Branching (polymer chemistry) Branching (polymer chemistry) In polymer chemistry, branching occurs by the replacement of a substituent, e.g., a hydrogen atom, on a monomer subunit, by another covalently bonded chain of that polymer; or, in the case of a graft copolymer, by a chain of another type. Branched polymers have more compact and symmetrical molecular conformations, and exhibit intra-heterogeneous dynamical behavior with respect to the unbranched polymers. In crosslinking rubber by vulcanization, short sulfur branches link polyisoprene chains (or a synthetic variant) into a multiply branched thermosetting elastomer. Rubber can also be so completely vulcanized that it becomes a rigid solid, so hard
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