Determination of Sulfur in Rubber Compounds: I. Precipitation of Barium Sulfate in the Presence of Picric Acid

1936 ◽  
Vol 8 (3) ◽  
pp. 176-178 ◽  
Author(s):  
C. Herbert Lindsly
Keyword(s):  
Barium Sulfate ◽  
Picric Acid ◽  
Rubber Compounds

Determination of Sulfur in Rubber Compounds. I. Precipitation of Barium Sulfate in the Presence of Picric Acid

1936 ◽  
Vol 9 (4) ◽  
pp. 648-660
Author(s):  
C. Herbert Lindsly
Keyword(s):  
Barium Sulfate ◽  
General Procedure ◽  
Picric Acid ◽  
Barium Chloride ◽  
Sulfate Solution ◽  
Rubber Compounds ◽  
Precipitation Procedure ◽  
Barium Chloride Solution ◽  
Made In

Abstract THERE is probably no single operation in analytical chemistry that has received more attention from investigators than that of precipitation of barium sulfate by means of a soluble barium salt for the determination of sulfate or of barium. The literature on this subject is voluminous and the conclusions reached by different investigators as to the proper procedure to employ in order to obtain a precipitate which will be filterable and reasonably pure are highly contradictory. The procedure which seems to be in most general use at present for the determination of sulfate is that of adding the barium chloride solution to the hot sulfate solution very slowly, stirring vigorously meanwhile, then allowing the whole to digest at an elevated temperature for several hours before filtering. The diversity of opinion as to the proper procedure arises, the author believes, from the fact that the barium sulfate precipitate is exceedingly sensitive to its environment and that a very slight change in the amount or kind of impurities present in the solutions during precipitation has a profound effect upon the crystal size and shape of the precipitated particles as well as upon their purity. Kolthoff and Vogelenzang (2) have stated that it is impossible to prescribe a general procedure for the accurate precipitation of sulfate in arbitrary mixtures. In other words, a precipitation procedure which gives satisfactory results in the determination of sulfur in copper ores, for instance, may not yield a satisfactory precipitate when applied to the determination of total sulfur in hard rubber dust, and a study of each type of determination, with due consideration for the amount and kind of impurities present, must be made in order to find the conditions necessary to obtain a precipitate which is pure and easily filterable.

Determination of Combined and Second Order Factor Effects for Simultaneous Optimization of Physical and Mechanical Properties of NR/BR Blend System

2014 ◽  
Vol 42 (4) ◽  
pp. 290-304
Author(s):  
Rajarajan Aiyengar ◽  
Jyoti Divecha
Keyword(s):  
Physical And Mechanical Properties ◽  
Second Order ◽  
Simultaneous Optimization ◽  
Order Effects ◽  
Elongation At Break ◽  
Five Factors ◽  
Rubber Compounds ◽  
Polybutadiene Rubber ◽  
Contour Plots

ABSTRACT The blends of natural rubber (NR), polybutadiene rubber (BR), and other forms of rubbers are widely used for enhancing the mechanical and physical properties of rubber compounds. Lots of work has been done in conditioning and mixing of NR/BR blends to improve the properties of its rubber compounds and end products such as tire tread. This article employs response surface methodology designed experiments in five factors; high abrasion furnace carbon black (N 330), aromatic oil, NR/BR ratio, sulfur, and N-oxydiethylene-2-benzothiazole sulfenamide for determination of combined and second order effects of the significant factors leading to simultaneous optimization of the NR/BR blend system. One of the overall optimum of eight properties existed at carbon 44 phr, oil 6.1 phr, NR/BR 78/22 phr with the following values of properties: tensile strength (22 MPa), elongation at break (528%), tear resistance (30 kg/mm), rebound resilience (67%), moderate hardness (68 International rubber hardness degrees) with low heat buildup (17 °C), permanent set (12%), and abrasion loss (57 mm3). More optimum combinations can easily be determined from the NR/BR blend system models contour plots.

Applications of Thermal Analytical Procedures in the Study of Elastomers and Elastomer Systems

1980 ◽  
Vol 53 (3) ◽  
pp. 437-511 ◽  
Author(s):  
D. W. Brazier
Keyword(s):  
Thermal Analysis ◽  
Dynamic Properties ◽  
Evolved Gas Analysis ◽  
Gas Analysis ◽  
International Standards ◽  
New Technique ◽  
Heating Rates ◽  
Single Experiment ◽  
Rubber Compounds

Abstract An attempt has been made to review the development of thermoanalytical procedures as they have been applied to elastomers and elastomer systems over the past 10 years. For all rubber industry products, temperature and its effects, either alone or in conjunction with the chemical environment, play an important role from the production stage through to the final failure of the product in the field. It is thus not surprising that thermal analysis, in which temperature is the prime variable, has found such diverse applications in elastomer studies. The identification and quantitative analysis of rubber formulations have received most attention. Such formulations produce characteristic “fingerprints” when studied in DTA, DSC, TG, or TMA. In DSC, the determination of the glass transition characteristics, the observation and determination of crystallinity, the detection of cyclization reactions, and the monitoring of thermal and oxidative degradation characteristics can all be observed in a single experiment covering the temperature range from −150 to +600°C. At normal heating rates, e.g., 20°C/min, such information is available in 40 min. TG/DTG analysis can yield the elastomer or elastomers content, oil and plasticizer, carbon black (level and often type), and inorganic ash in less than 60 min. Processing and curing can also be studied. Blend compatibility can be assessed on the basis of both Tg and crystallinity measurements and the data used to determine optimum mixing times. Sulfur vulcanization and peroxide curing of elastomers is readily monitored by DSC and can be used for confirmation analysis of the presence of curatives. Limitations in such analysis exist, but as understanding and ability to interpret cure exotherms increase, valuable information about the mechanism and the nature of the cured network will be obtained. The testing of rubber compounds involves many hours of labor by current procedures. The rapidity of thermal analysis promises to offer some relief. In addition to DSC and TG, TMA, a relatively new technique, offers a rapid approach to low-temperature testing. Dynamic mechanical analysis (DMA) offers a rapid route to determining dynamic properties, but as yet, relatively little has been published on the application of this new technique to elastomers. As environmental concern increases, techniques such as evolved gas analysis (EGA) and combined techniques such as TG/gas chromatography are predicted to play an important role. As for the future, it is readily apparent that the principles of the methods have been established and, in several cases, it now remains to reduce them to a practical level. In some areas, such as vulcanization studies, much remains to be undertaken to improve our interpretive skills. Although there is some indication that certain industries have produced “in-house” standards for the analysis of rubber compounds by DSC and TG/DTG, it will only be when national and international standards organizations study and produce standard procedures, that the techniques will be generally adopted. Maurer's prediction in 1969 of increased applications of DTA and TG in elastomer studies has undoubtedly proved correct, and with the proliferation of reliable commercial instrumentation, significant developments can be anticipated in the next decade.

Strongly fluorescent cysteamine-coated copper nanoclusters as a fluorescent probe for determination of picric acid

2018 ◽  
Vol 185 (11) ◽  
Author(s):  
Zhijun Bao ◽  
Kui Zhang ◽  
Jingyi Jian ◽  
Ziwei Hu ◽  
Kaisong Yuan ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Picric Acid ◽  
Copper Nanoclusters

Automated Determination of Urinary Inorganic Sulfates with the "AutoAnalyzer"

1971 ◽  
Vol 17 (12) ◽  
pp. 1183-1185 ◽  
Author(s):  
J P Dieu
Keyword(s):  
Barium Sulfate ◽  
Sampling Rate ◽  
Turbidimetric Method ◽  
Automated Determination

Abstract A turbidimetric method for inorganic sulfates in urine, based on the precipitation of barium sulfate, is adapted to the AutoAnalyzer. Coating of the flowcell with BaSO4 is avoided by an inter-sample air rinsing. Sampling rate is 40/h.

Ion-Exchange Paper—X-Ray Emission Procedure for Determination of Microgram Quantities of Mercury

1964 ◽  
Vol 47 (2) ◽  
pp. 391-394
Author(s):  
William B Link ◽  
Keith S Heine ◽  
J H Jones ◽  
Percy Wattlington
Keyword(s):  
Zinc Oxide ◽  
Titanium Dioxide ◽  
Emission Spectroscopy ◽  
Barium Sulfate ◽  
Magnesium Stearate ◽  
Magnesium Carbonate ◽  
Acid Solutions ◽  
X Ray ◽  
Aqueous Acid

Abstract A method has been developed for determining 1 μg of mercury in 100 ml of aqueous acid solution with a precision of ± 0.25 μg. In the method, the mercury is adsorbed by anion resinloaded paper and determined by X-ray emission spectroscopy. The method gave 75—125% recoveries of 1 μg of mercury from acid solutions containing 10 g of sodium sulfate, sodium chloride, iron oxide, magnesium carbonate, and calcium carbonate, and satisfactory recoveries from the HCl extract of carbon, barium sulfate, chromic oxide, bentonite, kaolin, talc, titanium dioxide, and magnesium stearate. Substantial changes in flow rate or acid concentration seem to have little effect on mercury absorption from HC1 solution. Mercury in zinc oxide or bismuth oxychloride cannot be determined by this technique.

Sign in / Sign up

Export Citation Format

Share Document