Polysulfide

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Polysulfide

A thermosetting resin, used as a building sealant.

Polysulfide

 

a derivative of hydrogen polysulfide, H2Sx where x = 2–9. Polysulfides are solids, ranging in color from light yellow to brownish red, with a specific, unpleasant odor.

Polysulfides of ammonia, alkali metals, and alkaline-earth metals are known—for example, potassium forms K2S2, K2S3, K2S4, K2S5, and K2S6. Sulfur atoms are arranged in an —S—S—S— chain in polysulfide molecules. The melting point of polysulfides is lower than that of sulfides. For example, the melting point of K2S is 835°C, whereas that of K2S6 is 183°C. Polysulfides are chemically very unstable; they decompose upon heating to form sulfides. In the presence of acids they liberate H2Sx which decomposes immediately into H2S and S.

Polysulfides are produced by fusing sulfides, hydroxides, or carbonates with sulfur; sulfur may be added to an aqueous sulfide solution. Polysulfides of calcium and barium are used against agricultural pests. Barium polysulfide is an effective depilatory.

References in periodicals archive ?
Polysulfide Oligomer Sealants: Synthesis, Properties, and Applications
Several researchers have demonstrated that various nanostructures can help trap the polysulfides within an electrode, but these designs run up against a second problem with lithium-sulfur batteries.
nautilei were polysulfides (primarily found at temperatures ranging between 6[degrees]C and 11[degrees]C, with concentrations up to 5 [micro]M).
Equipment for processing multicomponent, thermoset materials such as PUR, polyesters, silicones, and polysulfides.
My major approach involved polysulfides, which can increase the cellulose-hemicellulose yield in kraft pulping.
Europe's sealant market by volume 2012 Silicones 38% Polyurethanes 17% Plastisols 12% Acrylics 10% Polysulfides 9% Others 9% Butyl 5% Note: Table made from pie chart.
Their focus has been on developing the best in epoxies, silicones, polyurethanes, polysulfides, UV cures and other specialty adhesive systems.
Usable thermoplastics indude polyolefins, polyesters, polyamides, polyethers, polycarbonates, poly(ethersulfones), poly(etherimides), polysulfides, liquid crystalline polymers (LCPs), and fluoropolymers.
The DLC line appears to be dominated by products that fall into the following classifications as ingredients for rubber compounds, including coagents (for peroxide cured compounds); resins (hydrocarbon/coumarone - indene); liquid polymers (nitrile, EPDM, polysulfides, polybutadiene and polyisobutylene); silanes (for sulfur and peroxide cure); plasticizers; process oils; and greases and waxes.