Polyisobutylene-based mikto-arm star polymers synthesized via quasiliving cationic polymerization and atom transfer radical polymerization.

摘要

This research pertains to the synthesis of mikto-arm star polymers created via quasiliving cationic polymerization (QCP) and atom transfer radical polymerization (ATRP). The first part of this work focuses on the synthesis of cationic initiators that contain latent functionalities for initiation of ATRP polymerizations.; In the second part of this work, well-defined copolymers of polyisobutylene (PIB) and polystyrene (PS) were created by cationic polymerization. After transformation of the initiating site, poly(tert-butyl acrylate) (PtBA) was synthesized via ATRP. This block was later hydrolyzed to form poly(acrylic acid) (PAA), which serves as a hydrophilic segment of the material. The polymers had narrow PDIs and target polymer compositions. However, molecular weights were higher than expected when low molecular weight polymers were targeted. This is attributed to a complexation between the Lewis acid, titanium tetrachloride (TiCl4), and the carbonyl group in the initiators.