18.2 The development of plastics involved experimentation and discovery The search for Isoprene a lightweight, nonbreakable polymerization moldable polyisoprene material began With the Fig 18.5 isoprene molecules invention of react with one another to vulcanized form polyisoprene the fundamental chemical unit rubber(硫化橡 of natural rubber, which 胶) comes from rubber trees18.2 The development of plastics involved experimentation and discovery • The search for a lightweight, nonbreakable, moldable material began with the invention of vulcanized rubber (硫化橡 胶). + + isoprene polyisoprene polymerization Fig18.5 isoprene molecules react with one another to form polyisoprene, the fundamental chemical unit of natural rubber, which comes from rubber trees