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
Natural rubber using gas chromatography/mass spectrometry (GC/MS) and gas chromatography (GC) indicates that they contain sulphur, ammonia, alkenes, ketones, esters, hydrogen sulphite, nitrogen, and low molecular weight fatty acids (C2-C5). When latex concentrate is produced from rubber, sulphuric acid is used for coagulation. This produces malodourous hydrogen sulphide. The industry can mitigate these bad odours with scrubber systems. Latex is the polymer cis-1,4-polyisoprene – with a molecular weight of 100,000 to 1,000,000 daltons. Typically, a small percentage (up to 5% of dry mass) of other materials, such as proteins, fatty acids, resins, and inorganic materials (salts) are found in natural rubber. Polyisoprene