The Dispersion of Carbon Black in Rubber Part I. Rapid Method for Assessing Quality of Dispersion

1992 ◽  
Vol 65 (5) ◽  
pp. 973-997 ◽  
Author(s):  
A. Y. Coran ◽  
J-B. Donnet
Keyword(s):  
Carbon Black ◽  
Mixing Time ◽  
Poor Performance ◽  
Raw Material ◽  
Rubber Part ◽  
Reproducible Method ◽  
Internal Mixer ◽  
Kinetics Of ◽  
Carbon Black Dispersion

Abstract Carbon black is the most important reinforcing filler for rubbers. The incorporation of carbon black into rubber vulcanizates generally gives improved strength, extensibility, fatigue resistance, abrasion resistance, etc. In order to exert its beneficial influence on the properties of rubber vulcanizates, the carbon black must be sufficiently dispersed therein. Indeed, poor dispersion can, in itself, give rise to detrimental effects (e.g. reduced product life, poor performance in service, poor product appearance, poor processing characteristics, poor product uniformity, raw-material waste, high finished-product rejection rates, and excessive energy usage). These inadequacies are generally the result of the presence of rather large, undispersed agglomerates. The present work was initiated in order to develop an improved understanding of the carbon-black dispersion process including the understanding of factors which affect the kinetics of dispersion. The work described here is focused on methodology for reproducibly mixing carbon black with rubber in the laboratory, and reproducibility, but rapidly and easily estimating the degree of dispersion of the carbon black into the rubber as a function of mixing time. Procedures were developed for introducing rubber, filler, and other ingredients into a small, laboratory internal mixer and for mixing the batches for various periods of time. Also, an improved, simple-to-use, reproducible method for determining the degree of carbon black dispersion in rubber has been adapted. The extent of dispersion was correlated with various measures of tensile strength and with other performance-related properties.

The Dispersion of Carbon Black in Rubber Part IV. The Kinetics of Carbon Black Dispersion in Various Polymers

1994 ◽  
Vol 67 (2) ◽  
pp. 237-251 ◽  
Author(s):  
A. Y. Coran ◽  
F. Ignatz-Hoover ◽  
P. C. Smakula
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
Natural Rubber ◽  
Kinetic Parameters ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Rapid Technique ◽  
Rubber Part ◽  
Kinetics Of ◽  
Carbon Black Dispersion

Abstract A rapid technique for evaluating the rate and state of dispersion of carbon black in natural rubber has been extended to study the dispersion of carbon black in various polymers. The technique measures the extent and rate of dispersion of the black in the rubber. The kinetics of dispersion was characterized for a variety of polymers (e.g. SBR, EPDM, IR, IIR, BR and NR). Kinetic parameters were correlated with molecular weight and molecular weight distribution.

Contributions of Elastomer Behavior to Mechanisms of Carbon Black Dispersion

1984 ◽  
Vol 57 (1) ◽  
pp. 153-167 ◽  
Author(s):  
N. Nakajima ◽  
E. R. Harrell
Keyword(s):  
Carbon Black ◽  
Effective Means ◽  
High Stress ◽  
Flow State ◽  
Breakdown Mechanism ◽  
Roll Mill ◽  
Highly Stretchable ◽  
Internal Mixer ◽  
Region Ii ◽  
Carbon Black Dispersion

Abstract In order to achieve good mixing of elastomer and carbon black, the elastomer domains must be reduced in size, that is, the elastomer must be broken into smaller pieces. If this is the only requirement, Region I of the Tokita-White scheme may be most preferred, because the elastomer easily breaks up at this state. However, it is too stiff for compaction of the compound; that is, the elastomer is too stiff to conform to the complex topology of carbon black. If the compaction is the only requirement. Region IV is most preferred, because the material is in the melt-flow state. In reality, Region II, the rubbery, highly stretchable state gives the best result. It appears that the use of Region II is a compromise. However, there is a more important reason for the preference of Region II, that is, the effectiveness of this region for the breakdown of carbon black agglomerates. The breakdown mechanism involves elastomer as a medium for the transfer of force. The effectiveness of the elastomer medium depends on its ability to stretch with the development and maintenance of a high stress. The former may be characterized by the failure envelop and the latter by the stress relaxation experiments. In roll mill as well as internal mixer processing, the folding of compound and the subsequent stretching of it, e.g., lamination mechanism, are the effective means for carbon black dispersion. It is postulated that the lamination mechanism generates localized high shear fields, which force carbon black agglomerates to rotate in the high modulus medium; this results in peeling of the aggregates from the outer shells of the agglomerates.

An Approach to the Modeling of Mixing of Elastomers

1981 ◽  
Vol 54 (2) ◽  
pp. 266-276 ◽  
Author(s):  
N. Nakajima
Keyword(s):  
Carbon Black ◽  
Flow Behavior ◽  
Practical Importance ◽  
Scale Up ◽  
Intermediate Stage ◽  
Material Behavior ◽  
Raw Material ◽  
Dynamic Visualization ◽  
Scale Temperature ◽  
Internal Mixer

Abstract In recent years, the process of mixing elastomers with carbon black has been the subject of various studies. In particular, the process involving the use of the internal mixer has been examined systematically, and Palmgren has published a general review on the state of the art. A method was proposed for the control and scale-up which is based on the energy input for mixing; then, properties were evaluated as a function of the mixing energy. This method was used for evaluating the performance of different types of elastomers and carbon blacks in the internal mixer. Although the method represents significant progress in understanding the mixing process and is of practical importance, it still treats the mixer essentially as a “black box”. In order to elucidate the mechanism of mixing, visualization must be performed. One type is static visualization, in which the machine is stopped at an intermediate stage and the contents are taken out for inspection. Another is dynamic visualization through transparent walls of a mixer. These observations enable us to construct a model for the deformation-flow behavior of materials and a model for the mixing mechanism. These models, in turn, guide us to laboratory measurements of the material behavior which are pertinent to the mixing mechanisms. With respect to mill processability, Tokita and White classified raw material behavior into four regions, which are functions of a given material and dependent on the time scale, temperature, and magnitude of strain. This classification is applicable not only to the millability of the raw elastomer but also to the ease of mixing with carbon black. This interpretation may be extended to the processability of the material in the internal mixer.

scholarly journals APLIKASI QUALITY FUNGTION DEPLOYMENT (QFD) PADA PENINGKATAN MUTU SUWAR SUWIR TAPE HANDAYANI 82 DI KABUPATEN BONDOWOSO

2018 ◽  
Vol 12 (01) ◽  
pp. 1
Author(s):  
Ade Galuh Rakhmadevi ◽  
Sih Yuwanti ◽  
Bambang Herry Purnomo
Keyword(s):  
Sampling Method ◽  
Heating Temperature ◽  
Mixing Time ◽  
Research Result ◽  
Heating Time ◽  
Raw Material ◽  
Quality Attribute ◽  
Fixed Composition ◽  
Acidity Level

The intensity industrial competition required Tape Handayani 82 factory to develop its quality to compete in the market. The development of quality could be done by searching information about quality attribute of suwar suwir as costumer expectation. The purpose of this research was to identify quality attribute of suwar suwir and technical response requiring improvement, which could fulfill costumer expectation. Data was taken by distributing questionnaire to 65 respondents with non probability sampling method at 4 subdistrict in Bondowoso Regency, and interview to the producer of suwar suwir “Tape Handayani 82”. The research result showed that the quality attributs that needed to be improved were the fixed composition, the self life of the product, the fixed texture, the label of composition, the suitability of the product with the label, the taste variation and packaging form. The technical responses which improved in relation to quality improvement were the composition of the additional materials, the composition of the raw material, the maturity of the tape, the heating temperature, the heating time, the acidity level the tape, the stirring technique, the mixing time, the primary packaging type, smoothing technique, chilling time and fiber removal. The target value to the technical response of the Handayani 82 factory was less than the bencmark. This mean that suwar suwir of Tape Handayani 82 has not met the target in fulfilling the quality of suwar suwir as costumer expectation. Keywords: quality, suwar suwir, quality function deploment (QFD), customer

Influence of Morphology and Particle Size of Powdered Rubber on Mill Processing

1975 ◽  
Vol 48 (2) ◽  
pp. 254-262 ◽  
Author(s):  
P. L. Bleyie
Keyword(s):  
Particle Size ◽  
Carbon Black ◽  
Granular Material ◽  
Specific Energy ◽  
Mixing Time ◽  
Considerable Effect ◽  
Area Increase ◽  
Surface Area Increase ◽  
Powdered Rubber ◽  
Carbon Black Dispersion

Abstract The powdered rubber method leads to a considerable shortening of mill mixing time and hence to a reduction of the specific energy required. While the transition from granular material to powder (from above 1 mm to below 1 mm particle size) has considerable effect both on mixing time and on specific energy, the effect of size reduction on specific energy for sizes below 1 mm is substantially smaller than expected from the surface area increase, probably, because a large part of the energy is used for carbon black dispersion. No effect of specific surface on specific energy and mixing time was found.

The Dispersion of Carbon Black in Rubber Part III. The Effect of Dispersion Quality on the Dynamic Mechanical Properties of Filled Natural Rubber

1992 ◽  
Vol 65 (5) ◽  
pp. 1016-1041 ◽  
Author(s):  
A. Y. Coran ◽  
J-B. Donnet
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Natural Rubber ◽  
Shear Strain ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Short Period ◽  
Dispersion Quality ◽  
Carbon Black Dispersion

Abstract The Part I of this series described a rapid method for determining the quality of carbon-black dispersion. The second paper (Part II) was concerned with the kinetics of the dispersion of carbon black into natural rubber (dispersion quality as a function of mixing time) in an internal mixer. In this paper we consider the effects of changes in dispersion quality on the dynamic mechanical properties of both unvulcanized and vulcanized natural rubber. The effects of changes in the degree of carbon-black dispersion were measured by using a new prototype moving-die rheometer (which is presently being developed at Monsanto Instruments & Equipment Research Laboratory). By using this prototype rheometer, G′ and G″ were measured as functions of shear-strain amplitude, temperature, and frequency. Increases in the degree of carbon-black dispersion in uncured natural rubber (starting from very poor dispersion quality) give decreases in the values of both G′ and G″. The decrease in dynamic moduli with increases in the degree of carbon-black dispersion might be explained on the basis of a network of agglomerates which exists when the quality of dispersion is extremely poor. In the case of uncured samples, values of G′, measured at low strains (e.g. ±1%), become reduced after the imposition of a larger (±50%) sinusoidal shear strain for a short period of time (e.g. 3 s). Then, with the passage of time, the reduced value of G′ partially recovers. The extent of this recovery increases with increases in the dispersion rating DR. Similar results were obtained with respect to the loss modulus G″. In both cases, the extent of recovery is much less when the carbon black is very poorly dispersed. The unrecoverable proportion of G′ or G″ is also considered to be due to a network composed of mutually interactive agglomerates of carbon black.

scholarly journals Kinetics of drying and quality of the apple cultivars Granny Smith, Idared and Jonagold

2010 ◽  
Vol 55 (3) ◽  
pp. 261-272 ◽  
Author(s):  
Dragana Paunovic ◽  
Branislav Zlatkovic ◽  
Dusica Mirkovic
Keyword(s):  
Technological Process ◽  
Air Temperature ◽  
World Market ◽  
Polyphenolic Compounds ◽  
Raw Material ◽  
Maximum Speed ◽  
Three Samples ◽  
Apple Slices ◽  
Kinetics Of

Apple is nutritionally valuable and present as fresh fruit in human nutrition throughout the year. Also apple is a raw material in food processing, primarily in the production of juices, nectars, refreshing soft drinks, marmalades, jams, compotes, apple cider vinegar and dried fruits. In the last decade on the world market there is a great interest in dried apple products (commercially called apple chips). During preservation by drying the technological process aimed at the final product of optimal quality is required. The subject of this paper is the kinetics of the apple cv. Granny Smith, cv. Idared and cv. Jonagold drying in laboratory dehydrator for the purpose of pinpointing at which level of humidity the maximum speed of evaporation is achieved and at which level of humidity apple slices begin to change in colour and geometric shape. Parameters of the drying process were the same for all three cultivars, 3hrs at air temperature of 70oC and 5hrs at air temperature of 50o. The amount of evaporated water is expressed in relative and absolute units of measure. The purpose of this paper is to determine which one of the three tested cultivars provides the best properties for drying, i.e. in terms of oxidation of polyphenolic compounds to find the cultivar which will provide that the final product is technologically and organoleptically the most acceptable. The results showed that the sample cv. Granny Smith expressed the least oxidation of polyphenolic compounds (browning), curved edges and shrivelled apple slices. After that the sample cv. Jonagold followed. The sample cv. Idared showed the worst results. Following the drying kinetics of all three samples, it can be concluded that the cultivars Granny Smith and Jonagold were achieving the lower maximum speed of evaporation, unlike the cultivar Idared. The cultivars Granny Smith and Jonagold have attained consistent drying and in this way the technological process was finished with a smaller temperature stress for plant tissue, resulting in a much better quality of the final product.

scholarly journals KINETICS OF GRINDING OF VEGETABLE RAW MATERIALS DURING ELECTRIC DISCHARGE EXTRACTION

2021 ◽  
Vol 64 (6) ◽  
pp. 76-82
Author(s):  
Valery T. Kazub ◽  
Maria K. Kosheleva ◽  
Stanislav P. Rudobashta
Keyword(s):  
Electric Discharge ◽  
Raw Materials ◽  
Experimental Studies ◽  
Perforated Plate ◽  
Raw Material ◽  
Optimal Size ◽  
Filtration Time ◽  
Extraction Chamber ◽  
Kinetics Of

The influence of the degree of grinding of the particles of growing raw materials during electric discharge extraction on the quality of the obtained extracts was studied. Each discharge during electro-discharge extraction contributes to the grinding of a part of the raw material, which is confirmed by granulometric analysis. The particle size of the raw material should be controlled, since excessive grinding of the extracts results in cloudy, difficult to clarify and poorly filtered. The design of the extraction chamber is proposed, in which the grounded electrode is made in the form of a perforated plate, called a false bottom, with the optimal size of the holes and their density, which eliminates the over-grinding of the raw material particles, which leads to the production of turbid and difficult-to-filter extracts. Since the extraction of raw materials is carried out at a certain ratio of solid-liquid phases, the volume of the chamber from the sieve to the bottom does not significantly affect the kinetics of the extraction process itself, since it is intended for collecting the smallest particles of processed raw materials, the mass of which does not exceed 15-16% of the loaded mass of raw materials. The device of the extraction chamber, due to the high turbulence and intensive mixing of the suspension under the action of cavitation and shock waves initiated by the discharge in the liquid, allows you to remove small particles of raw materials less than 1 mm in size from the working area of the chamber. The results of the study show that the extraction of target components from various raw materials using a chamber with a false bottom can significantly reduce the content of the smallest particles of raw materials in the extract. It facilitates the filtration of the extract, reduces the filtration time, significantly reduces the likelihood of turbidity of the solution due to suspension, which improves the quality of the extract. Experimental studies of the developed electric discharge chamber with a false bottom, conducted with various types of plant raw materials, confirm the effectiveness of extraction in the chamber of the proposed design.

Online Characterization of the Effect of Mixing Parameters on Carbon Black Dispersion in Rubber Compounds Using Electrical Conductivity

2004 ◽  
Vol 77 (1) ◽  
pp. 147-160 ◽  
Author(s):  
H. H. Le ◽  
S. Ilisch ◽  
B. Jakob ◽  
H.-J. Radusch
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Mixing Parameters ◽  
Rubber Compounds ◽  
Mixing Regime ◽  
Internal Mixer ◽  
Optimal Mixing ◽  
Insight Into ◽  
Carbon Black Dispersion

Abstract The influences of mixing parameters on the carbon black dispersion can be characterized using the electrical conductivity online measured from internal mixer. As a measure for monitoring the development of carbon black dispersion, a normalized conductivity with regard to the conductivity measured at the BIT (black incorporation time) has been suggested. It is observed that in spite of different mixing parameters, the mixtures possessing the same normalized conductivity factor K/KBIT deliver the same carbon black dispersion and the same mechanical properties. Based on normalized conductivity, a deeper insight into the mixing kinetics can be provided to find an optimal mixing regime.

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