Styrene-diene block copolymers were first developed
by Shell utilizing anionic block copolymerization
of styrene with butadiene (S–B–S) and styrene
with isoprene (S–I–S) and were introduced commercially
in 1966 as Kraton®. Phillips Petroleum Co.
entered this field in 1968 with radial styrenic block
copolymers. In 1972 Shell added the S–EB–S