Sulfur vulcanization are merely the additives used for vulcanisation and that other compounds may also be added to the rubber such as fillers or polymer stabilizers. Ordinary sulfur (octasulfur) is rarely used despite its low cost. Because of the low melting point of S vs the cure temperatures, attempted vulcanization with ordinary results in sulfur bloom. Instead, various forms of polymeric sulfur are used instead. It is also possible to replace sulfur with other sulfur-donating compounds, for example accelerators bearing disulphide groups, in what is often termed 'efficient vulcanization' (EV). Disulfur dichloride may also be used for 'cold vulcanization'. Under normal circumstances,
Rubber toughening and crazing interaction theory, and more recently those including the effects of critical ligament thickness, critical plastic area, voiding and cavitation, damage competition and others. In 1956, the microcrack theory became the first to explain the toughening effect of a dispersed rubber phase in a polymer. Two key observations that went into the initial theory and subsequent expansion were as follows: (1) microcracks form voids over which styrene-butadiene copolymer fibrils form to prevent propagation, and (2) energy stored during elongation of toughened epoxies is released upon breaking of rubber particles. The theory concluded that the combined energy to initiate microcracks