Polymer architecture via abstraction of a hydrogen, can create a mid-chain growth site. Branching can be quantified by the branching index. An effect related to branching is chemical crosslinking - the formation of covalent bonds between chains. Crosslinking tends to increase T and increase strength and toughness. Among other applications, this process is used to strengthen rubbers in a process known as vulcanization, which is based on crosslinking by sulfur. Car tires, for example, are highly crosslinked in order to reduce the leaking of air out of the tire and to toughen their durability. Eraser rubber, on the other hand, is not
Frasch process Frasch process The Frasch process is a method to extract sulphur from underground deposits. It is the only industrial method of recovering sulphur from elemental deposits. Most of the world's sulfur was obtained this way until the late 20th century, when sulfur recovered from petroleum and gas sources became more commonplace (see Claus process). In the Frasch process, superheated water is pumped into the sulphur deposit; the sulfur melts and is extracted. The Frasch process is able to produce high purity sulfur. The Frasch sulfur process works best on either salt domes or bedded evaporite deposits, where sulfur is found