Preparation of periodic copolymers by living anionic polymerization mechanism assisted with a versatile programmed monomer addition mode

Abstract

Assisted by a versatile programmed monomer addition mode, the well-defined periodic Poly(styrene-per-isoprene) [Poly(St-per-Is)] copolymers are innovatively prepared by living anionic polymerization (LAP) of a general monomer pair of styrene and isoprene. For comparison, the random Poly(St-ran-Is) and diblock PS-b-PI copolymers are also synthesized. The Differential Scanning Calorimetry (DSC) analysis shows that the periodic Poly(St-per-Is) copolymers always have relatively higher glass transition temperature (Tgs) than the corresponding random Poly(St-ran-Is) analogues with the same molar ratio [St]/[Is] and close molecular weight (MW). The Tgs of copolymers follow a general tendency of Tg,Poly(St-per-Is) > Tg,PS-b-PI > Tg,Poly(St-ran-Is). The reason is rationalized to the different sequence of styrene and isoprene units arranged along the copolymers.