Solid polysulfide elastomer

Standard test formulations are shown in Table 11.3 for the two types of solid polysulfide elastomers. These use the recommended cure systems for each with a normal amount of N774 carbon black as reinforcement. 

Thiokol Corporation, which is the exclusive producer of polysulfide elastomers in the free world, is now a major producer of solid rocket engines and has annual sales of many millions of dollam. TTiiokol (now Morton-Thiokol) is the sole supplier of solid rocket boosters for the space shuttle mission and is listed on the New York Stock Exchange. 

Thiokol (structure 4.70), which was the first synthetic elastomer, was synthesized by Patrick in the 1920s, by the condensation of alkylene dichlorides and sodium polysulfides. These solvent-resistant elastomers have limited uses because of their foul odor. They can be reduced to liquid polymers that can be reoxidized to solid elastomers, which is used in caulking material and some rocket propellant formulations ... 

In addition to the liquid polysulfides, polysulfide millable gum elastomers have been used for many years with conventional rubber processing equipment. Compounds based on solid elastomers are being used in the manufacture of paint spray hose, rollers, and printing blankets for the graphic arts industry. New applications for these versatile materials are still being developed. 

The original material, which was based on the reaction of ethylene dichloride with sodium polysulfide, was a solid elastomer. Generally, this chemistry yields products that tend to be difficult to process and the high temperatures needed to band and compound them result in a foul smelling material. 

A process was developed in 1943 to make polysulfides as a reactive liquid polymer with mercaptan-end groups. These terminals lend themselves readily to oxidation to high molecular weight elastomeric compounds. As a result, the liquid polymers could be compounded with greater facility than the solid elastomers. 

Polysulfide - sol- fId [ISV] (1849) n. A family of sulfur-containing polymers prepared by condensing organic polyhahdes with sodium polysulfides in aqueous suspension. They range from liquids to solid elastomers. 

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