Imidization reactions onto PMMA copolymers were performed in the presence of primary amines. This study allowed establishing a correlation between the functional group of the primary amine and the reactivity of the primary amine toward ester groups of PMMA. This correlation was allowed by using model PMMA/PMAA copolymers, i.e., obtained using a chain transfer agent by radical polymerization. According to the suggested mechanism of PMMA imidization, methylamine afforded higher content of glutarimide groups, hence leading to high T-g values of about 160 degrees C. The use of bulky groups for the primary amine instead, i.e., cyclohexyl, decreased the content of glutarimide function. Thermogravimetric analysis revealed a high thermostability of imidized PMMA with a starting degradation temperature of about 400 degrees C, also dependant of the amine functional group. (C) 2010 Wiley Periodicals, Inc. Appl Polym Sci 118: 1867-1871, 2010