Star poly(methyl methacrylate) with end-functionalized arm chains by ruthenium-catalyzed living radical polymerization

Abstract

Star polymers with end-functionalized arm chains (surface-functionalized star polymers) were synthesized by the in situ linking reaction between ethylene glycol dimethacrylate (linking agent) and an α-end-functionalized linear living poly(methyl methacrylate) in RuCl2(PPh3)3-catalyzed living radical polymerization, the terminal on the surface functionalities included amides, alcohols, amines, and esters. The star polymers were obtained in high yields (75-90%) with initiating systems consisting of a functionalized 2-chloro-2-phenylacetate or -acetamide [F - C(O)CHPhCl; F = nPrNH -, HOCH2CH2O -, Me2NCH2CH2O -, or EtO - ; initiator] and n-Bu3N (additive). The yield was lower with a functionalized 2-bromoisobutyrate [Me2NCH2CH2OC(O)CMe2Br] initiator or with Al(Oi-Pr)3 as an additive. Multi-angle laser light scattering analysis showed that the star polymers had arm numbers of 10-100, radii of gyration of 6-23 nm, and weight-average molecular weights of 1.3 × 105 to 3.0 × 106, which could be controlled by the molar ratio of the linking agent to the linear living polymers. © 2002 Wiley Periodicals, Inc. J. Polym. Sci. Part A: Polym. Chem.