Behavior of Quartz and Carbon Black Pellets at Elevated Temperatures

2016 ◽  
pp. 153-160
Author(s):  
Fei Li ◽  
Merete Tangstad
Keyword(s):  
Carbon Black ◽  
Elevated Temperatures

Ionic Crosslinking of Carboxylated SBR

1983 ◽  
Vol 56 (5) ◽  
pp. 942-958 ◽  
Author(s):  
Kyosaku Sato
Keyword(s):  
Zinc Oxide ◽  
Carbon Black ◽  
Elevated Temperatures ◽  
Ion Clusters ◽  
Ionic Crosslinking ◽  
Reinforcing Fillers ◽  
Ionic Bonds ◽  
Tan Δ ◽  
And Shifts ◽  
Ionic Crosslinks

Abstract 1. Ionic bonding of carboxylated SBR with zinc oxide is detectable by means of measurements of the temperature dependence of tan δ. There is an α peak in the region of 60°C at 3.5 Hz. The position and shape of the α peak are strongly dependent on the state of cure of the vulcanizates. Without permanent crosslinking, the α peak is a plateau; as the crosslink density increases, the α peak becomes sharper and shifts to lower temperatures. The presence of carbon black causes the α peak to shift to higher temperatures, regardless of the presence of permanent crosslinks. 2. Ionic bonds in carboxylated SBR reacted with zinc oxide are in the form of ion clusters which function as crosslinks at room temperature. The ionic crosslinks provide carboxylated SBR with high tensile strength in the absence of reinforcing fillers. The presence of carbon black causes the 300% modulus to increase. The ionic crosslinks are labile, and the strength is lost at moderately elevated temperatures. A mixed cure system consisting of both sulfur and zinc oxide provides higher heat resistance than either of the single cure systems.

scholarly journals Effect of Ti3C2Tx MXenes etched at elevated temperatures using concentrated acid on binder-free supercapacitors

RSC Advances ◽  
2020 ◽  
Vol 10 (68) ◽  
pp. 41837-41845
Author(s):  
Sunil Kumar ◽  
Dongwoon Kang ◽  
Hyeryeon Hong ◽  
Malik Abdul Rehman ◽  
Yeon-jae Lee ◽  
...  
Keyword(s):  
Carbon Black ◽  
Elevated Temperatures ◽  
Different Temperatures ◽  
Binder Free ◽  
C 50

The effect of Ti3C2Tx MXene etched at different temperatures (25 °C, 50 °C, and 80 °C) on the capacitance of supercapacitors without the use of conducting carbon-black or a binder was studied.

New Elastomers by Reactive Processing. Part I. Vulcanizable Precured Alloys from NBR and ACM

1990 ◽  
Vol 63 (4) ◽  
pp. 599-612 ◽  
Author(s):  
A. Y. Coran
Keyword(s):  
Carbon Black ◽  
Elevated Temperatures ◽  
Continuous Phase ◽  
Dispersed Phase ◽  
Mixing Process ◽  
Reactive Processing ◽  
Dynamic Vulcanization ◽  
Hot Air ◽  
Air Resistance ◽  
Generator Type

Abstract The dynamic vulcanization of ACM (the dispersed phase) during its mixing with NBR (the continuous phase) can produce a new type of millable specialty elastomer alloy. The millable dynamic vulcanizate containing the crosslinked dispersed phase can be later mixed with curatives for the continuous phase, fillers, antidegradants, etc. The completed mixture of millable dynamic vulcanizate with the additional curatives (for the NBR), fillers, stabilizers, etc. can then be vulcanized e.g., in a heated mold. Thus, the dynamic vulcanization technique is a means of separately controlling the vulcanization of individual phases of a blend of elastomers. Since the ACM can be completely vulcanized during the dynamic vulcanization stage of the mixing process, the usual postcuring associated with ACM technology is not necessary. Also, since the continuous or external phase is NBR, the prevulcanized millable alloy exhibits processability more similar to that of NBR than to that of ACM. Sticking and splitting on the roll mill is less of a problem after dynamic vulcanization than before dynamic vulcanization. The dynamic vulcanization of the ACM can be achieved by using the soap-sulfur type or the diamine-generator type curatives during the mixing process at elevated temperatures. Compositions filled either with carbon black (N326) or silica (Hisil 233) give compositions of excellent hot-oil resistance and room-temperature set. (Compression-set testing has not yet been done at this early stage of our research.) As in the case of conventional NBR stocks, the silica-filled compositions give excellent hot-air resistance whereas, carbon-black-filled compositions give fair hot-air resistance. In either the black-filled or the silica-filled compositions, provided that at least half of the rubber polymer is ACM, essentially complete resistance to ozone attack is obtained.

Carbon Black Structure and the Tear Resistance of Vulcanizates

1959 ◽  
Vol 32 (4) ◽  
pp. 1180-1184
Author(s):  
V. G. Epshtein
Keyword(s):  
Carbon Black ◽  
Elevated Temperatures ◽  
Carbon Blacks ◽  
Tear Resistance

Abstract 1. The increase in tear resistance of vulcanizates, where carbon blacks are added in considerable amounts, is related to the formation of secondary black structures and is manifested especially when certain blacks are used (channel, anthracene and acetylene). 2. The presence of secondary black structures brings about an increase in the tear resistance at elevated temperatures.

Filler Effect on the Heat Stability of Vulcanized Elastomeric Compositions

1973 ◽  
Vol 46 (4) ◽  
pp. 927-937 ◽  
Author(s):  
M. Q. Fetterman
Keyword(s):  
Elevated Temperature ◽  
Carbon Black ◽  
Heat Resistance ◽  
Elevated Temperatures ◽  
Heat Stability ◽  
Rubber Compound ◽  
Hydrated Silica ◽  
Serviceable Life ◽  
Good Heat Resistance ◽  
Good Heat

Abstract The purpose of this study was to determine filler effects on heat stability of vulcanized elastomeric compositions. Carbon-black reinforced compounds, designed to have good heat resistance, were modified by substituting hydrated silica for all or part of the black. Since a simple replacement of silica for black would result in dissimilar original properties, the substituted compounds were further revised to minimize this dissimilarity. This was accomplished through curative correction and/or addition of an organosilane coupling agent. Silica substitution did not provide permanency of properties at elevated temperatures, but in all cases the serviceable life of the compound was extended. Since silica substitution had minimum effect on other properties and reduced the rate of degradation at elevated temperature, this may be considered a reasonable alternative to completely redesigning a proven rubber compound in order to improve its heat resistance.

Effective Degree of Immobilization of Rubber Occluded within Carbon Black Aggregates

1972 ◽  
Vol 45 (5) ◽  
pp. 1171-1194 ◽  
Author(s):  
A. I. Medalia
Keyword(s):  
Carbon Black ◽  
Low Temperatures ◽  
Elevated Temperatures ◽  
Effectiveness Factor ◽  
Effective Volume ◽  
Equilibrium Conditions ◽  
Secondary Network ◽  
Equilibrium Modulus ◽  
Highly Loaded ◽  
Effective Degree

Abstract The conclusions of the present work may be summarized as follows. 1. The effective volume of carbon black in rubber, as measured by the low-strain equilibrium modulus, is equal to the true volume of carbon plus about half of the occluded volume of rubber calculated from the DBP absorption of the carbon black. 2. Breakdown of aggregates on incorporation in rubber may diminish the volume of occluded rubber; thus, calculations based on the same modulus data would give a somewhat higher effectiveness factor—perhaps of the order of 0.6, depending on the degree of breakdown assumed. 3. Under non-equilibrium conditions various processes may either raise or lower the measured modulus and (thus) the occluded volume effectiveness factor : (a) At moderate to high strains, strain amplification raises the modulus. (b) At low temperatures, amplification of the rate of strain raises the modulus (relative to that of the gum). (c) In a highly loaded vulcanizate, the secondary network of carbon black raises the modulus measured at low strain and low or moderate temperature. (d) The modulus can be lowered by molecular slippage, especially with thermal blacks, or with graphitized furnace blacks, at elevated temperatures and/or high strains.

Chemical Interaction between Carbon Black and Elastomers — Crosslinking of Chlorosulfonated Polyethylene by Carbon Black

1994 ◽  
Vol 67 (4) ◽  
pp. 662-671 ◽  
Author(s):  
A. Roychoudhury ◽  
S. K. De ◽  
P. P. De ◽  
J. A. Ayala ◽  
G. A. Joyce
Keyword(s):  
Carbon Black ◽  
Elevated Temperatures ◽  
Chemical Interaction ◽  
Surface Oxidation ◽  
Rubber Content ◽  
Chlorosulfonated Polyethylene ◽  
Surface Sites ◽  
Bound Rubber ◽  
Thermometric Titration ◽  
Oxidized Carbon

Abstract Surface oxidation of a carbon black leads to an increased elastomer-filler bonding between the chlorosulfonated polyethylene and the carbon black. The increased interaction appears to be related to the increased concentration and reactivity of the oxygen containing sites in the oxidized carbon black, as deduced from the moisture adsorption and thermometric titration results. The bound rubber content is substantially higher for the oxidized carbon black. The reactive surface sites of the carbon black also promote the crosslinking of the elastomer at elevated temperatures.

Effect of Cis-Trans Ratio on the Physical Properties of 1,4 Polybutadienes

1957 ◽  
Vol 30 (4) ◽  
pp. 1118-1141 ◽  
Author(s):  
J. N. Short ◽  
V. Thornton ◽  
G. Kraus
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Physical Properties ◽  
Low Temperatures ◽  
Elevated Temperatures ◽  
Trans Content ◽  
Wide Range ◽  
Brittle Point ◽  
Low Sulfur ◽  
In Cis

Abstract The physical properties of vulcanized 1,4 polybutadienes, prepared by heterogeneous catalysis and ranging from 95 per cent cis to nearly 100 per cent trans configuration, were investigated in gum and tread formulations. Comparisons were made at equal effective (physical) degree of crosslinking for both gum- and carbon black-reinforced stocks and for black stocks at equal 300 per cent modulus. In general, as polybutadienes require less sulfur for adequate vulcanization than trans polybutadienes. Vulcanizates of all 1,4 polybutadienes exceeding 15 per cent in cis content are completely rubbery at ordinary temperatures. Polybutadiene of 93 per cent trans content yields tough, leathery, crystalline vulcanizates at 80° F, which become rubbery at moderately elevated temperatures. Without exception the important physical properties change little between 25 and 80 per cent cis content. At both ends of this range the tensile strength of both gum and black stocks rises as a consequence of increasing chain regularity. However, in gum tensile strength not even the highest cis polybutadienes are equivalent to natural or synthetic cis-polyisoprenes. Black stocks of very good tensile strength with elongations ranging from 500 to 700 per cent are obtained with both cis- and trans-polybutadienes. At the crosslinking level for optimum tensile strength, modulus increases with trans content. The cis-polybutadienes have excellent resilience and low hysteresis and maintain their resilience to temperatures as low as −40° F. The latter is true even of the highest as polymers which crystallize at these temperatures. The tendency to crystallize rapidly at low temperatures disappears between 87 and 82 per cent cis content so that polymers of moderately high cis unsaturation have exceptional low-temperature characteristics. These polymers remain completely rubbery down to their brittle point (ca. −85° C). The excellent resilience of cis-polybutadiene is particularly apparent in carbon black-reinforced stocks. Because of the inherently low modulus of these stocks and their low sulfur requirement, these may be vulcanized to rather high degrees of crosslinking. This results in further improvements in resilience and heat build-up with only moderate sacrifices in tensile strength and ultimate elongation. Vulcanizates of 70 to 80 per cent trans-polybutadienes exhibit evidence of crystallinity over a wide range of temperatures and are probably not completely melted at room temperature. Although their resilience is less than that of the high cis-polybutadienes, it is still somewhat better than that of SBR, particularly at low temperatures. The 1,4 polybutadienes are more resistant to oxidative scission than emulsion polybutadiene or SBR and are greatly superior to natural rubber in this respect. The dominant effect in the aging of 1,4 polybutadienes is crosslinking. Because of their low sulfur requirements the cis polybutadienes offer a particular advantage in aging resistance. None of the polybutadienes exhibits ozone resistance comparable to Hevea.

Thermo-Oxidative Behavior of Carbon Black Composites for Self-Regulating Heaters

2019 ◽  
Vol 34 ◽  
pp. 66-80
Author(s):  
Radu Setnescu ◽  
Marius Lungulescu ◽  
Adela Bara ◽  
Alina Caramitu ◽  
Sorina Mitrea ◽  
...  
Keyword(s):  
Carbon Black ◽  
Polymer Matrix ◽  
Elevated Temperatures ◽  
Conductive Filler ◽  
Limiting Factor ◽  
Conductive Composites ◽  
Major Interest ◽  
Materials Used ◽  
Crystallinity Changes ◽  
Physical Changes

The composite materials for self-regulating heaters are conductive composites based on a polymer matrix and a dispersed conductive filler consisting in either carbon black or another carbon material, such as graphite or nanotubes. Similar materials are suitable for sensors and current limitations. As these materials used in heating applications work usually at elevated temperatures in presence of air, the ageing processes would be an important limiting factor of their lifetime. Therefore, thermal oxidation processes and crystallinity changes during the service of these products are of major interest in durability studies. The potential interference of carbon-based materials with the oxidation and ageing of polymer matrix shall be known in order to correctly estimate the durability of such materials. The effect of radiation exposure is studied taking into account the potential use of such materials in radiation environments. In this work, the activation energies of some initial, unaged and aged products at elevated temperatures are compared in order to characterize the effect of thermo-oxidative ageing and hence to evaluate their durability. The effect of some antioxidants is also discussed. The crystallinity, calculated from DSC was used for evaluation of the physical changes induced within the aged materials, following the procedures described in previous work. FTIR-ATR technique was used for characterization of chemical changes induced by ageing.

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