Synthesis of block-graft polymers by anionic polymerizations

Two poly(4-methylstyrene) (P4MS)-block-polystyrene (PS)-block-P4MS triblock copolymers were prepared by successive anionic addition of styrene and 4-methylstyrene monomers as the core backbone (CB) for the architecture of block-graft polymers. Both terminal 4-methylstyrene blocks of CB were metalated with a sec-butyllithium (sec-BuLi)/tetramethylethylenediamine (TMEDA) complex in cyclohexane. The first-generation block-graft polymer (1BG) was prepared by anionic polymerization of α-melbylstyrene by the lithiated CB in tetrahydrofuran (THF) at -78°C and subsequently the terminal graft ends were capped with a small amount of 4-methylstyrene. The characterization of those block-graft polymers was carried out in detail.