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 ?
[USPRwire, Thu Jul 25 2019] Sealants based on polysulfide polymers are solvent and chemical resistant, have good flexibility and adhere to various materials including steel, aluminum, concrete, glass, wood, etc.
[ClickPress, Fri Jul 26 2019] Sealants based on polysulfide polymers are solvent and chemical resistant, have good flexibility and adhere to various materials including steel, aluminum, concrete, glass, wood, etc.
Polysulfide sealants are widely used in construction and transportation applications, especially insulated glass window seals.
Peng et al., "Polysulfide shuttle control: towards a lithium-sulfur battery with superior capacity performance up to 1000 cycles by matching the sulfur/electrolyte loading," Journal of Power Sources, vol.
Generally, the sheet resistance of metal is lower than that of a commercial FTO glass, but only noble metals like gold (Au) or platinum (Pt) are available as a counter electrode of QDSSCs to avoid their corrosion in polysulfide electrolyte solution.
"Until now, there has been no such method, but the new sulphur-limonene polysulfide addresses this urgent need."
Common additives used in the process include emulsified vegetable oil or calcium polysulfide. "Essentially, [the] additives interact with the contaminants to render them less toxic or, in some cases, inert," said Elias Rodriguez, an EPA spokesman.
Polysulfide Oligomer Sealants: Synthesis, Properties, and Applications
Bound sulfane sulfur is incorporated into proteins as persulfide or polysulfide, which release [H.sub.2]S under reducing conditions (see Fig.
After the Mooney viscosities have reached the maximum value, the compounds show some sort of reversion which could be linked to a change within the polysulfide linkages.
Herein, we prepared a novel carbyne polysulfide material containing a conducting carbon skeleton and energy-storing sulfur side chain without other elements by coheating carbyne and sulfur.