Sulfur vulcanization in the processing and compounding of rubber by Hancock and his colleagues led to a more reliable process. Around 1900, disulfiram was introduced as a vulcanizing agent, and became widely used. In 1905 George Oenslager discovered that a derivative of aniline called thiocarbanilide accelerated the reaction of sulfur with rubber, leading to shorter cure times and reducing energy consumption. This breakthrough was almost as fundamental to the rubber industry as Goodyear's sulfur cure. Accelerators made the cure process faster, improved the reliability of the process and enabled vulcanization to be applied to synthetic polymers. One year after his discovery, Oenslager
Toughening several mechanisms that can be employed to toughen a given material such as limiting the initial amount of inclusions, dispersing small particles that will not initiate fracture, or the addition of plasticizers in the case of polymers. Toughening Toughening refers to improving the fracture resistance of a given material. Crack propagation has an associated irreversible work, which is related to a material's toughness. Designing against this crack propagation leads to toughening the material. For the case of a ductile material such as a metal, this toughness is typically proportional to the fracture stress and strain as well as the gauge