''Thiokol'' is a

trade mark A trademark (also written trade mark or trade-mark) is a form of intellectual property that consists of a word, phrase, symbol, design, or a combination that identifies a product or service from a particular source and distinguishes it from oth ...

for various organic polysulfide polymers. Thiokol polymers are used as an

elastomer An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus (E) and high failure strain compared with other materials. The term, a portmanteau of ''ela ...

in seals and

sealant Sealant is a substance used to block the passage of fluids through openings in materials, a type of Seal (mechanical), mechanical seal. In building construction ''sealant'' is sometimes synonymous with ''caulk'' (especially if acrylic latex or ...

s. The distinction between the polymers first commercialized by the Thiokol Chemical Company and subsequent polysulfide materials is often unclear. The name Thiokol is a

portmanteau In linguistics, a blend—also known as a blend word, lexical blend, or portmanteau—is a word formed by combining the meanings, and parts of the sounds, of two or more words together.

of the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

words for

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

() and

glue Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advantage ...

()

Preparation and structure

A variety of thiokols are recognized. Typically they are prepared by the combination of

2-chloroethanol 2-Chloroethanol (also called ethylene chlorohydrin or glycol chlorohydrin) is an organic chemical compound with the chemical formula HOCH2CH2Cl and the ''simplest'' beta-halohydrin (chlorohydrin). This colorless liquid has a pleasant ether-like od ...

formaldehyde Formaldehyde ( , ) (systematic name methanal) is an organic compound with the chemical formula and structure , more precisely . The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as ...

, and sodium polysulfide (Na₂S_''x''). The chloroethanol is produced in situ from ethylene oxide and

hydrogen chloride The Chemical compound, compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hyd ...

. The rank ''x'' of the polysulfide is an important variable. Crosslinking agents are used, such as

1,2,3-trichloropropane 1,2,3-Trichloropropane (TCP) is an organic compound with the formula CHCl(CH2Cl)2. It is a colorless liquid that is used as a solvent and in other specialty applications. Production 1,2,3-Trichloropropane is produced by the addition of chlorin ...

. An idealized polymer is represented by this formula HS(CH₂CH₂OCH₂OCH₂CH₂SS)_''n''CH₂CH₂OCH₂OCH₂CH₂SH. Thiol-terminated resins can be cured oxidatively.

History

In 1838, Swiss chemists reported the preparation of hydrophobic rubbery materials by the alkylation of sodium polysulfide with 1,2-dichloroethane. In 1926 chemists Joseph C. Patrick and

Nathan Mnookin Thiokol was an American corporation concerned initially with rubber and related chemicals, and later with rocket and missile propulsion systems. Its name is a portmanteau of the Greek words for sulfur () and glue (), an allusion to the company's ...

further developed this class of materials, which first achieved commercial success as sealants for fuel lines, exploiting the solvent resistance of these materials. The company

Thiokol Thiokol was an American corporation concerned initially with rubber and related chemicals, and later with rocket and missile propulsion systems. Its name is a portmanteau of the Greek words for sulfur () and glue (), an allusion to the company ...

was founded in 1929 to produce these polymers. In the 1940s, thiol-terminated liquid resins were produced. Curing could be effected oxidatively, e.g. using lead oxides and later perborates. Thiokol polymers were used as a binder in

solid rocket A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants (fuel/ oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder. The inception of gunpowder rockets in warfare can be cr ...

fuel, a commercial success.

References

Elastomers Inorganic polymers Sulfur compounds {{polymer-stub