Syndiospecific Coordination Polymerization of Si‐H‐Containing Styrenes Catalyzed by Scandium Complex and Synthesis of Styrene‐Based Triblock Copolymers

The controlled syndiospecific polymerization of three Si‐H‐containing styrenes, that is, 4‐(methylhydrosilyl)styrene (FSt‐1), 4‐(dimethylhydrosilyl)styrene (FSt‐2) and 4‐(diisopropylhydrosilyl)styrene (FSt‐3), is realized in the presence of (C 5 Me 4 SiMe 3 )Sc (CH 2 C 6 H 5 ) 2 (THF)/[Ph 3 C][B(C 6 F 5 ) 4 ]. Then a series of FSt‐b‐styrene‐b‐FSt triblock copolymers ( FSt‐St‐FSt ) are synthesized facilely via a sequential monomer feeding process (FSt‐2, styrene, and FSt‐2, respectively) during the polymerization. The syndiotactic polystyrene (sPS) block in the middle endows the copolymer with high melting point above 250 °C, whereas the Si‐H groups on monomer FSt‐2 introduce functional pendants to the end‐blocks (with Si–H content of 31–63 mol%). Finally by a mild and high‐effective hydrosilylation reaction, novel polar‐group functionalized sPS is obtained.