A New Method for the Direct Determination of Rubber. A Preliminary Communication

1938 ◽  
Vol 11 (2) ◽  
pp. 438-438
Author(s):  
E. Kheraskova ◽  
E. Korsunskaya
Keyword(s):  
Acetic Acid ◽  
Natural Rubber ◽  
Direct Determination ◽  
Methyl Groups ◽  
Butadiene Rubber ◽  
Double Bonds ◽  
Synthetic Rubber ◽  
Oxidation Of Organic Compounds ◽  
Preliminary Communication

Abstract The conventional methods for the direct determination of rubber cannot be used for determining natural rubber in the presence of sodium-butadiene rubber. These methods are based either on precipitation of the rubber from solution or on the determination, by one method or another, of the double bonds in the rubber molecule. Since natural rubber and synthetic rubber differ in their solubilities but little, the method of precipitation obviously cannot be used for their separation. Nor are methods which involve determining the double bonds adequate to distinguish them, because both kinds of rubber are unsaturated compounds. It was therefore of interest to develop a method of analysis based on the determination of the methyl groups, which are present only in the natural rubber molecule. Kuhn and L'Orsa (Z. angew. Chem., 44, 847 (1931)) have shown that, in the oxidation of organic compounds, a methyl group connected with a carbon atom is partially oxidized to acetic acid. The object was to develop this reaction into a method of rubber analysis by establishing the optimum conditions for the quantitative oxidation to acetic acid of all the methyl groups in the rubber hydrocarbon.

The Determination of Unsaturation in Butadiene Synthetic Rubber

1948 ◽  
Vol 21 (4) ◽  
pp. 830-834
Author(s):  
P. P. Kobeko ◽  
E. K. Moskvina
Keyword(s):  
Carbon Tetrachloride ◽  
Natural Rubber ◽  
Carbon Disulfide ◽  
Addition Product ◽  
Butadiene Rubber ◽  
Synthetic Rubber ◽  
Iodine Chloride ◽  
Hydrolysis Of

Abstract 1. It has been found that synthetic rubber does not precipitate from a solution of dichloromethane by the addition of Wijs reagent, whereas natural rubber does precipitate under the same conditions. The reverse relation occurs with carbon disulfide as solvent. 2. A method has been developed for the determination of the unsaturation of butadiene rubber in solution in dichloromethane by the use of Wijs reagent. 3. It has been demonstrated that, by the use of a solution of iodine chloride in carbon tetrachloride, the reaction with rubber is complicated by the hydrolysis of iodine chloride during titration, but not by the substitution of hydrogen by halogen nor by the hydrolysis of the rubber-halogen addition product. 4. The possibility of obtaining accurate values for unsaturation by a calculation of this hydrolysis is demonstrated. 5. Two methods have been developed for the determination of the unsaturation of natural and butadiene rubbers.

Direct determination of trace amounts of acetic acid using a novel ambient glow discharge ion source

2010 ◽  
Vol 21 (10) ◽  
pp. 1219-1222 ◽  
Author(s):  
Xiao Hao Wang ◽  
Kun Liu ◽  
Fei Tang ◽  
Jiu Ming He ◽  
Xue Ye Wei ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Glow Discharge ◽  
Direct Determination ◽  
Ion Source

Chlorinated Isoprene Rubbers in Adhesive Composites

2017 ◽  
Vol 44 (5) ◽  
pp. 25-28 ◽  
Author(s):  
A.A. Zuev ◽  
L.R. Lyusova ◽  
N.P. Boreiko
Keyword(s):  
Natural Rubber ◽  
Scientific Research ◽  
Scientific Research Institute ◽  
Physicomechanical Properties ◽  
Butadiene Rubber ◽  
Technological Factors ◽  
Nitrile Butadiene Rubber ◽  
Synthetic Rubber ◽  
Adhesive Materials ◽  
Isoprene Rubber

Now there is not a single area of industry that can do without adhesive elastomer materials. Composites based on synthetic rubbers comprise 75% of the total volume of adhesive materials produced, which is due to the combination of unique properties typical of the elastomer base of the adhesive. The base of many imported adhesives for the bonding of rubber to metal is chlorinated natural rubber. As an alternative, chlorinated synthetic isoprene rubber has been proposed, developed at the Scientific Research Institute for Synthetic Rubber in St Petersburg. The chlorinated isoprene rubber was compared with imported chlorinated natural rubber in adhesive composites, and the physicomechanical properties of mixes based on a blend of chlorinated rubber and nitrile butadiene rubber were investigated. The investigation was conducted on chlorinated natural rubber of grade Pergut S20, chlorinated isoprene rubber SKI-3, and nitrile butadiene rubbers of grades BNKS-28AMN and SKN-26S. The influence of the ratio of chlorinated rubber to nitrile butadiene rubber and the technological factors of mix preparation on the properties of films produced from them was established. It was shown that, in terms of the level of properties, home-produced chlorinated rubber can be used as the base for adhesives for hot bonding of rubber to metal instead of imported Pergut S20.

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.

A Direct Determination of Rubber Hydrocarbon. Chromic Acid Oxidation Method

1943 ◽  
Vol 16 (3) ◽  
pp. 660-667 ◽  
Author(s):  
V. L. Burger ◽  
W. E. Donaldson ◽  
J. A. Baty
Keyword(s):  
Acetic Acid ◽  
Chromic Acid ◽  
Direct Determination ◽  
Acid Oxidation ◽  
Laboratory Procedure ◽  
Oxidation Method ◽  
Chromic Acid Oxidation

Abstract A method for the direct determination of rubber is reported. This method utilizes the property of rubber hydrocarbon when oxidized by chromic acid to form definite and reproducible amounts of acetic acid. This determination has been reduced to a comparatively simple laboratory procedure, whose accuracy (in the absence of interferences) is 1 to 2 per cent.

Apparatus for the Direct Determination of the Dynamic Bulk Modulus

1957 ◽  
Vol 30 (2) ◽  
pp. 449-459
Author(s):  
J. E. McKinney ◽  
S. Edelman ◽  
R. S. Marvin
Keyword(s):  
Natural Rubber ◽  
Bulk Modulus ◽  
Direct Measurement ◽  
Static Pressure ◽  
Direct Determination ◽  
Preliminary Evaluation ◽  
Air Bubbles ◽  
Frequency Range ◽  
Piezoelectric Crystals

Abstract An apparatus has been developed for the direct measurement of the real and imaginary parts of the dynamic bulk modulus of solid and liquid materials over the frequency range of 50 to 10,000 cps. Piezoelectric crystals serving as driver and detector, together with the sample and a confining liquid, are contained in a cavity small compared with the wavelength of sound at these frequencies. Static pressure is superposed to eliminate the effect of small air bubbles. The complex compliances of the sample, confining liquid, and the cavity, are additive in this region, where the compliance is pure dilatation. The dynamic compliances of several natural rubber-sulfur mixtures were obtained in a preliminary evaluation of the behavior of the apparatus.

The Ozonization of Unsaturated Compounds. III. The Addition of Ozone to Internal and External Double Bonds in Butadiene Rubber

1959 ◽  
Vol 32 (1) ◽  
pp. 284-287 ◽  
Author(s):  
A. I. Yakubchik ◽  
N. G. Kasatkina ◽  
T. E. Pavlovskaya
Keyword(s):  
Quantitative Determination ◽  
Butadiene Rubber ◽  
Double Bonds ◽  
Ozone Absorption ◽  
Unsaturated Compounds

Abstract 1. It was established that the curves of ozone absorption by butadiene rubbers do not show breaks. 2. Sodium butadiene rubber was ozonized 25, 50, 75 and 100%. From the quantitative determination of the external double bonds which add ozone it was established that there is no strict selectivity in the ozonization of the double bonds of rubber: the external double bonds are ozonized more rapidly than the internal and their ozonization is completed earlier than the ozonization of the internal double bonds.

Stereochemistry of isopentenyl pyrophosphate isomerase

1972 ◽  
Vol 182 (1068) ◽  
pp. 277-295 ◽  
Keyword(s):  
Acetic Acid ◽  
Deuterium Oxide ◽  
Mevalonic Acid ◽  
Methyl Groups ◽  
Farnesyl Pyrophosphate ◽  
Soluble Enzyme ◽  
Pig Liver ◽  
Isopentenyl Pyrophosphate ◽  
Prototropic Isomerization ◽  
Preliminary Communication

Mevalonic acid stereospecifically labelled with tritium in the 2-position was incubated, in a deuterium oxide medium containing adenosine triphosphate, with a soluble enzyme pre­paration from pig liver; and so converted into farnesyl pyrophosphate. This was hydrolysed enzymically to farnesol which was oxidized, by ozone followed by sodium hypoiodite, to acetic acid originating from the terminal isopropylidene group of farnesol. The tritium in this acetic acid was found, on analysis by a recently developed enzymic method, to be present largely in chiral methyl groups the chirality of which was R or S according to the chirality at C-2 of the parent mevalonic acid. It is deduced that these chiral methyl groups were formed on the enzyme isopentenyl pyrophosphate isomerase, by addition of a deuteron from the medium to the 3 re , 4 re face of the double bond in isopentenyl pyrophosphate. The stereo­chemical relationship between the added and abstracted hydrogen in the prototropic isomerization mediated by this enzyme is thereby established. A preliminary communication of these results has been made (Clifford, Cornforth, Mallaby & Phillips 1971).

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.

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