Ultrafast synthesis of core cross-linked star poly(p-methylstyrene) with high syndiotacticity through living coordination polymerization

Abstract

The ultrafast synthesis of core cross-linked star poly(p-methylstyrene) (s-PMS) with syndiotactic arms was reported for the first time through a coupling reaction between the active species of metal-poly(p-methylstyrene) and the cross-linker of divinylbenzene (DVB). The effects of the molecular weight of the polymeric active species, DVB loading and coupling time on the efficient synthesis of s-PMS were investigated. The kinetics of the coupling reaction showed that narrowly distributed s-PMS was provided within a short coupling time (10 min), but an s-PMS with multimodal distribution was formed upon prolonging the coupling time due to star–star coupling. When the molecular weight of the living poly(p-methylstyrene) was 3.2 × 10⁴ g mol⁻¹ and the molar ratio of the DVB-to-yttrium catalyst was 10 : 1, a narrowly distributed s-PMS (PDI ∼ 1.06) was prepared in high yield (93.5%) in a coupling time of 10 minutes. Compared to linear PMS, s-PMS with the same molecular weight has lower solution viscosity and smaller hydrodynamic radius.