Science, Tech, Math › Science Thermosetting Plastic Definition Share Flipboard Email Print Epoxy resin is an example of a thermosetting plastic. chonticha wat, Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Anne Marie Helmenstine, Ph.D. Facebook Twitter Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. Learn about our Editorial Process Updated on September 29, 2022 A thermosetting plastic is a polymer that irreversibly becomes rigid when heated. Such a material is also known as a thermoset or thermosetting polymer. Initially, the polymer is a liquid or soft solid. Heat provides energy for chemical reactions that increase the cross-linking between polymer chains, curing the plastic. The rate of curing may be increased in many cases by increasing pressure or by adding a catalyst. Examples Many common plastics are thermosets. They include: Vulcanized rubberFiberglass (a fiber-reinforced polymer composite)Polyester resinPolyurethaneMelamineBakeliteSilicone resinEpoxy resin Sources Ellis, B. (ed.) (1993). Chemistry and Technology of Epoxy Resins. Springer Netherlands. ISBN 978-94-010-5302-0 IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). "Thermosetting Polymer". doi:10.1351/goldbook.TT07168 Cite this Article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "Thermosetting Plastic Definition." ThoughtCo, Sep. 29, 2022, thoughtco.com/definition-of-thermosetting-plastic-605734. Helmenstine, Anne Marie, Ph.D. (2022, September 29). Thermosetting Plastic Definition. Retrieved from https://www.thoughtco.com/definition-of-thermosetting-plastic-605734 Helmenstine, Anne Marie, Ph.D. "Thermosetting Plastic Definition." ThoughtCo. https://www.thoughtco.com/definition-of-thermosetting-plastic-605734 (accessed June 8, 2023). copy citation