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 as if the rubber was not present. As temperature increases past the glass transition temperature, the rubber phase will increase the crack initiation energy. At this point the crack self-propagates due to the stored elastic energy in the material. As temperature rises further past the glass transition of the rubber phase, the impact strength of a rubber-polymer composite still dramatically increases as crack propagation requires additional energy input. Epoxy resins are a highly useful class of materials used in engineering applications. Some of these include use for adhesives, fiber-reinforced composites, and electronics coatings. Their rigidity and low crack propagation resistance