Various synthetic products, such as GR-S, neoprene, butyl rubber, and nitrile rubber, closely resemble natural rubber in their physical properties and vulcanization ability. These materials are typically produced through the polymerization of butadiene, isoprene, or similar unsaturated hydrocarbons, or by copolymerizing these hydrocarbons with styrene, isobutylene, acrylonitrile, or other polymerizable compounds. While they serve similar functions to natural rubber, they may excel in some applications and fall short in others, and are often used alongside natural rubber.