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 is relieved and voiding occurs. The energy absorption due to this increase in volume is theoretically negligible. Instead, it is the consequent shear band formation that accounts for increased toughness. Before debonding, as the strain increases, the rubber phases is forced to stretch further strengthening the matrix. Debonding between the matrix and the rubber reduces the toughness, creating the need for strong adhesion between the polymer and rubber phases. The damage competition theory models the relative contributions of shear yielding and craze failure, when both are present. there are two main assumptions: crazing, microcracks, and cavitation dominate in brittle systems,