. This is because that the microstructure of aggregate is impenetrable so that the carbon black particles are limited in cement paste, that is, the carbon black content in paste is compacted and large amount of conductive paths are generated by lapped adjacent carbon black particles in paste. The double percolation in the electrical conduction in carbon black-filled cement-based composites is observed when the carbon black volume fraction is 7.5% and sand-binder ratio is 1.4, and its resistivity is only 3200 Ωcm, so that a sand-binder ratio of 1.4 and 7.5% carbon black volume fraction or more are recommended for attaining high conductivity with a compromise between workability and conductivity.

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