Microwave-Assisted Synthesis of Core-Crosslinked Star Polymers with Benzophenone Derivatives in the Core

Abstract

Core-crosslinked star polymers, which have polyethylene oxide (PEO) as a shell and cross-linked poly(2-{4′-iodobenzoyloxy}-ethyl methacrylate) (PIEMA) with benzophenone derivatives as a core, have been successfully synthesized by an “arm-first” method. PEO-b-PIEMA was prepared via atom transfer radical polymerization (ATRP) of 2-{4′-iodobenzoyloxy}-ethyl methacrylate (4-IEMA) with preformed PEO-Br as a macroinitiator. Core-crosslinked star polymers (CCSP) were efficiently synthesized by ultrafast carbonylation reactions under air by flash microwave irradiation in the presence of dicobalt octacarbonyl in 6 min. Gel permeation chromatography (GPC) trace of CCSP showed a drastic shift to a higher molecular weight when compared to precursor polymer, PEO-b-PIEMA diblock copolymer, indicating that the carbonylation reaction was fully progressed. The CCSP with benzophenone was successfully immobilized on a silicon wafer through a photochemical reaction under UV irradiation.