Poly sulfide compounding

Poly sulfide compounds that are compatible with epoxy resins are liquid elastomers at room temperature. The most significant commercial resin of this type is LP-3 from Toray. The predominant product is a mercaptan-terminated liquid polymer (LP) that contains approximately 37% bound sulfur (see Fig. 7.2). It is the high concentration of sulfur linkages that provides these products with their unique chemical properties. A sulfur odor is noticeable during processing, making ventilation important. 

A powerful and efficient method for the preparation of poly(ketone)s is the direct polycondensation of dicarboxylic acids with aromatic compounds or of aromatic carboxylic acids using phosphorus pentoxide/methanesulfonic acid (PPMA)16 or polyphosphoric acid (PPA)17 as the condensing agent and solvent. By applying both of these reagents to the synthesis of hexafluoroisopropylidene-unit-containing aromatic poly(ketone)s, various types of poly(ketone)s such as poly(ether ketone) (11), poly(ketone) (12), poly(sulfide ketone) (13), and poly-... 

Addition of chemical catalysts. Compounds such as anthraquinone or poly sulfide or a mixture of the two are introduced into the Kraft cooking liquor. 

In its solutions in liquid NIL. cesium is like the other alkali metals, a powerful reducing agent, so that in such solutions, titrations of cesium poly sulfide with cesium are made by eleclrumeiric methods. The solubility of cesium salts in liquid NHi increases markedly with the radius of an anion (the chloride. CsCI. 0.0227 moles per kg. the bromide. CsBr, 0.215 moles per kg. and the iodide. Csl. 5.84 moles per kg), though the values are less than for the corresponding rubidium compounds. 

Thorium sulfide, ThSz, is obtained by the action of H2S or sulfur on thonum metal. The oxysulfide, ThOS. has been obtained in several ways, one of which is by the action of CS2 on thorium dioxide at elevated temperatures. At 800°C and under pressure, sulfur combines with thonum to yield compounds with approximately die formulas ThS, TI12S3, and TI13S7 The first two have semimetallic properties and may be employed as ceramics for use with highly electropositive metals, whereas the last appears to be a poly sulfide. 

Poly sulfide Reactions in the Formation of Organosulfur and Other Organic Compounds in the Geosphere... 

Hydrogen sulfide derivatives can also be used for partial reduction of poly-nitro compounds. 

The Schiff bases with two benzylidenimine residues bridged by polysulfide chains of different lengths can act as potentially bidentate ligands. These compounds have been obtained by reaction of sulfur with benzylamine in the presence of PbO. They have been characterized by X-ray, NMR, IR and chromatographic techniques." The structural analysis of three of them, having = 2,3 and 4 and R = H, showed that the overall geometry is dominated by the conformation of the poly sulfide chain. ... 

In ordinary organic chemistry, thioether is a synonym for sulfide. A thioether or sulfide is a compound that contains the R—S—R link. This is in contrast to the nomenclature of polymer chemistry. A polysulfide is a polymer that contains the —S—S— group in the backbone. However, a poly (sulfide), with sulfide in brackets, such as poly(phenylene sulfide) or... 

Poly(sulfides) are mainly used for adhesives, coatings, and sealants, because they are easily crosslinkable, even at room temperature. Functional groups and building blocks of poly(ethersulfone) (PES) and related compounds are shown in Figure 7.1. 

TABLE 15.4 Typical Engineering Properties of Reinforced Poly(Phenylene Sulfide) Compounds... 

Figure 15.1 Tensile creep of reinforced poly(phenylene sulfide) compounds at 35 mpa (5000 psi) stress.

Amine activating agents added in the process of peroxidic curing of poly-sulfidic oligomers are introduced directly into the system, before peroxide or hydroperoxide introduction. The mechanism of aminic compounds action is based on the formation of ion radicals, in keeping with the following reactions ... 

Beside the Mg " ion intercalation compounds, elemental sulfur also was explored as the conversion-type cathode. It was reported that a Mg-S battery had a 1200 mAh/g of specific capacity versus S at 0.89 V in the first discharge, but diminished to 394 mAh/g in the second discharge mainly due to the dissolution of long-chain magnesium poly sulfide (MgS , n > 4) [35]. 

This reaction between poly sulfide liquid polymers and epoxy resins is catalyzed or promoted by organic amine compounds. Although a considerable number have been evaluated, final selection has narrowed the list down to a few practical catalysts among which ate DMP-30 , Rohm and Haas) (tri-dimethylamino-methyl phenol), DET (diethylenetriamine), and BDA (benzyldimethylamine). The amine catalysts are used in a fairly high ratio, in most cases 10% based on weight of the epoxy resin. Because of the coreaction of primary amines such as DET, they are more properly classified as reactive hardeners. The general reaction of a polysulfide liquid polymer, an epoxy resin, and a primary amine hardener is ... 

---