In the present study, first, maleic anhydridestyrene (MA-St), maleic anhydride-allyl phenyl ether (MA-APhE), maleic anhydride-heptene-1(MA-Hp), and maleic anhydride-allyl propionate (MA-AP) copolymers have been synthesized in different solvents in the presence of azobisisobutyronitrile (AIBN) at 70 degrees C. Then, these four copolymers have been reacted with aniline at 60 degrees C in N,N-dimethyl formamide (DMF), and maleamidic acid derivatives of these copolymers have been synthesized. Next, they have been obtained from their maleimide derivatives by heating under vacuum at 150 degrees C. All these polymers have been characterized by Fourier Transform infrared spectroscopy (FTIR) and investigated their thermal properties by using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) methods. The analyses results showed that thermal properties of maleimide derivatives of maleic anhydride copolymers changed as depend on the neighbor monomers of maleic anhydride. (c) 2006 Wiley Periodicals, Inc.