Science, Tech, Math › Science Block Copolymer Definition (Chemistry) Share Flipboard Email Print Douglas Sacha / 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. 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. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated July 21, 2019 A block copolymer is a copolymer formed when the two monomers cluster together and form 'blocks' of repeating units. For example, a polymer made up of X and Y monomers joined together like: -Y-Y-Y-Y-Y-X-X-X-X-X-Y-Y-Y-Y-Y-X-X-X-X-X- is a block copolymer where -Y-Y-Y-Y-Y- and -X-X-X-X-X- groups are the blocks. Block Copolymer Examples The material used to make automobile tires is a block copolymer called SBS rubber (acrylonitrile butadiene styrene). The blocks in SBS rubber are polystyrene and polybutadiene (StyreneButatineStyrene). Nitrile and ethylene-vinyl acetate are also copolymers.