Quantitative Determination of Natural Rubber Hydrocarbon by Refractive Index Measurements

1951 ◽  
Vol 23 (11) ◽  
pp. 1653-1656 ◽  
Author(s):  
Rachel Fanning ◽  
Norman Bekkedahl
Keyword(s):  
Refractive Index ◽  
Natural Rubber ◽  
Quantitative Determination

Quantitative Determination of Natural Rubber Hydrocarbon by Refractive Index Measurements

1952 ◽  
Vol 25 (3) ◽  
pp. 680-688
Author(s):  
Rachel J. Fanning ◽  
Norman Bekkedahl
Keyword(s):  
Refractive Index ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
Original Sample ◽  
Hydrocarbon Content ◽  
Good Grade ◽  
Different Sources ◽  
Better Than

Abstract Rubbers from different sources vary considerably in rubber hydrocarbon content, from 70 per cent or less for some of the wild varieties to about 95 per cent for a good grade of plantation rubber. The quality of a rubber is measured to a great extent by the percentage of rubber hydrocarbon. A new procedure for the quantitative determination of this hydrocarbon has been developed, which involves the measurement of refractive index of a solution of a known weight of acetone-extracted rubber in a known weight of 1-bromonaphthalene. From the observed data and from other previously determined or known physical constants, such as the densities and refractive indexes of the rubber hydrocarbon and the solvent, the percentage of hydrocarbon in the original sample can be calculated. This new method gives results as good as, or better than, other existing methods, and is simpler and less time-consuming to perform.

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.

Quantitative Determination of Copper in Natural Rubber

1953 ◽  
Vol 26 (1) ◽  
pp. 251-256 ◽  
Author(s):  
Lewis T. Milliken
Keyword(s):  
Carbon Tetrachloride ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
Oxidation Process ◽  
Aqueous Suspension ◽  
Wet Oxidation ◽  
Acid Extract ◽  
Organic Solution ◽  
Determination Of Copper

Abstract A procedure is recommended in which small amounts of copper in rubber can be measured quantitatively by determining the depth of color of a copper carbamate complex in a carbon tetrachloride solution. The complex is formed in an alkaline solution prepared from an acid extract of the rubber ashed at 550° C. This procedure yields results which are as reliable as those obtained by the more tedious and time-consuming procedures involving the wet-oxidation process which are at present recommended by standardizing organizations. The use of an organic solution rather than an aqueous suspension gives better reproducibility, permits easier use of a photometer, and reduces the interference due to iron by a factor of ten.

Analysis of Tire Tread Rubbers by Gas Chromatography

1969 ◽  
Vol 42 (5) ◽  
pp. 1350-1365
Author(s):  
E. A. Ney ◽  
A. B. Heath
Keyword(s):  
Gas Chromatography ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
Decomposition Products ◽  
Percentage Ratio

Abstract A method is presented which allows the simultaneous quantitative determination of natural rubber, polybutadiene and SBR in tire components. The method consists in pyrolyzing samples of cured and filled ternary rubber mixtures at 450°–550° C and subjecting the decomposition products to programmed gas chromatography. The quantities of dipentene, vinyl cyclohexene, and styrene formed during pyrolysis are then used to determine the percentage ratio of natural rubber, polybutadiene and SBR in the vulcanizate.

Measurement of Refractive Index of Elastomers

1952 ◽  
Vol 25 (3) ◽  
pp. 693-699 ◽  
Author(s):  
Aurelia Arnold ◽  
Irving Madorsky ◽  
Lawrence A. Wood
Keyword(s):  
Refractive Index ◽  
Standard Deviation ◽  
Natural Rubber ◽  
Light Source ◽  
Transition Temperatures ◽  
Incandescent Light ◽  
Synthetic Rubber ◽  
Second Order Transition ◽  
The Government

Abstract The measurement of the refractive index of elastomers is discussed, with particular reference to GR-S rubber and the use of an Abbé type of refractometer. Detailed descriptions of the apparatus used and the procedure for GR-S rubber are given. Common sources of error are discussed and methods of minimizing these errors are given. A detailed stady has been made of the precision obtainable with GR-S polymers using the Abbé type of refractometer with an incandescent light source. It was found that the standard deviation corresponding to variability of a single random determination was 0.00007. The method has been used for several years as the basis for the determination of bound styrene in copolymers of butadiene and styrene, and is currently employed for control purposes in the government-owned synthetic rubber plants. It has also been used for determining the percentage of rubber hydrocarbon in natural rubber and for locating second-order transition temperatures.

Quantitative determination of longitudinal and transverse cross-relaxation rates

1999 ◽  
Vol 96 (9/10) ◽  
pp. 1608-1615
Author(s):  
T. E. Malliavin ◽  
H. Desvaux ◽  
M. A. Delsuc
Keyword(s):  
Quantitative Determination ◽  
Cross Relaxation ◽  
Relaxation Rates
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