styreneisoprenestyrene
Styreneisoprenestyrene, often abbreviated as SIS, is a synthetic elastomer belonging to the thermoplastic elastomer family. It is a block copolymer, meaning it is composed of repeating segments of different monomers. In the case of SIS, these monomers are styrene and isoprene. Specifically, SIS has a structure where polystyrene blocks are at the ends of a polyisoprene block. This arrangement is often described as a triblock copolymer (S-I-S).
The unique properties of SIS arise from its molecular structure. The styrene blocks are hard and glassy
SIS exhibits a combination of properties that make it useful in a variety of applications. It is