Investigation of the Thermal Conductivity of Rubber

1938 ◽  
Vol 11 (2) ◽  
pp. 359-371 ◽  
Author(s):  
L. Frumkin ◽  
Yu Dubinker
Keyword(s):  
Thermal Conductivity ◽  
Zinc Oxide ◽  
Carbon Black ◽  
Natural Rubber ◽  
Considerable Increase ◽  
Large Percentage ◽  
K Value ◽  
Synthetic Rubber ◽  
Coefficient Of Thermal Conductivity

Abstract 1. The apparatus for the determination of the coefficients of thermal conductivity which is described is satisfactory for the investigation of rubber mixtures. 2. A review of the results of the determinations of K values of various mixtures leads to the following conclusions: (a) The thermal conductivity of rubber mixtures containing synthetic rubber is greater than that of mixtures containing natural rubber. (b) The addition of zinc oxide even in considerable quantities to rubber mixtures containing a large percentage (55 per cent) of carbon black does not substantially increase thermal conductivity. (c) In the case of carcass mixtures a considerable increase in the coefficient of thermal conductivity is observed when the content of zinc oxide is increased from 7.5 to 15 per cent by weight; on further increase in the zinc oxide K increases but little. (d) The K value of carcass mixtures before vulcanization is smaller than that of the same mixtures after vulcanization by an average of 23 per cent. (e) The thermal conductivity of uncured tread mixtures is the same as that of vulcanized mixtures. (f) The coefficient of vulcanization has no effect on the K value of unloaded mixtures and mixtures containing fillers. (g) The K value of rubber mixtures increases sharply with addition up to 60 per cent by volume of fillers with good thermal conductivity (zinc oxide and graphite), but only slowly with the addition of fillers of medium thermal conductivity (carbon black). In other words, the curve of the relation between the coefficient of thermal conductivity and the percentage by volume of graphite and of zinc oxide is convex to the filler axis and is concave in the case of carbon black.

Extraction and identification of fillers and pigments from pyrolyzed rubber and tire samples

1996 ◽  
Vol 54 ◽  
pp. 174-175
Author(s):  
P. Sadhukhan ◽  
J. B. Zimmerman
Keyword(s):  
Zinc Oxide ◽  
Electron Microscope ◽  
Carbon Black ◽  
Natural Rubber ◽  
Transmission Electron Microscope ◽  
Rolling Resistance ◽  
Synthetic Polymers ◽  
Nitrogen Atmosphere ◽  
Transmission Electron ◽  
Curing Agents

Rubber stocks, specially tires, are composed of natural rubber and synthetic polymers and also of several compounding ingredients, such as carbon black, silica, zinc oxide etc. These are generally mixed and vulcanized with additional curing agents, mainly organic in nature, to achieve certain “designing properties” including wear, traction, rolling resistance and handling of tires. Considerable importance is, therefore, attached both by the manufacturers and their competitors to be able to extract, identify and characterize various types of fillers and pigments. Several analytical procedures have been in use to extract, preferentially, these fillers and pigments and subsequently identify and characterize them under a transmission electron microscope.Rubber stocks and tire sections are subjected to heat under nitrogen atmosphere to 550°C for one hour and then cooled under nitrogen to remove polymers, leaving behind carbon black, silica and zinc oxide and 650°C to eliminate carbon blacks, leaving only silica and zinc oxide.

Determination of Peroxides in Synthetic Rubbers

1945 ◽  
Vol 18 (4) ◽  
pp. 874-876
Author(s):  
Richard F. Robey ◽  
Herbert K. Wiese
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
High Molecular Weight ◽  
Active Oxygen ◽  
Lower Molecular Weight ◽  
Synthetic Rubber ◽  
High Molecular Weight Polymers ◽  
Methanol Solutions

Abstract Peroxides are found in synthetic rubbers either as the result of attack by oxygen, usually from the air, or as a residue from polymerization operations employing peroxide catalysts. Because of possible detrimental effects of active oxygen on the properties of the rubber, a method of quantitative determination is needed. The concentration of peroxides in substances of lower molecular weight may be determined with ferrous thiocyanate reagent, either titrimetrically as recommended by Yule and Wilson or colorimetrically as by Young, Vogt, and Nieuwland. Unfortunately, many highly polymeric substances are not soluble in the acetone and methanol solutions employed in these procedures. This is also the case with hydrocarbon monomers, such as butadiene, containing appreciable concentrations of soluble high molecular weight polymers. Bolland, Sundralingam, Sutton and Tristram recommended benzene as a solvent for natural rubber samples and the reagent made up in methanol. However, most synthetic rubbers are not readily soluble even in this combination. The following procedure employs the ferrous thiocyanate reagent in combination with a solvent capable of maintaining considerable concentrations of synthetic rubber in solution. The solvent comprises essentially 20 per cent ethanol in chloroform.

Structural Characterization of Filled Vulcanizates Part 1. Determination of the Concentration of Chemical Crosslinks in Natural Rubber Vulcanizates Containing High Abrasion Furnace Black

1967 ◽  
Vol 40 (3) ◽  
pp. 866-882 ◽  
Author(s):  
M. Porter
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Volume Fraction ◽  
Exponential Relationship ◽  
Furnace Black ◽  
Simple Linear Relationship ◽  
Chemical Crosslinks ◽  
Natural Rubber Vulcanizates

Abstract The degree to which HAF black restricts the swelling of natural rubber vulcanizates in n-decane has been determined using a vulcanizing system in which the stoichiometry of crosslinking is unaffected by the carbon black. The dependence of the degree of restriction, as measured by the ratio of the volume fractions of rubber in the filled and unfilled vulcanizates swollen to equilibrium, on the concentration of carbon black follows an exponential relationship previously proposed by Lorenz and Parks. This is found to be equivalent to a simple linear relationship between the apparent and actual crosslink concentrations: napparent/nactual=1+Kϕ, where K is a constant characteristic of the filler and φ is its volume fraction in the vulcanizate. The relation has been used to determine actual crosslink concentrations in filled natural rubber vulcanizates. HAF black is found to cause increases of up to 25 per cent in the yield of polymer to polymer crosslinks in conventional sulfur vulcanizing systems, accompanied by changes in rate of cure and of crosslink reversion. All these are small compared with the effect of the filler on many physical properties.

Determination of the coefficient of thermal conductivity of glass and polymer fibers

1969 ◽  
Vol 26 (9) ◽  
pp. 523-526 ◽  
Author(s):  
O. F. Shlenskii ◽  
N. I. Goncharuk ◽  
V. Ya. Gal'tsov
Keyword(s):  
Thermal Conductivity ◽  
Polymer Fibers ◽  
Coefficient Of Thermal Conductivity

Ozonolytic Degradation of Interpolymers of Natural Rubber with Methyl Methacrylate and Styrene

1958 ◽  
Vol 31 (1) ◽  
pp. 82-85
Author(s):  
D. Barnard
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
Natural Rubber ◽  
Accurate Determination ◽  
Synthetic Polymers ◽  
Polymer Chains ◽  
Low Molecular Weight ◽  
Rubber Content ◽  
Tert Butyl Hydroperoxide

Abstract The preparation of graft and block interpolymers of natural rubber and synthetic polymers has made it desirable that the number and size of polymer chains attached to rubber be readily determinate. The degradation of unsaturated polymers with tert-butyl hydroperoxide in the presence of osmium tet oxide has been used for the determination of free polystyrene in SBR and carbon black in several elastomers, and has recently been applied to the present problem. The accurate determination of the rubber content of interpolymers by quantitative ozonolysis essentially according to the method of Boer and Kooyman suggested that this might be made the basis of isolation of the attached polymer, the rubber being degraded into fragments of low molecular weight, from which the polymer could be separated by conventional techniques. The method should be applicable to any interpolymer, or mixture, of a polyunsaturated and a saturated polymer and is illustrated with reference to interpolymers of natural rubber (NR)-polymethyl methacrylate (PMM) and NR-polystyrene (PS).

Dependence of Thermal Conductivity of Carbon Black Filled Rubber on Several Factors

2009 ◽  
Vol 87-88 ◽  
pp. 536-541 ◽  
Author(s):  
Jun Ping Song ◽  
Lian Xiang Ma
Keyword(s):  
Thermal Conductivity ◽  
Carbon Black ◽  
Natural Rubber ◽  
Influencing Factors ◽  
Specific Area ◽  
Volume Percent ◽  
Filled Rubber ◽  
Two Factors

Five kinds of carbon black filled natural rubber were prepared, and thermal conductivity was studied considering two factors, which include temperature and volume percent of the filler. It was found that thermal conductivity had relevance to temperature and volume percent of carbon black, besides, structure and specific area of carbon black were also very important influencing factors. Moreover, reuniting phenomenon of nanometer grade of carbon black has much effect on thermal conductivity.

Experimental Study on Thermal Conductivity Property of Rubber Composites Filled with Carbon Nanotubes

2011 ◽  
Vol 221 ◽  
pp. 373-376 ◽  
Author(s):  
Ze Peng Wang ◽  
Yan He
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Experimental Study ◽  
Carbon Black ◽  
Natural Rubber ◽  
Rubber Composites ◽  
Conductivity Property

Thermal conductivity of rubber composites filled with CNTs (carbon nanotubes) and N234 CB (carbon black) were investigated. Result indicated that Thermal conductivity of NR (natural rubber) filled with CNTs is higher than that of NR filled with CB in the case of the same filling amount. CNTs can better improve the performance of thermal conduct of rubber composites than CB. The more the filling content of CNTs is, the higher thermal conductivity of NR composites.

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