Identification of Natural and Synthetic Polyisoprene Vulcanizates by the Carbon-14 Dating Technique

1977 ◽  
Vol 50 (4) ◽  
pp. 819-827 ◽  
Author(s):  
H. Y. Chen
Keyword(s):  
Natural Rubber ◽  
Radiocarbon Dating ◽  
Radioactivity Measurement ◽  
Limited Data ◽  
Carbon 14 ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract The idea of using the radiocarbon dating technique for the differentiation of natural rubber from synthetic rubber is novel and has never been tested before experimentally. The experiments were designed to demonstrate the feasibility of the approach rather than to perfect the technique. With the limited data gathered here, it was shown that the radiocarbon dating technique furnishes results with accuracy quite satisfactory for the analysis of gum rubbers. For the cured samples, the accuracy is reduced mainly by the errors introduced from steps other than that of the radioactivity measurement. A further reduction of the accuracy results if the age of the natural rubber in the stock is not known. We conclude that the technique is feasible and yields results of an accuracy which is probably the best ever achieved by any known technique.

scholarly journals Historical and Recent Achievements in the Field of Microbial Degradation of Natural and Synthetic Rubber

2012 ◽  
Vol 78 (13) ◽  
pp. 4543-4551 ◽  
Author(s):  
Meral Yikmis ◽  
Alexander Steinbüchel
Keyword(s):  
Natural Rubber ◽  
Microbial Degradation ◽  
Environmental Biotechnology ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Key Enzymes ◽  
Degrading Bacterium ◽  
Synthetic Rubber ◽  
Natural And Synthetic

ABSTRACTThis review intends to provide an overview of historical and recent achievements in studies of microbial degradation of natural and synthetic rubber. The main scientific focus is on the key enzymes latex-clearing protein (Lcp) from the Gram-positiveStreptomycessp. strain K30 and rubber oxygenase A (RoxA) from the Gram-negativeXanthomonassp. strain 35Y, which has been hitherto the only known rubber-degrading bacterium that does not belong to the actinomycetes. We also emphasize the importance of knowledge of biodegradation in industrial and environmental biotechnology for waste natural rubber disposal.

Migration of Antioxidants and Accelerators in Natural and Synthetic Rubber II. Sulfenamide System Studies and Comparison of Age Resister Migration under Inert and Practical Conditions

1969 ◽  
Vol 42 (3) ◽  
pp. 892-902 ◽  
Author(s):  
James E. Lewis ◽  
Marvin L. Deviney ◽  
Lawrence E. Whittington
Keyword(s):  
Diffusion Coefficient ◽  
Carbon Black ◽  
Natural Rubber ◽  
Count Data ◽  
Diffusion Coefficients ◽  
Oil Migration ◽  
Carbon 14 ◽  
Synthetic Rubber ◽  
End Use ◽  
In Cis

Abstract Radiochemical techniques developed for studying extender oil migration in various elastomers have been adapted for use in investigating the migration of age resisters and curatives. This paper contains basic diffusion coefficient data for nine compounds including both staining and nonstaining antioxidants and members of the sulfenamide, thiazole and thiuram accelerator series. Techniques for synthesizing these age resisters and curatives in the carbon-14 and sulfur-35 labelled form are described. Migration was studied in natural rubber, SBR, cis-polybutadiene and EPT vulcanizates. Computer techniques were used to calculate diffusion coefficients from radiochemical count data. Results from preliminary migration studies under practical curing and end-use conditions are also presented. In the case of phenyl-2-naphthylamine migration in cis-polybutadiene, a pronounced decrease in diffusivity with increasing surface area of the carbon black filler was observed.

Natural and Synthetic Rubber. I. Products of the Destructive Distillation of Natural Rubber

1929 ◽  
Vol 2 (3) ◽  
pp. 441-451 ◽  
Author(s):  
Thomas Midgley ◽  
Albert L. Henne
Keyword(s):  
Experimental Data ◽  
Natural Rubber ◽  
Atmospheric Pressure ◽  
Experimental Results ◽  
Double Bonds ◽  
Synthetic Rubber ◽  
Single Bonds ◽  
Natural And Synthetic

Abstract Two hundred pounds of pale crepe rubber have been destructively-distilled at atmospheric pressure. The distillate was fractionated and its components identified from C5 to C10, as shown in the table. Assuming that the Staudinger formula is correct, that the single bonds furthest from the double bonds are the weaker spots and that the formation of six-carbon rings is favored, it has been shown that nearly all of the compounds actually isolated could be predicted. The experimental results, together with forthcoming experimental data, are expected to be used to throw light upon the formula of the rubber molecule.

Kinetic Analysis of Organic Halides. II. Analysis of Macromolecules Built up of Monohalide Units

1951 ◽  
Vol 24 (2) ◽  
pp. 436-446 ◽  
Author(s):  
G. Salomon ◽  
C. Koningsberger
Keyword(s):  
Natural Rubber ◽  
Kinetic Analysis ◽  
Vinyl Chloride ◽  
Physical Factors ◽  
Organic Bases ◽  
Synthetic Rubber ◽  
Organic Halides ◽  
First Time ◽  
Natural And Synthetic

Abstract A number of hydrochlorides of natural and synthetic rubbers and allied polymers have been prepared and subjected to kinetic analysis with organic bases. The hydrochlorides of natural rubber react at 100° C at a rate identical to that of low-molecular tertiary chlorides. At 50° C the reactivity of the polymer is, however, reduced by physical factors. The hydrochloride of GR-S (a synthetic rubber made from butadiene and styrene) has been prepared for the first time by heating the swollen polymer with HC1 under pressure. Kinetic analysis of this product revealed two fractions: the expected secondary chloride, and a small fraction of a very reactive (tertiary?) chloride. After elimination of experimental difficulties, we succeeded in the preparation and kinetic identification of the pure tertiary hydrobromide of natural rubber. Attempts to prepare the secondary bromide under peroxide conditions failed. Kinetic analysis of two types of Neoprene revealed the presence of a small quantity of allylic groups in the polymer, while 95 per cent of the chlorine in Neoprene has the expected stability of a vinyl chloride. This stability can be used for the identification of Neoprene.

Liquid guayule natural rubber, a renewable and crosslinkable processing aid in natural and synthetic rubber compounds

2020 ◽  
Vol 276 ◽  
pp. 122933
Author(s):  
Xianjie Ren ◽  
Cindy S. Barrera ◽  
Janice L. Tardiff ◽  
Andres Gil ◽  
Katrina Cornish
Keyword(s):  
Natural Rubber ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
Natural And Synthetic

Natural and Synthetic Rubber. XV. Oxygen in Rubber

1936 ◽  
Vol 9 (1) ◽  
pp. 74-82
Author(s):  
Thomas Midgley ◽  
A. L. Henne ◽  
A. F. Shepard ◽  
Mary W. Renoll
Keyword(s):  
Natural Rubber ◽  
Quantitative Data ◽  
Hydroxyl Group ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract It has been shown that natural rubber conthins oxygen, while synthetic rubber is oxygen free. This oxygen appears to be of an hydroxylic type, and its quantity corresponds to about one hydroxyl group for each one thousand isoprene units of the rubber molecule. Rubber has been allowed to oxidize and a mechanism is proposed to interpret the quantitative data recorded.

Effect of Temperature on Resilience of Natural and Synthetic Rubber

1943 ◽  
Vol 16 (4) ◽  
pp. 881-887
Author(s):  
H. C. Jones ◽  
E. G. Snyder
Keyword(s):  
Natural Rubber ◽  
Effect Of Temperature ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract The necessity of the substitution of synthetic elastomers for natural rubber has been forced on the rubber compounder by the exigencies of war. His background of a hundred years of research and compounding is his principal weapon for making this conversion in the shortest possible time. Too often he finds that this background fails and that practices invaluable in the development of natural rubber stocks are worthless in the case of synthetic rubber, or at least are subject to a different interpretation.

Lignin as a Compounding Ingredient for Natural Rubber

1957 ◽  
Vol 30 (2) ◽  
pp. 639-651 ◽  
Author(s):  
I. Sagajllo
Keyword(s):  
Natural Rubber ◽  
High Resistance ◽  
Pilot Plant ◽  
Test Results ◽  
Dry Powder ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
Pilot Plant Scale ◽  
Made In ◽  
Natural And Synthetic

Abstract Important claims have been made in recent years regarding the capacity of lignin to reinforce natural and synthetic rubber. In 1949 Dawson reviewed the literature on the use of lignin in rubber and drew particular attention to the work of Keilen and Pollak who had shown that in certain circumstances lignin could be considered to rival EPC black in its ability to yield strong GR-S vulcanizates with high resistance to tear. Raff and his coworkers subsequently showed that the reinforcement of GR-S by lignin is enhanced if the lignin, before coprecipitation with the latex, is subjected to oxidation; other workers studied the application of lignin to the reinforcement of different elastomers, the influence of coprecipitation conditions on the properties of the product, and the problem of overcoming the delaying effect of lignin on vulcanization of lignin-natural rubber coprecipitates. Keilen and Pollak in their experiments incorporated lignin into rubber by coprecipitation at the latex stage, but they indicated that similar results could be obtained if lignin “in the gelled state” was added to rubber by milling. No reinforcement was observed however when lignin was added to rubber as a dry powder. Lignin is potentially an abundant and cheap material which according to the above claims should extend the range of useful compounds available to rubber manufacturers. The present paper describes work undertaken to gain firsthand knowledge of the technique of coprecipitating lignin with natural rubber from preserved latex, to learn something about the properties of natural rubber compounds prepared from lignin coprecipitates, and to study possible ways of incorporating lignin into rubber by means other than coprecipitation. It also records test results for masterbatches prepared by the Rubber Research Institute of Malaya from fresh latex on a pilot plant scale.

Natural and Synthetic Rubber. VII. Fractional Precipitation of Natural Rubber

1931 ◽  
Vol 4 (4) ◽  
pp. 547-551
Author(s):  
Thomas Midgley ◽  
Albert L. Henne ◽  
Mary W. Renoll
Keyword(s):  
Natural Rubber ◽  
Fractional Precipitation ◽  
Synthetic Rubber ◽  
Alcohol Benzene ◽  
Natural And Synthetic

Abstract Temperature—concentration diagrams are given of the systems natural rubber—alcohol—benzene, pure rubber—alcohol—benzene and synthetic rubber—alcohol—benzene. A method based on these diagrams is given for the separation of nitrogen-free rubber hydrocarbon by fractional precipitation of natural rubber from a mixture of alcohol and benzene.

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