Synthesis of high molecular weight isobutylene-α-methylstyrene copolymers containing alkenyl groups with a half sandwich scandium initiator system under mild conditions

Cationic copolymerizations of isobutylene (IB) and two alkenyl functionalized α-MeSt derivatives, respectively, 4-(2-methyl-2-propenyl)-α-methylstyrene (FSt1) and 4-(2-propenyl)-α-methylstyrene (FSt2), catalyzed by the half sandwich scandium complex, [(C₅Me₄SiMe₃)Sc(CH₂SiMe₃)₂THF]/[Ph₃C][B(C₆F₅)₄], at −35 °C produced a new family of high molecular weight random copolymers with pendant alkenyl groups (M_n: 12.3–18.7 × 10⁴ g mol⁻¹, CC: 1–20 mol%). Through post-modification, epoxy functionalized copolymers were obtained efficiently, demonstrating that the resulting copolymers with pendant alkenyl groups can serve as functional polyisobutylene based rubbery materials.