Bound—Rubber Formation in Diene Polymer Stocks

1958 ◽  
Vol 31 (2) ◽  
pp. 369-373 ◽  
Author(s):  
P. B. Stickney ◽  
E. E. McSweeney ◽  
W. J. Mueller ◽  
S. T. Palinchak
Keyword(s):  
Particle Size ◽  
Carbon Black ◽  
Recent Work ◽  
Experimental Approach ◽  
Polymer Gel ◽  
Fine Powders ◽  
Bound Rubber ◽  
Close Relationship ◽  
Static Extraction ◽  
Rubber Filler

Abstract The phenomenon of insolubilization of rubber by carbon black has been known for at least twenty-seven years. There have been many attempts during this time to establish a relationship between insolubilization, or bound rubber formation, and reinforcement of rubber by carbon black. It was postulated, as far back as 1925, that there was a parallelism between particle size and insolubilization. This in spite of the fact that the methods available for determining particle size of very fine powders at that time were relatively crude. It was postulated at that time that there was a close relationship between the phenomena of vulcanization and reinforcement. This concept has had recurrent periods of popularity since that time. The insolubilization of rubber by carbon black, or other pigments, has been estimated by various techniques by the early investigators in the field. In more recent work, the trend has been toward a very straightforward experimental approach. Bound rubber in an uncured rubber-filler compound is usually determined by static extraction using the same apparatus and techniques used in determining the gel content of unfilled polymers. It follows that, using this method, polymer insoluble because of crosslinking, or gel, cannot be distinguished from polymer insolubilized by incorporation of fine fillers. In investigating the formation of bound rubber, therefore, the presence of gel in the polymer being used, or formation of polymer gel during processing must be taken into account.

PROPERTIES OF SBR FILLED WITH CARBON BLACK AND ARAMID PULP HYBRID FILLER: COMPARISON BETWEEN PREDISPERSED ARAMID PULP AND CONVENTIONAL ARAMID PULP

2016 ◽  
Vol 89 (4) ◽  
pp. 640-652 ◽  
Author(s):  
Manuchet Nillawong ◽  
Pongdhorn Sae-oui ◽  
Krisda Suchiva ◽  
Chakrit Sirisinha
Keyword(s):  
Carbon Black ◽  
Hybrid Composites ◽  
Aramid Fiber ◽  
Rubber Content ◽  
Hybrid Filler ◽  
Fiber Loading ◽  
Bound Rubber ◽  
Extended Range ◽  
Heat Buildup ◽  
Rubber Filler

ABSTRACT Compounds of SBR incorporated with hybrid filler of carbon black (CB) and aramid pulp were prepared. The ratio of CB to aramid pulp was varied and its effects on viscoelastic and mechanical properties of the rubber were investigated. Two aramid pulp types were used in this study: conventional aramid pulp (CAP) and the predispersed aramid pulp (PAP). The rubber–filler interaction as indicated by bound rubber content decreases with increasing aramid pulp loading, regardless of the aramid pulp type. This results in a decrease in tensile and abrasion properties with increasing fiber loading. The energy dissipation properties of the hybrid composites are also poorer than those of the CB/SBR composite, as reflected by the heat buildup values. Use of predispersed aramid fiber resulted in improved dispersion of the fiber in SBR. Thus, Mooney viscosities of the PAP-filled systems are lower than those of the CAP-filled systems, but the percentages of elongation at breaks are higher. The distinct feature of aramid fiber/CB hybrid SBR composites is their high moduli over an extended range of temperatures up to 80°C that is unattainable with the use of CB alone.

Evidence for Chemical Interaction in Carbon and Polymer Associations. Extension of Original Work on Effect of Carbon Black Structure

1969 ◽  
Vol 42 (3) ◽  
pp. 858-873 ◽  
Author(s):  
A. M. Gessler
Keyword(s):  
Free Radical ◽  
Carbon Black ◽  
Natural Rubber ◽  
Chemical Interaction ◽  
Ethylene Propylene ◽  
Bound Rubber ◽  
Close Relationship ◽  
Subsequent Behavior ◽  
High Structure ◽  
Free Radical Activity

Abstract Selected proposals regarding the mechanism of carbon and polymer interaction were reviewed from the literature. With this material as background, the bound rubber capacity of low and high structure HAF blacks was studied over a broad concentration range in four previously unstudied polymers: ethylene-propylene copolymer, chlorinated butyl, cis-1,4-polybutadiene, and natural rubber. Experimental evidence from the resulting work was combined with that from a similar previous study involving five polymers: polyisobutylene, butyl, two ethylene-propylene terpolymers differing in free radical activity, and SBR. With low structure black, the extent of bound rubber formation varies with the activity of the polymer functionality, in accordance with expectation. Previously proposed mechanisms for the bonding of rubber and black are used to resolve the differences which are shown. With high structure black, the primary carbon-to-polymer bonding effects referred to above are overshadowed by the formation, in situ, of a facile, new free radical source which is proposed to result from the mechanical breakage of aggregated carbon black structure during the milling of rubber and black. This imposed free radical activity is shown to have a profound effect on the subsequent behavior of the polymer. The inclusion of sulfur (2.0 php) in bound rubber systems leads to some extremely interesting results. Except for natural rubber, polymer is not crosslinked by the action of sulfur alone, even when the systems are heated as in vulcanization. The high bound rubber levels which are formed when sulfur and black are both present, especially with butyl, are proposed to result first from a reaction of sulfur with the black, and second, from reaction of this sulfur-modified black with the polymer. The close relationship between vulcanization and reinforcement is thus attested.

Bound Rubber and Mechanical Properties of Diene Polymers

1958 ◽  
Vol 31 (2) ◽  
pp. 374-386 ◽  
Author(s):  
S. T. Palinchak ◽  
E. E. McSweeney ◽  
W. J. Mueller ◽  
P. B. Stickney
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Tensile Strength ◽  
Carbon Black ◽  
Diethylene Glycol ◽  
Abrasion Resistance ◽  
Gel Formation ◽  
Bound Rubber ◽  
Stabilizing Effect

Abstract 1. Tensile strength is apparently a function of the particle size of the pigment and how well it is dispersed in a polymer. 2. Modulus and abrasion resistance are apparently functions of the interaction of the pigment and the polymer. This cannot be attributed entirely to bound-rubber formation, since bound rubber may occur without reinforcement, as shown by the results with silica pigment. 3. Results of processing studies show that Philblack O has a stabilizing effect on the polymer during processing and more consistent and better properties are obtained if processing is performed with carbon black present at temperatures below those for gel formation. This effect is more pronounced for less stable polymers such as polybutadiene. 4. Philblack O slows down gel formation. 5. It is possible that silica may have a destabilizing effect on polybutadiene unless it is buffered with agents such as resins, stearic acids, and diethylene glycol.

Mixing of Carbon Black with Rubber. II. Mechanism of Carbon Black Incorporation

1985 ◽  
Vol 58 (4) ◽  
pp. 774-784 ◽  
Author(s):  
George R. Cotten
Keyword(s):  
Molecular Weight ◽  
Particle Size ◽  
Carbon Black ◽  
Cross Section ◽  
Effective Cross Section ◽  
Rubber Content ◽  
Narrow Channels ◽  
Second Stage ◽  
Bound Rubber ◽  
Average Size

Abstract The present study leads to postulating the following mechanism for carbon black incorporation. During the first stage of incorporation, carbon black agglomerates become encapsulated by the polymer. At this stage, the interstices within these agglomerates are still filled with air, giving a very weak, crumbly composite. The rubber becomes forced into these interstices during the second stage of incorporation. As the rubber is being forced through the narrow channels between the aggregates, bound rubber is being formed. The immobilized layer of the polymer tends to reduce the effective cross section of the channels through which more rubber must pass before reaching the inner part of the agglomerates. Thus, as the activity of carbon black increases, e.g., higher bound rubber, the incorporation time increases. At a given carbon black activity, the effective thickness of the immobilized polymer layer would increase with increasing molecular weight of polymer, but be independent of the oil loading. This agrees with experimental observation that the incorporation time increases with molecular weight of the polymer, while oil loading has no effect other than that associated with the lowering of bound rubber content. The average size of channels through which rubber must pass depends also on the carbon black morphology. The size of these channels would be expected to increase with increasing structure of carbon black, and (to a lesser extent) with increasing particle size. These parameters have the expected influence on the incorporation time; since the incorporation time decreases with increasing DBPA value and decreasing tint.

The Stockpile Thesis and Industrial Relations at Kambalda

1986 ◽  
Vol 28 (3) ◽  
pp. 353-366
Author(s):  
Helen Lang
Keyword(s):  
Recent Work ◽  
Social Life ◽  
Industrial Relations ◽  
Mining Town ◽  
Close Relationship ◽  
Nickel Mining ◽  
Industrial Disputes ◽  
Strategic Variable ◽  
Consensual Approach

Some recent work on industrial relations in the Australian minirtg industry has focused on a close relationship between the incidence of strikes and the stockpiling of the mineral mined. It is argued that when demand for a mineral falls and the stockpile grows, management can afford the disruption to production caused by strikes. Hence management will take action to provoke strikes by introducing changes in work practices it knows will be opposed by unionists. Not only are the unions more likely to be defeated, but the company concerned is also able to reduce the size of its stockpile of ore. A case-study of the nickel-mining centre of Kambalda in Western Australia suggests that the size of the stockpile isfar less relevant when management and unions have a consensual approach to industrial relations. The stockpile is a strategic variable rather than a cause of industrial disputes. Whether the stockpile is manipulated as part of management's strategy will depend on innumerable, interdependent factors, including the organization of social life in a mining town and whether effective co operative relations develop between managers and unions.

STUDY ON NANOMORPHOLOGY OF HIGH-STRUCTURE CARBON BLACK AND ITS BOUND RUBBER BY AFM

2012 ◽  
Vol 19 (01) ◽  
pp. 1250003
Author(s):  
JIAN CHEN ◽  
YONGZHONG JIN ◽  
JINGYU ZHANG ◽  
YAFENG WU ◽  
CHUNCAI MENG
Keyword(s):  
Carbon Black ◽  
Cluster Structure ◽  
Chemical Activity ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Atomic Force ◽  
Filled Rubber ◽  
Bound Rubber ◽  
Styrene Butadiene ◽  
High Structure

Bound rubber in carbon black (CB) filled rubber (natural rubber (NR) and styrene–butadiene rubber (SBS)) was prepared by the solvent method. The nanomorphology of CB and rubber/CB soluble rubber was observed by atomic force microscope. The results show that high-structure CB DZ13 has a "grape cluster" structure which consists of many original particles with the grain size of about 30–50 nm. Graphitizing process of CB decreases the amount of bound rubber. The NR/DZ13 soluble rubber with island–rim structure has been obtained, where the islands are DZ13 particles and the rims around the islands are occupied by NR film. But when the graphitized DZ13 particles were used as fillers of rubber, we have only observed that some graphitized DZ13 particles were deposited on the surface of the globular-like NR molecular chains, instead of the spreading of NR molecular chains along the surface of DZ13 particles, indicating that graphitized DZ13 has lower chemical activity than ungraphitized DZ13. Especially, we have already observed an interesting unusual bound rubber phenomenon, the blocked "bracelet" structure with the diameter of about 600 nm in which CB particles were blocked in ring-shaped SBS monomer.

Effect of Diameter and Surface Area of Carbon Black Particles on Certain Properties of Rubber Compounds

1944 ◽  
Vol 17 (2) ◽  
pp. 451-474
Author(s):  
D. Parkinson
Keyword(s):  
Particle Size ◽  
Tensile Strength ◽  
Carbon Black ◽  
Abrasion Resistance ◽  
Particle Diameter ◽  
Stiffness Modulus ◽  
Carbon Structures ◽  
Rubber Compounds ◽  
Regular Manner ◽  
Tear Resistance

Abstract Carbon blacks can be grouped into different classes according to the way in which their fineness of division relates to different properties in rubber. Within any one class the principal properties vary in a regular manner with particle size. The normal class consists of the furnace carbons, Kosmos (Dixie)-40, Statex, the rubber-grade impingement carbons, and possibly, the color-grade impingement carbons. The subnormal classes consist of thermal carbons and acetylene and lamp blacks. Irrespective of the above classification, the properties which depend more on fineness of division than on other factors are rebound resilience, abrasion resistance, tensile strength and tear resistance. The lower limit of particle diameter for best tensile strength and tear resistance appears to be higher than that for abrasion resistance. B.S.I, hardness and electrical conductivity are properties which depend at least as much on other factors as on particle size. Stiffness (modulus) depends more on other factors than on particle size. Factors modifying the effects of particle size (or specific surface) include the presence of carbon-carbon structures and a reduction in strength of bond in rubber-carbon structures. Carbon black is thought to exist in rubber in four states: agglomerated, flocculated, dispersed, and bonded to the rubber molecules (the reënforcing fraction). Abrasion resistance is regarded as providing the only reliable measure of reënforcement.

scholarly journals Effect of Particle Size Distribution on Powder Packing and Sintering in Binder Jetting Additive Manufacturing of Metals

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Yun Bai ◽  
Grady Wagner ◽  
Christopher B. Williams
Keyword(s):  
Particle Size ◽  
Additive Manufacturing ◽  
Large Degree ◽  
Full Density ◽  
Powder Particle Size ◽  
Powder Mixtures ◽  
Fine Powders ◽  
Sintering Shrinkage ◽  
The Impact ◽  
Binder Jetting

The binder jetting additive manufacturing (AM) process provides an economical and scalable means of fabricating complex parts from a wide variety of materials. While it is often used to fabricate metal parts, it is typically challenging to fabricate full density parts without large degree of sintering shrinkage. This can be attributed to the inherently low green density and the constraint on powder particle size imposed by challenges in recoating fine powders. To address this issue, the authors explored the use of bimodal powder mixtures in the context of binder jetting of copper. A variety of bimodal powder mixtures of various particle diameters and mixing ratios were printed and sintered to study the impact of bimodal mixtures on the parts' density and shrinkage. It was discovered that, compared to parts printed with monosized fine powders, the use of bimodal powder mixtures improves the powder's packing density (8.2%) and flowability (10.5%), and increases the sintered density (4.0%) while also reducing the sintering shrinkage (6.4%).

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