What Is a Block Copolymer

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.