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 toughening and CTBN toughened epoxies. Engineers use an energy-balance approach to model how particle size and rubber modulus factors influence material toughness. Both particle size and modulus show positive correlation with brittle-tough transition temperatures. They are both shown to affect the cavitation process occurring at the crack tip process zone early in deformation, preceding large-scale crazing and shear yielding. In order to show increased toughness under strain, the volumetric strain must overcome the energy of void formation as modeled by the equation: formula_1 "where formula_2 and formula_3 are the shear modulus and bulk modulus of the rubber, formula_4 is the volume