SBS
SBS(Styrene Butadiene Styrene)
Poly(styrene-butadiene-styrene), or SBS, is a hard rubber that's used for things like the soles of shoes, tire treads, and other places where durability is important. It's a type of copolymer called a block copolymer. Its backbone chain is made up of three segments. The first is a long chain of polystyrene, the middle is a long chain of polybutadiene, and the last segment is another long section of polystyrene. Here's a picture:
