The monomer, N-(4-bromophenyl)-2-methacrylamide (BrPMAAm) has been synthesized by reacting 4-bromoaniline with methacryloyl chloride in the presence of triethylamine (NR3) at 0-5°C. Copolymerization of BrPMAAm with n-butyl methacrylate (n-BMA) has been carried out in 1,4-dioxane by free radical solution polymerization at (70 ± 0.1)°C utilizing 2,2′-azobisisobutyronitrile (AIBN) as an initiator in different in-feed ratios. The composition of the copolymer was determined by the elemental analysis. The comonomer reactivity ratios determined by Fineman-Ross (FR), Kelen-Tüdös (KT), and extended Kelen-Tüdös (EKT) methods. The copolymers were characterized by FTIR, 1H-, and 13C NMR spectroscopic technique. Gel permeation chromatography was employed for estimating the weight-average (Mw) and number-average (M̄n) molecular weights and polydispersity index (PDI) of the copolymers. Glass transition temperatures (Tg) were determined by differential scanning calorimetry and found to be characteristic of copolymer composition. As the N-(4-bromophenyl)-2-methacrylamide content increases, the Tg increases from 339 to 437 K. Thermal stabilities of the homo- and copolymers were calculated using thermogravimetric analysis. Thermally stable copolymers were obtained by the incorporation of BrPMAAm units as the initial decomposition temperature of the copolymers increased with the increase in concentration of BrPMAAm units. © 2007 Wiley Periodicals, Inc.