Block Copolymer Definition (Chemistry)

Nitrile, a plastic commonly used in disposable gloves, is a block copolymer.
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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:


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.

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Helmenstine, Anne Marie, Ph.D. "Block Copolymer Definition (Chemistry)." ThoughtCo, Aug. 27, 2020, Helmenstine, Anne Marie, Ph.D. (2020, August 27). Block Copolymer Definition (Chemistry). Retrieved from Helmenstine, Anne Marie, Ph.D. "Block Copolymer Definition (Chemistry)." ThoughtCo. (accessed May 12, 2021).