Poly sulfide rank

Aromatic polysulfides in which the sulfur atoms are attached directly to the aromatic ring, such as those studied in this work, have a substantially higher T value than the xylylene-containing polysulfides. Table II, which includes data on poly(phenylene sulfides), shows the relationships involving sulfur rank, ring substitution, and glass-transition temperature for aromatic polysulfides. 

Polarization infrared spectral data. X-ray analysis and normal coordinate treatment revealed the stable molecular conformation of poly(methylene disulfide) to be the GG G form [88] which was also confirmed from the results of semi-empirical CNDO/2SCF MO calculations [89]. Poly(ethylene disulfide) was also found to exist in a similar conformation as that of poly(methylene disulfide) [90]. Under vacuum at 50 °C, polysulfide polymers of methylene and ethylene with sulfur rank of two and four were exposed to UV radiation [91]. While poly(methylene disulfide) and poly(methylene tetrasulfide) yielded polymeric carbon monosulfide, hydrogen sulfide and carbon disulfide as the major degradation products, the ethylene counterparts produced the same compounds except carbon disulfide. The tetrasulfide polymers also formed volatile products which on condensation gave the original polymer. 

The aliphatic thioethers (polysulfides) are unique among condensation polymers in being produced in an emulsion polymerization. The rank jr (Table 17.2, II.C) has an influence on the number of sulfur atoms in each polymer linkage. The tacky or liquid polymers are cast or applied as pastes in the case of sealants. The sulfur analog of poly(phenylene oxide) is poly(phenylene sulfide) (Table 17.2, II.C), which can be made by a condensation reaction between p-dichlorobenzene and sodium sulfide. The highly crystalline polymer is solvent resistant and has a low coefficient of friction. It can be injection molded at about 300°C and can also be used as a powder spray coating. 

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