Sulfur vulcanization Sulfur vulcanization Sulfur vulcanization or sulfur vulcanisation is a chemical process for converting natural rubber or related polymers into more durable materials by heating them with sulfur or other equivalent curatives or accelerators. Sulfur forms cross-links (bridges) between sections of polymer chain which results in increased rigidity and durability, as well as other changes in the mechanical and electronic properties of the material. A vast array of products are made with vulcanized rubber, including tires, shoe soles, hoses, and conveyor belts. The term is derived from Vulcan, the Roman god of fire. The main polymers subjected to sulfur vulcanization are
Rubber elasticity could be backwards or forwards, so the net time average formula_19 will be zero. However, one can use the root mean square as a useful measure of that distance. Ideally, the polymer chain's movement is purely entropic (no enthalpic, or heat-related, forces involved). By using the following basic equations for entropy and Helmholtz free energy, we can model the driving force of entropy "pulling" the polymer into an unstretched conformation. Note that the force equation resembles that of a spring: "F=kx". Note that the elastic coefficient formula_22 is temperature dependent. If we increase the rubber temperature, the elastic coefficient also