T – Thiokol Rubber
Polysulfide

Properties

Polysulfides, also called polythioethers or Thiokols (T), are compounds with thioether functions in the backbone. They are typically liquid polymers that can be crosslinked by oxidizing the polymer’s terminals thiol groups (-SH) to disulfide (-S-S-) links. Common curing agents are oxygen donating compounds such as manganese dioxide, cumene hydroperoxide, and p-quinone dioxime. Other organic hydro peroxides, aldehydes and metallic paint driers can also function as curatives.

Thiokol elastomers exhibit low moisture and gas permeability, good flex crack resistance, outstanding low temperature flexibility as well as good resistance to oil, ozone, oxygen and many chemicals including ethers, ketones and aromatic hydrocarbons. However, polythioethers have some major limitations. For example, they have poor heat resistance, low tear and tensile strength and compression set properties, and thus, are less versatile from a performance standpoint than most other elastomers. They are also not resistant to many polar solvents including (fatty) esters, mercaptans, amines, and chlorinated hydrocarbons.

 

Commercial Polysulfide Elastomers

Important manufacturers and suppliers of liquid and solid polysulfides include Zeon, PolySpec, and BlueStar.

 

Applications

Polysulfides are widely used as the base polymer for sealants, caulks, and adhesives in various applications within the building & construction, aircraft, and automobile industry. Other industrial applications include highways sealants, molding / potting compounds, and concrete coatings.

The typical working temperature range is -45°C to +105°C. However, some grades can withstand temperatures up to 150/170°C (for a short time).