This article describes the synthesis of new methacrylic-phosphonated monomer PM(B) obtained from the diethyl-1,2-epoxide-propyl 2-phosphonate opening by methacrylic acid in presence of the tetrabutyl ammonium bromide as catalyst. Both its homopolymerization and copolymerization with methyl methacrylate (MMA) have been achieved in acetonitrile at 80 degrees C in the presence of 4,4'-azobisisobutyronitrile. The determination of the reactivity ratios evidenced a statistical copolymer structure. Then, terpolymer of low degree of polymerization and composed of MMA, butyl methacrylate (BuMA) and PM(B) was synthesized and showed a high thermal stability (no degradation before 300 degrees C). This phosphonate terpolymer was incorporated in an acrylate formulation, polymerized under UV-light, and the resulting coating was subjected to the salt spray test. High resistance towards corrosion was observed as no corrosion occurred even after 1100 hrs to the salt spray test. This result was also confirmed by Electrochemical Impedance Spectroscopy. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5090-5100, 2009