Sulfur isoprene units of the polymer. This process, patented in 1843, made rubber a major industrial product, especially in automobile tires. Because of the heat and sulfur, the process was named vulcanization, after the Roman god of the forge and volcanism. Being abundantly available in native form, sulfur was known in ancient times and is referred to in the Torah (Genesis). English translations of the Bible commonly referred to burning sulfur as "brimstone", giving rise to the term "fire-and-brimstone" sermons, in which listeners are reminded of the fate of eternal damnation that await the unbelieving and unrepentant. It is from this
Rubber toughening changes. For impact strength testing on PMMA where failure occurs by shear-yielding, the optimum size of filler PBA-core PMMA-shell particle was shown in one case to be 250 nm. In the three-point bend test, where failure is due to crazing, 2000 nm particles had the most significant toughening effect. Temperature has a direct effect on the fracture mechanics. At low temperatures, below the glass transition temperature of the rubber, the dispersed phase behaves like a glass rather than like a rubber that toughens the polymer. As a result, the continuous phase will fail by mechanisms characteristic of the pure polymer,