The NEC is developed by NFPA's Committee on the National Electrical Code, which consists of 19 (20 in 2008) code-making panels and a technical correlating committee.Work on the NEC is sponsored by the National Fire Protection Association.The NEC is approved as an American national standard by the American National Standards Institute (ANSI). It is formally identified as ANSI/NFPA 70. First published in 1897, the NEC is updated and published every three years.he NEC is approved as an American national standard by the American National Standards Institute (ANSI). It is formally identified as ANSI/NFPA 70. First published in 1897, the NEC is updated and published every three years.
Neoprene or polychloroprene is a family of synthetic rubbers that are produced by polymerization of chloroprene.Neoprene exhibits good chemical stability and maintains flexibility over a wide temperature range.eoprene is produced by free-radical polymerization of chloroprene. In commercial production, this polymer is prepared by free radical emulsion polymerization. Polymerization is initiated using potassium persulfate.
Isoprene was first isolated by thermal decomposition of natural rubber. It is most readily available industrially as a byproduct of the thermal cracking of naphtha or oil, as a side product in the production of ethylene. About 800,000 tonnes are produced annually. About 95% of isoprene production is used to produce cis-1,4-polyisopreneâa synthetic version of natural rubber. Natural rubber consists mainly of poly-cis-isoprene with a molecular weight of 100,000 to 1,000,000. Typically natural rubber contains a few percent of other materials, such as proteins, fatty acids, resins, and inorganic materials.