Elemental Sulfur as a Plasticizer for Polysulfide Polymers and Other Polymers

1966 ◽  
Vol 39 (4) ◽  
pp. 1030-1040
Author(s):  
A. V. Tobolsky ◽  
N. Takahashi
Keyword(s):  
Mechanical Properties ◽  
Specific Volume ◽  
Elemental Sulfur ◽  
Preliminary Information ◽  
Quantitative Extraction ◽  
Metastable Condition ◽  
Molten Sulfur ◽  
Liquid Condition ◽  
Polysulfide Polymers ◽  
Elemental Form

Abstract So-called elastic sulfur obtained by quick-quenching molten sulfur from a temperature of 250° C to a temperature of about −10° C is really a mixture of polymeric sulfur and monomeric S8 sulfur, the latter in a metastable condition, Quick-quenched sulfur is elastic because of the plasticizing effect of the liquid S8 sulfur on the polymeric sulfur. In this publication we show that large concentrations of S8 can exist dissolved in a liquid condition in other polymers where it also acts as a plasticizer. In many cases these compositions appear completely stable, i.e., there is no tendency for the dissolved sulfur to crystallize out. The best example is crosslinked polyethylene tetrasulfide polymers. These polymers can retain 40 per cent of dissolved sulfur in the form of liquid S8 over indefinitely long periods of time. We prove that the sulfur is in its elemental form by quantitative extraction with CS2. The specific volume of the dissolved sulfur shows it is in a liquid condition. The mechanical properties of the sulfur plasticized crosslinked polymers are just what would be expected from this type of structure. Preliminary information concerning sulfur in other polymers is presented.

Reinforcement of Natural Rubber with Silanized Precipitated Silica Nanofiller

2005 ◽  
Vol 78 (5) ◽  
pp. 793-805 ◽  
Author(s):  
A. Ansarifar ◽  
N. Ibrahim ◽  
M. Bennett
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Zinc Oxide ◽  
Reaction Mechanism ◽  
Energy Density ◽  
Natural Rubber ◽  
Elemental Sulfur ◽  
Stored Energy ◽  
Tear Strength ◽  
Precipitated Silica

Abstract The effect of a large amount of precipitated amorphous white silica nanofiller, pre-treated with bis[3-triethoxysilylpropyl-)tetrasulfide (TESPT), on the mechanical properties of a sulfur-cured natural rubber (NR) was studied. TESPT chemically adheres silica to rubber and also prevents silica from interfering with the reaction mechanism of sulfur-cure. The silica particles were fully dispersed in the rubber, which was cured primarily by using sulfur in TESPT, or, by adding a small amount of elemental sulfur to the cure system. The cure was also optimized by incorporating sulphenamide accelerator and zinc oxide into the rubber. The hardness, tear strength, tensile strength, and stored energy density at break of the vulcanizate were substantially improved when the filler was added. Interestingly, these properties were also enhanced when the rubber was cured primarily by using sulfur in TESPT.

Quantitative extraction and determination of elemental sulfur and stoichiometric oxidation of sulfide to elemental sulfur by Thiobacillus thiooxidans

1993 ◽  
Vol 39 (12) ◽  
pp. 1166-1168 ◽  
Author(s):  
C. W. Chan ◽  
Isamu Suzuki
Keyword(s):  
Quantitative Analysis ◽  
Biological System ◽  
Analytical Method ◽  
Elemental Sulfur ◽  
Sulfide Oxidation ◽  
Thiobacillus Thiooxidans ◽  
Color Formation ◽  
Ferric Thiocyanate ◽  
Quantitative Extraction

A sensitive and quantitative analytical method for determining elemental sulfur in a biological system was developed. Elemental sulfur was determined after extraction with petroleum ether by cyanolysis and ferric thiocyanate color formation in acetone. The method was successfully applied to show that sulfide was oxidized by Thiobacillus thiooxidans to elemental sulfur nearly stoichiometrically when further oxidation of elemental sulfur was inhibited by N-ethylmaleimide.Key words: elemental sulfur, quantitative analysis, sulfide oxidation, Thiobacillus thiooxidans.

scholarly journals Sulfur/Organic Copolymers as Curing Agents for Rubber

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 870 ◽  
Author(s):  
Jakub Wręczycki ◽  
Dariusz Bieliński ◽  
Rafał Anyszka
Keyword(s):  
Mechanical Properties ◽  
Crosslink Density ◽  
Elemental Sulfur ◽  
Freezing Point ◽  
Petroleum Industry ◽  
Polymeric Materials ◽  
Mechanical Analysis ◽  
Radical Copolymerization ◽  
Scanning Calorimetry ◽  
Free Radical Copolymerization

It is widely acknowledged that waste sulfur generated from the petroleum industry creates huge storage and ecological problems. Therefore, the various methods of utilization are becoming increasingly attractive research topics worldwide. The thermal ability of elemental sulfur to homolytic cleavage of S8 rings enables its free radical copolymerization with unsaturated organic species and the obtaining of chemically stable polymeric materials. Here we report a novel possibility to use sulfur/organic copolymers obtained via “inverse vulcanization” as curatives for rubber. For this purpose, several various sulfur/organic copolymers were synthesized and analyzed from the point of view of their performance as rubber crosslinking agents. Solvent extraction was used to purify sulfur/organic copolymers from unreacted (elemental) sulfur. Thermal properties of the prepared copolymers were characterized by thermogravimetric analysis and differential scanning calorimetry (TGA–DSC). Crosslink density and structure of cured elastomers was studied by equilibrium swelling, thiol-amine analysis and freezing point depression. Mechanical properties of the vulcanizates were determined under static and dynamic conditions (DMA—dynamic mechanical analysis). It is proved that the utilization of sulfur/organic copolymers as curatives enables an effective crosslinking process of rubbers. Taking into account the results of a crosslink density analysis and mechanical properties of the vulcanizates cured with purified copolymers, it is evident that relatively long copolymer macromolecules are also involved in the formation of chemical bonds between unsaturated rubber macromolecules.

Detection of Reactive Sulfur Molecules (S6, S7, S9, S∞) in Commercial Sulfur, in Sulfur Minerals, and in Sulfur Melts Slowly Cooled to 20 °C [1].

1988 ◽  
Vol 43 (5) ◽  
pp. 581-589 ◽  
Author(s):  
Ralf Steudel ◽  
Birger Holz
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Liquid Chromatography ◽  
Quantitative Analysis ◽  
High Pressure Liquid Chromatography ◽  
Solid Solutions ◽  
Elemental Sulfur ◽  
Surface Composition ◽  
Pale Yellow ◽  
Gaseous Sulfur

Abstract Quantitative analysis by high-pressure liquid chromatography shows that all commercial samples of elemental sulfur besides S8 contain traces of S7 (up to 0.56%) and in some cases also S6, S9 , and polymeric sulfur (S∞). Pure S8 can be obtained by recrystallization from CS2 . Elemental sulfur minerals also quite often contain traces of S7 (up to 0.3%). Since neither irradiation by daylight at 20 °C nor heating to 90 °C for 41 days did convert α-S8 into S7 , the reactive sulfur molecules Sn (n≠8) are believed to origin from liquid or gaseous sulfur which are known to be complex equilibrium mixtures of many Sn species. Sulfur melts slowly cooled (within 0.6 to 145 h) from 122 to 20 °C in fact contain S7 (minimum 0.2%) and at cooling rates of <24 h also other non-S8 molecules. Solid solutions of S7 in α-S8 have also been prepared by cocrystallization of the compounds from CS2. In contrast to pure α-S8, these solid solutions are pale-yellow at 77 K, and the implications of these findings for the surface composition of Jupiter’s satellite Io and for the mechanical properties of “formed sulfur” (Prills, Rotoform, Slates, etc.) are discussed.

scholarly journals Theoretical and experimental study of the effect of wollastonite on the physical and mechanical properties of concrete

2021 ◽  
Vol 2094 (2) ◽  
pp. 022077
Author(s):  
S S Dobrosmyslov ◽  
A S Voronin ◽  
Y V Fadeev ◽  
I G Endzhievskaya ◽  
S V Khartov
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Specific Volume ◽  
Mechanical Characteristics ◽  
Bending Strength ◽  
Theoretical Study ◽  
Chemical Interaction ◽  
Physical And Mechanical Properties ◽  
Internal Stresses ◽  
Physical And Mechanical Characteristics

Abstract As part of the work, an experimental and theoretical study of the effect of adding wollastonite on the physical and mechanical characteristics of concrete was carried out. The internal stress was calculated according to Hooke’s law. The change in the specific volume was determined from the change in the volume of the hydrated phase. The calculation of the chemical interaction was carried out within the framework of thermodynamic equilibrium. According to the results of the work, it was shown that the addition of wollastonite leads to a linear decrease in the value of internal stresses, which is consistent with experimental results on the increase in compressive and bending strength.

scholarly journals Исследование свойств конструкционных материалов методом инструментального индентирования с помощью портативного нанотвердомера

2020 ◽  
Vol 13 (1) ◽  
pp. 66-73
Author(s):  
А.С. Усейнов ◽  
А.А. Русаков ◽  
В.И. Яковлев ◽  
Е.В. Гладких
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Ability To Work ◽  
Standard Samples ◽  
Gas Industry ◽  
Solid Polymers ◽  
Preliminary Information ◽  
Instrumental Indentation

A modification of the "NanoScan-4 D" nanohardness meter, which allows of measuring the mechanical properties of articles by the instrumental indentation according to GOST R8.748-2011 under conditions close to industrial fabrication, has been developed. The main advantage of the described device, unlike most modern portable hardness testers, is the ability to work with a wide class of materials (from metals to solid polymers) since the study of the mechanical properties of products does not require preliminary information on the elastic modulus of the material being tested. Presented are the experimental data obtained on standard samples of the enterprise: polycarbonate and aluminum, as well as on various metal articles used as parts of machines and mechanisms of the oil and gas industry. The measured values of hardness coincide with the values obtained on a laboratory nanohardness meter taking into account the inherent errors of this type of equipment.

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