synthetic rubber

noun
  1. any of several substances similar to natural rubber in properties and uses, produced by the polymerization of an unsaturated hydrocarbon, as butylene or isoprene, or by the copolymerization of such hydrocarbons with styrene, butadiene, or the like.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for synthetic rubber

synthetic rubber

noun
  1. any of various synthetic materials, similar to natural rubber, made by polymerizing unsaturated hydrocarbons, such as isoprene and butadiene
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012