A novel sulfonyl-containing monomer, 4,4'-sulfonyl-bis(trifluorovinyloxy)biphenyl, and the resulting fluoropolymers with good thermal stability have been prepared. The monomer was synthesized by two steps using 4,4'-sulfonyldiphenol as starting material and characterized by FT-IR, H-1 NMR, C-13 NMR. F-19 NMR and element analysis in detail. Fluoropolymers containing sulfonyl and perfluorocyclobutyl units were prepared by different polymerization methods. A series Of fluoropolymers with higher molecular weights were obtained by solution polymerization in diphenyl ether. The molecular weight is dependent on the polymerization time, polymerization temperature and the concentration of the monomer. The resulting polymers show excellent Solubility in conventional solvents and good thermal stability with a high decomposition temperature about 500 degrees C measured by TGA. (c) 2005 Elsevier Ltd. All rights reserved.