Nitroxide polymer brushes prepared by surface-initiated ARGET ATRP and their selective oxidation performances

Polymer brushes with 2,2,6,6-tetramethyl-4-piperidyl methacrylate (TMPM) units, grafted on the cross-linked polystyrene (PS) microspheres, were synthesized via surface-initiated ARGET (activators regenerated by electron transfer) ATRP (atom transfer radical polymerization). They were further oxidized to yield nitroxide polymer brushes containing nitroxide radical units (TEMPO). The obtained polymer brushes were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron spin resonance (ESR) and gel permeation chromatography (GPC). The catalytic properties of nitroxide polymer brushes for selective oxidation of benzyl alcohol were investigated. The results showed that the performances were good and the yield was up to 96%. Furthermore, the block brush had similar catalyst properties to non-supported TEMPO in terms of activity and selectivity. It could be recovered by centrifugation. The unity of high catalyst property and easy recovery was achieved.