A new methacrylate monomer containing perfluorocyclobutyl and sulfonyl units, p-(2-(p-(benzenesulfonyl)phenoxy)perfluorocyclobutoxy)phenyl methacrylate, was synthesized from commercially available reagents in good yield and this kind of methacrylate can be homopolymerized by free radical polymerization using 2,2'-azobis(isobutyronitrile) as initiator or atom transfer radical polymerization using methyl 2-bromopropionate as initiator and CuBr/PMDETA as catalytic system. The reactivity ratios for BSPPFCBPMA and MMA were found to be r(1) = 1.2436 and r(2) = 0.8171 determined by Fineman-Ross method, and r(1) = 1.2279 and r(2) = 0.8023 by Kelen-Tudos method respectively. The resultant polymethacrylates bearing perfluorocyclobutyl and sulfonyl functionalities exhibit excellent thermal stability as evidenced from thermogravimetric analysis and the decomposition temperature rose dramatically with the increasing of molecular weights. Random copolymers of BSPPFCBPMA and methyl methacrylate were obtained by free radical copolymerization and their thermo-stabilities increase while raising the contents of BSPPFCBPMA. (C) 2009 Elsevier Ltd. All rights reserved.