Regular Comb Polystyrenes and Graft Polyisoprene/Polystyrene Copolymers with Double Branches (“Centipedes”). Quality of (1,3-Phenylene)bis(3-methyl-1-phenylpentylidene)dilithium Initiator in the Presence of Polar Additives

The synthesis of regularly spaced comb polystyrenes and graft polyisoprene/polystyrene copolymers with two branches at each junction point (centipedes) is presented. The synthetic approach involves the selective replacement of two chlorines of SiCl 4 by polystyrene (PS) followed by step−growth polymerization of the produced (PS) 2 SiCl 2 with α,ω-dilithium PS or 1,4 polyisoprene (PI). The polydispersity indices of the reaction products, PS- g -PS 2 (homocentipedes) and PI- g -PS 2 (cocentipedes), varied between 2.0 and 3.0 but was reduced to 1.2−1.3 by fractionation. The quality of (1,3-phenylene)bis(3-methyl-1-phenylpentylidene)dilithium initiator (DLI), used for the synthesis of the dianion, in the presence of polar additives (THF, Et 3 N, and s -BuOLi), was evaluated.