Reinforcement of Elastomers by Carbon Black

1978 ◽  
Vol 51 (2) ◽  
pp. 297-321 ◽  
Author(s):  
Gerard Kraus
Keyword(s):  
Carbon Black ◽  
Size Distribution ◽  
Viscoelastic Behavior ◽  
Aggregate Size ◽  
Surface Oxidation ◽  
Spatial Arrangement ◽  
Indirect Measure ◽  
Dominant Characteristic ◽  
Average Size ◽  
Physical And Chemical

Abstract The reinforcement of elastomers by carbon black is governed by the morphology of the black and its physical and chemical interactions with the polymer. The latter are strongly affected by graphitization and surface oxidation. In modern rubber-grade carbon blacks strong bonding of the polymer to the carbon black surface is effected by several mechanisms, but surface chemical differences between blacks are relatively small, so that the dominant characteristic becomes the morphology. This is determined by the average size and size distribution of the particles which are fused together to form primary aggregates resembling branched random coils, the spatial arrangement of the particles in these aggregates, and the number of particles per aggregate and its distribution. This highly complex morphology can, to a first approximation, be represented by the specific surface area accessible to rubber and some, usually indirect, measure of the volume pervaded by the primary aggregates (“structure”). Important mechanical properties of reinforced rubbers depend to different degrees on these two characteristics, often in rather complex manner. Their effects on viscoelastic and failure properties are described. Additionally, some very recent observations on the effects of carbon black on network structure and the influence of the breadth of the aggregate size distribution on viscoelastic behavior are discussed.

Carbon Black Dispersion and Reinforcement

1952 ◽  
Vol 25 (4) ◽  
pp. 843-857 ◽  
Author(s):  
E. M. Dannenberg
Keyword(s):  
Electrical Resistivity ◽  
Carbon Black ◽  
Aggregate Size ◽  
Surface Oxidation ◽  
Light Transmittance ◽  
Rubber Matrix ◽  
Carbon Blacks ◽  
Improved Technique ◽  
High Degree ◽  
Carbon Black Dispersion

Abstract Different mixing conditions were employed to obtain vulcanizates, varying only in degree of carbon black dispersion, with natural and synthetic rubbers, using a single sample of a commercial grade HAF black. Light transmittance measurements on dilute solutions of dissolved unvulcanized stocks prepared by an improved technique were used to evaluate the size of carbon black aggregates in cold GR-S and natural rubber stocks. Electron micrographs of films show the high degree of carbon black aggregation, even after prolonged mixing. A limiting degree of dispersion or a minimum aggregate size is obtained very rapidly as mixing is increased. Black incorporation and dispersion appear to take place simultaneously; a high degree of abrasion reinforcement was noted in most rubbers with mixing (less than 75 seconds) barely sufficient to incorporate the black. Carbon blacks in general respond rapidly to mixing, and the chainlike aggregates characteristic of reinforcing carbon blacks observed under the electron microscope are practically unchanged after mixing with rubber. Dispersion of carbon blacks during mixing depends on the packing and coherence of their agglomerates resulting from such factors as surface oxidation and extent of mechanical bulk densification. There is some evidence that oil-type furnace blacks disperse more easily than channel blacks. A major cause of the disappointing abrasion reinforcement with most noncarbon pigments possessing extreme fineness may be the tendency for excessively strong aggregate binding and resulting large aggregates in rubber. A striking rise in electrical resistivity was observed as the amount of mixing was increased. As the size of the aggregates did not change, the higher electrical resistivity cannot be explained by assuming better dispersion and breakdown of conductive carbon paths. Increased mixing might provide better distribution of the carbon aggregates in in the rubber matrix without change in size of aggregates.

Effect of Carbon Black Structure Aggregate Size Distribution on Properties of Reinforced Rubber

1975 ◽  
Vol 48 (4) ◽  
pp. 538-547 ◽  
Author(s):  
C. J. Stacy ◽  
P. H. Johnson ◽  
G. Kraus
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Light Scattering ◽  
Carbon Black ◽  
Size Distribution ◽  
Aggregate Size ◽  
Size Distributions ◽  
Reliable Criterion ◽  
Broad Distribution ◽  
Aggregate Size Distribution

Abstract 1. Broadening of the aggregate size distribution of carbon black leads to significant changes in optical properties, such as lower tinting strength and greater dissymmetry of light scattering. 2. Effects on vulcanizate properties are generally small, the most significant effect being lower hysteresis for blacks of broad distribution. 3. In moderately severe service, treadwear is unaffected by differences in breadth of aggregate size distribution sufficient to cause large changes in tinting strength. 4. Tinting strength is not a reliable criterion of treadwear quality unless carbon blacks of equal structure and breadth of ASD are compared. 5. The results of this study do not contradict earlier results on carbon black blends which show significant losses in treadwear resistance as a result of severely broadened nodule (“particle”) size and, incidentally, also aggregate size distributions.

STUDYING OF THE CHEMICAL COMPOSITION OF THE POWDER FROM BROCCOLI CABBAGE AS RAW MATERIAL FOR PRODUCTION OF FUNCTIONAL FOODS

2019 ◽  
Author(s):  
Т.И. КРЯЧКО ◽  
В.Д. МАЛКИНА ◽  
В.В. МАРТИРОСЯН ◽  
С.А. СМИРНОВА ◽  
Н.А. ГОЛУБКИНА ◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Raw Materials ◽  
Raw Material ◽  
Size Of Particles ◽  
Average Size ◽  
Food Staples ◽  
Physical And Chemical

Представлен сравнительный анализ гранулометрических, органолептических и физико-химических показателей качества порошков из капусты брокколи, полученных конвективным и лиофильным способами сушки из отечественного сорта Тонус и импортного гибрида Маратон F1. По показателям гранулометрического состава исследованные образцы порошков конвективной и лиофильной сушек относятся к грубодисперсным системам. Меньшие значения среднего размера частиц (0,14–0,15 мм) имеют порошки из брокколи гибрида Маратон F1 двух способов сушки. Проведен анализ морфологии частиц порошков из капусты брокколи по характеристикам распределения вытянутости, гладкости и яркости. По гранулометрическому составу и морфологии частиц из порошков капусты брокколи сорта Тонус и гибрида Маратон F1существенных различий не обнаружено. Органолептические показатели – вкус, запах, цвет порошков капусты брокколи сорта Тонус и гибрида Маратон F1соответствовали использованному сырьевому источнику. Содержание белков, жиров и углеводов в порошках, полученных конвективным и лиофильным способами сушки, практически одинаково. Установлена сохранность витамина С в порошках при переработке свежей капусты: сорта Тонус в среднем на 26%, гибрида Маратон F1на 53,5%. Сохранность полифенольных соединений в порошках из брокколи сорта Тонус и гибрида Маратон F1, выработанных двумя способами сушки, составила 57,8–67,8%. Комплексные исследования показали, что порошки из капусты брокколи, выработанные из отечественного и импортного сырья, имеют ценный химический состав, что позволяет отнести их к перспективному продовольственному сырью для использования в технологиях функциональных продуктов питания. The comparative analysis of granulometric, organoleptic and physical and chemical indicators of quality of powders of cabbage of the broccoli received convective and liofilny by ways of drying from a domestic grade the Tonus and an import hybrid Maraton F1is submitted. On indicators of particle size distribution the studied samples of powders of convective and liofilny drying belong to grubodispersny systems. Smaller values of the average size of particles of 0,14–0,15 mm have hybrid broccoli powders Maraton of F1 of two ways of drying. The analysis of morphology of particles of powders of cabbage of broccoli according to characteristics of distribution of elongation, smoothness and brightness is carried out. On particle size distribution and morphology of particles of powders of cabbage of broccoli of a grade the Tonus and a hybrid Maraton F1of essential distinctions isn’t revealed. Organoleptic indicators – taste, a smell, color of powders of cabbage of broccoli of a grade the Tonus and a hybrid Maraton of F1corresponded to the used raw source. Content of proteins, fats and carbohydrates in the powders received convective and liofilny by ways of drying were almost close. The safety of vitamin C in powders when processing fresh cabbage is established: grades the Tonus on average 26%, a hybrid Maraton F1– 53,5%. Safety of polyphenolic connections in grade powders the Tonus and a hybrid Maraton of F1developed on two ways of drying made 57,8–67,8%. Complex researches have shown that the powders of cabbage of broccoli produced from domestic and import raw materials have the valuable chemical composition that allows to carry them to perspective food staples for use in technologies of functional food.

Sign in / Sign up

Export Citation Format

Share Document