Sulphur-containing polymers

Hydrolytic instability or, alternatively, a tendency to revert to simple forms is shown by a number of sulphur-containing polymers. Some examples are shown in Figure 29.16 (a) plastic sulphur , (b) a polymer unstable at room temperature, (c) and (d) the (3 form of suphur trioxide. 

Costa Bizzarri, P., Della Casa, C., Ferruti, P., Ghedini, N., Pilati, F., and Scapini, G., Mannich bases in polymer synthesi.s, VI. Sulphur containing polymers by exchange reaction between 2,6-bis(dimethylamino-methyl)-4-methylphenol and dithiols. Polymer Commun., 25, 115, 1984. 

Laos, M., Angeloni, A. S., Tramontini. M.. and Femiti, P., The Mannich ba.scs in polymer synlhcsi.s. 9. Sulphur containing polymers by polycondensalion reaction of bis Mannich bases of dicaiboxyamides with 1,3-dimercaplobenzene. Polymer Comnmn., 25, 281, 1984. 

Lottia, N., Siracusab, V., Finellia, L., Marchesea, P., and Munaria, A. (2006) Sulphur-containing polymers Synthesis and thermal properties of novel polyesters based on dithiotriethylene glycol. Eur. Polym. J., 42 (12), 3374-3382. 

The thermal behaviour of sulphur containing polymers has been reported on [302]. The major breakdown in poly(l,4-phenylene sulphide)... 

Radiation-induced Degradation.—There have been several reports on radiation effects in polymers,288 including single crystals,287 fluoropolymers,288 polyamides,289 polysiloxanes,270 polyethylene and its copolymers,271 polypropylene,272 polyolefins,273 polystyrene and its copolymers,274 poly(vinyl chloride) and related polymers,275 rubbers,278 polysulphones and other sulphur-containing polymers,277 polycarbonate,278 nylon,279 poly(vinylpyridines),280 and wool.281... 

Sulphur has also been used extensively [101-105] as an additive and the yield of carbon from acenaphthylene can be increased. The use of too much sulphur resulted in a non-graphitizing carbon, but for a lesser amount, the reverse was true [101]. Greinke and Lewis [104] showed that sulphur incorporated in a strained ring system could be readily eliminated in the early stages of carbonization, but when incorporated in aromatic hydrocarbons, the sulphur containing polymer was stable up to high temperatures (1500°C) [99]. Rand [106] considered sulphur to be undesirable in pitch precursors used for making carbon fiber. 

Two types of sulphur-containing polymers are of commercial significance, namely polysulphide elastomers and polysulphones. These materials have very different characterisitics and are considered separately in this chapter. 

This oxygen flask combustion - titration method is capable of determining total sulphur in amoimts down to 50 ppm in sulphur containing polymers. 

This procedure is capable of determining down to 500 ppm of total sulphur in sulphur containing polymers with an accuracy of + 5%. 

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