Invention:
Methods of vulcanization using a high content sulfur polymer, instead of elemental sulfur, have been developed for tire rubber production. The resulting high sulfur content polymers are referred to as Chalcogenide Hybrid Inorganic/Organic Polymers (CHIP) materials have improved polymer compatibility and efficient crosslinking. Furthermore, this technology suppresses "reversion," the loss of rubber stiffness over time, which is an undesirable quality.
Background:
Vulcanization of rubber and other polymeric materials is a well-established method for enhancing physical properties by chemical crosslinking. Vulcanized materials are generally more thermally, chemically, and physically robust than their non-vulcanized analogs. These increased characteristics are attributed to the formation of carbon-sulfur bonds which allow for bridging of the polymer chains by varying numbers of sulfur atoms to form crosslinked networks. While accelerator additives are used to increase the speed of vulcanization, thus permitting polymerization at lower temperatures and greater efficiency, vulcanization still requires high temperatures and suffers from inefficient mixing of components due to poor incompatibility which results in incomplete curing and undesirable decomposition. Hence, there is a need for technology for improved polymer compatibility and lower-temperature curing.
Applications:
- Tire rubber vulcanization
- Latex manufacturing
- Suitable for natural, synthetic, or a combination of materials
Advantages:
- Improved solubility in tire rubber precursors compared to elemental sulfur and improved crosslinking
- "Reversion" suppression
Status: issued U.S. patent #11,674,005
