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 few large cracks in untoughened polymer accounts for a large fraction of the increase in fracture energy. Interaction between rubber particles and crazes puts elongation pressures onto the particles in the direction of stress. If this force overcomes the surface adhesion between the rubber and polymer, debonding will occur, thereby diminishing the toughening effect associated with crazing. If the particle is harder, it will be less able to deform, and thus debonding occurs under less stress. This is one reason why dispersed rubbers, below their own glass transition temperature, do not toughen plastics effectively. Shear yielding theory is one that,