Synthesis and Properties of Block Copolymers of Isoprene and 1,3-Cyclohexadiene

Abstract

Anionic block copolymerization of isoprene and 1,3-cyclohexadiene (1,3-CHD) was carried out in the presence of a dilithium initiator derived from 1,3-diisopropenylbenzene. A special seeding technique, namely multistep seeding with isoprene, was developed to promote the efficiency of the dilithium initiator. Triblock, PCHD-PI-PCHD, pentablock, PCHD-PS-PI-PS-PCHD, and heptablock copolymers, PCHD-PI-PS-PI-PS-PI-PCHD, were synthesized using multistep seeded dilithium initiators. Phase separation and mechanical properties of the resulting block copolymers were investigated by DSC, TEM, and tensile strength test.