Determination of Hydroperoxides in Rubber and Synthetic Polymers

1947 ◽  
Vol 20 (1) ◽  
pp. 45-54
Author(s):  
H. A. Laitinen ◽  
J. S. Nelson
Keyword(s):  
Acid Solution ◽  
Ferrous Iron ◽  
Synthetic Polymers ◽  
Colorimetric Determination ◽  
Thiocyanate Complex ◽  
Styrene Copolymer ◽  
Ferric Thiocyanate ◽  
Ferric Salt ◽  
Butadiene Styrene

Abstract Ferrous iron has been used as a reagent for the determination of peroxide by numerous investigators. Yule and Wilson estimated peroxide in cracked gasoline by shaking with an acid solution of ferrous thiocyanate and back-titrating the resulting ferric salt with titanous chloride. The method was criticized by Young, Vogt, and Nieuwland, who used the color of the resulting ferric thiocyanate complex as a basis for a colorimetric determination of peroxide. In this procedure methanol was used as the solvent. Bolland, Sundralingam, Sutton and Tristram modified the method to enable rubber samples to be analyzed by changing the solvent to a mixture of benzene and methanol (73 per cent benzene by volume). For determining peroxide in GR-S (butadiene-styrene copolymer) and other butadiene copolymers it would be desirable to employ a solvent rich in benzene, since these polymers tend towards insolubility upon oxidation. A solvent composed largely of benzene would also improve the sensitivity of the determination, since larger quantities of polymer could be dissolved in a given volume of solvent.

Small Amounts of Copper in Dyes and Rubber Chemicals. Colorimetric Determination with Zinc Dibenzyldithiocarbamate

1953 ◽  
Vol 26 (1) ◽  
pp. 257-262
Author(s):  
R. I. Martens ◽  
R. E. Githens
Keyword(s):  
Carbon Tetrachloride ◽  
Acid Solution ◽  
Specific Method ◽  
Colorimetric Determination ◽  
Acid Solutions ◽  
Metallic Ions ◽  
Reagent Solution ◽  
Cent Solution ◽  
Dyed Fabrics

Abstract This work was undertaken to provide a more specific method for the routine determination of small amounts of copper in rubber chemicals, dyes, and dyed fabrics. A dithiocarbamate type of reagent—a 0.01 per cent solution of zinc dibenzyldithiocarbamate in carbon tetrachloride—will selectively extract copper from acid solutions containing relatively large amounts of most other metals. The method is accurate and reproducible to about 0.5 microgram in the range of 0.5 to 40 micrograms of copper. No precipitations or filtrations are required. The reagent is commercially available, the reagent solution and the color of the extracted copper dibenzyldithiocarbamate are stable, and the acid solution remaining after extraction may be used to determine other metals. Because copper dibenzyldithiocarbamate is selectively extracted from solutions containing relatively large amounts of many other metallic ions, the reagent may be used to determine small amounts of copper in metals and their salts.

Analytical Methods in Rubber Chemistry. (IV) The Determination of Peroxidic Oxygen

1942 ◽  
Vol 15 (1) ◽  
pp. 72-74 ◽  
Author(s):  
J. L. Bolland ◽  
A. Sundralingam ◽  
D. A. Sutton ◽  
G. R. Tristram
Keyword(s):  
Acid Solution ◽  
Potassium Iodide ◽  
Analytical Methods ◽  
Stannous Chloride ◽  
Colorimetric Method ◽  
Modified Technique ◽  
Ferric Salt ◽  
Effective Contact ◽  
Analytical Reagent

Abstract In the previous publication, of Farmer, Tristram and Bolland, it was stated that methods were required to estimate the various forms in which oxygen occurs united to the rubber molecule, and a method for the estimation of hydroxyl oxygen was discussed. The determination of peroxidic oxygen in oxidized rubber presents two distinct problems. It is necessary to employ a method which, first, is satisfactory in the presence of unsaturation and, secondly, ensures effective contact between the long rubber chains and the analytical reagent. These requirements are both satisfied by the modification described below of the colorimetric method of Young, Vogt and Nieuwland. Before describing the modified technique, some mention must be made of the earlier methods and of the errors which arise when they are applied to the determination of peroxidic oxygen in unsaturated compounds. All the earlier methods for the determination of peroxidic oxygen depend on the oxidation of potassium iodide and titration of the liberated iodine. This method is open to the objection that the liberated iodine immediately attacks the double bonds remaining in the oxidized material. This difficulty was recognized by Stephens, who, using a method in which the peroxidic oxygen was reduced with stannous chloride, succeeded in estimating about 80 per cent of the total peroxide present in cyclohexene peroxide. Yule and Wilson estimated the peroxide in cracked gasoline by shaking with an acid solution of ferrous thiocyanate and back-titrating the resulting ferric salt with titanous chloride. The results were later contested by Young, Vogt and Nieuwland, who described the colorimetric method which has been adopted, with some modification, in the present work.

31. The Determination of Copper and Iron in Dairy Products

1931 ◽  
Vol 3 (1-2) ◽  
pp. 93-100 ◽  
Author(s):  
W. Williams
Keyword(s):  
Dairy Products ◽  
Colorimetric Determination ◽  
Ferric Thiocyanate ◽  
Iron Contamination ◽  
Wet Ashing ◽  
High Degree ◽  
Very High ◽  
Determination Of Copper ◽  
Colorimetric Methods

1. Two colorimetric methods for determination of copper have been described, viz. the xanthate and the sodium diethyl-dithio-carbamate. Both methods have given satisfactory results but the carbamate method has proved to be more sensitive and less liable to error from possible contamination than the xanthate method.2. The colorimetric determination of iron by the modification of the ferric thiocyanate method has been proved to give a very high degree of accuracy and excellent results have been obtained.3. A method of wet ashing has been described whereby organic matter is oxidised by the use of concentrated sulphuric acid and sodium nitrate and copper and iron extracted from the fat.4. A number of results are given showing the amount of copper and iron contamination that the cream is subjected to during the course of butter manufacture, and the distribution of copper and iron in the cream, butter and buttermilk.

scholarly journals Assessment of the viscoelastic properties of modified bitumens containing styrene-butadiene-styrene copolymer

2015 ◽  
Vol 10 (4) ◽  
pp. 299-308 ◽  
Author(s):  
Mieczysław Słowik
Keyword(s):  
Tensile Test ◽  
Elastic Recovery ◽  
Asphalt Binders ◽  
Modified Bitumen ◽  
Styrene Copolymer ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Temperature Susceptibility ◽  
Butadiene Styrene

The viscoelastic behaviour of styrene-butadiene-styrene copolymer modified asphalt binders during tensile test and inverse creep test (retarded strain recovery after unloading) has been analysed in the presented paper. Laboratory tests have been conducted on two specimens of road bitumen: 20/30 and 50/70 penetration grade, which have been subjected to modification with the additive of 9% concentrate of SBS elastomer modified bitumen. When the two were mixed, the samples of polymer modified binders containing 3% or 6% by mass of the SBS elastomer were obtained. Force-ductility (tensile) test that has been followed by the extended procedure for the determination of elastic recovery, has been used as the research method. The results of the study have showed a significant improvement of the effect of modifications on the elastic properties and the temperature susceptibility reduction obtained only in the case of binders, where the polymer constitutes a dispersing phase forming a continuous network throughout the bitumen. Moreover, the temperature susceptibility coefficients, defined on the basis of the tensile test results, have been proposed as an alternative or extension to the previously widely used parameter, the Penetration Index.

scholarly journals Original Research Article Investigation of Antioxidant Potential in Ocimum basilicum Flower

2021 ◽  
pp. 56-64
Author(s):  
Sadaf Khurshid Kayani
Keyword(s):  
Antioxidant Capacity ◽  
Column Chromatography ◽  
Antioxidant Properties ◽  
Ocimum Basilicum ◽  
Original Research ◽  
Thiocyanate Complex ◽  
Dark Bottle ◽  
Phenolic Contents ◽  
Ferric Thiocyanate

Aims: The present work is particularly focused on antioxidant properties of flower of Ocimum basilicum plant. Study Design: Study is basically designed on Column chromatography of extracts. Place and Duration of Study: Sample collection and all experimental work was done in Chemistry Department Government College University, Lahore. The study comprises duration of 6 months. Methodology: The flower of Ocimum basilicum were collected, dried and grinded. It was soaked in methanol-water (70:30) in dark bottle for a week. Followed by a scheme (column chromatography). After TLC of extracts, three activities were done. Phosphomolybdate, Ferric thiocyanate (FTC), and Folin-Ciocalteu (FC reagent) for determination of antioxidant capacity, peroxidation, determination of total phenols respectively. Results: The sample OC2 and crude have maximum absorbance at the concentration of 100µl, 200µl and 300µl. The results show that crude has maximum antioxidant capacity. The phenolic contents are in the increasing order of fraction OC2, OC5, and crude. The maximum phenolic contents are present in crude. Reference has the maximum ability for peroxidation for ferric thiocyanate complex by giving red colour. Conclusion: Overall it is concluded that Ocimum basilicum flower has antioxidant capacity as good as a standard antioxidant. It is recommended in food/medicine as natural herbal product.

Sign in / Sign up

Export Citation Format

Share Document